Fabrication of Titanium Bonded Joint Specimens for High Temperature Testing

NASA Technical Reports Server (NTRS)

Smeltzer, Stanley S., III; Kovach, Michael P.; Hudson, Wanda

2005-01-01

Four sets of adhesively bonded, titanium lap-shear coupon specimens were fabricated for ultimate strength testing according to the ASTM D1002 and D3165 standards. Important features of the fabrication methods, processing details, and lap-shear test results are presented for specimens fabricated using a modified bismaleimide adhesive, EA 9673, on titanium. Surface treatment of the titanium was performed using surface abrasion followed by one of two separate chemical etching processes. Although cure cycle requirements are different among most adhesives, a single surface preparation method was sought as the preferred method for conditioning the titanium specimens prior to bonding and curing. A fabrication process using a combination of low-pressure grit-blasting of the titanium surface followed by anodization with a sodium hydroxide solution applied to the D1002 specimen geometry provided the highest lapshear strengths in the study. Additionally, difficulties documented during the fabrication process of the D3165 specimens along with features of the D3165 geometry were identified as factors that contributed to lower lap-shear strength results for the D3165 specimens as compared to the results for the D1002 specimens.

Optical, Physical, and Chemical Properties of Surface Modified Titanium Dioxide Powders

DTIC Science & Technology

2011-02-01

coefficient depends on the optical efficiency factor, QCM , the geometric cross section, G, and the particle mass as indicated by the relationship in eq 2...diffraction sensor with a RODOS powder dispersing unit. The instrument houses a HeNe laser (632.8 nm) and Fourier lens. Upon introduction of the

Thomson scattering in the average-atom approximation.

PubMed

Johnson, W R; Nilsen, J; Cheng, K T

2012-09-01

The average-atom model is applied to study Thomson scattering of x-rays from warm dense matter with emphasis on scattering by bound electrons. Parameters needed to evaluate the dynamic structure function (chemical potential, average ionic charge, free electron density, bound and continuum wave functions, and occupation numbers) are obtained from the average-atom model. The resulting analysis provides a relatively simple diagnostic for use in connection with x-ray scattering measurements. Applications are given to dense hydrogen, beryllium, aluminum, and titanium plasmas. In the case of titanium, bound states are predicted to modify the spectrum significantly.

Function of Platelet-Induced Epithelial Attachment at Titanium Surfaces Inhibits Microbial Colonization.

PubMed

Maeno, M; Lee, C; Kim, D M; Da Silva, J; Nagai, S; Sugawara, S; Nara, Y; Kihara, H; Nagai, M

2017-06-01

The aim of this study was to evaluate the barrier function of platelet-induced epithelial sheets on titanium surfaces. The lack of functional peri-implant epithelial sealing with basal lamina (BL) attachment at the interface of the implant and the adjacent epithelium allows for bacterial invasion, which may lead to peri-implantitis. Although various approaches have been reported to combat bacterial infection by surface modifications to titanium, none of these have been successful in a clinical application. In our previous study, surface modification with protease-activated receptor 4-activating peptide (PAR4-AP), which induced platelet activation and aggregation, was successful in demonstrating epithelial attachment via BL and epithelial sheet formation on the titanium surface. We hypothesized that the platelet-induced epithelial sheet on PAR4-AP-modified titanium surfaces would reduce bacterial attachment, penetration, and invasion. Titanium surface was modified with PAR4-AP and incubated with platelet-rich plasma (PRP). The aggregated platelets released collagen IV, a critical BL component, onto the PAR4-AP-modified titanium surface. Then, human gingival epithelial cells were seeded on the modified titanium surface and formed epithelial sheets. Green fluorescent protein (GFP)-expressing Escherichia coli was cultured onto PAR4-AP-modified titanium with and without epithelial sheet formation. While Escherichia coli accumulated densely onto the PAR4-AP titanium lacking epithelial sheet, few Escherichia coli were observed on the epithelial sheet on the PAR4-AP surface. No bacterial invasion into the interface of the epithelial sheet and the titanium surface was observed. These in vitro results indicate the efficacy of a platelet-induced epithelial barrier that functions to prevent bacterial attachment, penetration, and invasion on PAR4-AP-modified titanium.

The effect of silver or gallium doped titanium against the multidrug resistant Acinetobacter baumannii.

PubMed

Cochis, A; Azzimonti, B; Della Valle, C; De Giglio, E; Bloise, N; Visai, L; Cometa, S; Rimondini, L; Chiesa, R

2016-02-01

Implant-related infection of biomaterials is one of the main causes of arthroplasty and osteosynthesis failure. Bacteria, such as the rapidly-emerging Multi Drug Resistant (MDR) pathogen Acinetobacter Baumannii, initiate the infection by adhering to biomaterials and forming a biofilm. Since the implant surface plays a crucial role in early bacterial adhesion phases, titanium was electrochemically modified by an Anodic Spark Deposition (ASD) treatment, developed previously and thought to provide osseo-integrative properties. In this study, the treatment was modified to insert gallium or silver onto the titanium surface, to provide antibacterial properties. The material was characterized morphologically, chemically, and mechanically; biological properties were investigated by direct cytocompatibility assay, Alkaline Phosphatase (ALP) activity, Scanning Electron Microscopy (SEM), and Immunofluorescent (IF) analysis; antibacterial activity was determined by counting Colony Forming Units, and viability assay. The various ASD-treated surfaces showed similar morphology, micrometric pore size, and uniform pore distribution. Of the treatments studied, gallium-doped specimens showed the best ALP synthesis and antibacterial properties. This study demonstrates the possibility of successfully doping the surface of titanium with gallium or silver, using the ASD technique; this approach can provide antibacterial properties and maintain high osseo-integrative potential. Copyright © 2015 Elsevier Ltd. All rights reserved.

Prospects of using titanium nickelide implants with modified surface in dental implantology.

PubMed

Razdorsky, V V

2008-06-01

Corrosion resistance and biocompatibility of 60 specimens of titanium nickelide with modified surfaces implanted into spongy bone were studied in rabbit experiments. Specimens modified by molybdenum ions exhibited high inertness and favorable tissue reaction. No accumulation of nickel and titanium ions in animal organs was detected.

The synergistic effect of TiO2 nanoporous modification and platelet-rich plasma treatment on titanium-implant stability in ovariectomized rats.

PubMed

Jiang, Nan; Du, Pinggong; Qu, Weidong; Li, Lin; Liu, Zhonghao; Zhu, Songsong

For several decades, titanium and its alloys have been commonly utilized for endosseous implantable materials, because of their good mechanical properties, chemical resistance, and biocompatibility. But associated low bone mass, wear and loss characteristics, and high coefficients of friction have limited their long-term stable performance, especially in certain abnormal bone-metabolism conditions, such as postmenopausal osteoporosis. In this study, we investigated the effects of platelet-rich plasma (PRP) treatment and TiO 2 nanoporous modification on the stability of titanium implants in osteoporotic bone. After surface morphology, topographical structure, and chemical changes of implant surface had been detected by scanning electron microscopy (SEM), atomic force microscopy, contact-angle measurement, and X-ray diffraction, we firstly assessed in vivo the effect of PRP treatment on osseointegration of TiO 2 -modified implants in ovariectomized rats by microcomputed tomography examinations, histology, biomechanical testing, and SEM observation. Meanwhile, the potential molecular mechanism involved in peri-implant osseous enhancement was also determined by quantitative real-time polymerase chain reaction. The results showed that this TiO 2 -modified surface was able to lead to improve bone implant contact, while PRP treatment was able to increase the implant surrounding bone mass. The synergistic effect of both was able to enhance the terminal force of implants drastically in biomechanical testing. Compared with surface modification, PRP treatment promoted earlier osteogenesis with increased expression of the RUNX2 and COL1 genes and suppressed osteoclastogenesis with increased expression of OPG and decreased levels of RANKL. These promising results show that PRP treatment combined with a TiO 2 -nanomodified surface can improve titanium-implant biomechanical stability in ovariectomized rats, suggesting a beneficial effect to support the success of implants in osteoporotic bone.

The synergistic effect of TiO2 nanoporous modification and platelet-rich plasma treatment on titanium-implant stability in ovariectomized rats

PubMed Central

Jiang, Nan; Du, Pinggong; Qu, Weidong; Li, Lin; Liu, Zhonghao; Zhu, Songsong

2016-01-01

For several decades, titanium and its alloys have been commonly utilized for endosseous implantable materials, because of their good mechanical properties, chemical resistance, and biocompatibility. But associated low bone mass, wear and loss characteristics, and high coefficients of friction have limited their long-term stable performance, especially in certain abnormal bone-metabolism conditions, such as postmenopausal osteoporosis. In this study, we investigated the effects of platelet-rich plasma (PRP) treatment and TiO2 nanoporous modification on the stability of titanium implants in osteoporotic bone. After surface morphology, topographical structure, and chemical changes of implant surface had been detected by scanning electron microscopy (SEM), atomic force microscopy, contact-angle measurement, and X-ray diffraction, we firstly assessed in vivo the effect of PRP treatment on osseointegration of TiO2-modified implants in ovariectomized rats by microcomputed tomography examinations, histology, biomechanical testing, and SEM observation. Meanwhile, the potential molecular mechanism involved in peri-implant osseous enhancement was also determined by quantitative real-time polymerase chain reaction. The results showed that this TiO2-modified surface was able to lead to improve bone implant contact, while PRP treatment was able to increase the implant surrounding bone mass. The synergistic effect of both was able to enhance the terminal force of implants drastically in biomechanical testing. Compared with surface modification, PRP treatment promoted earlier osteogenesis with increased expression of the RUNX2 and COL1 genes and suppressed osteoclastogenesis with increased expression of OPG and decreased levels of RANKL. These promising results show that PRP treatment combined with a TiO2-nanomodified surface can improve titanium-implant biomechanical stability in ovariectomized rats, suggesting a beneficial effect to support the success of implants in osteoporotic bone. PMID:27695328

New advanced surface modification technique: titanium oxide ceramic surface implants: long-term clinical results

NASA Astrophysics Data System (ADS)

Szabo, Gyorgy; Kovacs, Lajos; Barabas, Jozsef; Nemeth, Zsolt; Maironna, Carlo

2001-11-01

The purpose of this paper is to discuss the background to advanced surface modification technologies and to present a new technique, involving the formation of a titanium oxide ceramic coating, with relatively long-term results of its clinical utilization. Three general techniques are used to modify surfaces: the addition or removal of material and the change of material already present. Surface properties can also be changed without the addition or removal of material, through the laser or electron beam thermal treatment. The new technique outlined in this paper relates to the production of a corrosion-resistant 2000-2500 A thick, ceramic oxide layer with a coherent crystalline structure on the surface of titanium implants. The layer is grown electrochemically from the bulk of the metal and is modified by heat treatment. Such oxide ceramic-coated implants have a number of advantageous properties relative to implants covered with various other coatings: a higher external hardness, a greater force of adherence between the titanium and the oxide ceramic coating, a virtually perfect insulation between the organism and the metal (no possibility of metal allergy), etc. The coated implants were subjected to various physical, chemical, electronmicroscopic, etc. tests for a qualitative characterization. Finally, these implants (plates, screws for maxillofacial osteosynthesis and dental root implants) were applied in surgical practice for a period of 10 years. Tests and the experience acquired demonstrated the good properties of the titanium oxide ceramic-coated implants.

Surface insulating properties of titanium implanted alumina ceramics by plasma immersion ion implantation

NASA Astrophysics Data System (ADS)

Zhu, Mingdong; Song, Falun; Li, Fei; Jin, Xiao; Wang, Xiaofeng; Wang, Langping

2017-09-01

The insulating property of the alumina ceramic in vacuum under high voltage is mainly limited by its surface properties. Plasma immersion ion implantation (PIII) is an effective method to modify the surface chemical and physical properties of the alumina ceramic. In order to improve the surface flashover voltage of the alumina ceramic in vacuum, titanium ions with an energy of about 20 keV were implanted into the surface of the alumina ceramic using the PIII method. The surface properties of the as-implanted samples, such as the chemical states of the titanium, morphology and surface resistivity, were characterized by X-ray photoelectron spectroscopy, scanning electron microscope and electrometer, respectively. The surface flashover voltages of the as-implanted alumina samples were measured by a vacuum surface flashover experimental system. The XPS spectra revealed that a compound of Ti, TiO2 and Al2O3 was formed in the inner surface of the alumina sample. The electrometer results showed that the surface resistivity of the implanted alumina decreased with increased implantation time. In addition, after the titanium ion implantation, the maximum hold-off voltage of alumina was increased to 38.4 kV, which was 21.5% higher than that of the unimplanted alumina ceramic.

Using sewage sludge pyrolytic gas to modify titanium alloy to obtain high-performance anodes in bio-electrochemical systems

NASA Astrophysics Data System (ADS)

Gu, Yuan; Ying, Kang; Shen, Dongsheng; Huang, Lijie; Ying, Xianbin; Huang, Haoqian; Cheng, Kun; Chen, Jiazheng; Zhou, Yuyang; Chen, Ting; Feng, Huajun

2017-12-01

Titanium is under consideration as a potential stable bio-anode because of its high conductivity, suitable mechanical properties, and electrochemical inertness in the operating potential window of bio-electrochemical systems; however, its application is limited by its poor electron-transfer capacity with electroactive bacteria and weak ability to form biofilms on its hydrophobic surface. This study reports an effective and low-cost way to convert a hydrophobic titanium alloy surface into a hydrophilic surface that can be used as a bio-electrode with higher electron-transfer rates. Pyrolytic gas of sewage sludge is used to modify the titanium alloy. The current generation, anodic biofilm formation surface, and hydrophobicity are systematically investigated by comparing bare electrodes with three modified electrodes. Maximum current density (15.80 A/m2), achieved using a modified electrode, is 316-fold higher than that of the bare titanium alloy electrode (0.05 A/m2) and that achieved by titanium alloy electrodes modified by other methods (12.70 A/m2). The pyrolytic gas-modified titanium alloy electrode can be used as a high-performance and scalable bio-anode for bio-electrochemical systems because of its high electron-transfer rates, hydrophilic nature, and ability to achieve high current density.

A noninterventional study documenting use and success of implants with a new chemically modified titanium surface in daily dental practice.

PubMed

Luongo, Giuseppe; Oteri, Giacomo

2010-01-01

A new chemically modified titanium surface, SLActive, has recently been developed. The results obtained in controlled clinical trials indicate that this implant can be safely used and that it offers predictable results. The goal of this noninterventional study was to verify that the success rates of implants used in daily dental practice are comparable to those reported in controlled clinical trials. This study was a prospective, noninterventional study using implants with a chemically modified surface according to the daily dental practice procedures applied by private practitioners. The choice of the implantation procedure and the loading protocol were the responsibility of the investigator and were chosen according to the patient's needs. Thirty clinical centers actively participated in this study, and 226 patients were treated, of which, 8 patients were lost to follow-up. Because of the noninterventional design of the study, the patients were not selected according to strictly defined inclusion/exclusion criteria. Thus, the study included individuals with risk factors such as smoking (24%), untreated gingivitis or periodontitis (9%), and bruxism (6%). The implants were equally distributed between mandible (46%) and maxilla (54%). A bone augmentation procedure was done in 31% of the cases. Early loading (functional loading between 48 hours and 3 months after implant insertion) was applied most frequently (48%), followed by the conventional loading protocol (3 to 6 months after implant placement, 34%). Immediate restoration and immediate loading were rare (7% and 2%, respectively). Of 276 implants inserted and documented, 5 implants failures were reported, all of which were associated with a sinus floor augmentation procedure. The survival rate was 98.2% at the 1-year follow-up visit. The results showed that implants with a chemically modified surface can be successfully restored with success rates similar to those reported in formal clinical trials under more controlled conditions.

Accelerated cell-surface interlocking on plasma polymer-modified porous ceramics.

PubMed

Rebl, Henrike; Finke, Birgit; Schmidt, Jürgen; Mohamad, Heba S; Ihrke, Roland; Helm, Christiane A; Nebe, J Barbara

2016-12-01

Excellent osseointegration of permanent implants is crucial for the long lasting success of the implantation. To improve the osseointegrative potential, bio-inert titanium alloy surfaces (Ti6Al4V) are modified by plasma chemical oxidation (PCO®) of the titanium-oxide layer to a non-stoichiometric, amorphous calcium phosphate layer. The native titanium-oxide film measuring only a few nanometers is converted by PCO® to a thick porous calcium phosphate layer of about 10μm. In a second step the PCO surface is combined with a cell adhesive plasma-polymerized allylamine (PPAAm) nano film (5 and 50nm). Independent of the PPAAm coating homogeneity, the human osteoblast-like MG-63 cells show a remarkable increase in cell size and well-developed filopodia. Analyses of the actin cytoskeleton reveal that the cells mold to the pore shape of the PPAAm-covered PCO, thereby establishing a strong attachment to the surface. Interestingly, we could demonstrate that even though our untreated PCO shows excellent hydrophilicity, this alone is not sufficient to facilitate fast cell spreading, but the positive surface charges mediated by PPAAm. This multilayer composite material guarantees enhanced interlocking of the cells with the porous surface. Copyright © 2016 Elsevier B.V. All rights reserved.

Biomimetic whisker-shaped apatite coating of titanium powder.

PubMed

Sim, Young Uk; Kim, Jong Hee; Yang, Tae Young; Yoon, Seog Young; Park, Hong Chae

2010-05-01

Biomimetic apatite coatings on chemically modified titanium powder have been processed and the resulting coating layers evaluated in terms of morphology, composition and structure, using TF-XRD, XPS, SEM, TEM and FTIR analysis. After 7 days immersion in a simulated body fluid (SBF), nanometer-sized fine precipitates with an amorphous whisker-like phase and a Ca/P atomic ratio of 1.94 were obtained on the external surface of the titanium particles. When the immersion time in SBF was extended to 16 days, the coating layer consisted of the whisker-like nanostructured crystals of carbonated hydroxyapatite with a atomic ratio of 3; in such a case, a double coating layer was developed. The double layer could be divided into two regions and could be clearly distinguished: an inner dense region (approximately 200 nm in thickness) which may include hard agglomerated crystals and an outer less dense region (> 500 nm in thickness) in which crystals are loosely distributed.

Titanium modified with layer-by-layer sol-gel tantalum oxide and an organodiphosphonic acid: a coating for hydroxyapatite growth.

PubMed

Arnould, C; Volcke, C; Lamarque, C; Thiry, P A; Delhalle, J; Mekhalif, Z

2009-08-15

Titanium and its alloys are widely used in surgical implants due to their appropriate properties like corrosion resistance, biocompatibility, and load bearing. Unfortunately when metals are used for orthopedic and dental implants there is the possibility of loosening over a long period of time. Surface modification is a good way to counter this problem. A thin tantalum oxide layer obtained by layer-by-layer (LBL) sol-gel deposition on top of a titanium surface is expected to improve biocorrosion resistance in the body fluid, biocompatibility, and radio-opacity. This elaboration step is followed by a modification of the tantalum oxide surface with an organodiphosphonic acid self-assembled monolayer, capable of chemically binding to the oxide surface, and also improving hydroxyapatite growth. The different steps of this proposed process are characterized by surfaces techniques like contact angle, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM).

Impact of plasma chemistry versus titanium surface topography on osteoblast orientation.

PubMed

Rebl, Henrike; Finke, Birgit; Lange, Regina; Weltmann, Klaus-Dieter; Nebe, J Barbara

2012-10-01

Topographical and chemical modifications of biomaterial surfaces both influence tissue physiology, but unfortunately little knowledge exists as to their combined effect. There are many indications that rough surfaces positively influence osteoblast behavior. Having determined previously that a positively charged, smooth titanium surface boosts osteoblast adhesion, we wanted to investigate the combined effects of topography and chemistry and elucidate which of these properties is dominant. Polished, machined and corundum-blasted titanium of increasing microroughness was additionally coated with plasma-polymerized allylamine (PPAAm). Collagen I was then immobilized using polyethylene glycol diacid and glutar dialdehyde. On all PPAAm-modified surfaces (i) adhesion of human MG-63 osteoblastic cells increased significantly in combination with roughness, (ii) cells resemble the underlying structure and melt with the surface, and (iii) cells overcome the restrictions of a grooved surface and spread out over a large area as indicated by actin staining. Interestingly, the cellular effects of the plasma-chemical surface modification are predominant over surface topography, especially in the initial phase. Collagen I, although it is the gold standard, does not improve surface adhesion features comparably. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Nanolayer formation on titanium by phosphonated gelatin for cell adhesion and growth enhancement

PubMed Central

Zhou, Xiaoyue; Park, Shin-Hye; Mao, Hongli; Isoshima, Takashi; Wang, Yi; Ito, Yoshihiro

2015-01-01

Phosphonated gelatin was prepared for surface modification of titanium to stimulate cell functions. The modified gelatin was synthesized by coupling with 3-aminopropylphosphonic acid using water-soluble carbodiimide and characterized by 31P nuclear magnetic resonance and gel permeation chromatography. Circular dichroism revealed no differences in the conformations of unmodified and phosphonated gelatin. However, the gelation temperature was changed by the modification. Even a high concentration of modified gelatin did not form a gel at room temperature. Time-of-flight secondary ion mass spectrometry showed direct bonding between the phosphonated gelatin and the titanium surface after binding. The binding behavior of phosphonated gelatin on the titanium surface was quantitatively analyzed by a quartz crystal microbalance. Ellipsometry showed the formation of a several nanometer layer of gelatin on the surface. Contact angle measurement indicated that the modified titanium surface was hydrophobic. Enhancement of the attachment and spreading of MC-3T3L1 osteoblastic cells was observed on the phosphonated gelatin-modified titanium. These effects on cell adhesion also led to growth enhancement. Phosphonation of gelatin was effective for preparation of a cell-stimulating titanium surface. PMID:26366080

Study of Crystallographic Texture During Thermo-Mechanical Processing of Boron Modified Ti-Alloys

DTIC Science & Technology

2009-07-15

project developed a processing strategy for boron-modified titanium alloy Ti- 6Al - 4V , and developed an understanding of the deformation and...develop the processing strategy for boron modified titanium alloy Ti- 6Al - 4V 2. To understand the deformation and transformation mechanisms as a function...strength-to-weight ratio, excellent mechanical properties and corrosion resistance, titanium (Ti) and its alloys, especially (α+β) alloys like Ti- 6Al - 4V

Durable warmth retention finishing of down using titanium dioxide optimized by RSM

NASA Astrophysics Data System (ADS)

Li, Huihao; Qi, Lu; Li, Jun

2017-03-01

A new product, referred to herein as modified down, was prepared by grafting down fiber with titanium dioxide. Grafting modification brings new functionalities to down Using response surface methodology (RSM); the effect of titanium dioxide concentration, KH550 concentration, and baking temperature on the warmth retention is studied using the response surface method (RSM) to obtain the optimal experimental formula and models. The optimal preparation conditions for modified down were 19.35% titanium dioxide, 15.81% KH550, 10min baking time, and 115 °C temperature. The warmth retention of the modified down was 79.98%, The structure and property of modified down were characterized and analyzed by using Flat Plate Warmth Retaining Tester, FT-IR, and TG. The CLO value increased by 27.28%, the thermal resistance increased by 27.34%. The ultimate residual quantities of the modified down fibers were 30.05%.

40 CFR 721.10021 - Magnesium potassium titanium oxide.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium potassium...

40 CFR 721.10021 - Magnesium potassium titanium oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium potassium...

40 CFR 721.10021 - Magnesium potassium titanium oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium potassium...

40 CFR 721.10021 - Magnesium potassium titanium oxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Magnesium potassium titanium oxide... Specific Chemical Substances § 721.10021 Magnesium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as magnesium potassium...

Osteoblastic differentiating potential of dental pulp stem cells in vitro cultured on a chemically modified microrough titanium surface.

PubMed

DE Colli, Marianna; Radunovic, Milena; Zizzari, Vincenzo L; DI Giacomo, Viviana; DI Nisio, Chiara; Piattelli, Adriano; Calvo Guirado, José L; Zavan, Barbara; Cataldi, Amelia; Zara, Susi

2018-03-30

Titanium surface modification is critical for dental implant success. Our aim was to determine surfaces influence on dental pulp stem cells (DPSCs) viability and differentiation. Implants were divided into sandblasted/acid-etched (control) and sandblasted/acid-etched coated with calcium and magnesium ions (CaMg), supplied as composite (test). Proliferation was evaluated by MTT, differentiation checking osteoblastic gene expression, PGE2 secretion and matrix formation, inflammation by Interleukin 6 (IL-6) detection. MTT and IL-6 do not modify on test. A PGE2 increase on test is recorded. BMP2 is higher on test at early experimental points, Osterix and RUNX2 augment later. Alizarin-red S reveals higher matrix production on test. These results suggest that test surface is more osteoinductive, representing a start point for in vivo studies aiming at the construction of more biocompatible dental implants, whose integration and clinical performance are improved and some undesired effects, such as implant stability loss and further surgical procedures, are reduced.

Effect of sandblasting intensity on microstructures and properties of pure titanium micro-arc oxidation coatings in an optimized composite technique

NASA Astrophysics Data System (ADS)

Wang, Hong-Yuan; Zhu, Rui-Fu; Lu, Yu-Peng; Xiao, Gui-Yong; He, Kun; Yuan, Y. F.; Ma, Xiao-Ni; Li, Ying

2014-02-01

Sandblasting is one of the most effective methods to modify a metal surface and improve its properties for application. Micro-arc oxidation (MAO) could produce a ceramic coating on a dental implant, facilitating cellular differentiation and osseocomposite on it. This study aims to deposit bioceramic Ca- and P-containing coatings on sandblasted commercially pure titanium by an optimum composite technique to improve the bioactive performance. The effect of sandblasting intensity on microstructures and properties of the implant coatings is examined, and the modified surfaces are characterized in terms of their topography, phase, chemical composition, mechanical properties and hydroxyapatite (HA)-inducing ability. The results show that a moderate sandblasting micromachines the substrate in favorable combination of rough and residual stresses; its MAO coating deposits nano-hydroxyapatite after immersion in simulated body fluid (SBF) for 5 days exhibiting better bioactivity. The further improvement of the implant surface performance is attributed to an optimized composite technique.

40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lead strontium titanium zirconium... Specific Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead strontium...

40 CFR 721.10598 - Lead strontium titanium zirconium oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lead strontium titanium zirconium... Specific Chemical Substances § 721.10598 Lead strontium titanium zirconium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lead strontium...

Effect of autoclaving on the surfaces of TiN -coated and conventional nickel-titanium rotary instruments.

PubMed

Spagnuolo, G; Ametrano, G; D'Antò, V; Rengo, C; Simeone, M; Riccitiello, F; Amato, M

2012-12-01

To evaluate the effects of repeated autoclave sterilization cycles on surface topography of conventional nickel-titanium ( NiTi ) and titanium nitride ( TiN )-coated rotary instruments. A total of 60 NiTi rotary instruments, 30 ProTaper (Dentsply Maillefer) and 30 TiN -coated AlphaKite (Komet/Gebr. Brasseler), were analysed. Instruments were evaluated in the as-received condition and after 1, 5 and 10 sterilization cycles. After sterilization, the samples were observed using scanning electron microscope (SEM), and surface chemical analysis was performed on each instrument with energy dispersive X-ray spectroscopy (EDS). Moreover, the samples were analysed by atomic force microscopy (AFM), and roughness average (Ra) and the root mean square value (RMS) of the scanned surface profiles were recorded. Data were analysed by means of anova followed by Tukey's test. Scanning electron microscope observations revealed the presence of pitting and deep milling marks in all instruments. EDS analysis confirmed that both types of instruments were composed mainly of nickel and titanium, whilst AlphaKite had additional nitride. After multiple autoclave sterilization cycles, SEM examinations revealed an increase in surface alterations, and EDS values indicated changes in chemical surface composition in all instruments. Ra and RMS values of ProTaper significantly increased after 5 (P = 0.006) and 10 cycles (P = 0.002) with respect to the as-received instruments, whilst AlphaKite showed significant differences compared with the controls after 10 cycles (P = 0.03). Multiple autoclave sterilization cycles modified the surface topography and chemical composition of conventional and TiN -coated NiTi rotary instruments. © 2012 International Endodontic Journal.

40 CFR 721.10031 - Lithium potassium titanium oxide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

40 CFR 721.10031 - Lithium potassium titanium oxide.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

40 CFR 721.10031 - Lithium potassium titanium oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

40 CFR 721.10031 - Lithium potassium titanium oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

40 CFR 721.10031 - Lithium potassium titanium oxide.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Lithium potassium titanium oxide. 721... Substances § 721.10031 Lithium potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as lithium potassium titanium oxide (PMN P-02...

40 CFR 721.10553 - Potassium titanium oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Potassium titanium oxide. 721.10553... Substances § 721.10553 Potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as potassium titanium oxide (PMN P-06-149; CAS No. 12673-69...

40 CFR 721.10553 - Potassium titanium oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Potassium titanium oxide. 721.10553... Substances § 721.10553 Potassium titanium oxide. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as potassium titanium oxide (PMN P-06-149; CAS No. 12673-69...

Glow discharge plasma pretreatment enhances osteoclast differentiation and survival on titanium plates.

PubMed

Kawai, Hiroyuki; Shibata, Yo; Miyazaki, Takashi

2004-05-01

Despite the fact that several reports have demonstrated osteoclast activity on various bioactive ceramics, osteoclast functions on surface-modified titanium have not come under focus. This study aimed to examine whether the increasing surface energy of glow discharge plasma (GDP) involved in protein adhesion containing the RGD (Arg-Gly-Asp) sequence affects osteoclast responses on titanium plates. We examined osteoclast differentiation and survival rates on titanium plates with and without GDP. The amounts of osteoclasts on titanium plates were not increased by GDP after 1 week. However, osteoclast differentiation was greatly activated by GDP pretreatment, as tartrate-resistant acid phosphatase synthesis significantly increased on the titanium plates with GDP. Additionally, since the presence of osteoclasts was detected only on the titanium plates with GDP, even after 4h cultivation in a coculture test, the osteoclasts survival rate was increased by GDP pretreatment. As osteoclast responses were affected even on surface modified metallic materials, we concluded that novel approaches are needed not only for osteoclastic resorption on ceramic materials but also for osteoclast responses on surface-modified metallic materials.

Surface characteristics, corrosion and bioactivity of chemically treated biomedical grade NiTi alloy.

PubMed

Chembath, Manju; Balaraju, J N; Sujata, M

2015-11-01

The surface of NiTi alloy was chemically modified using acidified ferric chloride solution and the characteristics of the alloy surface were studied from the view point of application as a bioimplant. Chemically treated NiTi was also subjected to post treatments by annealing at 400°C and passivation in nitric acid. The surface of NiTi alloy after chemical treatment developed a nanogrid structure with a combination of one dimensional channel and two dimensional network-like patterns. From SEM studies, it was found that the undulations formed after chemical treatment remained unaffected after annealing, while after passivation process the undulated surface was filled with oxides of titanium. XPS analysis revealed that the surface of passivated sample was enriched with oxides of titanium, predominantly TiO2. The influence of post treatment on the corrosion resistance of chemically treated NiTi alloy was monitored using Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS) in Phosphate Buffered Saline (PBS) solution. In the chemically treated condition, NiTi alloy exhibited poor corrosion resistance due to the instability of the surface. On the other hand, the breakdown potential (0.8V) obtained was highest for the passivated samples compared to other surface treated samples. During anodic polarization, chemically treated samples displayed dissolution phenomenon which was predominantly activation controlled. But after annealing and passivation processes, the behavior of anodic polarization was typical of a diffusion controlled process which confirmed the enhanced passivity of the post treated surfaces. The total resistance, including the porous and barrier layer, was in the range of mega ohms for passivated surfaces, which could be attributed to the decrease in surface nickel content and formation of compact titanium oxide. The passivated sample displayed good bioactivity in terms of hydroxyapatite growth, noticed after 14days immersion in Hanks' solution. Copyright © 2015 Elsevier B.V. All rights reserved.

The crevice corrosion of cathodically modified titanium in chloride solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lingen, E. van der

1995-12-01

The susceptibility of titanium to crevice corrosion in low-pH chloride solutions at elevated temperatures can result in major practical problems. Although Grade 7 titanium is considered the most crevice-corrosion resistant material available for these environments, the price increase of palladium has limited the utilization of this alloy. A cost-effective titanium alloy, containing 0.2% ruthenium by mass, has been developed for use in environments of increased chloride concentration and temperature. The crevice corrosion resistance of the Ti-0.2% Ru alloy has been evaluated and compared with that of ASTM commercially pure Grade 2 titanium, Grade 7 titanium (Ti-0.12 to 0.25% palladium bymore » mass) and Grade 12 titanium (Ti-0.8% Ni-0.3% Mo). The results indicated that the cathodically modified titanium alloys, Ti-0.2% Ru and Grade 7 titanium, showed similar resistance to crevice corrosion attack in all the solutions tested, and that their behavior was significantly better than that of Grade 2 and Grade 12 titanium.« less

Protein adsorption and biomimetic mineralization behaviors of PLL-DNA multilayered films assembled onto titanium

NASA Astrophysics Data System (ADS)

Gao, Wenli; Feng, Bo; Ni, Yuxiang; Yang, Yongli; Lu, Xiong; Weng, Jie

2010-11-01

Titanium and its alloys are frequently used as surgical implants in load bearing situations, such as hip prostheses and dental implants, owing to their biocompatibility, mechanical and physical properties. In this paper, a layer-by-layer (LBL) self-assembly technique, based on the polyelectrolyte-mediated electrostatic adsorption of poly-L-lysine (PLL) and DNA, was used to the formation of multilayer on titanium surfaces. Then bovine serum albumin (BSA) adsorption and biomimetic mineralization of modified surfaces were studied. The chemical composition and wettability of assembled substrates were investigated by X-ray photoelectron spectroscopy (XPS), fluorescence microscopy and water contact angle measurement, respectively. The XPS analysis indicated that the layers were assembled successfully through electrostatic attractions. The measurement with ultraviolet (UV) spectrophotometer revealed that the LBL films enhanced ability of BSA adsorption onto titanium. The adsorption quantity of BSA on the surface terminated with PLL was higher than that of the surface terminated with DNA, and the samples of TiOH/P/D/P absorbed BSA most. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) showed that samples of assembled PLL or/and DNA had better bioactivity in inducing HA formation. Thus the assembling of PLL and DNA onto the surface of titanium in turn via a layer-by-layer self-assembly technology can improve the bioactivity of titanium.

Light-driven OR and XOR programmable chemical logic gates.

PubMed

Szaciłowski, Konrad; Macyk, Wojciech; Stochel, Grazyna

2006-04-12

Photoelectrodes made of nanocrystalline titanium dioxide modified with various pentacyanoferrates exhibit unique photoelectrochemical properties; photocurrent direction can be switched from anodic to cathodic and vice versa upon changes in photoelectrode potential and incident light wavelength (PhotoElectrochemical Photocurrent Switching, PEPS effect). At certain potentials, anodic photocurrent generated upon UV irradiation has the same intensity as the cathodic photocurrent generated upon visible irradiation. Under these conditions, simultaneous irradiation with UV and visible light results in compensation of anodic and cathodic photocurrents, and zero net photocurrent is observed. This process can be used for construction of unique light-driven chemical logic gates.

The development of nano-modified Ti(C,N) cermets.

PubMed

Rong, Chunlan; Chen, Wenling; Zhang, Xiaobo; Liu, Ning

2007-01-01

The unique combination of mechanical properties such as excellent wear resistance and good chemical stability at elevated temperature helps titanium carbonitride based (Ti (C, N)-based) cermets to play an important roles in metal cutting operations. Nowadays, cermets cutting tools are widely used for semi-finishing and finishing works on steel and cast iron. However, their brittleness is still an unavoidable limitation for their utilization. With the development of nano-technology, nano-modified cermets have received more attention due to the high toughening enhancements. In this review, the development of nano-modified Ti(C,N) cermets is discussed including the fabrication, microstructure, mechanical properties, cutting performance and the practical applications in different fields. Many patents having important effect on the development of cermets were noticed, too.

Analytical investigations of poly(acrylic acid) coatings electrodeposited on titanium-based implants: a versatile approach to biocompatibility enhancement.

PubMed

De Giglio, E; Cometa, S; Cioffi, N; Torsi, L; Sabbatini, L

2007-12-01

A polyacrylic acid film was synthesized on titanium substrates from aqueous solutions via an electroreductive process for the first time. This work was done in order to develop a versatile coating for titanium-based orthopaedic implants that acts as both an effective bioactive surface and an effective anti-corrosion barrier. The chemical structure of the PAA coating was investigated by X-ray photoelectron spectroscopy (XPS). Scanning electron microscopy (SEM) was employed to evaluate the effect of annealing treatment on the morphology of the coatings in terms of their uniformity and porosity. Inductively coupled plasma mass spectrometry was used to measure ion concentrations in ion release tests performed on Ti-6Al-4V sheets modified with PAA coatings (annealed and unannealed). Results indicate that the annealing process produces coatings that possess considerable anti-corrosion performance. Moreover, the availability and the reactivity of the surface carboxylic groups were exploited in order to graft biological molecules onto the PAA-modified titanium implants. The feasibility of the grafting reaction was tested using a single aminoacid residue. A fluorinated aminoacid was selected, and the grafting reaction was monitored both by XPS, using fluorine as a marker element, and via quartz crystal microbalance (QCM) measurements. The success of the grafting reaction opens the door to the synthesis of a wide variety of PAA-based coatings that are functionalized with selected bioactive molecules and promote positive reactions with the biological system interfacing the implant while considerably reducing ion release into surrounding tissues.

The effect of elastomer chain length on properties of silicone-modified polyimide adhesives

NASA Technical Reports Server (NTRS)

St.clair, A. K.; St.clair, T. L.; Ezzell, S.

1981-01-01

A series of polyimides containing silicone elastomers was synthesized in order to study the effects of the elastomer chain length on polymer properties. The elastomer with repeat units varying from n=10 to 105 was chemically reacted into the backbone of an addition polyimide oligomer via reactive aromatic amine groups. Glass transition temperatures of the elastomer and polyimide phases were observed by torsional braid analysis. The elastomer-modified polyimides were tested as adhesives for bonding titanium in order to determine their potential for aerospace applications. Adhesive lap shear tests were performed before and after aging bonded specimens at elevated temperatures.

Immobilization of hyaluronic acid on plasma-sprayed porous titanium coatings for improving biological properties.

PubMed

Ao, Haiyong; Xie, Youtao; Qin, An; Ji, Heng; Yang, Shengbing; Huang, Liping; Zheng, Xuebin; Tang, Tingting

2014-01-01

In the present study, hyaluronic acid (HyA) was covalently immobilized onto titanium coatings to improve their biological properties. Diffuse reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy were employed to characterize the HyA-modified titanium coating. HyA-modified titanium coatings possess better cell-material interaction, and human mesenchymal stem cells present good adhesive morphologies on the surface of TC-AAH. The results of subsequent cellular evaluation showed that the immobilization of HyA on titanium coatings could improve hMSC attachment, proliferation, and differentiation. In vivo evaluation of implants in rabbit femur condyle defect model showed improvements of early osseointegration and bone-to-implant contact of TC-AAH. In conclusion, immobilization of HyA could improve biological properties of titanium coatings.

Titanium nitride plasma-chemical synthesis with titanium tetrachloride raw material in the DC plasma-arc reactor

NASA Astrophysics Data System (ADS)

Kirpichev, D. E.; Sinaiskiy, M. A.; Samokhin, A. V.; Alexeev, N. V.

2017-04-01

The possibility of plasmochemical synthesis of titanium nitride is demonstrated in the paper. Results of the thermodynamic analysis of TiCl4 - H2 - N2 system are presented; key parameters of TiN synthesis process are calculated. The influence of parameters of plasma-chemical titanium nitride synthesis process in the reactor with an arc plasmatron on characteristics on the produced powders is experimentally investigated. Structure, chemical composition and morphology dependencies on plasma jet enthalpy, stoichiometric excess of hydrogen and nitrogen in a plasma jet are determined.

Characterization of poly(Sodium Styrene Sulfonate) Thin Films Grafted from Functionalized Titanium Surfaces

PubMed Central

Zorn, Gilad; Baio, Joe E.; Weidner, Tobias; Migonney, Veronique; Castner, David G.

2011-01-01

Biointegration of titanium implants in the body is controlled by their surface properties. Improving surface properties by coating with a bioactive polymer is a promising approach to improve the biological performance of titanium implants. To optimize the grafting processes, it is important to fully understand the composition and structure of the modified surfaces. The main focus of this study is to provide a detailed, multi-technique characterization of a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film grafted from titanium surfaces via a two-step procedure. Thin titanium films (~50 nm thick with an average surface roughness of 0.9±0.2nm) prepared by evaporation onto silicon wafers were used as smooth model substrates. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) showed that the titanium film was covered with a TiO2 layer that was at least 10nm thick and contained hydroxyl groups present at the outermost surface. These hydroxyl groups were first modified with a 3-methacryloxypropyltrimethoxysilane (MPS) cross linker. XPS and ToF-SIMS showed that a monolayer of the MPS molecules were successfully attached onto the titanium surfaces. The pNaSS film was grafted from the MPS modified titanium through atom transfer radical polymerization. Again, XPS and ToF-SIMS were used to verify that the pNaSS molecules were successfully grafted onto the modified surfaces. Atomic force microscopy analysis showed that the film was smooth and uniformly covered the surface. Fourier transform infrared spectroscopy indicated an ordered array of grafted NaSS molecules were present on the titanium surfaces. Sum frequency generation vibration spectroscopy and near edge X-ray absorption fine structure spectroscopy illustrated that the NaSS molecules were grafted onto the titanium surface with a substantial degree of orientational order in the styrene rings. PMID:21892821

Charge-transfer complex formation between TiO2 nanoparticles and thiosalicylic acid: A comprehensive experimental and DFT study

NASA Astrophysics Data System (ADS)

Milićević, Bojana; Đorđević, Vesna; Lončarević, Davor; Dostanić, Jasmina M.; Ahrenkiel, S. Phillip; Dramićanin, Miroslav D.; Sredojević, Dušan; Švrakić, Nenad M.; Nedeljković, Jovan M.

2017-11-01

Under normal conditions, titanium dioxide does not absorb visible light photons due to large band gap. Nevertheless, when titanium dioxide nanoparticles (TiO2 NPs) are surface-modified with thiosalicylic acid (TSA), their optical properties are altered owing to the formation of charge transfer complex that initiates absorption in the visible spectral range. Colloidal and sol-gel techniques were used to synthesize uniform TiO2 NPs of different sizes (average diameters in the range 4-15 nm), and effects of their subsequent modification by TSA molecules were compared with effect of modification of commercial Degussa TiO2 powder. Thorough microstructural characterization of TiO2 nanoparticulates was performed including transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis, as well as nitrogen adsorption-desorption isotherms. Optical measurements revealed that all surface-modified TiO2 samples with TSA have similar spectral features independent of their morphological differences, and, more importantly, absorption onset of modified TiO2 samples was found to be red-shifted by 1.0 eV compared to the unmodified ones. The mode of binding between TSA and surface Ti atoms was analyzed by infrared spectroscopy. Finally, the quantum chemical calculations, based on density functional theory, were performed to support optical characterization of surface-modified TiO2 with TSA.

Cytocompatibility of Direct Laser Interference-patterned Titanium Surfaces for Implants.

PubMed

Hartjen, Philip; Nada, Ola; Silva, Thiago Gundelwein; Precht, Clarissa; Henningsen, Anders; Holthaus, Marzellus GROßE; Gulow, Nikolai; Friedrich, Reinhard E; Hanken, Henning; Heiland, Max; Zwahr, Christoph; Smeets, Ralf; Jung, Ole

2017-01-01

In an effort to generate titanium surfaces for implants with improved osseointegration, we used direct laser interference patterning (DLIP) to modify the surface of pure titanium grade 4 of four different structures. We assessed in vitro cytoxicity and cell attachment, as well as the viability and proliferation of cells cultured directly on the surfaces. Attachment of the cells to the modified surfaces was comparably good compared to that of cells on grit-blasted and acid-etched reference titanium surfaces. In concordance with this, viability and proliferation of the cells directly cultured on the specimens were similar on all the titanium surfaces, regardless of the laser modification, indicating good cytocompatibility. Copyright© 2017, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.

Decreased fibrous encapsulation and enhanced osseointegration in vitro by decorin-modified titanium surface.

PubMed

He, Ronghan; Lu, Yunxiang; Ren, Jianhua; Wang, Zhe; Huang, Junqi; Zhu, Lei; Wang, Kun

2017-07-01

Orthopedic implants, using materials such as titanium, are extensively used in clinical surgeries. Despite its popularity, titanium is still inadequate to reliable osseointegration due to aseptic loosing. Fibrous encapsulation on the titanium implant interface prevents osseointegration and leads to the loosing of orthopedic implant. In this study, decorin was loaded on titanium surface by polydopamine film to examine fibrous encapsulation inhibition and bone growth acceleration. The coating of decorin was evaluated by X-ray photoelectron spectroscopy (XPS) and fluorescence microscopy. Quantitative analysis showed increased decorin coating on titanium surface when decorin in the loading solution increases. To test the effect of decorin modification, fibroblast and osteoblast cultures were utilized in vitro. The results showed that the functions of fibroblasts (proliferation, migration and collagen synthesis) were significantly attenuated on the decorin-modified surfaces and this anti-fibrous effect could be due to fibrotic gene suppression by decorin. In contrast, osteoblastic activities, such as calcium deposition and alkaline phosphatase (ALP) activity, were enhanced by the modified decorin. These results suggest that decorin coating on titanium surface inhibited proliferation and function of fibroblasts and improved that of osteoblasts. Therefore, this study is potentially useful for enhancing orthopedic implant. Copyright © 2017 Elsevier B.V. All rights reserved.

Wetting of single crystal mullite by borosilicate and yttrium-aluminosilicate glasses and wetting phenomena of steels containing aluminum and titanium

NASA Astrophysics Data System (ADS)

Eldred, Benjamin Todd

This dissertation consists of two major sections. The first section concerns the wetting of single crystal mullite by borosilicate and yttrium-aluminosilicate glasses. The borosilicate glass showed poor wetting and interacted only moderately with the substrate. The yttrium-aluminosilicate glass interacted strongly with mullite and showed very good wetting. Balanced chemical equations between each glass and mullite were derived from EDS data. Wetting was found to be dependent on the crystallographic orientation of the substrate, in agreement with previous studies of the surface energy of mullite. The second section concerns the wetting phenomena of steels containing aluminum and titanium. A modified sessile drop technique was used to investigate the wetting of steels containing aluminum and/or titanium as a function of furnace atmosphere. It was found that the steel chemistry and furnace atmosphere had little effect on wetting except in the case of a particular ultra-low carbon steel containing both aluminum and titanium. This steel was found to show significantly lower contact angles than any other steel tested when it was in an atmosphere of pure hydrogen. As nitrogen was added to the atmosphere, the contact angle increased monotonically and irreversibly. The interaction between aluminum, titanium, and nitrogen is explained in terms of first-order interaction coefficients available in thermodynamic literature.

Cannulated screw and cable are superior to modified tension band in the treatment of transverse patella fractures.

PubMed

Tian, Yun; Zhou, Fang; Ji, Hongquan; Zhang, Zhishan; Guo, Yan

2011-12-01

Although the modified tension band technique (eg, tension band supplemented by longitudinal Kirschner wires) has long been the mainstay for fixation of transverse fractures of the patella, it has shortcomings, such as bad reduction, loosening of implants, and skin irritation. We conducted a retrospective comparison of the modified tension band technique and the titanium cable-cannulated screw tension band technique. We retrospectively reviewed 101 patients aged 22 to 85 years (mean, 56.6 years) with AO/OTA 34-C1 fractures (n = 68) and 34-C2 fractures (n = 33). Fifty-two patients were in the modified tension band group and 49 were in the titanium cable-cannulated screw tension band group. Followup was at least 1 year (range, 1-3 years). Comparison criteria were fracture reduction, fracture healing time, and the Iowa score for knee function. The titanium cable-cannulated screw tension band group showed improved fracture reduction, reduced healing time, and better Iowa score, compared with the modified tension band group. In the modified tension band group, eight patients experienced wire migration, three of these requiring a second operation. There were no complications in the titanium cable-cannulated screw tension band group. The titanium cable-cannulated screw tension band technique showed superior results and should be considered as an alternative method for treatment of transverse patellar fractures. Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Is there scientific evidence favoring the substitution of commercially pure titanium with titanium alloys for the manufacture of dental implants?

PubMed

Cordeiro, Jairo M; Barão, Valentim A R

2017-02-01

The development of Ti alloys to manufacture dental implants has emerged in recent years due to the increased failure of commercially pure titanium (cpTi) implants. Thus, this study reviews existing information about the mechanical, chemical, electrochemical, and biological properties of the main Ti alloys developed over the past few years to provide scientific evidence in favor of using Ti-based alloys as alternative to cpTi. Ti alloys may be considered viable substitutes in the fabrication of dental implants. Such evidence is given by the enhanced properties of alloys, such as a low elastic modulus, high tensile strength, satisfactory biocompatibility, and good corrosion and wear resistances. In addition, Ti alloys may be modified at the structural, chemical, and thermomechanical levels, which allows the development of materials in accordance with the demands of several situations encountered in clinical practice. Although several in vitro studies have established the superiority of Ti alloys over cpTi, mainly in terms of their mechanical properties, there is no scientific evidence that supports the total replacement of this material in vivo. This review demonstrates the superiority of β-type alloys. However, it is evident that in vivo studies are encouraged to test new alloys to consolidate their use as substitutes for cpTi. Copyright © 2016 Elsevier B.V. All rights reserved.

Effect of cathodic polarization on coating doxycycline on titanium surfaces.

PubMed

Geißler, Sebastian; Tiainen, Hanna; Haugen, Håvard J

2016-06-01

Cathodic polarization has been reported to enhance the ability of titanium based implant materials to interact with biomolecules by forming titanium hydride at the outermost surface layer. Although this hydride layer has recently been suggested to allow the immobilization of the broad spectrum antibiotic doxycycline on titanium surfaces, the involvement of hydride in binding the biomolecule onto titanium remains poorly understood. To gain better understanding of the influence this immobilization process has on titanium surfaces, mirror-polished commercially pure titanium surfaces were cathodically polarized in the presence of doxycycline and the modified surfaces were thoroughly characterized using atomic force microscopy, electron microscopy, secondary ion mass spectrometry, and angle-resolved X-ray spectroscopy. We demonstrated that no hydride was created during the polarization process. Doxycycline was found to be attached to an oxide layer that was modified during the electrochemical process. A bacterial assay using bioluminescent Staphylococcus epidermidis Xen43 showed the ability of the coating to reduce bacterial colonization and planktonic bacterial growth. Copyright © 2016 Elsevier B.V. All rights reserved.

Silver Nanoforms as a Therapeutic Agent for Killing Escherichia coli and Certain ESKAPE Pathogens.

PubMed

Kedziora, A; Korzekwa, K; Strek, W; Pawlak, A; Doroszkiewicz, W; Bugla-Ploskonska, G

2016-07-01

The scope of this study included the preparation of silver nanoforms with high antimicrobial efficacy, low cost, and ease of application. The term 'silver nanoforms' refers to silver located on the amorphous or crystalline titanium dioxide (TiO2). Silver nanoforms may be used as an alternative to antibiotics in killing bacteria. Pure and silver-incorporated titanium (used as a carrier) was prepared using the sol-gel-modified method. Physical and chemical properties of the samples were described, and the antibacterial activity was indicated using the following strains of bacteria: Staphylococcus aureus, Klebsiella pneumoniae (ESKAPE pathogens), and Escherichia coli. The results have shown that the antibacterial activity of silver nanoforms with amorphous TiO2 is much better than that in the samples based on anatase (crystalline TiO2). The sensitivity of the tested bacteria to silver nanoforms depends on physical and chemical properties of the nanoforms and individual characteristics of the bacteria. For the first time, significant participation of amorphous TiO2 in antibacterial compounds has been described through this study.

Ion-Doped Silicate Bioceramic Coating of Ti-Based Implant

PubMed Central

Mohammadi, Hossein; Sepantafar, Mohammadmajid

2016-01-01

Titanium and its alloy are known as important load-bearing biomaterials. The major drawbacks of these metals are fibrous formation and low corrosion rate after implantation. The surface modification of biomedical implants through various methods such as plasma spray improves their osseointegration and clinical lifetime. Different materials have been already used as coatings on biomedical implant, including calcium phosphates and bioglass. However, these materials have been reported to have limited clinical success. The excellent bioactivity of calcium silicate (Ca-Si) has been also regarded as coating material. However, their high degradation rate and low mechanical strength limit their further coating application. Trace element modification of (Ca-Si) bioceramics is a promising method, which improves their mechanical strength and chemical stability. In this review, the potential of trace element-modified silicate coatings on better bone formation of titanium implant is investigated. PMID:26979401

High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to γ-valerolactone

PubMed Central

Luo, Wenhao; Sankar, Meenakshisundaram; Beale, Andrew M.; He, Qian; Kiely, Christopher J.; Bruijnincx, Pieter C. A.; Weckhuysen, Bert M.

2015-01-01

The catalytic hydrogenation of levulinic acid, a key platform molecule in many biorefinery schemes, into γ-valerolactone is considered as one of the pivotal reactions to convert lignocellulose-based biomass into renewable fuels and chemicals. Here we report on the development of highly active, selective and stable supported metal catalysts for this reaction and on the beneficial effects of metal nano-alloying. Bimetallic random alloys of gold-palladium and ruthenium-palladium supported on titanium dioxide are prepared with a modified metal impregnation method. Gold-palladium/titanium dioxide shows a marked,~27-fold increase in activity (that is, turnover frequency of 0.1 s−1) compared with its monometallic counterparts. Although ruthenium-palladium/titanium dioxide is not only exceptionally active (that is, turnover frequency of 0.6 s−1), it shows excellent, sustained selectivity to γ-valerolactone (99%). The dilution and isolation of ruthenium by palladium is thought to be responsible for this superior catalytic performance. Alloying, furthermore, greatly improves the stability of both supported nano-alloy catalysts. PMID:25779385

In Situ Growth of Mesoporous Silica with Drugs on Titanium Surface and Its Biomedical Applications.

PubMed

Wan, Mimi; Zhang, Jin; Wang, Qi; Zhan, Shuyue; Chen, Xudong; Mao, Chun; Liu, Yuhong; Shen, Jian

2017-06-07

Mesoporous silica has been developed for the modification of titanium surfaces that are used as implant materials. Yet, the traditional modification methods failed to effectively construct mesoporous silica on the titanium surface evenly and firmly, in which the interaction between mesoporous silica and titanium was mainly physical. Here, in situ growth of mesoporous silica on a titanium surface was performed using a simple evaporation-induced self-assembly strategy. Meantime, in situ introduction of drugs (heparin and vancomycin) to mesoporous silica was also adopted to improve the drug-loading amount. Both the above-mentioned processes were completed at the same time. Transmission electron microscopy, N 2 adsorption-desorption isotherms, Fourier transform infrared spectroscopy, scanning electron microscopy, and water contact angle measurements were used to characterize the structure of the mesoporous silica film. Results indicated that the mesoporous silica film that in situ grew on the titanium surface was smooth, thin, transparent, and stable. Cytotoxicity, proliferation performance of osteoblast cells, and in vitro and in vivo studies of the antibacterial activity of the coating were tested. This is the first study to modify the titanium surface by the in situ growth of a mesoporous silica coating with two kinds of drugs. The stability of the mesoporous silica coating can be attributed to the chemical bonding between dopamine and silicon hydroxyl of the mesoporous silica coating, and the smooth surface of mesoporous silica is a result of the method of in situ growth. The large amount of drug-loading also could be ascribed to the in situ introduction of drugs during the synthetic process. The strategy proposed in this work will bring more possibilities for the preparation of advanced functional materials based on the combination of mesoporous structure and metallic materials.

The effect of hydrophilic titanium surface modification on macrophage inflammatory cytokine gene expression.

PubMed

Hamlet, Stephen; Alfarsi, Mohammed; George, Roy; Ivanovski, Saso

2012-05-01

Chemical modification of microrough titanium dental implants to produce a hydrophilic surface with increased wettability and improved surface energy has been demonstrated clinically to achieve superior bone wound healing and osseointegration compared to that achieved with a microrough titanium surface alone. As the recruitment of the necessary osseoinductive precursors involved in bone wound healing and osseointegration to the wound site is facilitated by the action of cytokines, this study sought to determine the in vitro effect of hydrophilic surface modification on the expression of pro-inflammatory cytokines from adherent macrophages. The surface topography and composition of the titanium surfaces was characterized by scanning electron microscopy and X-ray photoelectron spectroscopy. Macrophage attachment and proliferation was assessed using an MTT assay. The expression of 84 pro-inflammatory cytokines and chemokines by adherent RAW 264.7 cells, a murine leukaemic monocyte cell line, was assessed by PCR array after 24 h culture on either smooth polished, sand-blasted acid-etched (SLA) or hydrophilic-modified SLA (SLActive) titanium surfaces. Following 24 h culture on titanium, surface microroughness activated pro-inflammatory cytokine gene transcription in RAW 264.7 cells. Although there was no significant difference in the degree of cellular attachment or proliferation of RAW 264.7 cells to the different titanium surfaces, by 24 h the hydrophilic surface elicited a gene expression profile with significant down-regulation of the key pro-inflammatory cytokines Tnfα, IL-1α, IL-1β and the chemokine Ccl-2. Down-regulation of the expression of pro-inflammatory cytokine genes may thus modulate the inflammatory response and may facilitate the enhanced bone wound healing and osseointegration observed clinically using implants with a microrough hydrophilic surface. © 2011 John Wiley & Sons A/S.

Effects of a hybrid micro/nanorod topography-modified titanium implant on adhesion and osteogenic differentiation in rat bone marrow mesenchymal stem cells.

PubMed

Zhang, Wenjie; Li, Zihui; Huang, Qingfeng; Xu, Ling; Li, Jinhua; Jin, Yuqin; Wang, Guifang; Liu, Xuanyong; Jiang, Xinquan

2013-01-01

Various methods have been used to modify titanium implant surfaces with the aim of achieving better osseointegration. In this study, we fabricated a clustered nanorod structure on an acid-etched, microstructured titanium plate surface using hydrogen peroxide. We also evaluated biofunctionalization of the hybrid micro/nanorod topography on rat bone marrow mesenchymal stem cells. Scanning electron microscopy and x-ray diffraction were used to investigate the surface topography and phase composition of the modified titanium plate. Rat bone marrow mesenchymal stem cells were cultured and seeded on the plate. The adhesion ability of the cells was then assayed by cell counting at one, 4, and 24 hours after cell seeding, and expression of adhesion-related protein integrin β1 was detected by immunofluorescence. In addition, a polymerase chain reaction assay, alkaline phosphatase and Alizarin Red S staining assays, and osteopontin and osteocalcin immunofluorescence analyses were used to evaluate the osteogenic differentiation behavior of the cells. The hybrid micro/nanoscale texture formed on the titanium surface enhanced the initial adhesion activity of the rat bone marrow mesenchymal stem cells. Importantly, the hierarchical structure promoted osteogenic differentiation of these cells. This study suggests that a hybrid micro/nanorod topography on a titanium surface fabricated by treatment with hydrogen peroxide followed by acid etching might facilitate osseointegration of a titanium implant in vivo.

Calcium Phosphate Growth at Electropolished Titanium Surfaces

PubMed Central

Ajami, Elnaz; Aguey-Zinsou, Kondo-Francois

2012-01-01

This work investigated the ability of electropolished Ti surface to induce Hydroxyapatite (HA) nucleation and growth in vitro via a biomimetic method in Simulated Body Fluid (SBF). The HA induction ability of Ti surface upon electropolishing was compared to that of Ti substrates modified with common chemical methods including alkali, acidic and hydrogen peroxide treatments. Our results revealed the excellent ability of electropolished Ti surfaces in inducing the formation of bone-like HA at the Ti/SBF interface. The chemical composition, crystallinity and thickness of the HA coating obtained on the electropolished Ti surface was found to be comparable to that achieved on the surface of alkali treated Ti substrate, one of the most effective and popular chemical treatments. The surface characteristics of electropolished Ti contributing to HA growth were discussed thoroughly. PMID:24955535

Laser-modified titanium surfaces enhance the osteogenic differentiation of human mesenchymal stem cells.

PubMed

Bressel, Tatiana A B; de Queiroz, Jana Dara Freires; Gomes Moreira, Susana Margarida; da Fonseca, Jéssyca T; Filho, Edson A; Guastaldi, Antônio Carlos; Batistuzzo de Medeiros, Silvia Regina

2017-11-28

Titanium surfaces have been modified by various approaches with the aim of improving the stimulation of osseointegration. Laser beam (Yb-YAG) treatment is a controllable and flexible approach to modifying surfaces. It creates a complex surface topography with micro and nano-scaled patterns, and an oxide layer that can improve the osseointegration of implants, increasing their usefulness as bone implant materials. Laser beam irradiation at various fluences (132, 210, or 235 J/cm 2 ) was used to treat commercially pure titanium discs to create complex surface topographies. The titanium discs were investigated by scanning electron microscopy, X-ray diffraction, and measurement of contact angles. The surface generated at a fluence of 235 J/cm 2 was used in the biological assays. The behavior of mesenchymal stem cells from an umbilical cord vein was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, a mineralization assay, and an alkaline phosphatase activity assay and by carrying out a quantitative real-time polymerase chain reaction for osteogenic markers. CHO-k1 cells were also exposed to titanium discs in the MTT assay. The best titanium surface was that produced by laser beam irradiation at 235 J/cm 2 fluence. Cell proliferation analysis revealed that the CHO-k1 and mesenchymal stem cells behaved differently. The laser-processed titanium surface increased the proliferation of CHO-k1 cells, reduced the proliferation of mesenchymal stem cells, upregulated the expression of the osteogenic markers, and enhanced alkaline phosphatase activity. The laser-treated titanium surface modulated cellular behavior depending on the cell type, and stimulated osteogenic differentiation. This evidence supports the potential use of laser-processed titanium surfaces as bone implant materials, and their use in regenerative medicine could promote better outcomes.

Custom-made laser-welded titanium implant prosthetic abutment.

PubMed

Iglesia-Puig, Miguel A

2005-10-01

A technique to create an individually modified implant prosthetic abutment is described. An overcasting is waxed onto a machined titanium abutment, cast in titanium, and joined to it with laser welding. With the proposed technique, a custom-made titanium implant prosthetic abutment is created with adequate volume and contour of metal to support a screw-retained, metal-ceramic implant-supported crown.

Cadmium Telluride-Titanium Dioxide Nanocomposite for Photodegradation of Organic Substance.

PubMed

Ontam, Areeporn; Khaorapapong, Nithima; Ogawa, Makoto

2015-12-01

Cadmium telluride-titanium dioxide nanocomposite was prepared by hydrothermal reaction of sol-gel derived titanium dioxide and organically modified cadmium telluride. The crystallinity of titanium dioxide in the nanocomposite was higher than that of pure titanium dioxide obtained by the reaction under the same temperature and pressure conditions, showing that cadmium telluride induced the crystallization of titanium dioxide. Diffuse reflectance spectrum of the nanocomposite showed the higher absorption efficiency in the UV-visible region due to band-gap excitation of titanium dioxide. The nanocomposite significantly showed the improvement of photocatalytic activity for 4-chlorophenol with UV light.

Bacterial and fungal biofilm formation on anodized titanium alloys with fluorine.

PubMed

Perez-Jorge, Concepcion; Arenas, Maria-Angeles; Conde, Ana; Hernández-Lopez, Juan-Manuel; de Damborenea, Juan-Jose; Fisher, Steve; Hunt, Alessandra M Agostinho; Esteban, Jaime; James, Garth

2017-01-01

Orthopaedic device-related infections are closely linked to biofilm formation on the surfaces of these devices. Several modified titanium (Ti-6Al-4V) surfaces doped with fluorine were studied in order to evaluate the influence of these modifications on biofilm formation by Gram-positive and Gram-negative bacteria as well as a yeast. The biofilm studies were performed according to the standard test method approved by ASTM (Designation: E2196-12) using the Rotating Disk Reactor. Four types of Ti-6Al-4V samples were tested; chemically polished (CP), two types of nanostructures containing fluorine, nanoporous (NP) and nanotubular (NT), and non-nanostructured fluorine containing samples (fluoride barrier layers, FBL). Different species of Gram-positive cocci, (Staphylococcus aureus and epidermidis), Gram-negative rods (Escherichia coli, Pseudomonas aeruginosa), and a yeast (Candida albicans) were studied. For one of the Gram-positive (S. epidermidis) and one of the Gram-negative (E. coli) species a statistically-significant decrease in biofilm accumulation for NP and NT samples was found when compared with the biofilm accumulation on CP samples. The results suggest an effect of the modified materials on the biofilm formation.

Mineral of the month: titanium

USGS Publications Warehouse

Gambogi, Joseph

2004-01-01

From paint to airplanes, titanium is important in a number of applications. Commercial production comes from titanium-bearing ilmenite, rutile and leucoxene (altered ilmenite). These minerals are used to produce titanium dioxide pigment, as well as an assortment of metal and chemical products.

Zinc-ion implanted and deposited titanium surfaces reduce adhesion of Streptococccus mutans

NASA Astrophysics Data System (ADS)

Xu, Juan; Ding, Gang; Li, Jinlu; Yang, Shenhui; Fang, Bisong; Sun, Hongchen; Zhou, Yanmin

2010-10-01

While titanium (Ti) is a commonly used dental implant material with advantageous biocompatible and mechanical properties, native Ti surfaces do not have the ability to prevent bacterial colonization. The objective of this study was to evaluate the chemical composition and bacterial adhesive properties of zinc (Zn) ion implanted and deposited Ti surfaces (Zn-PIIID-Ti) as potential dental implant materials. Surfaces of pure Ti (cp-Ti) were modified with increasing concentrations of Zn using plasma immersion ion implantation and deposition (PIIID), and elemental surface compositions were characterized by X-ray photoelectron spectrometry (XPS). To evaluate bacterial responses, Streptococcus mutans were seeded onto the modifiedTi surfaces for 48 h and subsequently observed by scanning electron microscopy. Relative numbers of bacteria on each surface were assessed by collecting the adhered bacteria, reculturing and counting colony forming units after 48 h on bacterial grade plates. Ti, oxygen and carbon elements were detected on all surfaces by XPS. Increased Zn signals were detected on Zn-PIIID-Ti surfaces, correlating with an increase of Zn-deposition time. Substantial numbers of S. mutans adhered to cp-Ti samples, whereas bacterial adhesion on Zn-PIIID-Ti surfaces signficantly decreased as the Zn concentration increased ( p < 0.01). In conclusion, PIIID can successfully introduce Zn onto a Ti surface, forming a modified surface layer bearing Zn ions that consequently deter adhesion of S. mutans, a common bacterium in the oral environment.

Sprayable titanium composition

DOEpatents

Tracy, Chester E.; Kern, Werner; Vibronek, Robert D.

1980-01-01

The addition of 2-ethyl-1-hexanol to an organometallic titanium compound dissolved in a diluent and optionally containing a lower aliphatic alcohol spreading modifier, produces a solution that can be sprayed onto a substrate and cured to form an antireflection titanium oxide coating having a refractive index of from about 2.0 to 2.2.

A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro

PubMed Central

Liu, Chundong; Zhang, Yanli; Wang, Lichao; Zhang, Xinhua; Chen, Qiuyue; Wu, Buling

2015-01-01

Objective To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications. Materials and Methods Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts. Results The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes. Conclusions These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C. PMID:26529234

A Strontium-Modified Titanium Surface Produced by a New Method and Its Biocompatibility In Vitro.

PubMed

Liu, Chundong; Zhang, Yanli; Wang, Lichao; Zhang, Xinhua; Chen, Qiuyue; Wu, Buling

2015-01-01

To present a new and effective method of producing titanium surfaces modified with strontium and to investigate the surface characteristics and in vitro biocompatibility of titanium (Ti) surfaces modified with strontium (Sr) for bone implant applications. Sr-modified Ti surfaces were produced by sequential treatments with NaOH, strontium acetate, heat and water. The surface characteristics and the concentration of the Sr ions released from the samples were examined. Cell adhesion, morphology and growth were investigated using osteoblasts isolated from the calvaria of neonatal Sprague-Dawley rats. Expression of osteogenesis-related genes and proteins was examined to assess the effect of the Sr-modified Ti surfaces on osteoblasts. The modified titanium surface had a mesh structure with significantly greater porosity, and approximately5.37±0.35at.% of Sr was incorporated into the surface. The hydrophilicity was enhanced by the incorporation of Sr ions and water treatment. The average amounts of Sr released from the Sr-modified plates subjected to water treatment were slight higher than the plates without water treatment. Sr promoted cellular adhesion, spreading and growth compared with untreated Ti surfaces. The Sr-modified Ti plates also promoted expression of osteogenesis-related genes,and expression of OPN and COL-І by osteoblasts. Ti plates heat treated at 700°C showed increased bioactivity in comparison with those treated at 600°C. Water treatment upregulated the expression of osteogenesis-related genes. These results show that Sr-modification of Ti surfaces may improve bioactivity in vitro. Water treatment has enhanced the response of osteoblasts. The Sr-modified Ti heat-treated at 700°C exhibited better bioactivity compared with that heated at 600°C.

Oxygen-implanted induced formation of oxide layer enhances blood compatibility on titanium for biomedical applications.

PubMed

Hung, Wei-Chiang; Chang, Fang-Mo; Yang, Tzu-Sen; Ou, Keng-Liang; Lin, Che-Tong; Peng, Pei-Wen

2016-11-01

Titanium dioxide (TiO2) layers were prepared on a Ti substrate by using oxygen plasma immersion ion implantation (oxygen PIII). The surface chemical states, structure, and morphology of the layers were studied using X-ray photoelectron spectroscopy, X-ray diffraction, Raman microscopy, atomic force microscopy and scanning electron microscope. The mechanical properties, such as the Young's modulus and hardness, of the layers were investigated using nanoindentation testing. The Ti(4+) chemical state was determined to be present on oxygen-PIII-treated surfaces, which consisted of nanocrystalline TiO2 with a rutile structure. Compared with Ti substrates, the oxygen-PIII-treated surfaces exhibited decreased Young's moduli and hardness. Parameters indicating the blood compatibility of the oxygen-PIII-treated surfaces, including the clotting time and platelet adhesion and activation, were studied in vitro. Clotting time assays indicated that the clotting time of oxygen-PIII-treated surfaces was longer than that of the Ti substrate, which was associated with decreased fibrinogen adsorption. In conclusion, the surface characteristics and the blood compatibility of Ti implants can be modified and improved using oxygen PIII. Copyright © 2016 Elsevier B.V. All rights reserved.

In vivo performance of two different hydroxyapatite coatings on titanium prepared by discharging in electrolytes.

PubMed

Yamamoto, Hiroki; Shibata, Yo; Tachikawa, Tetsuhiko; Miyazaki, Takashi

2006-07-01

This study reports a discharging method for bone-like carbonated HA (cHA)-coating (Ca/P 1.71) and stoichiometric HA (sHA)-coating (Ca/P 1.67) with micrometer order thicknesses on titanium plates, using modified body fluid and acidic calcium phosphate solutions, respectively. In vivo histological performance of the HA coatings prepared by discharging in electrolytes was evaluated. Bone-contact indexes of HA coatings were measured microscopically. Additionally, bone-coating interface was analyzed by scanning electron microscopy and the use of an electron probe microanalyzer. Results demonstrated that there was no significant difference in contact index between HA coatings. However, the cHA coating was practically replaced by immature bone, and the titanium metal substrate was directly connected to the bone structure whereas the sHA coating layer remained and was partially detached from the titanium metal substrate. Since detached coating particles are pathogens, and can cause peri-implantitis, the cHA coating was more favorable than the sHA coating even if contact index was equivalent to that of the sHA coating. It is thought that coating thickness and chemical composition of coatings are important for biological stability of implants. In conclusion, since bone-like thin cHA coating showed high osteoconductivity and bone replacement, bone-like HA is superior to sHA coating for use in dental implants.

Formation and accumulation of radiation-induced defects and radiolysis products in modified lithium orthosilicate pebbles with additions of titanium dioxide

NASA Astrophysics Data System (ADS)

Zarins, Arturs; Valtenbergs, Oskars; Kizane, Gunta; Supe, Arnis; Knitter, Regina; Kolb, Matthias H. H.; Leys, Oliver; Baumane, Larisa; Conka, Davis

2016-03-01

Lithium orthosilicate (Li4SiO4) pebbles with 2.5 wt.% excess of silicon dioxide (SiO2) are the European Union's designated reference tritium breeding ceramics for the Helium Cooled Pebble Bed (HCPB) Test Blanket Module (TBM). However, the latest irradiation experiments showed that the reference Li4SiO4 pebbles may crack and form fragments under operation conditions as expected in the HCPB TBM. Therefore, it has been suggested to change the chemical composition of the reference Li4SiO4 pebbles and to add titanium dioxide (TiO2), to obtain lithium metatitanate (Li2TiO3) as a second phase. The aim of this research was to investigate the formation and accumulation of radiation-induced defects (RD) and radiolysis products (RP) in the modified Li4SiO4 pebbles with different contents of TiO2 for the first time, in order to estimate and compare radiation stability. The reference and the modified Li4SiO4 pebbles were irradiated with accelerated electrons (E = 5 MeV) up to 5000 MGy absorbed dose at 300-990 K in a dry argon atmosphere. By using electron spin resonance (ESR) spectroscopy it was determined that in the modified Li4SiO4 pebbles, several paramagnetic RD and RP are formed and accumulated, like, E' centres (SiO33-/TiO33-), HC2 centres (SiO43-/TiO3-) etc. On the basis of the obtained results, it is concluded that the modified Li4SiO4 pebbles with TiO2 additions have comparable radiation stability with the reference pebbles.

Effects of glucose concentration on osteogenic differentiation of type II diabetes mellitus rat bone marrow-derived mesenchymal stromal cells on a nano-scale modified titanium.

PubMed

Yamawaki, I; Taguchi, Y; Komasa, S; Tanaka, A; Umeda, M

2017-08-01

Diabetes mellitus (DM) is a common disease worldwide. Patients with DM have an increased risk of losing their teeth compared with other individuals. Dental implants are a standard of care for treating partial or full edentulism, and various implant surface treatments have recently been developed to increase dental implant stability. However, some studies have reported that DM reduces osseointegration and the success rate of dental implants. The purpose of this study was to determine the effects of high glucose levels for hard tissue formation on a nano-scale modified titanium surface. Titanium disks were heated at 600°C for 1 h after treatment with or without 10 m NaOH solution. All disks were incubated with type II DM rat bone marrow-derived mesenchymal stromal cells before exposure to one of four concentrations of glucose (5.5, 8.0, 12.0 or 24.0 mm). The effect of different glucose concentrations on bone marrow-derived mesenchymal stromal cell osteogenesis and inflammatory cytokines on the nano-scale modified titanium surface was evaluated. Alkaline phosphatase activity decreased with increasing glucose concentration. In contrast, osteocalcin production and calcium deposition were significantly decreased at 8.0 mm glucose, but increased with glucose concentrations over 8.0 mm. Differences in calcium/phosphate ratio associated with the various glucose concentrations were similar to osteocalcin production and calcium deposition. Inflammatory cytokines were expressed at high glucose concentrations, but the nano-scale modified titanium surface inhibited the effect of high glucose concentrations. High glucose concentration increased hard tissue formation, but the quality of the mineralized tissue decreased. Furthermore, the nano-scale modified titanium surface increased mineralized tissue formation and anti-inflammation, but the quality of hard tissue was dependent on glucose concentration. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Combining single source chemical vapour deposition precursors to explore the phase space of titanium oxynitride thin films.

PubMed

Rees, Kelly; Lorusso, Emanuela; Cosham, Samuel D; Kulak, Alexander N; Hyett, Geoffrey

2018-02-14

In this paper we report on a novel chemical vapour deposition approach to the formation and control of composition of mixed anion materials, as applied to titanium oxynitride thin films. The method used is the aerosol assisted chemical vapour deposition (AACVD) of a mixture of single source precursors. To explore the titanium-oxygen-nitrogen system the single source precursors selected were tetrakis(dimethylamido) titanium and titanium tetraisopropoxide which individually are precursors to thin films of titanium nitride and titanium dioxide respectively. However, by combining these precursors in specific ratios in a series of AACVD reactions at 400 °C, we are able to deposit thin films of titanium oxynitride with three different structure types and a wide range of compositions. Using this precursor system we can observe films of nitrogen doped anatase, with 25% anion doping of nitrogen; a new composition of pseudobrookite titanium oxynitride with a composition of Ti 3 O 3.5 N 1.5 , identified as being a UV photocatalyst; and rock-salt titanium oxynitride in the range TiO 0.41 N 0.59 to TiO 0.05 N 0.95 . The films were characterised using GIXRD, WDX and UV-vis spectroscopy, and in the case of the pseudobrookite films, assessed for photocatalytic activity. This work shows that a so-called dual single-source CVD approach is an effective method for the deposition of ternary mixed anion ceramic films through simple control of the ratio of the precursors, while keeping all other experimental parameters constant.

Grafting titanium nitride surfaces with sodium styrene sulfonate thin films

PubMed Central

Zorn, Gilad; Migonney, Véronique; Castner, David G.

2014-01-01

The importance of titanium nitride lies in its high hardness and its remarkable resistance to wear and corrosion, which has led to its use as a coating for the heads of hip prostheses, dental implants and dental surgery tools. However, the usefulness of titanium nitride coatings for biomedical applications could be significantly enhanced by modifying their surface with a bioactive polymer film. The main focus of the present work was to graft a bioactive poly(sodium styrene sulfonate) (pNaSS) thin film from titanium nitride surfaces via a two-step procedure: first modifying the surface with 3-methacryloxypropyltrimethoxysilane (MPS) and then grafting the pNaSS film from the MPS modified titanium through free radical polymerization. X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were used after each step to characterize success and completeness of each reaction. The surface region of the titanium nitride prior to MPS functionalization and NaSS grafting contained a mixture of titanium nitride, oxy-nitride, oxide species as well as adventitious surface contaminants. After MPS functionalization, Si was detected by XPS, and characteristic MPS fragments were detected by ToF-SIMS. After NaSS grafting, Na and S were detected by XPS and characteristic NaSS fragments were detected by ToF-SIMS. The XPS determined thicknesses of the MPS and NaSS overlayers were ∼1.5 and ∼1.7 nm, respectively. The pNaSS film density was estimated by the toluidine blue colorimetric assay to be 260 ± 70 ng/cm2. PMID:25280842

S. sanguinis adhesion on rough titanium surfaces: effect of culture media.

PubMed

Rodríguez-Hernández, Ana G; Muñoz-Tabares, José A; Godoy-Gallardo, Maria; Juárez, Antonio; Gil, Francisco-Javier

2013-03-01

Bacterial colonization plays a key role in dental implant failure, because they attach directly on implant surface upon implantation. Between different types of bacteria associated with the oral environment, Streptococcus sanguinis is essential in this process since it is an early colonizer. In this work the relationship between titanium surfaces modified by shot blasting treatment and S. sanguinis adhesion; have been studied in approached human mouth environment. Bacteria pre-inoculated with routinary solution were put in contact with titanium samples, shot-blasted with alumina and silicon carbide, and adhesion results were compared with those obtained when bacteria were pre-inoculated with modified artificial saliva medium and on saliva pre-coated titanium samples. Our results showed that bacterial adhesion on titanium samples was influenced by culture conditions. When S. sanguinis was inoculated in routinary culture media, colonies forming unities per square millimeter presented an increment correlated with roughness and surface energy, but separated by the type of particle used during shot-blasting treatment; whereas in modified artificial saliva only a relationship between bacteria adhered and the increment in both roughness and surface energy were observed, regardless of the particle type. Finally, on human saliva pre-coated samples no significant differences were observed among roughness, surface energy or particle. Copyright © 2012 Elsevier B.V. All rights reserved.

Osseointegration of zirconia implants: an SEM observation of the bone-implant interface.

PubMed

Depprich, Rita; Zipprich, Holger; Ommerborn, Michelle; Mahn, Eduardo; Lammers, Lydia; Handschel, Jörg; Naujoks, Christian; Wiesmann, Hans-Peter; Kübler, Norbert R; Meyer, Ulrich

2008-11-06

The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level. A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Göttinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface. Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography. The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level.

Electrochemical response of carbon paste electrode modified with mixture of titanium dioxide/zirconium dioxide in the detection of heavy metals: lead and cadmium.

PubMed

Nguyen, Phuong Khanh Quoc; Lunsford, Suzanne K

2012-11-15

A novel carbon modified electrode was developed by incorporating titanium dioxide/zirconium dioxide into the graphite carbon paste electrode to detect heavy metals-cadmium and lead. In this work, the development of the novel titanium dioxide/zirconium dioxide modified carbon paste electrode was studied to determine the optimum synthesis conditions related to the temperature, heating duration, amount and ratio of titanium dioxide/zirconium dioxide, and amount of surfactant, to create the most reproducible results. Using cyclic voltammetric (CV) analysis, this study has proven that the novel titanium dioxide/zirconium dioxide can be utilized to detect heavy metals-lead and cadmium, at relatively low concentrations (7.6×10(-6) M and 1.1×10(-5) M for Pb and Cd, respectively) at optimum pH value (pH=3). From analyzing CV data the optimal electrodes surface area was estimated to be 0.028 (±0.003) cm(2). Also, under the specific experimental conditions, electron transfer coefficients were estimated to be 0.44 and 0.33 along with the heterogeneous electron transfer rate constants of 5.64×10(-3) and 2.42×10(-3) (cm/s) for Pb and Cd, respectively. Copyright © 2012 Elsevier B.V. All rights reserved.

Titanium (IV) sol-gel chemistry in varied gravity environments

NASA Astrophysics Data System (ADS)

Hales, Matthew; Martens, Wayde; Steinberg, Theodore

Sol-gel synthesis in reduced gravity is a relatively new topic in the literature and further inves-tigation is essential to realise its potential and application to other sol-gel systems. The sol-gel technique has been successfully applied to the synthesis of silica systems of varying porosity for many diverse applications [1-5]. It is proposed that current methods for the synthesis of silica sol-gels in reduced gravity may be applied to titanium sol-gel processing in order to enhance desirable physical and chemical characteristics of the final materials. The physical and chemical formation mechanisms for titanium alkoxide based sol-gels, to date, is not fully understood. However, various authors [6-9] have described potential methods to control the hydrolysis and condensation reactions of titanium alkoxides through the use of chemical inhibitors. A preliminary study of the reaction kinetics of titanium alkoxide sol-gel reaction in normal gravity was undertaken in order to determine reactant mixtures suitable for further testing under varied gravity conditions of limited duration. Through the use of 1H Nuclear Magnetic Resonance spectroscopy (NMR) for structural analysis of precursor materials, Ultra-Violet-Visible spectroscopy (UV-VIS) and viscosity measurements, it was demonstrated that not only could the rate of the chemical reaction could be controlled, but directed linear chain growth within the resulting gel structure was achievable through the use of increased inhibitor concentrations. Two unique test systems have been fabricated to study the effects of varied gravity (reduced, normal, high) on the formation of titanium sol-gels. Whilst the first system is to be used in conjunction with the recently commissioned drop tower facility at Queensland University of Technology in Brisbane, Australia to produce reduced gravity conditions. The second system is a centrifuge capable of providing high gravity environments of up to 70 G's for extended periods of time. The test systems and experimental results obtained will be presented. 1. Okubo, T., Tsuchida, A., Okuda, T., Fujitsuna, K., Ishikawa, M., Morita, T., Tada, T. , Kinetic Analyses of Colloidal Crystallization in Microgravity -Aircraft Experiments. . Colloids and Surfaces A: Physicochemical and Engineering Aspects, 1999. 153: p. 515-524. 2. Okubo, T., Tsuchida, A., Kobayashi, K., Kuno, A., Morita, T., Fujishima, M., Kohno, Y., Kinetic Study of the Formation Reaction of Colloidal Silica Spheres in Microgravity Using Aircraft. Colloid Polymer Science, 1999. 277(5): p. 474-478. 3. Pienaar, C.L., Chiffoleau, G. J. A., Follens, L. R. A., Martens, J. A., Kirschhock, C. E. A., Steinberg, T. A., Effect of Gravity on the Gelation of Silica Sols. Chem. Mater., 2007. 19(4): p. 660-664. 4. Smith, D.D., et al., Effect of Microgravity on the Growth of Silica Nanostructures. Langmuir, 2000. 16(26): p. 10055-10060. 5. Zhang, X., Johnson, D.P., Manerbino, A.R., Moore, J.J., Schowengerdt, F. , Recent Mi-crogravity Results in the Synthesis of Porous Materials. AIP Conference Proceedings (Space Technology and Applications International Forum-1999, Pt. 1), 1999. 458: p. 88-93. 6. Dunbar, P.B., Bendzko, N.J.,, 1H and 13C NMR observation of the reaction of acetic acid with titanium isopropoxide. Materials Chemistry and Physics, 1999. 59: p. 26-35. 7. Krunks, M., Oja, I., T˜nsuaadu, K., Es-Souni, M., Gruselle, M., Niinistü,. L, Thermoanalytical study of acetylacetonate-modified titanium (iv) isopropoxide as precursor for TiO2 films. Journal of Thermal Analysis and Calorimetry, 2005: p. 483-488. 8. Moran, P.D., Bowmaker, G. A., Cooney, R. P., Vibrational Spectra and Molecular Associa-tion of Titanium Tetraisopropoxide. Inorg. Chem., 1998. 37(1): p. 2741-2748. 9. Somogyvari, A., Serpone, N.,, Evidence for five-coordination in titanium(1V) complexes. A nuclear magnetic resonance investigation. Canadian Journal of Chemistry, 1977. 56: p. 316-319.

40 CFR 721.10600 - Calcium cobalt lead strontium titanium tungsten oxide.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Calcium cobalt lead strontium titanium... Specific Chemical Substances § 721.10600 Calcium cobalt lead strontium titanium tungsten oxide. (a... calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No. 1262279-30-0) is subject to...

40 CFR 721.10600 - Calcium cobalt lead strontium titanium tungsten oxide.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Calcium cobalt lead strontium titanium... Specific Chemical Substances § 721.10600 Calcium cobalt lead strontium titanium tungsten oxide. (a... calcium cobalt lead strontium titanium tungsten oxide (PMN P-11-272; CAS No. 1262279-30-0) is subject to...

Osteoblastlike cell adhesion on titanium surfaces modified by plasma nitriding.

PubMed

da Silva, Jose Sandro Pereira; Amico, Sandro Campos; Rodrigues, Almir Olegario Neves; Barboza, Carlos Augusto Galvao; Alves, Clodomiro; Croci, Alberto Tesconi

2011-01-01

The aim of this study was to evaluate the characteristics of various titanium surfaces modified by cold plasma nitriding in terms of adhesion and proliferation of rat osteoblastlike cells. Samples of grade 2 titanium were subjected to three different surface modification processes: polishing, nitriding by plasma direct current, and nitriding by cathodic cage discharge. To evaluate the effect of the surface treatment on the cellular response, the adhesion and proliferation of osteoblastlike cells (MC3T3) were quantified and the results were analyzed by Kruskal-Wallis and Friedman statistical tests. Cellular morphology was observed by scanning electron microscopy. There was more MC3T3 cell attachment on the rougher surfaces produced by cathodic cage discharge compared with polished samples (P < .05). Plasma nitriding improves titanium surface roughness and wettability, leading to osteoblastlike cell adhesion.

Antibacterial activity and biofilm inhibition by surface modified titanium alloy medical implants following application of silver, titanium dioxide and hydroxyapatite nanocoatings.

PubMed

Besinis, A; Hadi, S D; Le, H R; Tredwin, C; Handy, R D

2017-04-01

One of the most common causes of implant failure is peri-implantitis, which is caused by bacterial biofilm formation on the surfaces of dental implants. Modification of the surface nanotopography has been suggested to affect bacterial adherence to implants. Silver nanoparticles are also known for their antibacterial properties. In this study, titanium alloy implants were surface modified following silver plating, anodisation and sintering techniques to create a combination of silver, titanium dioxide and hydroxyapatite (HA) nanocoatings. Their antibacterial performance was quantitatively assessed by measuring the growth of Streptococcus sanguinis, proportion of live/dead cells and lactate production by the microbes over 24 h. Application of a dual layered silver-HA nanocoating to the surface of implants successfully inhibited bacterial growth in the surrounding media (100% mortality), whereas the formation of bacterial biofilm on the implant surfaces was reduced by 97.5%. Uncoated controls and titanium dioxide nanocoatings showed no antibacterial effect. Both silver and HA nanocoatings were found to be very stable in biological fluids with material loss, as a result of dissolution, to be less than 0.07% for the silver nanocoatings after 24 h in a modified Krebs-Ringer bicarbonate buffer. No dissolution was detected for the HA nanocoatings. Thus, application of a dual layered silver-HA nanocoating to titanium alloy implants creates a surface with antibiofilm properties without compromising the HA biocompatibility required for successful osseointegration and accelerated bone healing.

Rolling contact fatigue of surface modified 440C using a 'Ge-Polymet' type disc rod test rig

NASA Technical Reports Server (NTRS)

Thom, Robert L.

1989-01-01

Through hardened 440 C martensitic stainless steel test specimens were surface modified and tested for changes in rolling contact fatigue using a disc on rod test rig. The surface modifications consisted of nitrogen, boron, titanium, chromium, tantalum, carbon, or molybdenum ion implantation at various ion fluences and energies. Tests were also performed on specimens reactively sputtered with titanium nitride.

Use Zircon-Ilmenite Concentrate in Steelmaking

NASA Astrophysics Data System (ADS)

Fedoseev, S. N.; Volkova, T. N.

2016-08-01

Market requirements cause a constant search for new materials and technologies, for their immediate use in increasing requirements for material and energy efficiency, as well as to the quality of steel. In practice, steel production in the tended recently of more stringent requirements for the chemical composition of the steel and its contamination by nonmetallic inclusions, gas and non-ferrous metals. The main ways of increasing of strength and performance characteristics fabricated metal products related to the profound and effective influence on the crystallizing metal structure by furnace processing of the melt with refining and modifying additives. It can be argued that the furnace processing of steel and iron chemically active metals (alkali-earth metals, rare-earth metals, and others.) is an integral part of modern production of high quality products and competitive technologies. Important condition for development of methods secondary metallurgy of steel is the use of relatively inexpensive materials in a variety of complex alloys and blends, allowing targeted control of physical and chemical state of the molten metal and, therefore, receive steel with improved performance. In this connection the development of modifying natural materials metallurgy technologies presented complex ores containing titanium and zirconium, is a very urgent task.

[Effect of surface modification using laser on wear resistance of titanium].

PubMed

Sato, Yohei

2005-02-01

Severe wear of cast commercial pure (CP) titanium teeth was observed in a clinical survey. This study evaluated the wear resistance of cast CP titanium and titanium alloy teeth after the surface was modified using laser technology. Teeth patterns were duplicated from artificial first molars (Livdent FB30, GC, Japan). All teeth specimens were cast with CP Ti grade 3 (T-Alloy H, GC) and Ti-6Al-7Nb (T-Alloy Tough, GC). After the occlusal surface was blasted with Al(2)O(3), the occlusal contact points were modified using a laser (Neo laser L, Girrbach, Germany) at the following irradiation conditions (voltage: 260 V; pulse: 7 ms; focus: 1.5 mm). These parameters were determined by preliminary study. As a control, Type IV gold alloy (PGA-3, Ishifuku, Japan) was also cast conventionally. Both maxillary and mandibular teeth were worn using an in vitro two-body wear testing apparatus that simulated chewing function (60 strokes/min; grinding distance: 2 mm under flowing water). Wear resistance was assessed as volume loss (mm(3)) at 5 kgf (grinding force) after 50,000 strokes. The results (n=5) were analyzed by ANOVA/Scheffé's test (alpha=0.05). The gold alloy showed the best wear resistance of all the metals tested. Of all the titanium specimens tested, the modified surface indicated significantly greater wear resistance than did conventional titanium teeth without surface modification (p<0.05). Wear resistance was increased by modification of the surface using a laser. If severe wear of titanium teeth was observed clinically, little wear occurred when the occlusal facets were irradiated using a laser.

Enhanced photocatalytic activity of wool fibers having titanium dioxide nanoparticles formed inside their cortex

NASA Astrophysics Data System (ADS)

Zhang, Hui; Sun, Runjun; Wu, Hailiang; Mao, Ningtao

2018-07-01

A wool-TiO2 nanoparticle composite material having TiO2 nanoparticles both infiltrated in the matrix between macrofibrils inside cortical cells of wool fibers and grafted on the fiber surface is obtained in this study, and the wool-nanoparticle composite material is found to have highly photocatalytic activities with an extremely narrow band gap of 2.8 eV. The wool fibers are obtained using three successive technical steps: wool fibers are swollen by using lithium bromide, then saturated with tetrabutyl titanate ethanol solution and subsequently treated in boiling water. It was demonstrated that the chemical bonds formed between the as-synthesized TiO2 nanoparticles and the wool fibers swollen by lithium bromide include C‑Ti4+(Ti3+), N‑Ti4+(Ti3+), O‑Ti3+, and S‑Ti4+(Ti3+) bonds. The modified wool fibers have shown markedly improved photocatalytic efficiency due to their enhanced visible light absorption capability, which is much better than the (N-doped) TiO2 coated wool fibers. In contrast, TiO2 modified wool fibers swollen by using formic acid have poorer photoactivity, this might be due to the elimination of trivalent titanium between TiO2 nanoparticles and the wool fibers.

Enhanced photocatalytic activity of wool fibers having titanium dioxide nanoparticles formed inside their cortex.

PubMed

Zhang, Hui; Sun, Runjun; Wu, Hailiang; Mao, Ningtao

2018-05-01

A wool-TiO2 nanoparticle composite material having TiO2 nanoparticles both infiltrated in the matrix between macrofibrils inside cortical cells of wool fibers and grafted on the fiber surface is obtained in this study, and the wool-nanoparticle composite material is found to have highly photocatalytic activities with an extremely narrow band gap of 2.8 eV. The wool fibers are obtained using three successive technical steps: wool fibers are swollen by using lithium bromide, then saturated with tetrabutyl titanate ethanol solution and subsequently treated in boiling water. It was demonstrated that the chemical bonds formed between the as-synthesized TiO2 nanoparticles and the wool fibers swollen by lithium bromide include C-Ti4+(Ti3+), N-Ti4+(Ti3+), O-Ti3+, and S-Ti4+(Ti3+) bonds. The modified wool fibers have shown markedly improved photocatalytic efficiency due to their enhanced visible light absorption capability, which is much better than the (N-doped) TiO2 coated wool fibers. In contrast, TiO2 modified wool fibers swollen by using formic acid have poorer photoactivity, this might be due to the elimination of trivalent titanium between TiO2 nanoparticles and the wool fibers. © 2018 IOP Publishing Ltd.

40 CFR 415.225 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production... producing titanium dioxide by the sulfate process must achieve the following new source performance standards (NSPS): Subpart V—Titanium Dioxide-Sulfate Process Pollutant or pollutant property NSPS effluent...

40 CFR 415.225 - New source performance standards (NSPS).

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production... producing titanium dioxide by the sulfate process must achieve the following new source performance standards (NSPS): Subpart V—Titanium Dioxide-Sulfate Process Pollutant or pollutant property NSPS effluent...

40 CFR 415.225 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production... producing titanium dioxide by the sulfate process must achieve the following new source performance standards (NSPS): Subpart V—Titanium Dioxide-Sulfate Process Pollutant or pollutant property NSPS effluent...

40 CFR 415.225 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production... producing titanium dioxide by the sulfate process must achieve the following new source performance standards (NSPS): Subpart V—Titanium Dioxide-Sulfate Process Pollutant or pollutant property NSPS effluent...

40 CFR 415.225 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production... producing titanium dioxide by the sulfate process must achieve the following new source performance standards (NSPS): Subpart V—Titanium Dioxide-Sulfate Process Pollutant or pollutant property NSPS effluent...

Laser-Modified Surface Enhances Osseointegration and Biomechanical Anchorage of Commercially Pure Titanium Implants for Bone-Anchored Hearing Systems

PubMed Central

Omar, Omar; Simonsson, Hanna; Palmquist, Anders; Thomsen, Peter

2016-01-01

Osseointegrated implants inserted in the temporal bone are a vital component of bone-anchored hearing systems (BAHS). Despite low implant failure levels, early loading protocols and simplified procedures necessitate the application of implants which promote bone formation, bone bonding and biomechanical stability. Here, screw-shaped, commercially pure titanium implants were selectively laser ablated within the thread valley using an Nd:YAG laser to produce a microtopography with a superimposed nanotexture and a thickened surface oxide layer. State-of-the-art machined implants served as controls. After eight weeks’ implantation in rabbit tibiae, resonance frequency analysis (RFA) values increased from insertion to retrieval for both implant types, while removal torque (RTQ) measurements showed 153% higher biomechanical anchorage of the laser-modified implants. Comparably high bone area (BA) and bone-implant contact (BIC) were recorded for both implant types but with distinctly different failure patterns following biomechanical testing. Fracture lines appeared within the bone ~30–50 μm from the laser-modified surface, while separation occurred at the bone-implant interface for the machined surface. Strong correlations were found between RTQ and BIC and between RFA at retrieval and BA. In the endosteal threads, where all the bone had formed de novo, the extracellular matrix composition, the mineralised bone area and osteocyte densities were comparable for the two types of implant. Using resin cast etching, osteocyte canaliculi were observed directly approaching the laser-modified implant surface. Transmission electron microscopy showed canaliculi in close proximity to the laser-modified surface, in addition to a highly ordered arrangement of collagen fibrils aligned parallel to the implant surface contour. It is concluded that the physico-chemical surface properties of laser-modified surfaces (thicker oxide, micro- and nanoscale texture) promote bone bonding which may be of benefit in situations where large demands are imposed on biomechanically stable interfaces, such as in early loading and in compromised conditions. PMID:27299883

The bonding of protective films of amorphic diamond to titanium

NASA Astrophysics Data System (ADS)

Collins, C. B.; Davanloo, F.; Lee, T. J.; Jander, D. R.; You, J. H.; Park, H.; Pivin, J. C.

1992-04-01

Films of amorphic diamond can be deposited from laser plasma ions without the use of catalysts such as hydrogen or fluorine. Prepared without columnar patterns of growth, the layers of this material have been reported to have ``bulk'' values of mechanical properties that have suggested their usage as protective coatings for metals. Described here is a study of the bonding and properties realized in one such example, the deposition of amorphic diamond on titanium. Measurements with Rutherford backscattering spectrometry and transmission electron microscopy showed that the diamond coatings deposited from laser plasmas were chemically bonded to Ti substrates in 100-200-Å-thick interfacial layers containing some crystalline precipitates of TiC. Resistance to wear was estimated with a modified sand blaster and in all cases the coating was worn away without any rupture or deterioration of the bonding layer. Such wear was greatly reduced and lifetimes of the coated samples were increased by a factor of better than 300 with only 2.7 μm of amorphic diamond.

SURFACE HARDENING OF TITANIUM BY TREATMENT IN MOLTEN BORAX

DOE Office of Scientific and Technical Information (OSTI.GOV)

Minkevich, A.N.; Shul'ga, Yu.N.

1957-01-01

The surface hardening of titanium and titanium alloys by treatment in molten borax was investigated. Commercial titanium, a titanium-tungsten alloy, and an aluminum-chromium-titanium alloy were used for the experiments. To prevent oxidation of the titanium and to protect the surface, electro-chemical protection was applied, the current density being 0.1 amp/cm/sup 2/ and the the specimens were coated with a thin layer of borax. The results showed that treatment in molten borax is an effective method of increasing surface hardness. However, the strength, mmalleabiltiy, and toughness of the hardness increase is discussed. (J.S.R.)

Surface modification of titanium and titanium alloys by ion implantation.

PubMed

Rautray, Tapash R; Narayanan, R; Kwon, Tae-Yub; Kim, Kyo-Han

2010-05-01

Titanium and titanium alloys are widely used in biomedical devices and components, especially as hard tissue replacements as well as in cardiac and cardiovascular applications, because of their desirable properties, such as relatively low modulus, good fatigue strength, formability, machinability, corrosion resistance, and biocompatibility. However, titanium and its alloys cannot meet all of the clinical requirements. Therefore, to improve the biological, chemical, and mechanical properties, surface modification is often performed. In view of this, the current review casts new light on surface modification of titanium and titanium alloys by ion beam implantation. (c) 2010 Wiley Periodicals, Inc.

Laser bioengineering of glass-titanium implants surface

NASA Astrophysics Data System (ADS)

Lusquiños, F.; Arias-González, F.; Penide, J.; del Val, J.; Comesaña, R.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pascual, M. J.; Durán, A.; Pou, J.

2013-11-01

Osseointegration is the mean challenge when surgical treatments fight against load-bearing bone diseases. Absolute bone replacement by a synthetic implant has to be completed not only from the mechanics point of view, but also from a biological approach. Suitable strength, resilience and stress distribution of titanium alloy implants are spoiled by the lack of optimal biological characteristics. The inert quality of extra low interstitial titanium alloy, which make it the most attractive metallic alloy for biomedical applications, oppose to an ideal surface with bone cell affinity, and capable to stimulate bone attachment bone growth. Diverse laser treatments have been proven as effective tools to modify surface properties, such as wettability in contact to physiological fluids, or osteoblast guided and slightly enhanced attachment. The laser surface cladding can go beyond by providing titanium alloy surfaces with osteoconduction and osteoinduction properties. In this research work, the laser radiation is used to produce bioactive glass coatings on Ti6Al4V alloy substrates. Specific silicate bioactive glass compositions has been investigated to achieve suitable surface tension and viscosity temperature behavior during processing, and to provide with the required release of bone growth gene up regulation agents in the course of resorption mediated by physiological fluids. The produced coatings and interfaces, the surface osteoconduction properties, and the chemical species release in simulated physiological fluid were characterized by scanning electron microscopy (SEM), hot stage microscopy (HSM), X-ray diffraction (XRD), X ray fluorescence (XRF), and Fourier transform infrared spectroscopy (FTIR).

A new modification of the individually designed polymer implant visible in X-ray for orbital reconstruction.

PubMed

Jazwiecka-Koscielniak, Ewa; Kozakiewicz, Marcin

2014-10-01

Orbital reconstruction makes higher demands on symmetry and axial precision than other parts of the skull, because the position of the eye globe determines proper vision. The aim of this study is to evaluate titanium surface marking of polymers (UHMW-PE and PA6) to check implants position in CT examination and clinical application of such modified individual implant. One hundred and twenty-four polymer blocks were prepared. New method of ultrasounds welding to connect the titanium markers to the polymer surface was developed and tested. Titanium marked polymer blocks were examined by CT to evaluate the quality of the cover. Then, two modified UHMW-PE individual implants were applied clinically and implant position was checked by CT. The biggest titanium cover was in PA6 [25 ± 18% of processed surface] and for UHMW-PE [19 ± 12%] without significance [p = 0.14]. Both covers were visible in CT. Clinical application revealed proper reconstruction, uneventful post-operational outcome and well visible surface of the implants in CT. The conducted tests make it possible to determine the suitability of ultrasonic technology for the deposition of titanium markers in polymer. The clinical use of modified individual implants allows to confirm the correct position of the implants because they are accurate visible in CT. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

Induced Infiltration of Hole-Transporting Polymer into Photocatalyst for Staunch Polymer-Metal Oxide Hybrid Solar Cells.

PubMed

Park, Jong Hwan; Jung, Youngsuk; Yang, Yooseong; Shin, Hyun Suk; Kwon, Soonchul

2016-10-05

For efficient solar cells based on organic semiconductors, a good mixture of photoactive materials in the bulk heterojunction on the length scale of several tens of nanometers is an important requirement to prevent exciton recombination. Herein, we demonstrate that nanoporous titanium dioxide inverse opal structures fabricated using a self-assembled monolayer method and with enhanced infiltration of electron-donating polymers is an efficient electron-extracting layer, which enhances the photovoltaic performance. A calcination process generates an inverse opal structure of titanium dioxide (<70 nm of pore diameters) providing three-dimensional (3D) electron transport pathways. Hole-transporting polymers was successfully infiltrated into the pores of the surface-modified titanium dioxide under vacuum conditions at 200 °C. The resulting geometry expands the interfacial area between hole- and electron-transport materials, increasing the thickness of the active layer. The controlled polymer-coating process over titanium dioxide materials enhanced photocurrent of the solar cell device. Density functional theory calculations show improved interfacial adhesion between the self-assembled monolayer-modified surface and polymer molecules, supporting the experimental result of enhanced polymer infiltration into the voids. These results suggest that the 3D inverse opal structure of the surface-modified titanium dioxide can serve as a favorable electron-extracting layer in further enhancing optoelectronic performance based on organic or organic-inorganic hybrid solar cell.

Incorporation of silver nanoparticles on the surface of orthodontic microimplants to achieve antimicrobial properties

PubMed Central

Venugopal, Adith; Muthuchamy, Nallal; Tejani, Harsh; Gopalan, Anantha-Iyengar; Lee, Kwang-Pill; Lee, Heon-Jin

2017-01-01

Objective Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial. PMID:28127534

Bactericidal effects and mechanisms of visible light-responsive titanium dioxide photocatalysts on pathogenic bacteria.

PubMed

Liou, Je-Wen; Chang, Hsin-Hou

2012-08-01

This review focuses on the antibacterial activities of visible light-responsive titanium dioxide (TiO(2)) photocatalysts. These photocatalysts have a range of applications including disinfection, air and water cleaning, deodorization, and pollution and environmental control. Titanium dioxide is a chemically stable and inert material, and can continuously exert antimicrobial effects when illuminated. The energy source could be solar light; therefore, TiO(2) photocatalysts are also useful in remote areas where electricity is insufficient. However, because of its large band gap for excitation, only biohazardous ultraviolet (UV) light irradiation can excite TiO(2), which limits its application in the living environment. To extend its application, impurity doping, through metal coating and controlled calcination, has successfully modified the substrates of TiO(2) to expand its absorption wavelengths to the visible light region. Previous studies have investigated the antibacterial abilities of visible light-responsive photocatalysts using the model bacteria Escherichia coli and human pathogens. The modified TiO(2) photocatalysts significantly reduced the numbers of surviving bacterial cells in response to visible light illumination. They also significantly reduced the activity of bacterial endospores; reducing their toxicity while retaining their germinating abilities. It is suggested that the photocatalytic killing mechanism initially damages the surfaces weak points of the bacterial cells, before totally breakage of the cell membranes. The internal bacterial components then leak from the cells through the damaged sites. Finally, the photocatalytic reaction oxidizes the cell debris. In summary, visible light-responsive TiO(2) photocatalysts are more convenient than the traditional UV light-responsive TiO(2) photocatalysts because they do not require harmful UV light irradiation to function. These photocatalysts, thus, provide a promising and feasible approach for disinfection of pathogenic bacteria; facilitating the prevention of infectious diseases.

Decomposition Pathways of Titanium Isopropoxide Ti(OiPr)4: New Insights from UV-Photodissociation Experiments and Quantum Chemical Calculations.

PubMed

Ershov, Kirill S; Kochubei, Sergei A; Kiselev, Vitaly G; Baklanov, Alexey V

2018-02-01

The UV-photodissociation at 266 nm of a widely used TiO 2 precursor, titanium tetraisopropoxide (Ti(O i Pr) 4 , TTIP), was studied under molecular-beam conditions. Using the MS-TOF technique, atomic titanium and titanium(II) oxide (TiO) were detected among the most abundant photofragments. Experimental results were rationalized with the aid of quantum chemical calculations (DLPNO-CCSD(T) and DFT). Contrary to the existing data in the literature, the new four-centered acetone-elimination reaction was found to be the primary decomposition process of TTIP. According to computational results, the effective activation barrier of this channel was ∼49 kcal/mol, which was ∼13 kcal/mol lower than that of the competing propylene elimination. The former process, followed by the dissociative loss of an H atom, was a dominating channel of TTIP unimolecular decay. The sequential loss of isopropoxy moieties via these two-step processes was supposed to produce the experimentally observed titanium atoms. In turn, the combination of these reactions with propylene elimination can lead to another detected species, TiO. These results indicate that the existing mechanisms of TTIP thermal and photoinitiated decomposition in the chemical-vapor deposition (CVD) of titanium dioxide should be reconsidered.

40 CFR 415.226 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2014 CFR

2014-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide... CFR 403.7, any new source subject to this subpart and producing titanium dioxide by the sulfate... and achieve the following pretreatment standards for new sources (PSNS): Subpart V—Titanium Dioxide...

40 CFR 415.226 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2011 CFR

2011-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide... CFR 403.7, any new source subject to this subpart and producing titanium dioxide by the sulfate... and achieve the following pretreatment standards for new sources (PSNS): Subpart V—Titanium Dioxide...

40 CFR 415.226 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2012 CFR

2012-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide... CFR 403.7, any new source subject to this subpart and producing titanium dioxide by the sulfate... and achieve the following pretreatment standards for new sources (PSNS): Subpart V—Titanium Dioxide...

40 CFR 415.226 - Pretreatment standards for new sources (PSNS).

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide... CFR 403.7, any new source subject to this subpart and producing titanium dioxide by the sulfate... and achieve the following pretreatment standards for new sources (PSNS): Subpart V—Titanium Dioxide...

Assessment of morphology, topography and chemical composition of water-repellent films based on polystyrene/titanium dioxide nanocomposites

NASA Astrophysics Data System (ADS)

Bolvardi, Beleta; Seyfi, Javad; Hejazi, Iman; Otadi, Maryam; Khonakdar, Hossein Ali; Drechsler, Astrid; Holzschuh, Matthias

2017-02-01

In this study, polystyrene (PS)/titanium dioxide (TiO2) films were fabricated through simple solution casting technique via a modified phase separation process. The presented approach resulted in a remarkable reduction in the required amount of nanoparticles for achieving superhydrophobicity. Scanning electron microscopy (SEM) and 3D confocal microscopy were utilized to characterize surface morphology and topography of samples, respectively. An attempt was made to give an in-depth analysis on the surface rough structure using 3D roughness profiles. It was found that high inclusions of non-solvent and nanoparticles resulted in a stable self-cleaning behavior due to the strong presence of hydrophobic TiO2 nanoparticles on the surface. Quite unexpectedly, low inclusions of nanoparticles and non-solvent also resulted in superhydrophobic property mainly due to the proper level of induced surface roughness. XPS analysis was also utilized to determine the chemical composition of the films' surfaces. The results of falling drop experiments showed that the sample containing a higher level of nanoparticles had a much lower mechanical resistance against the induced harsh conditions. All in all, the presented method has shown promising potential in fabrication of superhydrophobic surfaces with self-cleaning behavior using the lowest content of nanoparticles.

The use of magnetron sputtering for the deposition of thin titanium coatings on the surface of bioresorbable electrospun fibrous scaffolds for vascular tissue engineering: A pilot study

NASA Astrophysics Data System (ADS)

Bolbasov, E. N.; Antonova, L. V.; Stankevich, K. S.; Ashrafov, A.; Matveeva, V. G.; Velikanova, E. A.; Khodyrevskaya, Yu. I.; Kudryavtseva, Yu. A.; Anissimov, Y. G.; Tverdokhlebov, S. I.; Barbarash, L. S.

2017-03-01

The deposition of thin titanium coatings using magnetron spattering on the surface of bioresorbable fibrous scaffolds produced by electrospinning was investigated. Parameters that allow the surface modification without damaging the "macro" structure of scaffolds were determined. Physicochemical properties of the modified scaffolds were described using SEM, EDS, DSC, optical goniometry, and mechanical testing. It was shown that plasma treatment has a significant influence on the scaffolds' fiber surface relief. The modification process leads to a slight decrease of the scaffold mechanical performance mainly caused by polymer crystallization. Increasing the deposition time increases the amount of titanium on the surface. The biocompatibility of the modified scaffolds was studied using hybridoma of the endothelial cells of human umbilical vein and human lung carcinoma (EA.hy 926 cell line). Cell adhesion, viability, and secretion of interleukin-6 (IL6), interleukin-8 (IL8), and vascular endothelial growth factor (VEGF) were investigated. It was demonstrated that the deposition of thin titanium coatings on the fibrous scaffolds' surface enhances cell adhesion. Additionally, it was determined that modified scaffolds have proangiogenic activity.

Chemical Vapor Synthesis of Titanium Aluminides by Reaction of Aluminum Subchloride and Titanium Tetrachloride

NASA Astrophysics Data System (ADS)

Zakirov, Roman A.; Parfenov, Oleg G.; Solovyov, Leonid A.

2018-02-01

A new process for developing titanium aluminides (TiAls) using chemical vapor synthesis was investigated in a laboratory experiment. Aluminum subchloride (AlCl) was used as the reducing agent in the reaction with TiCl4 and the source of aluminum for Ti-Al alloy. Two types of products, with large crystals and fine particles, were fabricated. The large crystals were determined to be TiAl, with small amounts of Ti and Ti3Al phases. The composition of fine particles, on the other hand, varied in wide range.

Crystallography and Morphology of MC Carbides in Niobium-Titanium Modified As-Cast HP Alloys

NASA Astrophysics Data System (ADS)

Buchanan, Karl G.; Kral, Milo V.; Bishop, Catherine M.

2014-07-01

The microstructures of two as-cast heats of HP alloy stainless steels modified with niobium and titanium were examined with particular attention paid to the interdendritic niobium-titanium-rich carbides formed during solidification of these alloys. Generally, these precipitates obtain a blocky morphology in the as-cast condition. However, the (NbTi)C precipitates may obtain a nodular morphology. To provide further insight to the origin of the two different morphologies obtained by the (NbTi)C precipitates in the HP-NbTi alloy, the microstructure and crystallography of each have been studied in detail using scanning electron microscopy, transmission electron microscopy, various electron diffraction methods (EBSD, SAD, and CBED), and energy-dispersive X-ray spectroscopy.

Characterization of PEG-Like Macromolecular Coatings on Plasma Modified NiTi Alloy

NASA Astrophysics Data System (ADS)

Yang, Jun; Gao, Jiacheng; Chang, Peng; Wang, Jianhua

2008-04-01

A poly (ethylene glycol) (PEG-like) coating was developed to improve the biocompatibility of Nickel-Titanium (NiTi) alloy implants. The PEG-like macromolecular coatings were deposited on NiTi substrates at a room temperature of 298 K through a ECR (electron-cyclotron resonance) cold-plasma enhanced chemical vapor deposition method using tetraglyme (CH3-O-(CH2-CH2-O)4-CH3) as a precursor. A power supply with a frequency of 2.45 GHz was applied to ignite the plasma with Ar(argon) used as the carrier gas. Based on the atomic force microscopy (AFM) studies, a thin smooth coating on NiTi substrates with highly amorphous functional groups on the modified NiTi surfaces were mainly the same accumulated stoichiometric ratio of C and O with PEG. The vitro studies showed that platelet-rich plasma (PRP) adsorption on the modified NiTi alloy surface was significantly reduced. This study indicated that plasma surface modification changes the surface components of NiTi alloy and subsequently improves its biocompatibility.

Surface modification of 17-4PH stainless steel by DC plasma nitriding and titanium nitride film duplex treatment

NASA Astrophysics Data System (ADS)

Qi, F.; Leng, Y. X.; Huang, N.; Bai, B.; Zhang, P. Ch.

2007-04-01

17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.

Investigating the Mechanisms and Potential of Silk Fiber Metallization

DTIC Science & Technology

2013-09-30

in an ALD process, when using the modified metal infiltration process as outlined by Lee et al., the titanium isopropoxide (TIP) precursor...these fibers exhibited >2-fold increase in strain to breakage, and >4.5-fold increase in strength when infiltrated with zinc, titanium , or aluminum...fibers exhibited >2-fold increase in strain to breakage, and >4.5-fold increase in strength when infiltrated with zinc, titanium , or aluminum

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability

PubMed Central

Bsat, Suzan; Amin Yavari, Saber; Munsch, Maximilian; Valstar, Edward R.; Zadpoor, Amir A.

2015-01-01

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200–300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface. PMID:28788021

Effect of Alkali-Acid-Heat Chemical Surface Treatment on Electron Beam Melted Porous Titanium and Its Apatite Forming Ability.

PubMed

Bsat, Suzan; Yavari, Saber Amin; Munsch, Maximilian; Valstar, Edward R; Zadpoor, Amir A

2015-04-08

Advanced additive manufacturing techniques such as electron beam melting (EBM), can produce highly porous structures that resemble the mechanical properties and structure of native bone. However, for orthopaedic applications, such as joint prostheses or bone substitution, the surface must also be bio-functionalized to promote bone growth. In the current work, EBM porous Ti6Al4V alloy was exposed to an alkali acid heat (AlAcH) treatment to bio-functionalize the surface of the porous structure. Various molar concentrations (3, 5, 10M) and immersion times (6, 24 h) of the alkali treatment were used to determine optimal parameters. The apatite forming ability of the samples was evaluated using simulated body fluid (SBF) immersion testing. The micro-topography and surface chemistry of AlAcH treated samples were evaluated before and after SBF testing using scanning electron microscopy and energy dispersive X-ray spectroscopy. The AlAcH treatment successfully modified the topographical and chemical characteristics of EBM porous titanium surface creating nano-topographical features ranging from 200-300 nm in size with a titania layer ideal for apatite formation. After 1 and 3 week immersion in SBF, there was no Ca or P present on the surface of as manufactured porous titanium while both elements were present on all AlAcH treated samples except those exposed to 3M, 6 h alkali treatment. An increase in molar concentration and/or immersion time of alkali treatment resulted in an increase in the number of nano-topographical features per unit area as well as the amount of titania on the surface.

In vitro characterization of peptide-modified p(AAm-co-EG/AAc) IPN-coated titanium implants.

PubMed

Barber, Thomas A; Gamble, Lara J; Castner, David G; Healy, Kevin E

2006-07-01

Interpenetrating polymer networks (IPNs) of poly(acrylamide-co-ethylene glycol/acrylic acid) [p(AAm-co-EG/AAc)] functionalized with an -Arg-Gly-Asp- containing peptide derived from rat bone sialoprotein [bsp-RGD(15)] were grafted to titanium implants in an effort to modulate osteoblast behavior in vitro. Surface characterization data were consistent with the presence of an IPN, and ligand density measurements established that the range of peptide density on the modified implants spanned three orders of magnitude (0.01-20 pmol/cm2). In vitro biological characterization of the modified implants employing the primary rat calvarial osteoblast (RCO) model resulted in the identification of a critical ligand density (0.01

Electrochemical Cathodic Polarization, a Simplified Method That Can Modified and Increase the Biological Activity of Titanium Surfaces: A Systematic Review

PubMed Central

2016-01-01

Background The cathodic polarization seems to be an electrochemical method capable of modifying and coat biomolecules on titanium surfaces, improving the surface activity and promoting better biological responses. Objective The aim of the systematic review is to assess the scientific literature to evaluate the cellular response produced by treatment of titanium surfaces by applying the cathodic polarization technique. Data, Sources, and Selection The literature search was performed in several databases including PubMed, Web of Science, Scopus, Science Direct, Scielo and EBSCO Host, until June 2016, with no limits used. Eligibility criteria were used and quality assessment was performed following slightly modified ARRIVE and SYRCLE guidelines for cellular studies and animal research. Results Thirteen studies accomplished the inclusion criteria and were considered in the review. The quality of reporting studies in animal models was low and for the in vitro studies it was high. The in vitro and in vivo results reported that the use of cathodic polarization promoted hydride surfaces, effective deposition, and adhesion of the coated biomolecules. In the experimental groups that used the electrochemical method, cellular viability, proliferation, adhesion, differentiation, or bone growth were better or comparable with the control groups. Conclusions The use of the cathodic polarization method to modify titanium surfaces seems to be an interesting method that could produce active layers and consequently enhance cellular response, in vitro and in vivo animal model studies. PMID:27441840

Characterizations of the TiO2-x films synthesized by e-beam evaporation for endovascular applications

NASA Astrophysics Data System (ADS)

Lin, Zeng; Lee, In-Seop; Choi, Yoon-Jeong; Noh, In-Sup; Chung, Sung-Min

2009-02-01

Different chemical states of titanium oxide films were deposited on commercially pure Ti (CP Ti) by electron-beam evaporation at different oxygen flow rates to examine a possibility of their applications to endovascular stents. The surface morphology, chemical composition and crystal structure of the obtained titanium oxide films were analyzed by FE-SEM, XPS and XRD, respectively. As a function of the deposition parameters employed, the obtained titanium oxide films demonstrated different mixtures of anatase phase, Ti2O3 and TiO. By the formation of titanium oxide film on the CP Ti plate, the contact angle was decreased and the cellular activity of porcine aortic smooth muscle cells was increased. Post-deposition annealing was also found to be an important factor to achieve advantageous biocompatibility. When haemocompatibility was investigated by observing adhesion of blood platelets from platelet-rich plasma, less platelet adhesion was observed on titanium oxide films. These results indicated that titanium oxide film synthesized by e-beam evaporation could be applicable to coronary stents.

In vitro biological outcome of laser application for modification or processing of titanium dental implants.

PubMed

Hindy, Ahmed; Farahmand, Farzam; Tabatabaei, Fahimeh Sadat

2017-07-01

There are numerous functions for laser in modern implant dentistry including surface treatment, surface coating, and implant manufacturing. As laser application may potentially improve osseointegration of dental implants, we systematically reviewed the literature for in vitro biological responses to laser-modified or processed titanium dental implants. The literature was searched in PubMed, ISI Web, and Scopus, using keywords "titanium dental implants," "laser," "biocompatibility," and their synonyms. After screening the 136 references obtained, 28 articles met the inclusion criteria. We found that Nd:YAG laser was the most commonly used lasers in the treatment or processing of titanium dental implants. Most of the experiments used cell attachment and cell proliferation to investigate bioresponses of the implants. The most commonly used cells in these assays were osteoblast-like cells. Only one study was conducted in stem cells. These in vitro studies reported higher biocompatibility in laser-modified titanium implants. It seems that laser radiation plays a vital role in cell response to dental implants; however, it is necessary to accomplish more studies using different laser types and parameters on various cells to offer a more conclusive result.

Mesoporous titanosilicates with high loading of titanium synthesized in mild acidic buffer solution.

PubMed

Tang, Jianting; Liu, Jian; Yang, Jie; Feng, Zhaochi; Fan, Fengtao; Yang, Qihua

2009-07-15

Mesoporous titanosilicates with high titanium content were synthesized under mild acidic conditions (pH=4.4, HAc-NaAc buffer solution) by co-condensation of acetylacetone-modified titanium isopropoxide (Ti(OBu(n))(3) (acac)) and mixture of sodium silicate with tetramethoxysilane (TMOS) or tetraethoxysilane (TEOS) or tetrakis(2-hydroxyethyl)orthosilicate (EGMS), using block copolymer Pluronic P123 as template. The combined results of XRD, N(2) sorption and TEM show that the highly regular structure of the mesoporous titanosilicates can still be obtained when Ti/Si molar ratio in the final product is as high as 0.059. The results of UV-vis diffuse reflectance spectra and UV resonance Raman spectra show that the framework titanium species are predominant in the mesoporous titanosilicates when Ti/Si molar ratio in the final product is less than 0.042. The mixture of sodium silicate and EGMS was proved to be the best silicon source for the synthesis of titanosilicates with ordered mesostructure and high titanium content. The efficiency of this synthetic method may be attributed to the mild acidic medium as well as the modified hydrolysis-condensation rate and hydrophility of the precursors.

Shadow-casted ultrathin surface coatings of titanium and titanium/silicon oxide sol particles via ultrasound-assisted deposition.

PubMed

Karahan, H Enis; Birer, Özgür; Karakuş, Kerem; Yıldırım, Cansu

2016-07-01

Ultrasound-assisted deposition (USAD) of sol nanoparticles enables the formation of uniform and inherently stable thin films. However, the technique still suffers in coating hard substrates and the use of fast-reacting sol-gel precursors still remains challenging. Here, we report on the deposition of ultrathin titanium and titanium/silicon hybrid oxide coatings using hydroxylated silicon wafers as a model hard substrate. We use acetic acid as the catalyst which also suppresses the reactivity of titanium tetraisopropoxide while increasing the reactivity of tetraethyl orthosilicate through chemical modifications. Taking the advantage of this peculiar behavior, we successfully prepared titanium and titanium/silicon hybrid oxide coatings by USAD. Varying the amount of acetic acid in the reaction media, we managed to modulate thickness and surface roughness of the coatings in nanoscale. Field-emission scanning electron microscopy and atomic force microscopy studies showed the formation of conformal coatings having nanoroughness. Quantitative chemical state maps obtained by x-ray photoelectron spectroscopy (XPS) suggested the formation of ultrathin (<10nm) coatings and thickness measurements by rotating analyzer ellipsometry supported this observation. For the first time, XPS chemical maps revealed the transport effect of ultrasonic waves since coatings were directly cast on rectangular substrates as circular shadows of the horn with clear thickness gradient from the center to the edges. In addition to the progress made in coating hard substrates, employing fast-reacting precursors and achieving hybrid coatings; this report provides the first visual evidence on previously suggested "acceleration and smashing" mechanism as the main driving force of USAD. Copyright © 2016 Elsevier B.V. All rights reserved.

The chemical and mechanical effects of binding chitosan to implant quality titanium

NASA Astrophysics Data System (ADS)

Martin, Holly Joy

Biomedical implants are commonly made from commercially pure titanium and other metal alloys, which are chosen for their strength and density. To improve the stability and promote bone cell growth into the implant, efforts to bond coatings to metal have been extensively studied. Many coatings used are considered bioactive, which promote the adhesion and growth of the bone cells surrounding the implant [A.1]. Of these, the most commonly investigated coating is a ceramic called hydroxyapatite, which is brittle, leading to flaking and inadequate bone cell growth [A.2]. Alternate bioactive coatings are being examined, including chitosan, the deacetylated form of chitin. Chitin is the second most abundant polymer in nature [A.3] and is found in the exoskeletons of insects and shellfish [A.4]. Chitosan has been proven to have excellent biocompatibility [A.5], be non-toxic [A.3], and promote the adhesion and growth of bone cells [A.6 - A.7]. In this research, four treatment combinations were developed and tested in an attempt to improve film bonding. These treatment combinations were created using one of two silane molecules, aminopropyltriethoxysilane and triethoxsilylbutyraldehyde, and one of two metal treatments, passivation and piranha treatment. XPS was used to characterize the reaction steps for each of the treatment combinations. A significant decrease in TiO, along with significant increases in SiO x groups, C - N - H, and C = O, indicated that the reactions were proceeding as expected. XPS also indicated that, chemically, the chitosan films were not significantly different and were unchanged by the treatment combinations. Following chemical analysis, mechanical testing was performed on the four treatment combinations. No changes to the bulk properties were seen as demonstrated by nano-indentation, further indicating that the four treatment combinations did not change the chemical properties of chitosan. The bulk adhesion of the films was greatly improved for all four treatment combinations, as demonstrated by tensile testing. The highest value from this research, 19.50 +/- 1.63 MPa, was significantly higher than the previously published results of 1.6-1.8 MPa [A.10]. Overall, the treatments developed in this study significantly improved the adhesion of the chitosan film on the titanium substrate, without modifying the chemical or structural properties of chitosan.

The hydrogen embrittlement of titanium-based alloys

NASA Astrophysics Data System (ADS)

Tal-Gutelmacher, Ervin; Eliezer, Dan

2005-09-01

Titanium-based alloys provide an excellent combination of a high strength/weight ratio and good corrosion behavior, which makes these alloys among the most important advanced materials for a variety of aerospace, marine, industrial, and commercial applications. Although titanium is considered to be reasonably resistant to chemical attack, severe problems can arise when titanium-based alloys come in contact with hydrogen-containing environments, where they can pick up large amounts of hydrogen, especially at elevated temperatures. The severity and the extent of the hydrogen interaction with titanium-based alloys are directly related to the microstructure and composition of the titanium alloys. This paper addresses the hydrogen embrittlement of titanium-based alloys. The hydrogen-titanium interaction is reviewed, including the solubility of hydrogen in α and β phases of titanium and hydride formation. Also, the paper summarizes the detrimental effects of hydrogen in different titanium alloys.

Cobalt and Yttrium Modified TiO2 Nanotubes Based Dye-Sensitized Solar Cells for Solar-Energy Conversion

NASA Astrophysics Data System (ADS)

Shabanov, N. S.; Isaev, A. B.; Orudzhev, F. F.; Murliev, E. K.

2018-01-01

The solar-energy conversion in eosin-sensitized solar cells based on cobalt and yttrium modified TiO2 nanotubes has been studied.It is established that the doping with metal ions shifts the absorption edge for Co and Y doped titanium dioxide samples to longer and shorter wavelengths, respectively. The efficiency of solar energy conversion depends on the wide bandgap of the semiconductor anode and reaches a maximum (4.4%) for yttrium-doped TiO2 in comparison to that (4.1%) for pure titanium dioxide.

Effect of zirconium nitride physical vapor deposition coating on preosteoblast cell adhesion and proliferation onto titanium screws.

PubMed

Rizzi, Manuela; Gatti, Giorgio; Migliario, Mario; Marchese, Leonardo; Rocchetti, Vincenzo; Renò, Filippo

2014-11-01

Titanium has long been used to produce dental implants. Problems related to its manufacturing, casting, welding, and ceramic application for dental prostheses still limit its use, which highlights the need for technologic improvements. The aim of this in vitro study was to evaluate the biologic performance of titanium dental implants coated with zirconium nitride in a murine preosteoblast cellular model. The purpose of this study was to evaluate the chemical and morphologic characteristics of titanium implants coated with zirconium nitride by means of physical vapor deposition. Chemical and morphologic characterizations were performed by scanning electron microscopy and energy dispersive x-ray spectroscopy, and the bioactivity of the implants was evaluated by cell-counting experiments. Scanning electron microscopy and energy dispersive x-ray spectroscopy analysis found that physical vapor deposition was effective in covering titanium surfaces with zirconium nitride. Murine MC-3T3 preosteoblasts were seeded onto titanium-coated and zirconium nitride-coated screws to evaluate their adhesion and proliferation. These experiments found a significantly higher number of cells adhering and spreading onto zirconium nitride-coated surfaces (P<.05) after 24 hours; after 7 days, both titanium and zirconium nitride surfaces were completely covered with MC-3T3 cells. Analysis of these data indicates that the proposed zirconium nitride coating of titanium implants could make the surface of the titanium more bioactive than uncoated titanium surfaces. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Research of obtaining TiO2 by sol-gel method using titanium isopropoxide TIP and tetra-n-butyl orthotitanate TNB

NASA Astrophysics Data System (ADS)

Gómez de Salazar, J. M.; Nutescu Duduman, C.; Juárez Gonzalez, M.; Palamarciuc, I.; Barrena Pérez, M. I.; Carcea, I.

2016-08-01

Titanium dioxide crystallises in three polymorphs: anatase, rutile and brookite. Rutile is most stable form of the TiO2 polymorphs. In this paper we concentrate on obtaining rutile and anatase, both used in various applications. The chosen method is sol-gel, which is a reliable method used for obtaining titanium oxides. We prepared titanium dioxide with using titanium isopropoxide (TIP) with chemical construction (C12H28O4Ti) and tetra-n-butyl orthotitanate (TNB) with chemical construction (C16H36O4Ti). The experiments were carried out in order to compare the results of the samples with similar reaction conditions, but with different precursors, thus concluding which precursor gives best results. Using different analysis techniques as X-ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Thermogravimetric Analysis (TGA) we characterised the samples morphologically and structurally.

Effect of titanium on the creep deformation behaviour of 14Cr-15Ni-Ti stainless steel

NASA Astrophysics Data System (ADS)

Latha, S.; Mathew, M. D.; Parameswaran, P.; Nandagopal, M.; Mannan, S. L.

2011-02-01

14Cr-15Ni-Ti modified stainless steel alloyed with additions of phosphorus and silicon is a potential candidate material for the future cores of Prototype Fast Breeder Reactor. In order to optimise the titanium content in this steel, creep tests have been conducted on the heats with different titanium contents of 0.18, 0.23, 0.25 and 0.36 wt.% at 973 K at various stress levels. The stress exponents indicated that the rate controlling deformation mechanism was dislocation creep. A peak in the variation of rupture life with titanium content was observed around 0.23 wt.% titanium and the peak was more pronounced at lower stresses. The variation in creep strength with titanium content was correlated with transmission electron microscopic investigations. The peak in creep strength exhibited by the material with 0.23 wt.% titanium is attributed to the higher volume fraction of fine secondary titanium carbide (TiC) precipitates.

Erosion-resistant composite material

DOEpatents

Finch, C.B.; Tennery, V.J.; Curlee, R.M.

A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

Photofunctionalization of Titanium: An Alternative Explanation of Its Chemical-Physical Mechanism

PubMed Central

Pompella, Alfonso; Kubacki, Jerzy; Szade, Jacek; Roy, Robert A.; Hedzelek, Wieslaw

2016-01-01

Objectives To demonstrate that titanium implant surfaces as little as 4 weeks from production are contaminated by atmospheric hydrocarbons. This phenomenon, also known as biological ageing can be reversed by UVC irradiation technically known as photofunctionalization. To propose a new model from our experimental evidence to explain how the changes in chemical structure of the surface will affect the adsorption of amino acids on the titanium surface enhancing osteointegration. Methods In our study XPS and AES were used to analyze the effects of UVC irradiation (photofunctionalization) in reversing biological ageing of titanium. SEM was used to analyze any possible effects on the topography of the surface. Results UVC irradiation was able to reverse biological ageing of titanium by greatly reducing the amount of carbon contamination present on the implant surface by up to 4 times, while the topography of the surface was not affected. UVC photon energy reduces surface H2O and increases TiOH with many –OH groups being produced. These groups explain the super-hydrophilic effect from photofunctionalization when these groups come into contact with water. Significance Photofunctionalization has proven to be a valid method to reduce the amount of hydrocarbon contamination on titanium dental implants and improve biological results. The chemisorption mechanisms of amino acids, in our study, are dictated by the chemical structure and electric state present on the surface, but only in the presence of an also favourable geometrical composition at the atomical level. PMID:27309723

Stress corrosion in titanium alloys and other metallic materials

NASA Technical Reports Server (NTRS)

Harkins, C. G. (Editor); Brotzen, F. R.; Hightower, J. W.; Mclellan, R. B.; Roberts, J. M.; Rudee, M. L.; Leith, I. R.; Basu, P. K.; Salama, K.; Parris, D. P.

1971-01-01

Multiple physical and chemical techniques including mass spectroscopy, atomic absorption spectroscopy, gas chromatography, electron microscopy, optical microscopy, electronic spectroscopy for chemical analysis (ESCA), infrared spectroscopy, nuclear magnetic resonance (NMR), X-ray analysis, conductivity, and isotopic labeling were used in investigating the atomic interactions between organic environments and titanium and titanium oxide surfaces. Key anhydrous environments studied included alcohols, which contain hydrogen; carbon tetrachloride, which does not contain hydrogen; and mixtures of alcohols and halocarbons. Effects of dissolved salts in alcohols were also studied. This program emphasized experiments designed to delineate the conditions necessary rather than sufficient for initiation processes and for propagation processes in Ti SCC.

Color Anodizing of Titanium Coated Rolled Carbon Steel Plate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sarajan, Zohair; Mobarakeh, Hooman Nikbakht; Namiranian, Sohrab

As an important kind of structural materials, the titanium cladded steel plates have the advantages of both metals and have been applied in aviation, spaceflight, chemical and nuclear industries. In this study, the specimens which were prepared under soldering mechanism during rolling were anodized by electrochemical process under a given conditions. The color anodizing takes place by physical phenomenon of color interference. Part of incident light on the titanium oxide is reflected and the other part reflects inside coated titanium layer. Major part of the light which reflects from titanium-oxide interface, reflects again inside of the oxide layer.

Titanium: light, strong, and white

USGS Publications Warehouse

Woodruff, Laurel; Bedinger, George

2013-01-01

Titanium (Ti) is a strong silver-gray metal that is highly resistant to corrosion and is chemically inert. It is as strong as steel but 45 percent lighter, and it is twice as strong as aluminum but only 60 percent heavier. Titanium dioxide (TiO2) has a very high refractive index, which means that it has high light-scattering ability. As a result, TiO2 imparts whiteness, opacity, and brightness to many products. ...Because of the unique physical properties of titanium metal and the whiteness provided by TiO2, titanium is now used widely in modern industrial societies.

Effect of plastic-covered ultrasonic scalers on titanium implant surfaces.

PubMed

Mann, M; Parmar, D; Walmsley, A D; Lea, S C

2012-01-01

Maintaining oral health around titanium implants is essential. The formation of a biofilm on the titanium surface will influence the continuing success of the implant. These concerns have led to modified ultrasonic scaler instruments that look to reduce implant damage while maximising the cleaning effect. This study aimed to assess the effect of instrumentation, with traditional and modified ultrasonic scalers, on titanium implant surfaces and to correlate this with the oscillations of the instruments. Two ultrasonic insert designs (metallic TFI-10 and a plastic-tipped implant insert) were selected. Each scaler probe was scanned using a scanning laser vibrometer, under loaded and unloaded conditions, to determine their oscillation characteristics. Loads were applied against a titanium implant (100g and 200 g) for 10 s. The resulting implant surfaces were then scanned using laser profilometry and scanning electron microscopy (SEM). Insert probes oscillated with an elliptical motion with the maximum amplitude at the probe tip. Laser profilometry detected defects in the titanium surface only for the metallic scaler insert. Defect widths at 200 g high power were significantly larger than all other load/power conditions (P<0.02). Using SEM, it was observed that modifications to the implant surface had occurred following instrumentation with the plastic-tipped insert. Debris was also visible around the defects. Metal scalers produce defects in titanium implant surfaces and load and power are important factors in the damage caused. Plastic-coated scaler probes cause minimal damage to implant surfaces and have a polishing action but can leave plastic deposits behind on the implant surface. © 2011 John Wiley & Sons A/S.

Controlled electro-implementation of fluoride in titanium implant surfaces enhances cortical bone formation and mineralization.

PubMed

Taxt-Lamolle, Sébastien F; Rubert, Marina; Haugen, Håvard J; Lyngstadaas, Ståle Petter; Ellingsen, Jan Eirik; Monjo, Marta

2010-03-01

Previous studies have shown that bone-to-implant attachment of titanium implants to cortical bone is improved when the surface is modified with hydrofluoric acid. The aim of this study was to investigate if biological factors are involved in the improved retention of these implants. Fluoride was implemented in implant surfaces by cathodic reduction with increasing concentrations of HF in the electrolyte. The modified implants were placed in the cortical bone in the tibias of New Zealand white rabbits. After 4 weeks of healing, wound fluid collected from the implant site showed lower lactate dehydrogenase activity and less bleeding in fluoride-modified implants compared to control. A significant increase in gene expression levels of osteocalcin and tartrate-resistant acid phosphatase (TRAP) was found in the cortical bone attached to Ti implants modified with 0.001 and 0.01 vol.% HF, while Ti implants modified with 0.1% HF showed only induced TRAP mRNA levels. These results were supported by the performed micro-CT analyses. The volumetric bone mineral density of the cortical bone hosting Ti implants modified with 0.001% and 0.01% HF was higher both in the newly woven bone (<100 microm from the interface) and in the older Haversian bone (>100 microm). In conclusion, the modulation of these biological factors by surface modification of titanium implants with low concentrations of HF using cathodic reduction may explain their improved osseointegration properties. Copyright 2009 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Research to Conduct an Exploratory Experimental and Analytical Investigation of Alloys

DTIC Science & Technology

1978-03-01

d« (f n«r««a«rv on« 149*111* hv *l«c* f*u0«««> Titanium Aluminides , Alloy Development, Mechemical Properties, Powder Metallurgy, Forging, Joining...Ccmpcsition of Titanium 79 Aluminida Alloy 9 Nuclear Metals Reported REP Titanium 80 Aluminide Powder Size Distribution 10 Phase I, Task I...137 141 24 Chemical Composition of Titanium Aluminide Alloy TMCA Heat 75301 Ti-13.5Al-21.4Nb 25 Isothermal Forging Results 26 Tensile Results

Relating Chemical and Topographical Modification of Materials to Macroscopic Adhesion

DTIC Science & Technology

2011-11-14

CFRP, T800H/3900-2) and titanium alloy (Ti- 6Al - 4V ) surfaces are presented, before and after surface treatment, using a number of surface...Experimental: Titanium alloy (Ti- 6Al - 4V , an alloy consisting of 90% titanium , 6% aluminum and 4% vanadium, 0.063" thick) was purchased from...spectrum indicates a dramatic decrease in oxygen content and a concomitant increase in titanium metal alloy (Ti- 6Al - 4V ) at the surface. This

A study on the production of titanium carbide nano-powder in the nanostate and its properties

NASA Astrophysics Data System (ADS)

Shiryaeva, L. S.; Rudneva, S. V.; Galevsky, G. V.; Garbuzova, A. K.

2016-09-01

The plasma synthesis of titanium carbide nano-powder in the conditions close to industrial was studied. Titanium carbide TiC is a wear- and corrosion-resistant, hard, chemically inert material, demanded in various fields for the production of hard alloys, metal- ceramic tools, heat-resistant products, protective metal coatings. New perspectives for application titanium carbide in the nanostate can be found in the field of alloys modification with different composition and destination.

Titanium-based zeolitic imidazolate framework for chemical fixation of carbon dioxide

EPA Science Inventory

A titanium-based zeolitic imidazolate framework (Ti-ZIF) with high surface area and porous morphology was synthesized and itsefficacy was demonstrated in the synthesis of cyclic carbonates from epoxides and carbon dioxide.

Loose nanofiltration membrane for dye/salt separation through interfacial polymerization with in-situ generated TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Zhang, Qi; Fan, Lin; Yang, Zhen; Zhang, Runnan; Liu, Ya-nan; He, Mingrui; Su, Yanlei; Jiang, Zhongyi

2017-07-01

In this study, a high flux nanofiltration (NF) membrane with hybrid polymer-nanoparticle active layer was fabricated by chemical crosslinking of piperazine (PIP) and 1, 3, 5-benzene tricarbonyl trichloride (TMC). An in-situ generated method was applied to deposit titanium dioxide (TiO2) nanoparticles uniformly on the membrane surface, leading to the enhancement of the surface hydrophilicity, roughness and relative surface area of the polyamide (PA) layer. The morphology of the modified membrane was investigated by scanning electron microscopy (SEM) and Atomic force microscopy (AFM), also energy dispersive X-ray microanalysis (EDX) was used to analyze the distribution of Ti element. Chemical structure was observed by Fourier transmission infrared attenuated total reflectance (FTIR-ATR) spectroscopy. Remarkably, the optimal water flux of the loose NF membrane was 65.0 Lm-2 h-1 bar-1 nearly 5 times as much as the pure PA membrane flux. The rejections of the loose NF membranes for dyes were almost all greater than 95.0%, while the rejection for sodium sulfate (Na2SO4) was only about 17.0%, which indicated that the modified membrane had an impressive potential application for dye desalination and purification.

Mesoporous TiO2 and copper-modified TiO2 nanoparticles: A case study

NASA Astrophysics Data System (ADS)

Ajay Kumar, R.; Vasavi Dutt, V. G.; Rajesh, Ch.

2018-02-01

In this paper we report the synthesis of mesoporous titanium dioxide (M-TiO2) nanoparticles (NPs) and copper (Cu)-modified M-TiO2 NPs by the hydrothermal method at relatively low temperatures using cetyltrimethylammonium bromide (CTAB) as a template. In order to get ordered spherical particles and better interaction between cationic and anionic precursor, we have used titanium isopropoxide (TTIP) as titanium source and CTAB as surfactant. The process of modification by copper to M-TiO2 follows the impregnation method. The change in structural and optical properties of NPs were estimated using different characterization techniques like X-ray diffraction, field emission scanning electron microscopy, Brunner-Emmett-Teller curve and UV-Vis absorption analysis. M-TiO2 and Cu-modified M-TiO2 exhibit pure anatase crystalline phase and shows no evidence of CuO formation. Nitrogen adsorption-desorption hysteresis reveals that the material is mesoporous. Several samples synthesized at different process temperature were further studied in order to make them suitable for a wide range of applications.

Enhancing antimicrobial activity of TiO2/Ti by torularhodin bioinspired surface modification.

PubMed

Ungureanu, Camelia; Dumitriu, Cristina; Popescu, Simona; Enculescu, Monica; Tofan, Vlad; Popescu, Marian; Pirvu, Cristian

2016-02-01

Implant-associated infections are a major cause of morbidity and mortality. This study was performed using titanium samples coated by anodization with a titanium dioxide (TiO2) shielded nanotube layer. TiO2/Ti surface was modified by simple immersion in torularhodin solution and by using a mussel-inspired method based on polydopamine as bio adhesive for torularhodin immobilization. SEM analysis revealed tubular microstructures of torularhodin and the PDA ability to function as a catchy anchor between torularhodin and TiO2 surface. Corrosion resistance was associated with TiO2 barrier oxide layer and nano-organized oxide layer and the torularhodin surface modification does not bring significant changes in resistance of the oxide layer. Our results demonstrated that the torularhodin modified TiO2/Ti surface could effectively prevent adhesion and proliferation of Escherichia coli, Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and Pseudomonas aeruginosa. The new modified titanium surface showed good biocompatibility and well-behaved haemocompatibility. This biomaterial with enhanced antimicrobial activity holds great potential for future biomedical applications. Copyright © 2015 Elsevier B.V. All rights reserved.

Chemical analysis of extracting transition metal oxides from polymetallic ore by sulphate process

NASA Astrophysics Data System (ADS)

Enkh-Uyanga, Otgon-Uul; Munkhtsetseg, Baatar; Urangoo, Urtnasan; Tserendulam, Enkhtur; Agiimaa, Davaadorj

2017-06-01

In this research work we attempt to improve the purity of polymetallic ores in Mongolia whilst developing practical applications of its refinement processes and this paper presents the results of chemical research of extracting transition metal titanium oxides, ferrous oxide and rare earth oxides from polymetallic ore. Thereby, chemical and mineral analysis of polymetallic ore is carried out basis of responses to the support process at various degrees of water whereas transition metal sulphates solubility differ. As a result of sulphate and resulphurization process we have extracted anatase with 62.5 percent titanium dioxide and brookite mineral with 89.6 percent of titanium dioxide as well as mineral with 83.8 percent of ferrous oxide hematite and rare earth oxides with 57.6 percent of cerium oxide. These oxides are identified under various conditions in the thermal processing. The morphology structure and chemical content compound of the mineral has been verified as a result of the XRF, XRD, SEM-EDX analysis.

Photocatalytic removal of polychlorinated biphenyls (PCBs) using carbon-modified titanium oxide nanoparticles

NASA Astrophysics Data System (ADS)

Shaban, Yasser A.; El Sayed, Mohamed A.; El Maradny, Amr A.; Al Farawati, Radwan Kh.; Al Zobidi, Mosa I.; Khan, Shahed U. M.

2016-03-01

In this work, the sonicated sol-gel method was used for synthesizing carbon-modified titanium oxide nanoparticles. Carbon incorporation was achieved by using titanium (IV) isopropoxide as a titanium and carbon-containing precursor. The photocatalytic efficiency of the synthesized photocatalyst was assessed by examining the photocatalytic removal of polychlorinated biphenyls (PCBs) from aqueous solution. For comparison, unmodified (regular) titanium dioxide (n-TiO2) was used as a reference catalyst. To confirm the carbon incorporation in CM-n-TiO2 nanoparticles, energy dispersive spectroscopy (EDS) analysis was used. Significantly, the bandgap energy was found to be reduced from 2.99 eV for n-TiO2 to 1.8 eV for CM-n-TiO2, which in turn improved the performance of CM-n-TiO2 toward the photocatalytic removal of PCBs. The effects of CM-n-TiO2 loading, PCBs concentration, and pH of the solution on the photodegradation rate of PCBs were investigated. The highest removal rate was found to be at pH 5 and CM-n-TiO2 loading of 0.5 g L-1. According to Langmuir-Hinshelwood model, the photodegradation of PCBs using CM-n-TiO2 followed a pseudo-first order reaction kinetics.

Effect of Novel Quercetin Titanium Dioxide-Decorated Multi-Walled Carbon Nanotubes Nanocomposite on Bacillus subtilis Biofilm Development

PubMed Central

Raie, Diana S.; Mhatre, Eisha; El-Desouki, Doaa S.; Labena, Ahmed; El-Ghannam, Gamal; Farahat, Laila A.; Youssef, Tareq; Fritzsche, Wolfgang; Kovács, Ákos T.

2018-01-01

The present work was targeted to design a surface against cell seeding and adhering of bacteria, Bacillus subtilis. A multi-walled carbon nanotube/titanium dioxide nano-power was produced via simple mixing of carbon nanotube and titanium dioxide nanoparticles during the sol-gel process followed by heat treatment. Successfully, quercetin was immobilized on the nanocomposite via physical adsorption to form a quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite. The adhesion of bacteria on the coated-slides was verified after 24 h using confocal laser-scanning microscopy. Results indicated that the quercetin/multi-walled carbon nanotube/titanium dioxide nanocomposite had more negativity and higher recovery by glass surfaces than its counterpart. Moreover, coating surfaces with the quercetin-modified nanocomposite lowered both hydrophilicity and surface-attached bacteria compared to surfaces coated with the multi-walled carbon nanotubes/titanium dioxide nanocomposite. PMID:29346268

The Evaluation of High Temperature Adhesive Bonding Processes for Rocket Engine Combustion Chamber Applications

NASA Technical Reports Server (NTRS)

McCray, Daniel; Smith, Jeffrey; Rice, Brian; Blohowiak, Kay; Anderson, Robert; Shin, E. Eugene; McCorkle, Linda; Sutter, James

2003-01-01

NASA Glenn Research Center is currently evaluating the possibility of using high- temperature polymer matrix composites to reinforce the combustion chamber of a rocket engine. One potential design utilizes a honeycomb structure composed of a PMR-II- 50/M40J 4HS composite facesheet and titanium honeycomb core to reinforce a stainless steel shell. In order to properly fabricate this structure, adhesive bond PMR-II-50 composite. Proper prebond surface preparation is critical in order to obtain an acceptable adhesive bond. Improperly treated surfaces will exhibit decreased bond strength and durability, especially in metallic bonds where interface are susceptible to degradation due to heat and moisture. Most treatments for titanium and stainless steel alloys require the use of strong chemicals to etch and clean the surface. This processes are difficult to perform due to limited processing facilities as well as safety and environmental risks and they do not consistently yield optimum bond durability. Boeing Phantom Works previously developed sol-gel surface preparations for titanium alloys using a PETI-5 based polyimide adhesive. In support of part of NASA Glenn Research Center, UDRI and Boeing Phantom Works evaluated variations of this high temperature sol-gel surface preparation, primer type, and primer cure conditions on the adhesion performance of titanium and stainless steel using Cytec FM 680-1 polyimide adhesive. It was also found that a modified cure cycle of the FM 680-1 adhesive, i.e., 4 hrs at 370 F in vacuum + post cure, significantly increased the adhesion strength compared to the manufacturer's suggested cure cycle. In addition, the surface preparation of the PMR-II-50 composite was evaluated in terms of surface cleanness and roughness. This presentation will discuss the results of strength and durability testing conducted on titanium, stainless steel, and PMR-II-50 composite adherends to evaluate possible bonding processes.

Gentamicin coating of plasma chemical oxidized titanium alloy prevents implant-related osteomyelitis in rats.

PubMed

Diefenbeck, M; Schrader, C; Gras, F; Mückley, T; Schmidt, J; Zankovych, S; Bossert, J; Jandt, K D; Völpel, A; Sigusch, B W; Schubert, H; Bischoff, S; Pfister, W; Edel, B; Faucon, M; Finger, U

2016-09-01

Implant related infection is one of the most feared and devastating complication associated with the use of orthopaedic implant devices. Development of anti-infective surfaces is the main strategy to prevent implant contamination, biofilm formation and implant related osteomyelitis. A second concern in orthopaedics is insufficient osseointegration of uncemented implant devices. Recently, we reported on a macroporous titanium-oxide surface (bioactive TiOB) which increases osseointegration and implant fixation. To combine enhanced osseointegration and antibacterial function, the TiOB surfaces were, in addition, modified with a gentamicin coating. A rat osteomyelitis model with bilateral placement of titanium alloy implants was employed to analyse the prophylactic effect of gentamicin-sodiumdodecylsulfate (SDS) and gentamicin-tannic acid coatings in vivo. 20 rats were randomly assigned to four groups: (A) titanium alloy; PBS inoculum (negative control), (B) titanium alloy, Staphylococcus aureus inoculum (positive control), (C) bioactive TiOB with gentamicin-SDS and (D) bioactive TiOB plus gentamicin-tannic acid coating. Contamination of implants, bacterial load of bone powder and radiographic as well as histological signs of implant-related osteomyelitis were evaluated after four weeks. Gentamicin-SDS coating prevented implant contamination in 10 of 10 tibiae and gentamicin-tannic acid coating in 9 of 10 tibiae (infection prophylaxis rate 100% and 90% of cases, respectively). In Group (D) one implant showed colonisation of bacteria (swab of entry point and roll-out test positive for S. aureus). The interobserver reliability showed no difference in the histologic and radiographic osteomyelitis scores. In both gentamicin coated groups, a significant reduction of the histological osteomyelitis score (geometric mean values: C = 0.111 ± 0.023; D = 0.056 ± 0.006) compared to the positive control group (B: 0.244 ± 0.015; p < 0.05) was observed. The radiographic osteomyelitis scores confirmed these histological findings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Impedimetric PSA aptasensor based on the use of a glassy carbon electrode modified with titanium oxide nanoparticles and silk fibroin nanofibers.

PubMed

Benvidi, Ali; Banaei, Maryam; Tezerjani, Marzieh Dehghan; Molahosseini, Hosein; Jahanbani, Shahriar

2017-12-14

This article describes an impedimetric aptasensor for the prostate specific antigen (PSA), a widely accepted prostate cancer biomarker. A glassy carbon electrode (GCE) was modified with titanium oxide nanoparticles (TiO 2 ) and silk fibroin nanofiber (SF) composite. The aptasensor was obtained by immobilizing a PSA-binding aptamer on the AuNP-modified with 6-mercapto-1-hexanol. The single fabrication steps were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The assay has two linear response ranges (from 2.5 fg.mL -1 to 25 pg.mL -1 , and from 25 pg.mL -1 to 25 ng.mL -1 ) and a 0.8 fg.mL -1 detection limit. After optimization of experimental conditions, the sensor is highly selective for PSA over bovine serum albumin and lysozyme. It was successfully applied to the detection of PSA in spiked serum samples. Graphical abstract Schematic of the fabrication of an aptasensor for the prostate specific antigen (PSA). It is based on the use of a glassy carbon electrode modified with gold nanoparticles and titanium oxide-silk fibroin. The immobilization process of aptamer and interaction with PSA were followed by electrochemical impedance spectroscopy technique.

Effects of different titanium zirconium implant surfaces on initial supragingival plaque formation.

PubMed

John, Gordon; Becker, Jürgen; Schwarz, Frank

2017-07-01

The aim of the current study was the evaluation of biofilm development on different implant surfaces. Initial biofilm formation was investigated on five different implant surfaces, machined titanium (MTi), modified machined acid-etched titanium (modMATi), machined titanium zirconium (MTiZr), modified machined and acid-etched titanium zirconium (modMATiZr) and sandblasted large grid and acid-etched titanium zirconium surface (SLATiZr) for 24 and 48 h. Biocompatibility was tested after tooth brushing of the samples via cell viability testing with human gingival fibroblasts. After 24 h of biofilm collection, mean plaque surface was detected in the following descending order: After 24 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. Both M surfaces showed significant higher biofilm formation than the other groups. After 48 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. After tooth brushing: SLATiZr > modMATi > modMATiZr > MTi > MTiZr. All native samples depicted significant higher cell viability than their corresponding surfaces after biofilm removal procedure. The TiZr groups especially the modMATiZr group showed slower and less biofilm formation. In combination with the good biocompatibility, both modMA surfaces seem to be interesting candidates for surfaces in transgingival implant design. © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Manufacturing Chemical Equipment from Titanium - USSR

DTIC Science & Technology

1960-05-25

hydrochloric, sulfuric and orthophosphoric, oxalic, trichlor- and tri-flour- acetic acids , and of boiling solutions of formic and citric acids . Nor...sulfofrezon and oleinic acid . Titanium dust is explosive , therefore only wet grinding is being used. The cooling is done either by a ten percent solution of...pumping ore of various organic acids , solutions of chlorides, and of moderately concentrated hydrochloric acid.are made of titanium. Such apparatus

Characterization of a new stationary phase based on microwave immobilized polybutadiene on titanium oxide-modified silica.

PubMed

Morais, Lais S R; Jardim, Isabel C S F

2005-05-06

Titanium oxide-modified silica was prepared by reaction of silica with titanium tetrabutoxide and then was used as support in the preparation of stationary phases with self-immobilized polybutadiene (PBD) and PBD immobilized through microwave radiation. Chromatographic performance of the stationary phases was evaluated in terms of the efficiency (plates/m), asymmetry (A(s)), retention factor (k) and resolution (R(s)) of two standard sample mixtures, one of then containing the basic compound N,N-dimethylaniline. A microwave irradiation of 30 min at 520 W gave the best efficiency (86,500 N m(-1)), greater than that of a 6-day self immobilized phase (69,500 N m(-1)). Self-immobilized stationary phases prepared with bare silica were also studied for comparison. These resulted in lower chromatographic performance, 43,800 N m(-1), when compared to the self-immobilized phase prepared with titanized silica.

Germination and early plant development of ten plant species exposed to titanium dioxide and cerium oxide nanoparticles

EPA Science Inventory

Ten agronomic plant species were exposed to different concentrations of nano titanium dioxide (nTiO2) or nano cerium oxide (nCeO2) (0, 250, 500 and 1000 mg/L) to examine potential effects on germination and early seedling development. We modified a standard test protocol develop...

Three-dimensionally ordered macroporous (3DOM) gold-nanoparticle-doped titanium dioxide (GTD) photonic crystals modified electrodes for hydrogen peroxide biosensor.

PubMed

Li, Jianlin; Han, Tao; Wei, Nannan; Du, Jiangyan; Zhao, Xiangwei

2009-12-15

Gold nanoparticles have been introduced into the wall framework of titanium dioxide photonic crystals by the colloidal crystal template technique. The three-dimensionally ordered macroporous gold-nanoparticle-doped titanium dioxide (3DOM GTD) film was modified on the indium-tin oxide (ITO) electrode surface and used for the hydrogen peroxide biosensor. The direct electron transfer and electrocatalysis of horseradish peroxidase (HRP) immobilized on this film have been investigated. The 3DOM GTD film could provide a good microenvironment for retaining the biological bioactivity, large internal area, and superior conductivity. The HRP/3DOM GTD/ITO electrode exhibited two couples of redox peaks corresponding to the HRP intercalated in the mesopores and adsorbed on the external surface of the film with the formal potential of -0.19 and -0.52V in 0.1M PBS (pH 7.4), respectively. The HRP intercalated in the mesopores showed a surface-controlled process with a single proton transfer. The direct electron transfer between the adsorbed HRP and the electrode is achieved without the aid of an electron mediator. The H(2)O(2) biosensor displayed a rapid eletrocatalytic response (less than 3s), a wide linear range from 0.5 microM to 1.4mM with a detection limit of 0.2 microM, high sensitivity (179.9 microAmM(-1)), good stability and reproducibility. Compared with the free-Au doped titanium dioxide photonic crystals modified electrode, the GTD modified electrode could greatly enhance the response current signal, linear detection range and higher sensitivity. The 3DOM GTD provided a new matrix for protein immobilization and direct transfer study and opened a way for low conductivity electrode biosensor.

Acute and subchronic toxicity analysis of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles.

PubMed

Venkatasubbu, Gopinath Devanand; Ramasamy, S; Gaddam, Pramod Reddy; Kumar, J

2015-01-01

Nanoparticles are widely used for targeted drug delivery applications. Surface modification with appropriate polymer and ligands is carried out to target the drug to the affected area. Toxicity analysis is carried out to evaluate the safety of the surface modified nanoparticles. In this study, paclitaxel attached, folic acid functionalized, polyethylene glycol modified hydroxyapatite and titanium dioxide nanoparticles were used for targeted drug delivery system. The toxicological behavior of the system was studied in vivo in rats and mice. Acute and subchronic studies were carried out. Biochemical, hematological, and histopathological analysis was also done. There were no significant alterations in the biochemical parameters at a low dosage. There was a small change in alkaline phosphatase (ALP) level at a high dosage. The results indicate a safe toxicological profile.

Grafting strategy to develop single site titanium on an amorphous silica surface.

PubMed

Capel-Sanchez, M C; Blanco-Brieva, G; Campos-Martin, J M; de Frutos, M P; Wen, W; Rodriguez, J A; Fierro, J L G

2009-06-16

Titanium/silica systems were prepared by grafting a titanium alkoxide (titanium isopropoxide and titanium (triethanolaminate) isopropoxide) precursor onto amorphous silica. The grafting process, which consisted of the hydrolysis of the Ti precursor by the hydroxyl groups on the silica surface, yielded samples containing Ti-loadings of 1-1.6 wt %. The as synthesized and calcined TiO(2)-SiO(2) samples were characterized by UV-vis, FTIR, XPS, and XANES spectroscopic techniques. These systems were tested in the liquid-phase epoxidation of oct-1-ene with hydrogen peroxide reaction. Spectroscopic data indicated that titanium anchoring takes place by reaction between the alkoxide precursor and surface OH groups of the silica substrate. The nature of surface titanium species generated by chemical grafting depends largely on the titanium precursor employed. Thus, the titanium isopropoxide precursor yields tetrahedrally coordinated polymeric titanium species, which give rise to a low-efficiency catalyst. However, if an atrane precursor (titanium (triethanolaminate) isopropoxide) is employed, isolated titanium species are obtained. The fact that these species remain isolated even after calcination is due to the protective effect of the triethanolaminate ligand that avoids titanium polymerization. These differences in the titanium environment have a pivotal role in the performance of these systems in the epoxidation of alkenes with hydrogen peroxide.

Grafting Strategy to Develop Single Site Titanium on an Amorphous Silica Surface

DOE Office of Scientific and Technical Information (OSTI.GOV)

Capel-Sanchez, M.; Blanco-Brieva, G; Campos-Martin, J

2009-01-01

Titanium/silica systems were prepared by grafting a titanium alkoxide (titanium isopropoxide and titanium (triethanolaminate) isopropoxide) precursor onto amorphous silica. The grafting process, which consisted of the hydrolysis of the Ti precursor by the hydroxyl groups on the silica surface, yielded samples containing Ti-loadings of 1-1.6 wt %. The as synthesized and calcined TiO2-SiO2 samples were characterized by UV-vis, FTIR, XPS, and XANES spectroscopic techniques. These systems were tested in the liquid-phase epoxidation of oct-1-ene with hydrogen peroxide reaction. Spectroscopic data indicated that titanium anchoring takes place by reaction between the alkoxide precursor and surface OH groups of the silica substrate.more » The nature of surface titanium species generated by chemical grafting depends largely on the titanium precursor employed. Thus, the titanium isopropoxide precursor yields tetrahedrally coordinated polymeric titanium species, which give rise to a low-efficiency catalyst. However, if an atrane precursor (titanium (triethanolaminate) isopropoxide) is employed, isolated titanium species are obtained. The fact that these species remain isolated even after calcination is due to the protective effect of the triethanolaminate ligand that avoids titanium polymerization. These differences in the titanium environment have a pivotal role in the performance of these systems in the epoxidation of alkenes with hydrogen peroxide.« less

Surface Modifications and Their Effects on Titanium Dental Implants

PubMed Central

Jemat, A.; Ghazali, M. J.; Razali, M.; Otsuka, Y.

2015-01-01

This review covers several basic methodologies of surface treatment and their effects on titanium (Ti) implants. The importance of each treatment and its effects will be discussed in detail in order to compare their effectiveness in promoting osseointegration. Published literature for the last 18 years was selected with the use of keywords like titanium dental implant, surface roughness, coating, and osseointegration. Significant surface roughness played an important role in providing effective surface for bone implant contact, cell proliferation, and removal torque, despite having good mechanical properties. Overall, published studies indicated that an acid etched surface-modified and a coating application on commercial pure titanium implant was most preferable in producing the good surface roughness. Thus, a combination of a good surface roughness and mechanical properties of titanium could lead to successful dental implants. PMID:26436097

Activation of Osteoblastic Function on Titanium Surface with Titanium-Doped Hydroxyapatite Nanoparticle Coating: An In Vitro Study.

PubMed

Nakazawa, Masahiro; Yamada, Masahiro; Wakamura, Masato; Egusa, Hiroshi; Sakurai, Kaoru

Titanium-doped hydroxyapatite (TiHA) nanoparticles contain titanium atoms in the hydroxyapatite lattice, which can physicochemically functionalize the titanium surface without modification of the surface topography. This study aimed to evaluate the physicochemical properties of machined or microroughened titanium surfaces coated with TiHA nanoparticles and the functions of osteoblasts cultured on them. Titanium disks with commercially available surface topography, such as machined or sandblasted, large-grit, and acid-etched (SLA) surfaces, were coated with TiHA. The disks with original or TiHA-coated surfaces were evaluated in topography, wettability, and chemical composition. Osteoblastic cells from rat femurs were cultured on the disks and evaluated in proliferation and differentiation. TiHA coating changed from hydrophobicity to hydrophilicity on both machined and SLA surfaces. Calcium and phosphate atoms were detected all over the surface with TiHA coating regardless of the surface topography. However, the considerable change in the inherent surface topographies was not observed on both types of surfaces after TiHA coating. Osteoblastic proliferative activity at day 4 was increased by TiHA coating on both types of surfaces. TiHA coating did not enhance expressions of bone matrix-related genes such as osteocalcin, osteopontin, bone sialoprotein, alkaline phosphatase, and collagen I. However, depositions of collagen, osteocalcin, and calcium in the culture at days 7 and 20 were increased on both types of surface topographies with TiHA coating. TiHA coating enhanced extracellular matrix formation on smooth and microroughened titanium surfaces by increasing osteoblastic proliferative activity without the deterioration of differentiation through hydrophilic and chemical functionalization.

Preparation of titanium phosphates with additives in hydrothermal process and their powder properties for cosmetics.

PubMed

Onoda, Hiroaki; Yamaguchi, Taisuke

2013-04-01

In this study, titanium phosphates were prepared from titanium chloride and phosphoric acid, sodium pyrophosphate and sodium triphosphate solutions with water retention compounds in hydrothermal process as a novel white pigment for cosmetics. Their chemical composition, powder properties, photo catalytic activity, water retention and smoothness were studied. The addition of glycerin in the preparation from sodium pyrophosphate has the useful method to obtain homogenized spherical particles of titanium phosphate pigments for the cosmetics. These titanium phosphates had less photo catalytic activity to protect the sebum on the skin. © 2012 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

A NEW INNOVATIVE LOW COST MANUFACTURING PROCESS TO PRODUCE TITANIUM - PHASE II

EPA Science Inventory

Titanium with its inherent lightweight, corrosion resistance and mechanical properties is a critical and strategic metal in civilian and defense aviation, oil extraction and processing, water purification, the general chemical industry, and would be in automotive transportatio...

Chlorhexidine Uptake and Release From Modified Titanium Surfaces and Its Antimicrobial Activity.

PubMed

Ryu, Hyo-Sook; Kim, Yoon-Il; Lim, Bum-Soon; Lim, Young-Jun; Ahn, Sug-Joon

2015-11-01

Decontamination by adjunctive antiseptic agents such as chlorhexidine (CHX) is often recommended for the treatment of peri-implant infections. However, its action on the titanium implant surface needs further research. This study is designed to evaluate the ability of modified titanium surfaces to release chlorhexidine after periodic CHX exposure. Four titanium surfaces were prepared: 1) no surface treatment control (machined surface [MA]); 2) an acid mix of 10% HNO3 and 5% HF (HNF); 3) resorbable blast media (RBM); and 4) sandblasting and acid etching (SLA). Each surface was analyzed using a confocal laser scanning microscope and a scanning electron microscope. Each sample was incubated with whole saliva or phosphate-buffered saline for 2 hours. Measurements of CHX release were performed using spectrometry on days 1, 2, and 5 after 1-minute exposure to 0.5% chlorhexidine digluconate solution during a 5-day cycle. CHX-releasing experiments were repeated three consecutive times for 15 days. The antimicrobial activity of CHX-adsorbed disks was determined by a disk diffusion test using Streptococcus gordonii. The CHX-adsorbed titanium surfaces exhibited a short-term release of CHX, and CHX levels dropped rapidly within 3 days. SLA and RBM with smaller and narrower depressions released more CHX than HNF and MA, specifically in the saliva-coated group. The disk diffusion test revealed that after CHX uptake, saliva-coated SLA and RBM showed the highest antimicrobial activity. This study suggests that CHX release is significantly influenced by titanium surface modifications and that SLA and RBM might provide effective CHX uptake capacity in the saliva-filled oral cavity.

[Corrosion resistant properties of different anodized microtopographies on titanium surfaces].

PubMed

Fangjun, Huo; Li, Xie; Xingye, Tong; Yueting, Wang; Weihua, Guo; Weidong, Tian

2015-12-01

To investigate the corrosion resistant properties of titanium samples prepared by anodic oxidation with different surface morphologies. Pure titanium substrates were treated by anodic oxidation to obtain porous titanium films in micron, submicron, and micron-submicron scales. The surface morphologies, coating cross-sectional morphologies, crystalline structures, and surface roughness of these samples were characterized. Electrochemical technique was used to measure the corrosion potential (Ecorr), current density of corrosion (Icorr), and polarization resistance (Rp) of these samples in a simulated body fluid. Pure titanium could be modified to exhibit different surface morphologies by the anodic oxidation technique. The Tafel curve results showed that the technique can improve the corrosion resistance of pure titanium. Furthermore, the corrosion resistance varied with different surface morphologies. The submicron porous surface sample demonstrated the best corrosion resistance, with maximal Ecorr and Rp and minimal Icorr. Anodic oxidation technology can improve the corrosion resistance of pure titanium in a simulated body fluid. The submicron porous surface sample exhibited the best corrosion resistance because of its small surface area and thick barrier layer.

[A study on the bond interface between low-fusing dental porcelain and pure titanium].

PubMed

Mo, A; Cen, Y; Liao, Y; Wang, J; Shi, X

2001-09-01

To evaluate the bond interface between low fusing dental porcelain and pure titanium by observing the topography and detecting the ionic diffusion in the interface area. The low fusing-porcelain La-porcelain produced by the authors or Vita Titankeramik porcelain was fused to the surfaces of pure titanium. The topography of the interface between pure titanium and porcelain, and the structure of experimental materials were observed with SEM. The state of ionic diffusion in the interface area was investigated with EPMA. Excellent permeation and diffusion of La-porcelain were observed on the surfaces of pure titanium. The diffusion of ions of stannum and silicon was discovered in the interface area. The microstructure of La-porcelain to pure titanium bond interface was finer than that of Vita Titankeramik porcelain. Excellent bond can be produced in the interface between La-porcelain and pure titanium. The bonding mechanism may involve mechanical bond and chemical bond. The ionic diffusion of stannum plays an important role in the bonding of porcelain to pure titanium.

Chemical milling solution reveals stress corrosion cracks in titanium alloy

NASA Technical Reports Server (NTRS)

Braski, D. N.

1967-01-01

Solution of hydrogen flouride, hydrogen peroxide, and water reveals hot salt stress corrosion cracks in various titanium alloys. After the surface is rinsed in water, dried, and swabbed with the solution, it can be observed by the naked eye or at low magnification.

Investigation on the effect of collagen and vitamins on biomimetic hydroxyapatite coating formation on titanium surfaces.

PubMed

Ciobanu, Gabriela; Ciobanu, Octavian

2013-04-01

This study uses an in vitro experimental approach to investigate the roles of collagen and vitamins in regulating the deposition of hydroxyapatite layer on the pure titanium surface. Titanium implants were coated with a hydroxyapatite layer under biomimetic conditions by using a supersaturated calcification solution (SCS), modified by adding vitamins A and D3, and collagen. The hydroxyapatite deposits on titanium were investigated by means of scanning electron microscopy (SEM) coupled with X-ray analysis (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD) and Fourier transformed infrared (FTIR) spectroscopy. The results obtained have shown that hydroxyapatite coatings were produced in vitro under vitamins and collagen influence. Copyright © 2012 Elsevier B.V. All rights reserved.

Hydrolysis condensation reactions of titanium alkoxides in thin films: A study of the steric hindrance effect by X-ray photoelectron spectroscopy

NASA Astrophysics Data System (ADS)

Barlier, Vincent; Bounor-Legaré, Véronique; Boiteux, Gisèle; Davenas, Joël; Léonard, Didier

2008-06-01

An original approach based on X-ray photoelectron spectroscopy (XPS) is proposed to study the influence of the surrounding humidity on the hydrolysis-condensation reactions of five titanium alkoxides in thin films. More precisely, the influence of the nature of the ligands (propoxide, butoxide, isopropoxide, phenoxide, and 9H-carbazole-9-yl-ethyl-oxy) on the reaction rate was evidenced. The reaction advancement was evaluated by comparing XPS chemical compositions to theoretical compositions calculated for all the possible rates. XPS chemical environment information allowed validating the reliability of this approach through the evaluation of the condensation state. In both approaches, the influence of the steric hindrance on the reactivity of titanium alkoxides was highlighted to be similar to what has been previously observed in solution. Theses results corroborate the validity of our XPS approach to determine titanium alkoxide hydrolysis-condensation reactions in the specific application of thin films.

A Model to Simulate Titanium Behavior in the Iron Blast Furnace Hearth

NASA Astrophysics Data System (ADS)

Guo, Bao-Yu; Zulli, Paul; Maldonado, Daniel; Yu, Ai-Bing

2010-08-01

The erosion of hearth refractory is a major limitation to the campaign life of a blast furnace. Titanium from titania addition in the burden or tuyere injection can react with carbon and nitrogen in molten pig iron to form titanium carbonitride, giving the so-called titanium-rich scaffold or buildup on the hearth surface, to protect the hearth from subsequent erosion. In the current article, a mathematical model based on computational fluid dynamics is proposed to simulate the behavior of solid particles in the liquid iron. The model considers the fluid/solid particle flow through a packed bed, conjugated heat transfer, species transport, and thermodynamic of key chemical reactions. A region of high solid concentration is predicted at the hearth bottom surface. Regions of solid formation and dissolution can be identified, which depend on the local temperature and chemical equilibrium. The sensitivity to the key model parameters for the solid phase is analyzed. The model provides an insight into the fundamental mechanism of solid particle formation, and it may form a basic model for subsequent development to study the formation of titanium scaffold in the blast furnace hearth.

Acute and subchronic toxicity analysis of surface modified paclitaxel attached hydroxyapatite and titanium dioxide nanoparticles

PubMed Central

Venkatasubbu, Gopinath Devanand; Ramasamy, S; Gaddam, Pramod Reddy; Kumar, J

2015-01-01

Nanoparticles are widely used for targeted drug delivery applications. Surface modification with appropriate polymer and ligands is carried out to target the drug to the affected area. Toxicity analysis is carried out to evaluate the safety of the surface modified nanoparticles. In this study, paclitaxel attached, folic acid functionalized, polyethylene glycol modified hydroxyapatite and titanium dioxide nanoparticles were used for targeted drug delivery system. The toxicological behavior of the system was studied in vivo in rats and mice. Acute and subchronic studies were carried out. Biochemical, hematological, and histopathological analysis was also done. There were no significant alterations in the biochemical parameters at a low dosage. There was a small change in alkaline phosphatase (ALP) level at a high dosage. The results indicate a safe toxicological profile. PMID:26491315

Facile hydrothermal preparation of titanium dioxide decorated reduced graphene oxide nanocomposite

PubMed Central

Chang, Betty Yea Sze; Huang, Nay Ming; An’amt, Mohd Nor; Marlinda, Abdul Rahman; Norazriena, Yusoff; Muhamad, Muhamad Rasat; Harrison, Ian; Lim, Hong Ngee; Chia, Chin Hua

2012-01-01

A simple single-stage approach, based on the hydrothermal technique, has been introduced to synthesize reduced graphene oxide/titanium dioxide nanocomposites. The titanium dioxide nanoparticles are formed at the same time as the graphene oxide is reduced to graphene. The triethanolamine used in the process has two roles. It acts as a reducing agent for the graphene oxide as well as a capping agent, allowing the formation of titanium dioxide nanoparticles with a narrow size distribution (~20 nm). Transmission electron micrographs show that the nanoparticles are uniformly distributed on the reduced graphene oxide nanosheet. Thermogravimetric analysis shows the nanocomposites have an enhanced thermal stability over the original components. The potential applications for this technology were demonstrated by the use of a reduced graphene oxide/titanium dioxide nanocomposite-modified glassy carbon electrode, which enhanced the electrochemical performance compared to a conventional glassy carbon electrode when interacting with mercury(II) ions in potassium chloride electrolyte. PMID:22848166

Hydroxyapatite coating of titanium implants using hydroprocessing and evaluation of their osteoconductivity.

PubMed

Kuroda, Kensuke; Okido, Masazumi

2012-01-01

Many techniques for the surface modification of titanium and its alloys have been proposed from the viewpoint of improving bioactivity. This paper contains an overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound. There are two types of coating methods: pyroprocessing and hydroprocessing. In this paper, hydroprocessing for coating on the titanium substrate with HAp, carbonate apatite (CO(3)-Ap), a CO(3)-Ap/CaCO(3) composite, HAp/collagen, and a HAp/gelatin composite is outlined. Moreover, evaluation by implantation of surface-modified samples in rat tibiae is described.

Hydroxyapatite Coating of Titanium Implants Using Hydroprocessing and Evaluation of Their Osteoconductivity

PubMed Central

Kuroda, Kensuke; Okido, Masazumi

2012-01-01

Many techniques for the surface modification of titanium and its alloys have been proposed from the viewpoint of improving bioactivity. This paper contains an overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound. There are two types of coating methods: pyroprocessing and hydroprocessing. In this paper, hydroprocessing for coating on the titanium substrate with HAp, carbonate apatite (CO3–Ap), a CO3–Ap/CaCO3 composite, HAp/collagen, and a HAp/gelatin composite is outlined. Moreover, evaluation by implantation of surface-modified samples in rat tibiae is described. PMID:22400015

The effect of different surface treatments on the shear bond strength of luting cements to titanium.

PubMed

Abi-Rached, Filipe de Oliveira; Fonseca, Renata Garcia; Haneda, Isabella Gagliardi; de Almeida-Júnior, Antonio Alves; Adabo, Gelson Luis

2012-12-01

Although titanium presents attractive physical and mechanical properties, there is a need for improving the bond at the titanium/luting cement interface for the longevity of metal ceramic restorations. The purpose of this study was to evaluate the effect of surface treatments on the shear bond strength (SBS) of resin-modified glass ionomer and resin cements to commercially pure titanium (CP Ti). Two hundred and forty CP Ti cast disks (9.0 × 3.0 mm) were divided into 8 surface treatment groups (n=30): 1) 50 µm Al(2)O(3) particles; 2) 120 µm Al(2)O(3) particles; 3) 250 µm Al(2)O(3) particles; 4) 50 µm Al(2)O(3) particles + silane (RelyX Ceramic Primer); 5) 120 µm Al(2)O(3) particles + silane; 6) 250 µm Al(2)O(3) particles + silane; 7) 30 µm silica-modified Al(2)O(3) particles (Cojet Sand) + silane; and 8) 120 µm Al(2)O(3) particles, followed by 110 µm silica-modified Al(2)O(3) particles (Rocatec). The luting cements 1) RelyX Luting 2; 2) RelyX ARC; or 3) RelyX U100 were applied to the treated CP Ti surfaces (n=10). Shear bond strength (SBS) was tested after thermal cycling (5000 cycles, 5°C to 55°C). Data were analyzed by 2-way analysis of variance (ANOVA) and the Tukey HSD post hoc test (α=.05). Failure mode was determined with a stereomicroscope (×20). The surface treatments, cements, and their interaction significantly affected the SBS (P<.001). RelyX Luting 2 and RelyX U100 exhibited similar behavior for all surface treatments. For both cements, only the group abraded with 50 μm Al(2)O(3) particles had lower SBS than the other groups (P<.05). For RelyX ARC, regardless of silane application, abrasion with 50 μm Al(2)O(3) particles resulted in significantly lower SBS than abrasion with 120 μm and 250 μm particles, which exhibited statistically similar SBS values to each other. Rocatec + silane promoted the highest SBS for RelyX ARC. RelyX U100 presented the highest SBS mean values (P<.001). All groups showed a predominance of adhesive failure mode. The adhesive capability of RelyX Luting 2 and RelyX U100 on the SBS was decisive, while for RelyX ARC, mechanical and chemical factors were more influential. Copyright © 2012 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Enhanced human bone marrow mesenchymal stem cell functions on cathodic arc plasma-treated titanium.

PubMed

Zhu, Wei; Teel, George; O'Brien, Christopher M; Zhuang, Taisen; Keidar, Michael; Zhang, Lijie Grace

2015-01-01

Surface modification of titanium for use in orthopedics has been explored for years; however, an ideal method of integrating titanium with native bone is still required to this day. Since human bone cells directly interact with nanostructured extracellular matrices, one of the most promising methods of improving titanium's osseointegration involves inducing bio-mimetic nanotopography to enhance cell-implant interaction. In this regard, we explored an approach to functionalize the surface of titanium by depositing a thin film of textured titanium nanoparticles via a cathodic arc discharge plasma. The aim is to improve human bone marrow mesenchymal stem cell (MSC) attachment and differentiation and to reduce deleterious effects of more complex surface modification methods. Surface functionalization was analyzed by scanning electron microscopy, atomic force microscopy, contact angle testing, and specific protein adsorption. Scanning electron microscopy and atomic force microscopy examination demonstrate the deposition of titanium nanoparticles and the surface roughness change after coating. The specific fibronectin adsorption was enhanced on the modified titanium surface that associates with the improved hydrophilicity. MSC adhesion and proliferation were significantly promoted on the nanocoated surface. More importantly, compared to bare titanium, greater production of total protein, deposition of calcium mineral, and synthesis of alkaline phosphatase were observed from MSCs on nanocoated titanium after 21 days. The method described herein presents a promising alternative method for inducing more cell favorable nanosurface for improved orthopedic applications.

Transport Phenomena and Interfacial Kinetics in Multiphase Combustion Systems

DTIC Science & Technology

1993-08-01

morphological analysis using electron microscope images. Aggregate data obtained from CH4 flames seeded with titanium tetra- isopropoxide (TTIP-) vapor are now... Titanium tetra- isopropoxide 6. APPENDICES (Complete Papers Published During 2/15/92-2/14/93 Period; including Form 298 for each) HIGH TEMPERATURE CHEMICAL

Cathodic protection of two concrete bridge decks using titanium-mesh anodes : interim report.

DOT National Transportation Integrated Search

1991-01-01

Expanded titanium mesh with a layer of precious metal oxides sintered around it has recently been introduced to fulfill the need for a durable anode in the cathodic protection (CP) of concrete bridge decks. In addition to being resistant to chemical ...

Metallographic Preparation of Space Shuttle Reaction Control System Thruster Electron Beam Welds for Electron Backscatter Diffraction

NASA Technical Reports Server (NTRS)

Martinez, James

2011-01-01

A Space Shuttle Reaction Control System (RCS) thruster failed during a firing test at the NASA White Sands Test Facility (WSTF), Las Cruces, New Mexico. The firing test was being conducted to investigate a previous electrical malfunction. A number of cracks were found associated with the fuel closure plate/injector assembly (Fig 1). The firing test failure generated a flight constraint to the launch of STS-133. A team comprised of several NASA centers and other research institutes was assembled to investigate and determine the root cause of the failure. The JSC Materials Evaluation Laboratory was asked to compare and characterize the outboard circumferential electron beam (EB) weld between the fuel closure plate (Titanium 6Al-4V) and the injector (Niobium C-103 alloy) of four different RCS thrusters, including the failed RCS thruster. Several metallographic challenges in grinding/polishing, and particularly in etching were encountered because of the differences in hardness, ductility, and chemical resistance between the two alloys and the bimetallic weld. Segments from each thruster were sectioned from the outboard weld. The segments were hot-compression mounted using a conductive, carbon-filled epoxy. A grinding/polishing procedure for titanium alloys was used [1]. This procedure worked well on the titanium; but a thin, disturbed layer was visible on the niobium surface by means of polarized light. Once polished, each sample was micrographed using bright field, differential interference contrast optical microscopy, and scanning electron microscopy (SEM) using a backscatter electron (BSE) detector. No typical weld anomalies were observed in any of the cross sections. However, areas of large atomic contrast were clearly visible in the weld nugget, particularly along fusion line interfaces between the titanium and the niobium. This prompted the need to better understand the chemistry and microstructure of the weld (Fig 2). Energy Dispersive X-Ray Spectroscopy (EDS) was used to confirm the chemical composition of the variations in contrast in these areas. Niobium alloys generally require exposure to more aggressive chemical reagents than titanium alloys for etching because of niobium s chemical resistance; therefore, the titanium portion of the sample was etched first. A five second immersion in Kroll s reagent revealed a general microstructure on the titanium portion of the sample; however, the titanium heat affected zone closest to the weld, was over-etched due to higher concentrations of refined grains and an increase in eta-phase. The Kroll s etchant also revealed some microstructure in the weld nugget itself; the niobium portion of the sample remained unetched.

Corrosion resistance of nanostructured titanium.

PubMed

Garbacz, H; Pisarek, M; Kurzydłowski, K J

2007-11-01

The present work reports results of studies of corrosion resistance of pure nano-Ti-Grade 2 after hydrostatic extrusion. The grain size of the examined samples was below 90 nm. Surface analytical technique including AES combined with Ar(+) ion sputtering, were used to investigate the chemical composition and thicknesses of the oxides formed on nano-Ti. It has been found that the grain size of the titanium substrate did not influence the thickness of oxide formed on the titanium. The thickness of the oxide observed on the titanium samples before and after hydrostatic extrusion was about 6 nm. Tests carried out in a NaCl solution revealed a slightly lower corrosion resistance of nano-Ti in comparison with the titanium with micrometric grain size.

Standard Method for Analyzing Gases in Titanium and Titanium Alloys. Standard Method for the Chemical Analysis of Titanium Alloys.

DTIC Science & Technology

1982-10-28

form a non- soluble complex. After filtering and burning the non-pure molybdenum trioxide is weighed. Ammonia water is used to dissolve the molybdenum...niobium and tantalum should use the methyl alcohol distillation - curcumin absorption luminosity 66 method for determination. II. The Methyl Alcohol...Distillation - Curcumin Absorption Luminosity Method 1. Summary of Method In a phosphorus sulfate medium, boron and methyl alcohol produce methyl borate

Enhanced ultrasonically assisted turning of a β-titanium alloy.

PubMed

Maurotto, Agostino; Muhammad, Riaz; Roy, Anish; Silberschmidt, Vadim V

2013-09-01

Although titanium alloys have outstanding mechanical properties such as high hot hardness, a good strength-to-weight ratio and high corrosion resistance; their low thermal conductivity, high chemical affinity to tool materials severely impair their machinability. Ultrasonically assisted machining (UAM) is an advanced machining technique, which has been shown to improve machinability of a β-titanium alloy, namely, Ti-15-3-3-3, when compared to conventional turning processes. Copyright © 2013 Elsevier B.V. All rights reserved.

Real-time assessment of surface interactions with titanium passivation layer by surface plasmon resonance

PubMed Central

Hirata, Isao; Yoshida, Yasuhiro; Nagaoka, Noriyuki; Hiasa, Kyou; Abe, Yasuhiko; Maekawa, Kenji; Kuboki, Takuo; Akagawa, Yasumasa; Suzuki, Kazuomi; Van Meerbeek, Bart; Messersmith, Phillip B.; Okazaki, Masayuki

2011-01-01

The high corrosion resistance and strength-to-density ratio makes titanium widely used in major industry, but also in a gamut of medical applications. Here we report for the first time on our development of a titanium passivation layer sensor that makes use of surface plasmon resonance (SPR). The deposited titanium metal layer on the sensor was passivated in air, like titanium medical devices. Our ‘Ti-SPR sensor’ enables analysis of biomolecules interactions with the passivated surface of titanium in real time. As a proof of concept, corrosion of titanium passivation layer exposed to acid was monitored in real time. Also, the Ti-SPR sensor can accurately measure the time-dependence of protein adsorption onto titanium passivation layer with a sub-nanogram per square millimeter accuracy. Besides such SPR analyses, an SPR-imaging (SPRI) enables real-time assessment of chemical surface processes that occur simultaneously at ‘multiple independent spots’ on the Ti-SPR sensor, such as acid-corrosion or adhesion of cells. Our Ti-SPR sensor will therefore be very useful to study titanium-corrosion phenomena and biomolecular titanium-surface interactions with application in a broad range of industrial and biomedical fields. PMID:22154862

Manipulation of the osteoblast response to a Ti 6Al 4V titanium alloy using a high power diode laser

NASA Astrophysics Data System (ADS)

Hao, L.; Lawrence, J.; Li, L.

2005-07-01

To improve the bone integration of titanium-based implants a high power diode laser (HPDL) was used to modify the material for improved osteoblast cell response. The surface properties of un-treated and HPDL treated samples were characterized. Contact angles for the un-treated and the HPDL modified titanium alloy (Ti-6Al-4V) were determined with selected biological liquids by the sessile drop technique. The analysis revealed that the wettability of the Ti-6Al-4V improved after HPDL laser treatment, indicating that better interaction with the biological liquids occurred. Moreover, an in vitro human fetal osteoblast cells (hFOB 1.19) evaluation revealed a more favourable cell response on the HPDL laser treated Ti-6Al-4V alloy than on either un-treated sample or a mechanically roughened sample. It was consequently determined that the HPDL provides more a controllable and effective technique to improve the biocompatibility of bio-metals.

Characterization of ion beam modified ceramic wear surfaces using Auger electron spectroscopy

NASA Technical Reports Server (NTRS)

Wei, W.; Lankford, J.

1987-01-01

An investigation of the surface chemistry and morphology of the wear surfaces of ceramic material surfaces modified by ion beam mixing has been conducted using Auger electron spectroscopy and secondary electron microscopy. Studies have been conducted on ceramic/ceramic friction and wear couples made up of TiC and NiMo-bonded TiC cermet pins run against Si3N4 and partially stabilized zirconia disc surfaces modified by the ion beam mixing of titanium and nickel, as well as ummodified ceramic/ceramic couples in order to determine the types of surface changes leading to the improved friction and wear behavior of the surface modified ceramics in simulated diesel environments. The results of the surface analyses indicate that the formation of a lubricating oxide layer of titanium and nickel, is responsible for the improvement in ceramic friction and wear behavior. The beneficial effect of this oxide layer depends on several factors, including the adherence of the surface modified layer or subsequently formed oxide layer to the disc substrate, the substrate materials, the conditions of ion beam mixing, and the environmental conditions.

Bacterial adherence to anodized titanium alloy

NASA Astrophysics Data System (ADS)

Pérez-Jorge Peremarch, C.; Pérez Tanoira, R.; Arenas, M. A.; Matykina, E.; Conde, A.; De Damborenea, J. J.; Gómez Barrena, E.; Esteban, J.

2010-11-01

The aim of this study was to evaluate Staphylococcus sp adhesion to modified surfaces of anodized titanium alloy (Ti-6Al-4V). Surface modification involved generation of fluoride-containing titanium oxide nanotube films. Specimens of Ti-6Al-4V alloy 6-4 ELI-grade 23- meets the requirements of ASTM F136 2002A (AMS 2631B class A1) were anodized in a mixture of sulphuric/hydrofluoric acid at 20 V for 5 and 60 min to form a 100 nm-thick porous film of 20 nm pore diameter and 230 nm-thick nanotube films of 100 nm in diameter. The amount of fluorine in the oxide films was of 6% and of 4%, respectively. Collection strains and six clinical strains each of Staphylococcus aureus and Staphylococcus epidermidis were studied. The adherence study was performed using a previously published protocol by Kinnari et al. The experiments were performed in triplicates. As a result, lower adherence was detected for collection strains in modified materials than in unmodified controls. Differences between clinical strains were detected for both species (p<0.0001, Kruskal-Wallis test), although global data showed similar results to that of collection strains (p<0.0001, Kruskal-Wallis test). Adherence of bacteria to modified surfaces was decreased for both species. The results also reflect a difference in the adherence between S. aureus and S. epidermidis to the modified material. As a conclusion, not only we were able to confirm the decrease of adherence in the modified surface, but also the need to test multiple clinical strains to obtain more realistic microbiological results due to intraspecies differences.

Osseointegration improvement by plasma electrolytic oxidation of modified titanium alloys surfaces.

PubMed

Echeverry-Rendón, Mónica; Galvis, Oscar; Quintero Giraldo, David; Pavón, Juan; López-Lacomba, José Luis; Jiménez-Piqué, Emilio; Anglada, Marc; Robledo, Sara M; Castaño, Juan G; Echeverría, Félix

2015-02-01

Titanium (Ti) is a material frequently used in orthopedic applications, due to its good mechanical properties and high corrosion resistance. However, formation of a non-adherent fibrous tissue between material and bone drastically could affect the osseointegration process and, therefore, the mechanical stability of the implant. Modifications of topography and configuration of the tissue/material interface is one of the mechanisms to improve that process by manipulating parameters such as morphology and roughness. There are different techniques that can be used to modify the titanium surface; plasma electrolytic oxidation (PEO) is one of those alternatives, which consists of obtaining porous anodic coatings by controlling parameters such as voltage, current, anodizing solution and time of the reaction. From all of the above factors, and based on previous studies that demonstrated that bone cells sense substrates features to grow new tissue, in this work commercially pure Ti (c.p Ti) and Ti6Al4V alloy samples were modified at their surface by PEO in different anodizing solutions composed of H2SO4 and H3PO4 mixtures. Treated surfaces were characterized and used as platforms to grow osteoblasts; subsequently, cell behavior parameters like adhesion, proliferation and differentiation were also studied. Although the results showed no significant differences in proliferation, differentiation and cell biological activity, overall results showed an important influence of topography of the modified surfaces compared with polished untreated surfaces. Finally, this study offers an alternative protocol to modify surfaces of Ti and their alloys in a controlled and reproducible way in which biocompatibility of the material is not compromised and osseointegration would be improved.

Influence Of Carboxymethyl Cellulose For The Transport Of Titanium Dioxide Nanoparticles In Clean Silica And Mineral-Coated Sands

EPA Science Inventory

The transport properties of titanium dioxide (anatase polymorph) nanoparticles encapsulated by carboxymethyl cellulose (CMC) were evaluated as a function of changes in the solute chemical properties in clean quartz, amorphous aluminum and iron hydroxide-coated sands. While prist...

40 CFR 721.10021 - Magnesium potassium titanium oxide.

Code of Federal Regulations, 2010 CFR

2010-07-01

... or tight-fitting facepiece (either half- or full-face). As an alternative to the respiratory... significant new uses subject to reporting. (1) The chemical substance identified as magnesium potassium titanium oxide (PMN P-01-764; CAS No. 39290-90-9) is subject to reporting under this section for the...

Thin calcium phosphate coatings on titanium by electrochemical deposition in modified simulated body fluid.

PubMed

Peng, Ping; Kumar, Sunil; Voelcker, Nicolas H; Szili, Endre; Smart, Roger St C; Griesser, Hans J

2006-02-01

Adherent and optically semitransparent thin calcium phosphate (CaP) films were electrochemically deposited on titanium substrates in a modified simulated body fluid at 37 degrees C. Coatings deposited by using periodic pulsed potentials showed better adhesion and better mechanical properties than coatings deposited with use of a constant potential. Scanning electron microscopy was used to study the morphology of the coatings. The coatings displayed a polydispersed porous structure with pores in the range of a few nanometers to 1 mum. Furthermore, X-ray diffractometry and the O(1s) satellite peaks in X-ray photoelectron spectroscopy indicated that the coatings possessed a similar surface chemistry to that of natural bone minerals. These results were confirmed by inductively coupled plasma optical emission spectrometry, which yielded a Ca:P ratio of 1.65, close to that of hydroxyapatite. Contact mode atomic force microscopy (AFM) showed the average thickness of the coatings was in the order of 200 nm. Root-mean-square (RMS) roughness values, also derived by AFM, were shown to be much higher on the titanium-CaP surfaces in comparison with untreated titanium substrates, with RMS values of about 300 and 110 nm, respectively. Cell culture experiments showed that the CaP surfaces are nontoxic to MG63 osteoblastic cells in vitro and were able to support cell growth for up to 4 days, outperforming the untreated titanium surface in a direct comparison. These easily prepared coatings show promise for hard-tissue biomaterials. (c) 2005 Wiley Periodicals, Inc.

Characterization and cell behavior of titanium surfaces with PLL/DNA modification via a layer-by-layer technique.

PubMed

Gao, Wenli; Feng, Bo; Lu, Xiong; Wang, Jianxin; Qu, Shuxin; Weng, Jie

2012-08-01

This study describes the fabrication of two types of multilayered films onto titanium by layer-by-layer (LBL) self-assembly, using poly-L-lysine (PLL) as the cationic polyelectrolyte and deoxyribonucleic acid (DNA) as the anionic polyelectrolyte. The assembling process of each component was studied using atomic force microscopy (AFM) and quartz crystal balance (QCM). Zeta potential of the LBL-coated microparticles was measured by dynamic light scattering. Titanium substrates with or without multilayered films were used in osteoblast cell culture experiments to study cell proliferation, viability, differentiation, and morphology. Results of AFM and QCM indicated the progressive build-up of the multilayered coatings. The surface morphology of three types of multilayered films showed elevations in the nanoscale range. The data of zeta potential showed that the surface terminated with PLL displayed positive charge while the surface terminated with DNA displayed negative charge. The proliferation of osteoblasts on modified titanium films was found to be greater than that on control (p < 0.05) after 3 and 7 days culture, respectively. Alamar blue measurement showed that the PLL/DNA-modified films have higher cell viability (p < 0.05) than the control. Still, the alkaline phosphatase activity assay revealed a better differentiated phenotype on three types of multilayered surfaces compared to noncoated controls. Collectively our results suggest that PLL/DNA were successfully used to surface engineer titanium via LBL technique, and enhanced its cell biocompatibility. Copyright © 2012 Wiley Periodicals, Inc.

Surface modification of biomaterials using plasma immersion ion implantation and deposition

PubMed Central

Lu, Tao; Qiao, Yuqin; Liu, Xuanyong

2012-01-01

Although remarkable progress has been made on biomaterial research, the ideal biomaterial that satisfies all the technical requirements and biological functions is not available up to now. Surface modification seems to be a more economic and efficient way to adjust existing conventional biomaterials to meet the current and ever-evolving clinical needs. From an industrial perspective, plasma immersion ion implantation and deposition (PIII&D) is an attractive method for biomaterials owing to its capability of treating objects with irregular shapes, as well as the control of coating composition. It is well acknowledged that the physico-chemical characteristics of biomaterials are the decisive factors greatly affecting the biological responses of biomaterials including bioactivity, haemocompatibility and antibacterial activity. Here, we mainly review the recent advances in surface modification of biomaterials via PIII&D technology, especially titanium alloys and polymers used for orthopaedic, dental and cardiovascular implants. Moreover, the variations of biological performances depending on the physico-chemical properties of modified biomaterials will be discussed. PMID:23741609

PET fiber fabrics modified with bioactive titanium oxide for bone substitutes.

PubMed

Kokubo, Tadashi; Ueda, Takahiro; Kawashita, Masakazu; Ikuhara, Yuichi; Takaoka, Gikan H; Nakamura, Takashi

2008-02-01

A rectangular specimen of polyethylene terephthalate (PET) was soaked in a titania solution composed of titanium isopropoxide, water, ethanol and nitric acid at 25 degrees C for 1 h. An amorphous titanium oxide was formed uniformly on the surface of PET specimen, but did not form an apatite on its surface in a simulated body fluid (SBF) within 3 d. The PET plate formed with the amorphous titanium oxide was subsequently soaked in water or HCl solutions with different concentrations at 80 degrees C for different periods of time. The titanium oxide on PET was transformed into nano-sized anatase by the water treatment and into nano-sized brookite by 0.10 M HCl treatment at 80 degrees C for 8 d. The former did not form the apatite on its surface in SBF within 3 d, whereas the latter formed the apatite uniformly on its surface. Adhesive strength of the titanium oxide and apatite layers to PET plate was increased by pre-treatment of PET with 2 wt% NaOH solution at 40 degrees C for 2 h. A two-dimensional fabric of PET fibers 24 microm in diameter was subjected to the NaOH pre-treatment at 40 degrees C, titania solution treatment at 25 degrees C and subsequent 0.10 M HCl treatment at 80 degrees C. Thus treated PET fabric formed the apatite uniformly on surfaces of individual fibers constituting the fabric in SBF within 3 d. Two or three dimensional PET fabrics modified with the nano-sized brookite on surfaces of the individual fibers constituting the fabric by the present method are believed to be useful as flexible bone substitutes, since they could be integrated with living bone through the apatite formed on their constituent fibers.

Defect pair formation in fluorine and nitrogen codoped TiO2

NASA Astrophysics Data System (ADS)

Kordatos, A.; Kelaidis, N.; Chroneos, A.

2018-04-01

Titanium oxide is extensively investigated because of its high chemical stability and its photocatalytic properties; nevertheless, the large band gap limits its activity to a small portion of the solar spectrum. Nitrogen and fluorine codoping is an efficient defect engineering strategy to increase the photocatalytic activity of titanium oxide. In the present study, we apply density functional theory to investigate the interaction of nitrogen with fluorine and the formation of defect pairs. We show that in fluorine and nitrogen codoped titanium oxide, the FiNi, FONi, and FiNTi defects can form. Their impact on the electronic structure of titanium oxide is discussed.

Dispersion toughened ceramic composites and method for making same

DOEpatents

Stinton, David P.; Lackey, Walter J.; Lauf, Robert J.

1986-01-01

Ceramic composites exhibiting increased fracture toughness are produced by the simultaneous codeposition of silicon carbide and titanium disilicide by chemical vapor deposition. A mixture of hydrogen, methyltrichlorosilane and titanium tetrachloride is introduced into a furnace containing a substrate such as graphite or silicon carbide. The thermal decomposition of the methyltrichlorosilane provides a silicon carbide matrix phase and the decomposition of the titanium tetrachloride provides a uniformly dispersed second phase of the intermetallic titanium disilicide within the matrix phase. The fracture toughness of the ceramic composite is in the range of about 6.5 to 7.0 MPa.sqroot.m which represents a significant increase over that of silicon carbide.

Dispersion toughened ceramic composites and method for making same

DOEpatents

Stinton, D.P.; Lackey, W.J.; Lauf, R.J.

1984-09-28

Ceramic composites exhibiting increased fracture toughness are produced by the simultaneous codeposition of silicon carbide and titanium disilicide by chemical vapor deposition. A mixture of hydrogen, methyltrichlorosilane and titanium tetrachloride is introduced into a furnace containing a substrate such as graphite or silicon carbide. The thermal decomposition of the methyltrichlorosilane provides a silicon carbide matrix phase and the decomposition of the titanium tetrachloride provides a uniformly dispersed second phase of the intermetallic titanium disilicide within the matrix phase. The fracture toughness of the ceramic composite is in the range of about 6.5 to 7.0 MPa..sqrt..m which represents a significant increase over that of silicon carbide.

Precursor effect on the property and catalytic behavior of Fe-TS-1 in butadiene epoxidation

NASA Astrophysics Data System (ADS)

Wu, Mei; Zhao, Huahua; Yang, Jian; Zhao, Jun; Song, Huanling; Chou, Lingjun

2017-11-01

The effect of iron precursor on the property and catalytic behavior of iron modified titanium silicalite molecular sieve (Fe-TS-1) catalysts in butadiene selective epoxidation has been studied. Three Fe-TS-1 catalysts were prepared, using iron nitrate, iron chloride and iron sulfate as precursors, which played an important role in adjusting the textural properties and chemical states of TS-1. Of the prepared Fe-TS-1 catalysts, those modified by iron nitrate (FN-TS-1) exhibited a significant enhanced performance in butadiene selective epoxidation compared to those derived from iron sulfate (FS-TS-1) or iron chloride (FC-TS-1) precursors. To obtain a deep understanding of their structure-performance relationship, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Temperature programmed desorption of NH3 (NH3-TPD), Diffuse reflectance UV-Vis spectra (DR UV-Vis), Fourier transformed infrared spectra (FT-IR) and thermal gravimetric analysis (TGA) were conducted to characterize Fe-TS-1 catalysts. Experimental results indicated that textural structures and acid sites of modified catalysts as well as the type of Fe species influenced by the precursors were all responsible for the activity and product distribution.

Surface modification of titanium nitride film by a picosecond Nd:YAG laser

NASA Astrophysics Data System (ADS)

Gakovic, B.; Trtica, M.; Batani, D.; Desai, T.; Panjan, P.; Vasiljevic-Radovic, D.

2007-06-01

The interaction of a picosecond Nd:YAG laser (wavelength 532 nm, pulse duration 40 ps) with a polycrystalline titanium nitride (TiN) film was studied. The TiN thin film was deposited by physical vapour deposition on a silicon substrate. The titanium nitride/silicon system was modified with an energy fluence from 0.2 to 5.9 J cm-2. Multi-pulse irradiation was performed in air by a focused laser beam. Surface modifications were analysed after 1 100 successive laser pulses. Depending on the laser pulse energy and pulse count, the following phenomena were observed: (i) increased surface roughness, (ii) titanium nitride film cracking, (iii) silicon substrate modification, (iv) film exfoliation and (v) laser-induced periodical surface structures on nano- (NPSS) and micro-dimensions (MPSS).

Processing Method for Creating Ultra-Thin Lead Zirconate Titanate (PZT) Films Via Chemical Solution Deposition

DTIC Science & Technology

2008-12-01

n-propoxide and titanium isopropoxide , were measured with a graduated auto pipet and combined with 45 mL of 2-MOE in a 125 mL flask. The solution...nitrogen (N2). This anneal procedure was used to remove trapped hydrogen from the thin film. Following the anneal, a bi-layer of titanium (Ti) and...dioxide Ti titanium 10 NO. OF COPIES ORGANIZATION 1 ADMNSTR ELEC DEFNS TECHL INFO CTR ATTN DTIC OCP 8725 JOHN J KINGMAN RD STE

Rapidly solidified titanium alloys by melt overflow

NASA Technical Reports Server (NTRS)

Gaspar, Thomas A.; Bruce, Thomas J., Jr.; Hackman, Lloyd E.; Brasmer, Susan E.; Dantzig, Jonathan A.; Baeslack, William A., III

1989-01-01

A pilot plant scale furnace was designed and constructed for casting titanium alloy strips. The furnace combines plasma arc skull melting techniques with melt overflow rapid solidification technology. A mathematical model of the melting and casting process was developed. The furnace cast strip of a suitable length and width for use with honeycomb structures. Titanium alloys Ti-6Al-4V and Ti-14Al-21 Nb were successfully cast into strips. The strips were evaluated by optical metallography, microhardness measurements, chemical analysis, and cold rolling.

Titanium alkoxide compound

DOEpatents

Boyle, Timothy J [Albuquerque, NM

2007-08-14

A titanium alkoxide composition is provided, as represented by the chemical formula (OC.sub.6H.sub.5N).sub.2Ti(OC.sub.6H.sub.5NH.sub.2).sub.2. As prepared, the compound is a crystalline substance with a hexavalent titanium atom bonded to two OC.sub.6H.sub.5NH.sub.2 groups and two OC.sub.6H.sub.5N groups with a theoretical molecular weight of 480.38, comprising 60.01% C, 5.04% H and 11.66% N.

SU-F-T-54: Determination of the AAPM TG-43 Brachytherapy Dosimetry Parameters for A New Titanium-Encapsulated Yb-169 Source by Monte Carlo Calculations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reynoso, F; Washington University School of Medicine, St. Louis, MO; Munro, J

2016-06-15

Purpose: To determine the AAPM TG-43 brachytherapy dosimetry parameters of a new titanium-encapsulated Yb-169 source designed to maximize the dose enhancement during gold nanoparticle-aided radiation therapy (GNRT). Methods: An existing Monte Carlo (MC) model of the titanium-encapsulated Yb-169 source, which was described in the current investigators’ published MC optimization study, was modified based on the source manufacturer’s detailed specifications, resulting in an accurate model of the titanium-encapsulated Yb-169 source that was actually manufactured. MC calculations were then performed using the MCNP5 code system and the modified source model, in order to obtain a complete set of the AAPM TG-43 parametersmore » for the new Yb-169 source. Results: The MC-calculated dose rate constant for the new titanium-encapsulated Yb-169 source was 1.05 ± 0.03 cGy per hr U, indicating about 10% decrease from the values reported for the conventional stainless steel-encapsulated Yb-169 sources. The source anisotropy and radial dose function for the new source were found similar to those reported for the conventional Yb-169 sources. Conclusion: In this study, the AAPM TG-43 brachytherapy dosimetry parameters of a new titanium-encapsulated Yb-169 source were determined by MC calculations. The current results suggested that the use of titanium, instead of stainless steel, to encapsulate the Yb-169 core would not lead to any major change in the dosimetric characteristics of the Yb-169 source, while it would allow more low energy photons being transmitted through the source filter thereby leading to an increased dose enhancement during GNRT. Supported by DOD/PCRP grant W81XWH-12-1-0198 This investigation was supported by DOD/PCRP grant W81XWH-12-1- 0198.« less

Effect of applied voltage on surface properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

NASA Astrophysics Data System (ADS)

Chuan, Lee Te; Rathi, Muhammad Fareez Mohamad; Abidin, Muhamad Yusuf Zainal; Abdullah, Hasan Zuhudi; Idris, Maizlinda Izwana

2015-07-01

Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. This method has been widely used to modify the surface morphology of biomaterial especially titanium. This study aimed to investigate the effect of applied voltage on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different applied voltage (50-350 V), electrolyte concentration (0.04 M β-GP + 0.4 M CA), anodising time (10minutes) and current density (50 and 70 mA.cm-2) at room temperature. Surface oxide properties of anodised titanium were characterised by digital single-lens reflex camera (DSLR camera), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). At lower applied voltage (≤150 V), surface of titanium foils were relatively smooth. With increasing applied voltage (≥250 V), the oxide layer became more porous and donut-shaped pores were formed on the surface of titanium foils. The AFM results indicated that the surface roughness of anodised titanium increases with increasing of applied voltage. The porous and rough surface is able to promote the osseointegration and reduce the suffering time of patient.

Modified titanium implant as a gateway to the human body: the implant mediated drug delivery system.

PubMed

Park, Young-Seok; Cho, Joo-Youn; Lee, Shin-Jae; Hwang, Chee Il

2014-01-01

The aim of this study was to investigate the efficacy of a proposed new implant mediated drug delivery system (IMDDS) in rabbits. The drug delivery system is applied through a modified titanium implant that is configured to be implanted into bone. The implant is hollow and has multiple microholes that can continuously deliver therapeutic agents into the systematic body. To examine the efficacy and feasibility of the IMDDS, we investigated the pharmacokinetic behavior of dexamethasone in plasma after a single dose was delivered via the modified implant placed in the rabbit tibia. After measuring the plasma concentration, the areas under the curve showed that the IMDDS provided a sustained release for a relatively long period. The result suggests that the IMDDS can deliver a sustained release of certain drug components with a high bioavailability. Accordingly, the IMDDS may provide the basis for a novel approach to treating patients with chronic diseases.

Osseointegration properties of titanium dental implants modified with a nanostructured coating based on ordered porous silica and bioactive glass nanoparticles

NASA Astrophysics Data System (ADS)

Covarrubias, Cristian; Mattmann, Matías; Von Marttens, Alfredo; Caviedes, Pablo; Arriagada, Cristián; Valenzuela, Francisco; Rodríguez, Juan Pablo; Corral, Camila

2016-02-01

The fabrication of a nanoporous silica coating loaded with bioactive glass nanoparticles (nBG/NSC) on titanium dental implant surface and its in vitro and in vivo evaluation is presented. The coating was produced by a combined sol-gel and evaporation induced self-assembly process. In vitro bioactivity was assessed in simulated body fluid (SBF) and investigating the osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMSCs). A rat tibial model was employed to analyze the bone response to nBG/NSC-modified titanium implant surface in vivo. The nBG/NSC coating was confirmed at nano level to be constituted by a highly ordered nanoporous silica structure. The coating nanotopography in conjunction with the bioactivity of the BG particles accelerate the in vitro apatite formation and promote the osteogenic differentiation of hBMSCs in absence of osteogenic supplements. These properties accelerate the formation of bone tissue in the periphery of the implant after 3 weeks of implantation. Backscattered scanning electron microscopy images revealed the presence of gaps and soft tissue in the unmodified implant after 6 weeks, whereas the nBG/NSC-modified implant showed mature bone in intimate contact with the implant surface. The nBG/NSC coating appears promising for accelerating the osseointegration of dental implants.

Enhanced human bone marrow mesenchymal stem cell functions on cathodic arc plasma-treated titanium

PubMed Central

Zhu, Wei; Teel, George; O’Brien, Christopher M; Zhuang, Taisen; Keidar, Michael; Zhang, Lijie Grace

2015-01-01

Surface modification of titanium for use in orthopedics has been explored for years; however, an ideal method of integrating titanium with native bone is still required to this day. Since human bone cells directly interact with nanostructured extracellular matrices, one of the most promising methods of improving titanium’s osseointegration involves inducing bio-mimetic nanotopography to enhance cell–implant interaction. In this regard, we explored an approach to functionalize the surface of titanium by depositing a thin film of textured titanium nanoparticles via a cathodic arc discharge plasma. The aim is to improve human bone marrow mesenchymal stem cell (MSC) attachment and differentiation and to reduce deleterious effects of more complex surface modification methods. Surface functionalization was analyzed by scanning electron microscopy, atomic force microscopy, contact angle testing, and specific protein adsorption. Scanning electron microscopy and atomic force microscopy examination demonstrate the deposition of titanium nanoparticles and the surface roughness change after coating. The specific fibronectin adsorption was enhanced on the modified titanium surface that associates with the improved hydrophilicity. MSC adhesion and proliferation were significantly promoted on the nanocoated surface. More importantly, compared to bare titanium, greater production of total protein, deposition of calcium mineral, and synthesis of alkaline phosphatase were observed from MSCs on nanocoated titanium after 21 days. The method described herein presents a promising alternative method for inducing more cell favorable nanosurface for improved orthopedic applications. PMID:26677327

Establishment of Epithelial Attachment on Titanium Surface Coated with Platelet Activating Peptide

PubMed Central

Sugawara, Shiho; Maeno, Masahiko; Lee, Cliff; Nagai, Shigemi; Kim, David M.; Da Silva, John; Kondo, Hisatomo

2016-01-01

The aim of this study was to produce epithelial attachment on a typical implant abutment surface of smooth titanium. A challenging complication that hinders the success of dental implants is peri-implantitis. A common cause of peri-implantitis may results from the lack of epithelial sealing at the peri-implant collar. Histologically, epithelial sealing is recognized as the attachment of the basement membrane (BM). BM-attachment is promoted by activated platelet aggregates at surgical wound sites. On the other hand, platelets did not aggregate on smooth titanium, the surface typical of the implant abutment. We then hypothesized that epithelial BM-attachment was produced when titanium surface was modified to allow platelet aggregation. Titanium surfaces were coated with a protease activated receptor 4-activating peptide (PAR4-AP). PAR4-AP coating yielded rapid aggregation of platelets on the titanium surface. Platelet aggregates released robust amount of epithelial chemoattractants (IGF-I, TGF-β) and growth factors (EGF, VEGF) on the titanium surface. Human gingival epithelial cells, when they were co-cultured on the platelet aggregates, successfully attached to the PAR4-AP coated titanium surface with spread laminin5 positive BM and consecutive staining of the epithelial tight junction component ZO1, indicating the formation of complete epithelial sheet. These in-vitro results indicate the establishment of epithelial BM-attachment to the titanium surface. PMID:27741287

Corrosion of titanium: Part 1: aggressive environments and main forms of degradation.

PubMed

Prando, Davide; Brenna, Andrea; Diamanti, Maria Vittoria; Beretta, Silvia; Bolzoni, Fabio; Ormellese, Marco; Pedeferri, MariaPia

2017-11-11

Titanium has outstanding corrosion resistance due to the external natural oxide protective layer formed when it is exposed to an aerated environment. Despite this, titanium may suffer different forms of corrosion in severe environments: uniform corrosion, pitting and crevice corrosion, hydrogen embrittlement, stress-corrosion cracking, fretting corrosion and erosion. In this first review, forms of corrosion affecting titanium are analyzed based on a wide literature review. For each form of corrosion, the mechanism and most severe environment are reported according to the current understanding.In the second part, this review will address the possible surface treatments that can increase corrosion resistance on commercially pure titanium: Electrochemical anodizing, thermal oxidation, chemical oxidation and bulk treatments such as alloying will be considered, highlighting the advantages of each technique.

Thermo-mechanical modeling of laser treatment on titanium cold-spray coatings

NASA Astrophysics Data System (ADS)

Paradiso, V.; Rubino, F.; Tucci, F.; Astarita, A.; Carlone, P.

2018-05-01

Titanium coatings are very attractive to several industrial fields, especially aeronautics, due to the enhanced corrosion resistance and wear properties as well as improved compatibility with carbon fiber reinforced plastic (CFRP) materials. Cold sprayed titanium coatings, among the others deposition processes, are finding a widespread use in high performance applications, whereas post-deposition treatments are often used to modify the microstructure of the cold-sprayed layer. Laser treatments allow one to noticeably increase the superficial properties of titanium coatings when the process parameters are properly set. On the other hand, the high heat input required to melt titanium particles may result in excessive temperature increase even in the substrate. This paper introduces a thermo-mechanical model to simulate the laser treatment effects on a cold sprayed titanium coating as well as the aluminium substrate. The proposed thermo-mechanical finite element model considers the transient temperature field due to the laser source and applied boundary conditions using them as input loads for the subsequent stress-strain analysis. Numerical outcomes highlighted the relevance of thermal gradients and thermally induced stresses and strains in promoting the damage of the coating.

Scaling of titanium implants entrains inflammation-induced osteolysis

PubMed Central

Eger, Michal; Sterer, Nir; Liron, Tamar; Kohavi, David; Gabet, Yankel

2017-01-01

With millions of new dental and orthopedic implants inserted annually, periprosthetic osteolysis becomes a major concern. In dentistry, peri-implantitis management includes cleaning using ultrasonic scaling. We examined whether ultrasonic scaling releases titanium particles and induces inflammation and osteolysis. Titanium discs with machined, sandblasted/acid-etched and sandblasted surfaces were subjected to ultrasonic scaling and we physically and chemically characterized the released particles. These particles induced a severe inflammatory response in macrophages and stimulated osteoclastogenesis. The number of released particles and their chemical composition and nanotopography had a significant effect on the inflammatory response. Sandblasted surfaces released the highest number of particles with the greatest nanoroughness properties. Particles from sandblasted/acid-etched discs induced a milder inflammatory response than those from sandblasted discs but a stronger inflammatory response than those from machined discs. Titanium particles were then embedded in fibrin membranes placed on mouse calvariae for 5 weeks. Using micro-CT, we observed that particles from sandblasted discs induced more osteolysis than those from sandblasted/acid-etched discs. In summary, ultrasonic scaling of titanium implants releases particles in a surface type-dependent manner and may aggravate peri-implantitis. Future studies should assess whether surface roughening affects the extent of released wear particles and aseptic loosening of orthopedic implants. PMID:28059080

Effect of Extreme Wettability on Platelet Adhesion on Metallic Implants: From Superhydrophilicity to Superhydrophobicity.

PubMed

Moradi, Sona; Hadjesfandiari, Narges; Toosi, Salma Fallah; Kizhakkedathu, Jayachandran N; Hatzikiriakos, Savvas G

2016-07-13

In order to design antithrombotic implants, the effect of extreme wettability (superhydrophilicity to superhydrophobicity) on the biocompatibility of the metallic substrates (stainless steel and titanium) was investigated. The wettability of the surface was altered by chemical treatments and laser ablation methods. The chemical treatments generated different functionality groups and chemical composition as evident from XPS analysis. The micro/nanopatterning by laser ablation resulted in three different pattern geometry and different surface roughness and consequently wettability. The patterned surface were further modified with chemical treatments to generate a wide range of surface wettability. The influence of chemical functional groups, pattern geometry, and surface wettability on protein adsorption and platelet adhesion was studied. On chemically treated flat surfaces, the type of hydrophilic treatment was shown to be a contributing factor that determines the platelet adhesion, since the hydrophilic oxidized substrates exhibit less platelet adhesion in comparison to the control untreated or acid treated surfaces. Also, the surface morphology, surface roughness, and superhydrophobic character of the surfaces are contributing factors to platelet adhesion on the surface. Our results show that superhydrophobic cauliflower-like patterns are highly resistant to platelet adhesion possibly due to the stability of Cassie-Baxter state for this pattern compared to others. Our results also show that simple surface treatments on metals offer a novel way to improve the hemocompatibility of metallic substrates.

Wear evaluation of flank in burins of high speed steel modified with titanium ions

NASA Astrophysics Data System (ADS)

E Caballero, J.; V-Niño, E. D.

2017-12-01

This report shows the results obtained researching the flank wearing resistance performed by the high-speed steel (HSS) burins without any surface treatment (reference substrate) and others with surface treatment based on Titanium ions. The flank wearing was carried out by means of an industrial process by chip removal with repetitive tests of dry finished turning of AISI/SAE 1045 steel bars. The useful service life of the burins was evaluated according to ISO 3685:1993, and it was found that the burins treated with Titanium ions showed an increase in the flank wearing resistance with respect to the ones used as reference.

Effects of Material Properties on Sedimentation and Aggregation of Titanium Dioxide Nanoparticles of Anatase and Rutile in the Aqueous Phase

EPA Science Inventory

This study investigated the sedimentation and aggregation kinetics of titanium dioxide (TiO2) nanoparticles with varying material properties (i.e., crystallinity, morphology, and chemical compositions). Used in the study were various types of commercially available TiO2 nanoparti...

Development of binary and ternary titanium alloys for dental implants.

PubMed

Cordeiro, Jairo M; Beline, Thamara; Ribeiro, Ana Lúcia R; Rangel, Elidiane C; da Cruz, Nilson C; Landers, Richard; Faverani, Leonardo P; Vaz, Luís Geraldo; Fais, Laiza M G; Vicente, Fabio B; Grandini, Carlos R; Mathew, Mathew T; Sukotjo, Cortino; Barão, Valentim A R

2017-11-01

The aim of this study was to develop binary and ternary titanium (Ti) alloys containing zirconium (Zr) and niobium (Nb) and to characterize them in terms of microstructural, mechanical, chemical, electrochemical, and biological properties. The experimental alloys - (in wt%) Ti-5Zr, Ti-10Zr, Ti-35Nb-5Zr, and Ti-35Nb-10Zr - were fabricated from pure metals. Commercially pure titanium (cpTi) and Ti-6Al-4V were used as controls. Microstructural analysis was performed by means of X-ray diffraction and scanning electron microscopy. Vickers microhardness, elastic modulus, dispersive energy spectroscopy, X-ray excited photoelectron spectroscopy, atomic force microscopy, surface roughness, and surface free energy were evaluated. The electrochemical behavior analysis was conducted in a body fluid solution (pH 7.4). The albumin adsorption was measured by the bicinchoninic acid method. Data were evaluated through one-way ANOVA and the Tukey test (α=0.05). The alloying elements proved to modify the alloy microstructure and to enhance the mechanical properties, improving the hardness and decreasing the elastic modulus of the binary and ternary alloys, respectively. Ti-Zr alloys displayed greater electrochemical stability relative to that of controls, presenting higher polarization resistance and lower capacitance. The experimental alloys were not detrimental to albumin adsorption. The experimental alloys are suitable options for dental implant manufacturing, particularly the binary system, which showed a better combination of mechanical and electrochemical properties without the presence of toxic elements. Copyright © 2017 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Hydrothermally grown and self-assembled modified titanium and nickel oxide composite nanosheets on Nitinol-based fibers for efficient solid phase microextraction.

PubMed

Wang, Huiju; Song, Wenlan; Zhang, Min; Zhen, Qi; Guo, Mei; Zhang, Yida; Du, Xinzhen

2016-10-14

A novel titanium and nickel oxide composite nanosheets (TiO 2 /NiOCNSs) coating was in situ grown on a Nitinol (NiTi) wire by direct hydrothermal treatment and modified by self-assembly of trichlorophenylsilane for solid phase microextraction (SPME). TiO 2 /NiOCNSs were radially oriented and chemically bonded to the NiTi substrate with double-faced open access sites. Moreover the phenyl modified TiO 2 /NiOCNSs (TiO 2 /NiOCNSs-Ph) coating exhibited original surface supporting framework favorable for effective SPME. The extraction performance of TiO 2 /NiOCNSs-Ph coated NiTi (NiTi-TiO 2 /NiOCNSs-Ph) fiber was investigated for the concentration and detection of ultraviolet (UV) filters, polycyclic aromatic hydrocarbons (PAHs), phthalate acid esters and polychlorinated biphenyls coupled to HPLC with UV detection. The novel fiber exhibited better selectivity for UV filters and PAHs and presented greater extraction capability compared to commercial polydimethylsiloxane and polyacrylate fibers. Under the optimized conditions for SPME of UV filters, the proposed method presented linear ranges from 0.1 to 300μg/L with correlation coefficients of higher than 0.999 and limits of detection from 0.030μg/L to 0.064μg/L. Relative standard deviations (RSDs) were below 7.16% and 8.42% for intra-day and inter-day measurements with the single fiber, respectively. Furthermore RSDs for fiber-to-fiber reproducibility from 6.57% to 8.93% were achieved. The NiTi-TiO 2 /NiOCNSs-Ph fiber can be used up to 200 times. The proposed method was successfully applied to the preconcentration and determination of trace target UV filters in different environmental water samples. The relative recoveries from 87.3% to 104% were obtained with RSDs less than 8.7%. Copyright © 2016 Elsevier B.V. All rights reserved.

Lipopolysaccharide inhibits or accelerates biomedical titanium corrosion depending on environmental acidity

PubMed Central

Yu, Fei; Addison, Owen; Baker, Stephen J; Davenport, Alison J

2015-01-01

Titanium and its alloys are routinely used as biomedical implants and are usually considered to be corrosion resistant under physiological conditions. However, during inflammation, chemical modifications of the peri-implant environment including acidification occur. In addition certain biomolecules including lipopolysaccharide (LPS), a component of Gram-negative bacterial cell walls and driver of inflammation have been shown to interact strongly with Ti and modify its corrosion resistance. Gram-negative microbes are abundant in biofilms which form on dental implants. The objective was to investigate the influence of LPS on the corrosion properties of relevant biomedical Ti substrates as a function of environmental acidity. Inductively coupled plasma mass spectrometry was used to quantify Ti dissolution following immersion testing in physiological saline for three common biomedical grades of Ti (ASTM Grade 2, Grade 4 and Grade 5). Complementary electrochemical tests including anodic and cathodic polarisation experiments and potentiostatic measurements were also conducted. All three Ti alloys were observed to behave similarly and ion release was sensitive to pH of the immersion solution. However, LPS significantly inhibited Ti release under the most acidic conditions (pH 2), which may develop in localized corrosion sites, but promoted dissolution at pH 4–7, which would be more commonly encountered physiologically. The observed pattern of sensitivity to environmental acidity of the effect of LPS on Ti corrosion has not previously been reported. LPS is found extensively on the surfaces of skin and mucosal penetrating Ti implants and the findings are therefore relevant when considering the chemical stability of Ti implant surfaces in vivo. PMID:25634122

Identify OH groups in TiOF{sub 2} and their impact on the lithium intercalation properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Wei; Body, Monique; Legein, Christophe

A detailed investigation on the chemical composition of the cubic form of titanium oxyfluoride-based compound reveals the presence of OH groups substituting the oxide/ fluoride sublattice. The substitution of oxide by hydroxyl groups induces the presence of titanium vacancies (□) which were characterized by {sup 1}H and {sup 19}F solid-state NMR. {sup 1}H NMR shows that OH groups are present as bridging Ti-OH-Ti or terminal OH groups, i.e. sitting close to a titanium vacancy Ti-OH-□. The electrochemical properties vs. Li{sup +}/Li indicates that the presence of OH groups prevents the intercalation of lithium in the upper voltage region (1.2–3 Vmore » vs. Li{sup +}/Li). Indeed, a partial dehydroxylation of the framework enables to improve the reversibility of the lithium insertion/de-insertion processes. Since the presence of OH groups in this type of compounds is usual and depends on the synthesis method employed, this work enables to rationalize the different electrochemical behaviors reported in the literature and further highlights the importance of a good knowledge of the chemical composition with regard to the physico-chemical properties. - Graphical abstract: The substitution of oxide by hydroxyl groups inducing the formation of titanium vacancies (□), i.e., Ti{sub 1−x}□{sub x}O{sub 1-4x}(OH){sub 4x+y}F{sub 2−y}, was characterized by solid-state {sup 1}H and {sup 19}F NMR. - Highlights: • Evidences of the presence of OH groups and titanium vacancies in titanium oxyfluoride. • {sup 1}H NMR showed the presence of Ti-OH-Ti and Ti-OH-□ species. • The presence of OH groups limits the insertion of lithium within the interstitial sites.« less

The development of self-expanding peripheral stent with ion-modified surface layer

NASA Astrophysics Data System (ADS)

Lotkov, Alexander I.; Kashin, Oleg A.; Kudryashov, Andrey N.; Krukovskii, Konstantin V.; Kuznetsov, Vladimir M.; Borisov, Dmitry P.; Kretov, Evgenii I.

2016-11-01

In work researches of chemical composition of surface layers of self-expanding stents of nickel-titanium (NiTi) and their functional and mechanical properties after plasma immersion processing by ions of silicon (Si). It is established that in the treatment in the inner and outer surfaces of stents formed doped silicon layer with a thickness of 80 nm. The formation of the doped layer does not impair the functional properties of the stent. At human body temperature, the stent is fully restore its shape after removing the deforming load. The resulting graph of loading of stents during their compression between parallel plates. The research results allow the conclusion that Si-doped stents are promising for treatment of peripheral vascular disease. However, related studies on laboratory animals are required.

Nanometer-resolved chemical analyses of femtosecond laser-induced periodic surface structures on titanium

NASA Astrophysics Data System (ADS)

Kirner, Sabrina V.; Wirth, Thomas; Sturm, Heinz; Krüger, Jörg; Bonse, Jörn

2017-09-01

The chemical characteristics of two different types of laser-induced periodic surface structures (LIPSS), so-called high and low spatial frequency LIPSS (HSFL and LSFL), formed upon irradiation of titanium surfaces by multiple femtosecond laser pulses in air (30 fs, 790 nm, 1 kHz), are analyzed by various optical and electron beam based surface analytical techniques, including micro-Raman spectroscopy, energy dispersive X-ray analysis, X-ray photoelectron spectroscopy, and Auger electron spectroscopy. The latter method was employed in a high-resolution mode being capable of spatially resolving even the smallest HSFL structures featuring spatial periods below 100 nm. In combination with an ion sputtering technique, depths-resolved chemical information of superficial oxidation processes was obtained, revealing characteristic differences between the two different types of LIPSS. Our results indicate that a few tens of nanometer shallow HSFL are formed on top of a ˜150 nm thick graded superficial oxide layer without sharp interfaces, consisting of amorphous TiO2 and partially crystallized Ti2O3. The larger LSFL structures with periods close to the irradiation wavelength originate from the laser-interaction with metallic titanium. They are covered by a ˜200 nm thick amorphous oxide layer, which consists mainly of TiO2 (at the surface) and other titanium oxide species of lower oxidation states underneath.

Bioactive borate glass coatings for titanium alloys.

PubMed

Peddi, Laxmikanth; Brow, Richard K; Brown, Roger F

2008-09-01

Bioactive borate glass coatings have been developed for titanium and titanium alloys. Glasses from the Na(2)O-CaO-B(2)O(3) system, modified by additions of SiO(2), Al(2)O(3), and P(2)O(5), were characterized and compositions with thermal expansion matches to titanium were identified. Infrared and X-ray diffraction analyses indicate that a hydroxyapatite surface layer forms on the borate glasses after exposure to a simulated body fluid for 2 weeks at 37 degrees C; similar layers form on 45S5 Bioglass((R)) exposed to the same conditions. Assays with MC3T3-E1 pre-osteoblastic cells show the borate glasses exhibit in vitro biocompatibility similar to that of the 45S5 Bioglass((R)). An enameling technique was developed to form adherent borate glass coatings on Ti6Al4V alloy, with adhesive strengths of 36 +/- 2 MPa on polished substrates. The results show these new borate glasses to be promising candidates for forming bioactive coatings on titanium substrates.

Investigation of the structure and properties of titanium-stainless steel permanent joints obtained by laser welding with the use of intermediate inserts and nanopowders

NASA Astrophysics Data System (ADS)

Cherepanov, A. N.; Orishich, A. M.; Pugacheva, N. B.; Shapeev, V. P.

2015-03-01

Results of an experimental study of the structure, the phase composition, and the mechanical properties of laser-welded joints of 3-mm thick titanium and 12Kh18N10T steel sheets obtained with the use of intermediate inserts and nanopowdered modifying additives are reported. It is shown that that such parameters as the speed of welding, the radiation power, and the laser-beam focal spot position all exert a substantial influence on the welding-bath process and on the seam structure formed. In terms of chemical composition, most uniform seams with the best mechanical strength are formed at a 1-m/min traverse speed of laser and 2.35-kW laser power, with the focus having been positioned at the lower surface of the sheets. Under all other conditions being identical, uplift of the focus to workpiece surface or to a higher position results in unsteady steel melting, in a decreased depth and reduced degree of the diffusion-induced mixing of elements, and in an interpolate connection formed according to the soldering mechanism in the root portion of the seam. The seam material is an over-saturated copper-based solid solution of alloying elements with homogeneously distributed intermetallic disperse particles (Ti(Fe, Cr)2 and TiCu3) contained in this alloy. Brittle fracture areas exhibiting cleavage and quasi-cleavage facets correspond to coarse Ti(Fe, Cr)2 intermetallic particles or to diffusion zones primarily occurring at the interface with the titanium alloy. The reported data and the conclusions drawn from the numerical calculations of the thermophysical processes of welding of 3-mm thick titanium and steel sheets through an intermediate copper insert are in qualitative agreement with the experimental data. The latter agreement points to adequacy of the numerical description of the melting processes of contacting materials versus welding conditions and focal-spot position in the system.

An in vivo study on the effect of coating stability on osteointegration performance of collagen/hyaluronic acid multilayer modified titanium implants.

PubMed

Ao, Haiyong; Zong, Jiajia; Nie, Yanjiao; Wan, Yizao; Zheng, Xiebin

2018-03-01

Aseptic loosening of implant is one of the main causes of Ti-based implant failure. In our previous work, a novel stable collagen/hyaluronic acid (Col/HA) multilayer modified titanium coatings (TCs) was developed by layer-by-layer (LBL) covalent immobilization technique, which showed enhanced biological properties compared with TCs that were physically absorbed with Col/HA multilayer in vitro . In this study, a rabbit model with femur condyle defect was employed to compare the osteointegration performance of them. Results indicated that Col/HA multilayer with favourable stability could better facilitate osteogenesis around implants and bone-implant contact. The Col/HA multilayer covalent-immobilized TC may reduce aseptic loosening of implant.

Polishing and coating carbon fiber-reinforced carbon composites with a carbon-titanium layer enhances adhesion and growth of osteoblast-like MG63 cells and vascular smooth muscle cells in vitro.

PubMed

Bacáková, L; Starý, V; Kofronová, O; Lisá, V

2001-03-15

Carbon fiber-reinforced carbon composites (CFRC) are considered to be promising materials for orthopedic and dental surgery. Their mechanical properties can be tailored to be similar to those of bone, and their chemical composition (close to pure carbon) promises that they will be tolerated well by the surrounding tissue. In this study, CFRC composites were fabricated from phenolic resin and unidirectionally oriented Torayca carbon fibers by carbonization (1000 degrees C) and graphitization (2500 degrees C). The material then was cut with a diamond saw into sheets of 8 x 10 x 3 mm, and the upper surface was polished by colloidal SiO2 and/or covered with a carbon-titanium (C:Ti) layer (3.3 microm) using the plasma-enhanced physical vapor deposition method. Three different kinds of modified samples were prepared: polished only, covered only, and polished + covered. Untreated samples served as a control. The surface roughness of these samples, measured by a Talysurf profilometer, decreased significantly after polishing but usually did not decrease after coating with a C:Ti layer. On all three modified surfaces, human osteoblast-like cells of the MG63 line and rat vascular smooth muscle cells (both cultured in a Dulbecco's minimum essential medium with 10% fetal bovine serum) adhered at higher numbers (by 21-87% on day 1 after seeding) and exhibited a shorter population doubling time (by 13-40%). On day 4 after seeding, these cells attained higher population densities (by 61-378%), volume (by 18-37%), and protein content (by 16-120%). These results were more pronounced in VSMC than in MG63 cells and in both groups of C:Ti-covered samples than in the polished only samples. The release of carbon particles from the CFRC composites was significantly decreased--by 8 times in the polished only, 24 times in the covered only, and 42 times in the polished + covered samples. These results show that both polishing and carbon-titanium covering significantly improve the biocompatibility of CFRC composites in vitro, especially when these two modifications are combined.

Influence of spacer length on heparin coupling efficiency and fibrinogen adsorption of modified titanium surfaces

PubMed Central

Tebbe, David; Thull, Roger; Gbureck, Uwe

2007-01-01

Background Chemical bonding of the drug onto surfaces by means of spacer molecules is accompanied with a reduction of the biological activity of the drug due to a constricted mobility since normally only short spacer molecule like aminopropyltrimethoxysilane (APMS) are used for drug coupling. This work aimed to study covalent attachment of heparin to titanium(oxide) surfaces by varying the length of the silane coupling agent, which should affect the biological potency of the drug due to a higher mobility with longer spacer chains. Methods Covalent attachment of heparin to titanium metal and TiO2 powder was carried out using the coupling agents 3-(Trimethoxysilyl)-propylamine (APMS), N- [3-(Trimethoxysilyl)propyl]ethylenediamine (Diamino-APMS) and N1- [3-(Trimethoxy-silyl)-propyl]diethylenetriamine (Triamino-APMS). The amount of bound coupling agent and heparin was quantified photometrically by the ninhydrin reaction and the tolidine-blue test. The biological potency of heparin was determined photometrically by the chromogenic substrate Chromozym TH and fibrinogen adsorption to the modified surfaces was researched using the QCM-D (Quartz Crystal Microbalance with Dissipation Monitoring) technique. Results Zeta-potential measurements confirmed the successful coupling reaction; the potential of the unmodified anatase surface (approx. -26 mV) shifted into the positive range (> + 40 mV) after silanisation. Binding of heparin results in a strongly negatively charged surface with zeta-potentials of approx. -39 mV. The retaining biological activity of heparin was highest for the spacer molecule Triamino-APMS. QCM-D measurements showed a lower viscosity for adsorbed fibrinogen films on heparinised surfaces by means of Triamino-APMS. Conclusion The remaining activity of heparin was found to be highest for the covalent attachment with Triamino-APMS as coupling agent due to the long chain of this spacer molecule and therefore the highest mobility of the drug. Furthermore, the adsorption of fibrinogen on the differently heparinised surfaces in real time demonstrated that with longer spacer chains the ΔD/Δf ratios became higher, which is also associated with better biocompatible properties of the substrates in contact with a biosystem. PMID:17640335

Development and Characterization of Titanium Compound N anostructures

NASA Astrophysics Data System (ADS)

Zhou, Zhou

The development and characterization of titanium compound nanostructures have been achieved, for potential applications in energy industry. Oil and gas, one of the traditional industry fields, observes accumulating demands on active implementations of nanotechnology, for the numerous advantages that nanomaterials can introduce to both product performances and field operations. By using chemical vapor deposition and liquid exfoliation, various titanium compound nanostructures have been synthesized through this project. Attractively, these two material fabrication methods have been recognized to be industrial friendly in terms of cost efficiency and productivity. The development of nanostructures, aiming at oil and gas field applications, presents novel solutions for existing issues, such as low durability of drilling tools, high friction in mechanical operations and ineffective heat dissipation. Titanium compound nanostructures, including titanium borides, nitrides and sulfides are therefore investigated for such applications as protective coating, lubrication and thermal management.

Covalent Immobilization of Enoxacin onto Titanium Implant Surfaces for Inhibiting Multiple Bacterial Species Infection and In Vivo Methicillin-Resistant Staphylococcus aureus Infection Prophylaxis

PubMed Central

Nie, Bin'en; Long, Teng; Ao, Haiyong; Zhou, Jianliang; Tang, Tingting

2016-01-01

ABSTRACT Infection is one of the most important causes of titanium implant failure in vivo. A developing prophylactic method involves the immobilization of antibiotics, especially vancomycin, onto the surface of the titanium implant. However, these methods have a limited effect in curbing multiple bacterial infections due to antibiotic specificity. In the current study, enoxacin was covalently bound to an amine-functionalized Ti surface by use of a polyethylene glycol (PEG) spacer, and the bactericidal effectiveness was investigated in vitro and in vivo. The titanium surface was amine functionalized with 3-aminopropyltriethoxysilane (APTES), through which PEG spacer molecules were covalently immobilized onto the titanium, and then the enoxacin was covalently bound to the PEG, which was confirmed by X-ray photoelectron spectrometry (XPS). A spread plate assay, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to characterize the antimicrobial activity. For the in vivo study, Ti implants were inoculated with methicillin-resistant Staphylococcus aureus (MRSA) and implanted into the femoral medullary cavity of rats. The degree of infection was assessed by radiography, micro-computed tomography, and determination of the counts of adherent bacteria 3 weeks after surgery. Our data demonstrate that the enoxacin-modified PEGylated Ti surface effectively prevented bacterial colonization without compromising cell viability, adhesion, or proliferation in vitro. Furthermore, it prevented MRSA infection of the Ti implants in vivo. Taken together, our results demonstrate that the use of enoxacin-modified Ti is a potential approach to the alleviation of infections of Ti implants by multiple bacterial species. PMID:27799220

Biological Behavior of Osteoblast Cell and Apatite Forming Ability of the Surface Modified Ti Alloys.

PubMed

Zhao, Jingming; Hwang, K H; Choi, W S; Shin, S J; Lee, J K

2016-02-01

Titanium as one kind of biomaterials comes in direct contact with the body, making evaluation of biocompatibility an important aspect to biomaterials development. Surface chemistry of titanium plays an important role in osseointegration. Different surface modification alters the surface chemistry and result in different biological response. In this study, three kinds of mixed acid solutions were used to treat Ti specimens to induce Ca-P formation. Following a strong mixed acid activation process, Ca-P coating successfully formed on the Ti surfaces in simulated body fluid. Strong mixed acid increased the roughness of the metal surface, because the porous and rough surface allows better adhesion between Ca-P coatings and substrates. After modification of titanium surface by mixed acidic solution and subsequently H2O2/HCL treatment evaluation of biocompatibility was conducted from hydroxyapatite formation by biomimetic process and cell viability on modified titanium surface. Nano-scale modification of titanium surfaces can alter cellular and tissue responses, which may benefit osseointegration and dental implant therapy. Results from this study indicated that surface treatment methods affect the surface morphology, type of TiO2 layer formed and subsequent apatite deposition and biological responses. The thermo scientific alamarblue cell viability assay reagent is used to quantitatively measure the viability of mammalian cell lines, bacteria and fungi by incorporating a rapid, sensitive and reliable fluorometric/colorimetric growth indicator, without any toxic and side effect to cell line. In addition, mixed acid treatment uses a lower temperature and shorter time period than widely used alkali treatment.

Synthesis and characterization of a novel porous titanium silicate/g-C{sub 3}N{sub 4} hybrid nanocomposite catalyst for environmental applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adepu, Ajay Kumar; Narayanan, Venkatathri, E-mail: venkatathrin@yahoo.com, E-mail: ajay.kumar553@gmail.com

2016-04-13

Herein we developed a novel porous Titanium silicate/g-C{sub 3}N{sub 4} (TSCN) hybrid composite with a inorganic-organic heterojunction. The synthesized porous TSCN were well characterized by various analytical techniques for structural and chemical properties evaluation. FESEM results shows the growth of finely distributed porous titanium silicate on the surface of the g-C{sub 3}N{sub 4}. Porous TSCN hybrid nanocomposite has a great influence on the electronic and optical properties.

Laboratory Study on the Fatigue Resistance of Asphaltic Concrete Containing Titanium Dioxide

NASA Astrophysics Data System (ADS)

Buhari, Rosnawati; Ezree Abdullah, Mohd; Khairul Ahmad, Mohd; Azhar Tajudin, Saiful; Khatijah Abu Bakar, Siti

2018-03-01

This study aims to evaluate the fatigue performance of modified asphalt mixture using Indirect Tensile Fatigue Test. Titanium Dioxide (TiO2) powder in a form of rutile was used for producing asphalt concrete with lower mixing and compaction temperature compared to conventional hot mix asphalt without reducing its physical and mechanical also resistance to fatigue. The characteristic of the asphalt and modified asphalt was evaluated using penetration test, softening test and rotational viscosity test. Titanium dioxide of 2%, 4%, 6%, 8% and 10% by weight of asphalt has been incorporated into unaged 80/100 asphalt mix in order to improvise its performance and to fulfill the objectives of this experimental study. As a result, TiO2 as an additive is potential to decrease the penetration and increasing the softening point of the asphalt. In terms of fatigue performance testing, addition TiO2 additive does help in improving the fatigue properties as it shows greater result than the control asphalt. In conclusion, TiO2 is great in improving fatigue properties.

Immobilization of Ag nanoparticles/FGF-2 on a modified titanium implant surface and improved human gingival fibroblasts behavior.

PubMed

Ma, Qianli; Mei, Shenglin; Ji, Kun; Zhang, Yumei; Chu, Paul K

2011-08-01

The objective of this study was to form a rapid and firm soft tissue sealing around dental implants that resists bacterial invasion. We present a novel approach to modify Ti surface by immobilizing Ag nanoparticles/FGF-2 compound bioactive factors onto a titania nanotubular surface. The titanium samples were anodized to form vertically organized TiO(2) nanotube arrays and Ag nanoparticles were electrodeposited onto the nanotubular surface, on which FGF-2 was immobilized with repeated lyophilization. A uniform distribution of Ag nanoparticles/FGF-2 was observed on the TiO(2) nanotubular surface. The L929 cell line was used for cytotoxicity assessment. Human gingival fibroblasts (HGFs) were cultured on the modified surface for cytocompatibility determination. The Ag/FGF-2 immobilized samples displayed excellent cytocompatibility, negligible cytotoxicity, and enhanced HGF functions such as cell attachment, proliferation, and ECM-related gene expression. The Ag nanoparticles also exhibit some bioactivity. In conclusion, this modified TiO(2) nanotubular surface has a large potential for use in dental implant abutment. Copyright © 2011 Wiley Periodicals, Inc.

Surface characteristics and bioactivity of oxide film on titanium metal formed by thermal oxidation.

PubMed

Park, Yeong-Joon; Song, Ho-Jun; Kim, In; Yang, Hong-So

2007-04-01

In this study, we characterized the surface of oxide film formed on titanium metal through the use of thermal treatment and investigated the effect of surface characteristics on the bioactivity of titanium. The as-received sample group was prepared by polishing and cleaning CP-Ti as a control group, and thermally oxidized sample groups were prepared by heat treating at 530, 600, 700, 800, 900, and 1000 degrees C respectively. Micro-morphology, crystalline structure, chemical composition, and binding state were evaluated using FE-SEM, XRD, and XPS. The bioactivity of sample groups was investigated by observing the degree of calcium phosphate formation from immersion testing in MEM. The surface characterization tests showed that hydroxyl group content in titanium oxide film was increased, as the density of titanium atoms was high and the surface area was large. In MEM immersion test, initial calcium phosphate formation was dependent upon the thickness of titanium oxide, and resultant calcium phosphate formation depended on the content of the hydroxyl group of the titanium oxide film surface.

Enhanced in vitro biological activity generated by surface characteristics of anodically oxidized titanium--the contribution of the oxidation effect.

PubMed

Wurihan; Yamada, A; Suzuki, D; Shibata, Y; Kamijo, R; Miyazaki, T

2015-05-20

Anodically oxidized titanium surfaces, prepared by spark discharge, have micro-submicron surface topography and nano-scale surface chemistry, such as hydrophilic functional groups or hydroxyl radicals in parallel. The complexity of the surface characteristics makes it difficult to draw a clear conclusion as to which surface characteristic, of anodically oxidized titanium, is critical in each biological event. This study examined the in vitro biological changes, induced by various surface characteristics of anodically oxidized titanium with, or without, release of hydroxyl radicals onto the surface. Anodically oxidized titanium enhanced the expression of genes associated with differentiating osteoblasts and increased the degree of matrix mineralization by these cells in vitro. The phenotypes of cells on the anodically oxidized titanium were the same with, or without, release of hydroxyl radicals. However, the nanomechanical properties of this in vitro mineralized tissue were significantly enhanced on surfaces, with release of hydroxyl radicals by oxidation effects. In addition, the mineralized tissue, produced in the presence of bone morphogenetic protein-2 on bare titanium, had significantly weaker nanomechanical properties, despite there being higher osteogenic gene expression levels. We show that enhanced osteogenic cell differentiation on modified titanium is not a sufficient indicator of enhanced in vitro mineralization. This is based on the inferior mechanical properties of mineralized tissues, without either being cultured on a titanium surface with release of hydroxyl radicals, or being supplemented with lysyl oxidase family members.

Effects of Long Term Thermal Exposure on Chemically Pure (CP) Titanium Grade 2 Room Temperature Tensile Properties and Microstructure

NASA Technical Reports Server (NTRS)

Ellis, David L.

2007-01-01

Room temperature tensile testing of Chemically Pure (CP) Titanium Grade 2 was conducted for as-received commercially produced sheet and following thermal exposure at 550 and 650 K for times up to 5,000 h. No significant changes in microstructure or failure mechanism were observed. A statistical analysis of the data was performed. Small statistical differences were found, but all properties were well above minimum values for CP Ti Grade 2 as defined by ASTM standards and likely would fall within normal variation of the material.

Nondestructive Evaluation (NDE) Exploratory Development for Air Force Systems. Delivery Order 0001: Quick Reaction NDE and Characterization--Effects of Chemical Effects of Chemical Etching after Pre-Inspection Mechanical Cleaning on Fluorescent Penetrant Indications of Fatigue Cracks

DTIC Science & Technology

2011-08-01

Specimen 625 -58 Cleaned with 50-ksi Water Jet ....................... 18 Figure 12. SEM Images of Inconel Specimen 626-63 Cleaned with 50-ksi Water...SEM Images of Inconel Specimen 626-22 Cleaned with Wet Glass Bead.......................... 21 Figure 15. SEM Images of Titanium Specimen 625 -02...Figure 18. SEM Images of Titanium Specimen 625 -40 Cleaned with Dry Al2O3 (240 grit) ............... 24 Figure 19. SEM Images of Inconel Specimen

Effect of applied voltage on surface properties of anodised titanium in mixture of β-glycerophosphate (β-GP) and calcium acetate (CA)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuan, Lee Te, E-mail: gd130079@siswa.uthm.edu.my; Rathi, Muhammad Fareez Mohamad, E-mail: cd110238@siswa.uthm.edu.my; Abidin, Muhamad Yusuf Zainal, E-mail: cd110221@siswa.uthm.edu.my

Anodic oxidation is a surface modification method which combines electric field driven metal and oxygen ion diffusion for formation of oxide layer on the anode surface. This method has been widely used to modify the surface morphology of biomaterial especially titanium. This study aimed to investigate the effect of applied voltage on titanium. Specifically, the titanium foil was anodised in mixture of β-glycerophosphate disodium salt pentahydrate (β-GP) and calcium acetate monohydrate (CA) with different applied voltage (50-350 V), electrolyte concentration (0.04 M β-GP + 0.4 M CA), anodising time (10minutes) and current density (50 and 70 mA.cm{sup −2}) at room temperature. Surfacemore » oxide properties of anodised titanium were characterised by digital single-lens reflex camera (DSLR camera), field emission scanning electron microscope (FESEM) and atomic force microscopy (AFM). At lower applied voltage (≤150 V), surface of titanium foils were relatively smooth. With increasing applied voltage (≥250 V), the oxide layer became more porous and donut-shaped pores were formed on the surface of titanium foils. The AFM results indicated that the surface roughness of anodised titanium increases with increasing of applied voltage. The porous and rough surface is able to promote the osseointegration and reduce the suffering time of patient.« less

Biofilm formation on titanium implants counteracted by grafting gallium and silver ions.

PubMed

Cochis, Andrea; Azzimonti, Barbara; Della Valle, Cinzia; Chiesa, Roberto; Arciola, Carla Renata; Rimondini, Lia

2015-03-01

Biofilm-associated infections remain the leading cause of implant failure. Thanks to its established biocompatibility and biomechanical properties, titanium has become one of the most widely used materials for bone implants. Engineered surface modifications of titanium able to thwart biofilm formation while endowing a safe anchorage to eukaryotic cells are being progressively developed. Here surfaces of disks of commercial grade 2 titanium for bone implant were grafted with gallium and silver ions by anodic spark deposition. Scanning electron microscopy of the surface morphology and energy dispersive X-ray spectroscopy were used for characterization. Gallium-grafted titanium was evaluated in comparison with silver-grafted titanium for both in vivo and in vitro antibiofilm properties and for in vitro compatibility with human primary gingival fibroblasts. Surface-modified materials showed: (i) homogeneous porous morphology, with pores of micrometric size; (ii) absence of cytotoxic effects; (iii) ability to support in vitro the adhesion and spreading of gingival fibroblasts; and (iv) antibiofilm properties. Although both silver and gallium exhibited in vitro strong antibacterial properties, in vivo gallium was significantly more effective than silver in reducing number and viability of biofilm bacteria colonies. Gallium-based treatments represent promising titanium antibiofilm coatings to develop new bone implantable devices for oral, maxillofacial, and orthopedic applications. © 2014 Wiley Periodicals, Inc.

Surface characterization of nickel titanium orthodontic arch wires

PubMed Central

Krishnan, Manu; Seema, Saraswathy; Tiwari, Brijesh; Sharma, Himanshu S.; Londhe, Sanjay; Arora, Vimal

2015-01-01

Background Surface roughness of nickel titanium orthodontic arch wires poses several clinical challenges. Surface modification with aesthetic/metallic/non metallic materials is therefore a recent innovation, with clinical efficacy yet to be comprehensively evaluated. Methods One conventional and five types of surface modified nickel titanium arch wires were surface characterized with scanning electron microscopy, energy dispersive analysis, Raman spectroscopy, Atomic force microscopy and 3D profilometry. Root mean square roughness values were analyzed by one way analysis of variance and post hoc Duncan's multiple range tests. Results Study groups demonstrated considerable reduction in roughness values from conventional in a material specific pattern: Group I; conventional (578.56 nm) > Group V; Teflon (365.33 nm) > Group III; nitride (301.51 nm) > Group VI (i); rhodium (290.64 nm) > Group VI (ii); silver (252.22 nm) > Group IV; titanium (229.51 nm) > Group II; resin (158.60 nm). It also showed the defects with aesthetic (resin/Teflon) and nitride surfaces and smooth topography achieved with metals; titanium/silver/rhodium. Conclusions Resin, Teflon, titanium, silver, rhodium and nitrides were effective in decreasing surface roughness of nickel titanium arch wires albeit; certain flaws. Findings have clinical implications, considering their potential in lessening biofilm adhesion, reducing friction, improving corrosion resistance and preventing nickel leach and allergic reactions. PMID:26843749

Titanium Surface Roughing Treatments contribute to Higher Interaction with Salivary Proteins MG2 and Lactoferrin.

PubMed

Cavalcanti, Yuri Wanderley; Soare, Rodrigo Villamarim; Leite Assis, Marina Araújo; Zenóbio, Elton Gonçalves; Girundi, Francisco Mauro da Silva

2015-02-01

Some surface treatments performed on titanium can alter the composition of salivary pellicle formed on this abiotic surface. Such treatments modify the titanium's surface properties and can promote higher adsorption of proteins, which allow better integration of titanium to the biotic system. This study aimed to evaluate the interactions between salivary proteins and titanium disks with different surface treatments. Machined titanium disks (n = 48) were divided into four experimental groups (n = 12), according to their surface treatments: surface polishing (SP); acid etching (A); spot-blasting plus acid etching (SB-A); spot-blasting followed by acid etching and nano-functionalization (SB-A-NF). Titanium surfaces were characterized by surface roughness and scanning electron microscopy (SEM). Specimens were incubated with human saliva extracted from submandibular and sublingual glands. Total salivary protein adsorbed to titanium was quantified and samples were submitted to western blotting for mucin glycoprotein 2 (MG2) and lactoferrin identification. Surface roughness was statistically higher for SB-A and SB-A-NF groups. Scanning electron microscopy images confirmed that titanium surface treatments increased surface roughness with higher number of porous and scratches for SB-A and SB-A-NF groups. Total protein adsorption was significantly higher for SB-A and SB-A-NF groups (p < 0.05), which also presented higher interactions with MG2 and lactoferrin proteins. The roughing of titanium surface by spot-blasting plus acid etching treatments contribute to higher interaction with salivary proteins, such as MG2 and lactoferrin. Titanium surface roughing increases the interactions of the substratum with salivary proteins, which can influence the integration of dental implants and their components to the oral environment. However, those treatments should be used carefully intraorally, avoiding increase biofilm formation.

A titanium hydride gun for plasma injection into the T2-reversed field pinch device

NASA Astrophysics Data System (ADS)

Voronin, A. V.; Hellblom, K. G.

1999-02-01

A study of a plasma gun (modified Bostic type) with titanium hydride electrodes has been carried out. The total number of released hydrogen atoms was in the range 1016-1018 and the maximum plasma flow velocity was 2.5×105 m s-1. The ion density near the gun edge reached 1.8×1020 m-3 and the electron temperature was around 40 eV as estimated from probe measurements. No species other than hydrogen or titanium were seen in the plasma line radiation. The plasma injector was successfully used for gas pre-ionization in the Extrap T2 reversed-field pinch device (ohmic heating toroidal experiment (OHTE)).

THE HOT HARDNESS OF TITANIUM AND TITANIUM ALLOYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larson, F.R.

1958-07-01

The hot hardness of 27 different heats of titanium and titunium alloys was studied. Tests were conducted on a modified Rockwell machine in an argon atmosphere. Results indicate that low alloy heats lose their hardnesses at a fairly high even rate. On thc other hand, high alloy heats hold their hardnesses well up to about 1100 d F, and then the hardness drops off very sharply with increasing temperature. The influence of alloying elements in promoting resistance to softening was evaluated at 900 d F. Iron was found to be the most effective with the other elements being arranged inmore » order of decreasing effect, as follows: manganese, (auth)« less

Chances and limitations of nanosized titanium dioxide practical application in view of its physicochemical properties

NASA Astrophysics Data System (ADS)

Bogdan, Janusz; Jackowska-Tracz, Agnieszka; Zarzyńska, Joanna; Pławińska-Czarnak, Joanna

2015-02-01

Nanotechnology is a field of science that is nowadays developing in a dynamic way. It seems to offer almost endless opportunities of contribution to many areas of economy and human activity, in general. Thanks to nanotechnology, the so-called nanomaterials can be designed. They present structurally altered materials, with their physical, chemical and biological properties entirely differing from properties of the same materials manufactured in microtechnology. Nanotechnology creates a unique opportunity to modify the matter at the level of atoms and particles. Therefore, it has become possible to obtain items displaying new, useful properties, i.e. self-disinfecting and self-cleaning surfaces. Those surfaces are usually covered by a thin layer of a photocatalyst. The role of the photocatalyst is most of the time performed by the nanosized titanium dioxide (nano-TiO2). Excitation of nano-TiO2 by ultraviolet radiation initiates advanced oxidation processes and reactions leading to the creation of oxygen vacancies that bind water particles. As a result, photocatalytic surfaces are given new properties. Those properties can then be applied in a variety of disciplines, such as medicine, food hygiene, environmental protection or building industry. Practically, the applications include inactivation of microorganisms, degradation of toxins, removing pollutants from buildings and manufacturing of fog-free windows or mirrors.

Bone tissue reactions to biomimetic ion-substituted apatite surfaces on titanium implants.

PubMed

Ballo, Ahmed M; Xia, Wei; Palmquist, Anders; Lindahl, Carl; Emanuelsson, Lena; Lausmaa, Jukka; Engqvist, Håkan; Thomsen, Peter

2012-07-07

The aim of this study was to evaluate the bone tissue response to strontium- and silicon-substituted apatite (Sr-HA and Si-HA) modified titanium (Ti) implants. Sr-HA, Si-HA and HA were grown on thermally oxidized Ti implants by a biomimetic process. Oxidized implants were used as controls. Surface properties, i.e. chemical composition, surface thickness, morphology/pore characteristics, crystal structure and roughness, were characterized with various analytical techniques. The implants were inserted in rat tibiae and block biopsies were prepared for histology, histomorphometry and scanning electron microscopy analysis. Histologically, new bone formed on all implant surfaces. The bone was deposited directly onto the Sr-HA and Si-HA implants without any intervening soft tissue. The statistical analysis showed significant higher amount of bone-implant contact (BIC) for the Si-doped HA modification (P = 0.030), whereas significant higher bone area (BA) for the Sr-doped HA modification (P = 0.034), when compared with the non-doped HA modification. The differences were most pronounced at the early time point. The healing time had a significant impact for both BA and BIC (P < 0.001). The present results show that biomimetically prepared Si-HA and Sr-HA on Ti implants provided bioactivity and promoted early bone formation.

High-Quality TiS2 For Li/TiS2 Cells

NASA Technical Reports Server (NTRS)

Huang, Chen-Kuo; Surampudi, Subbarao; Shen, David H.; Delgiannis, Fotios; Halpert, Gerald

1992-01-01

Modified process for synthesis of battery-grade titanium sulfide (TiS2) yields substantially improved material for Li/TiS2 electrochemical cells. Includes all-vapor-phase reaction between sulfur and titanium. Product less dense and more homogeneous, consists of smaller particles of higher crystalline quality, and purer. Cells have high cathode utilization and long cycle life performance. Expected to find applications in rechargeable lithium batteries for spacecraft, military equipment, telecommunication systems, automobiles, and consumer products.

[A new method for microdrainage using a porous titanium nickelide endoprosthesis in resurgery of uncompensated glaucoma].

PubMed

Eremenko, A I; Mogil'naia, G M; Giunter, V E; Sakhnov, S N; Stebliuk, A N

2006-01-01

Experimental (23 rabbits) and clinical (42 patients with operated glaucoma) studies were conducted to evaluate the effect of a titanium nickelide implant on ocular tissue in modified deep sclerectomy in order to normalize intraocular pressure. Scleral morphological studies in the area of implant placement revealed the formation of a capsule with "fissures" and vessels. Clinically, there was intraocular pressure compensation in 92.8% of the patients operated on.

Multinuclear (27Al, 29Si, 47,49Ti) solid-state NMR of titanium substituted zeolite USY.

PubMed

Ganapathy, S; Gore, K U; Kumar, Rajiv; Amoureux, Jean-Paul

2003-01-01

Multinuclear solid-state NMR spectroscopy, employing 29Si MAS,27Al MAS/3Q-MAS and (47,49)Ti wide-line experiments, has been used for the structural characterization of titanium substituted ultra-stable zeolite Y (Ti-USY). 27Al MAS experiments show the presence of aluminum in four (Al(IV)), five (Al(V)), and six (Al(VI)) coordination, whereas the multiplicity within Al(IV) and Al(VI) is revealed by 27Al 3Q-MAS experiments. Two different tetrahedral and octahedral Al environments are resolved and their isotropic chemical shifts (delta(CS)) and second-order quadrupole interaction parameters (P(Q)) have been determined by a graphical analysis of the 3Q-MAS spectra. The emergence of signal with higher intensity at -101 ppm in the 29Si MAS spectrum of Ti-USY samples indicates the possible occurrence of Q4(3Si,1Ti) type silicon environments due to titanium substitution in the faujasite framework. High-field (11.74T) operation, using a probehead specially designed to handle a large sample volume, has enabled the acquisition of 47,49Ti static spectra and identification of the titanium environment in the zeolite. The chemical shielding and electric field gradient tensors for the titanium environment in the zeolite have been determined by a computer simulation of the quadrupolar broadened static 47,49Ti NMR spectra.

Effect of substrate surface treatment on electrochemically assisted photocatalytic activity of N-S co-doped TiO2 films

NASA Astrophysics Data System (ADS)

Parada-Gamboa, N. J.; Pedraza-Avella, J. A.; Meléndez, A. M.

2017-01-01

To investigate whether different metal surface treatments, performed on meshes of stainless steel 304 and titanium, affect the photocatalytic activity (PCA) of supported modified anodic TiO2 films, metallic substrates were coated with titanium isopropoxide sol-gel precursor modified with thiourea. Substrates were pretreated by some of the following techniques: a) sandblasting, b) pickling, c) hydroxylation and d) passivation. The as-prepared electrode materials were characterized by X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and voltammetry in the dark and under light UVA irradiation. PCA of modified N-S-TiO2 electrodes was evaluated by electrochemically assisted photocatalytic degradation of methyl orange. The results of XPS revealed that N and S were incorporated into the lattice of TiO2. FESEM showed that surface roughness and thickness of films varies depending on surface treatment. Voltammetric and XPS characterization of N-S co-doped TiO2 films supported on stainless steel revealed that their surface contains alpha-Fe2O3/FeOOH. Accordingly, iron contamination of the films coming from stainless steel was detrimental to the degradation of methyl orange. Prior to sol-gel coating process, sandblasting followed by nitric acid passivation for stainless steel or hydrofluoric acid pickling process in the case of titanium improved the PCA of N-S co-doped TiO2 films.

Biomineralized diamond-like carbon films with incorporated titanium dioxide nanoparticles improved bioactivity properties and reduced biofilm formation.

PubMed

Lopes, F S; Oliveira, J R; Milani, J; Oliveira, L D; Machado, J P B; Trava-Airoldi, V J; Lobo, A O; Marciano, F R

2017-12-01

Recently, the development of coatings to protect biomedical alloys from oxidation, passivation and to reduce the ability for a bacterial biofilm to form after implantation has emerged. Diamond-like carbon films are commonly used for implanted medical due to their physical and chemical characteristics, showing good interactions with the biological environment. However, these properties can be significantly improved when titanium dioxide nanoparticles are included, especially to enhance the bactericidal properties of the films. So far, the deposition of hydroxyapatite on the film surface has been studied in order to improve biocompatibility and bioactive behavior. Herein, we developed a new route to obtain a homogeneous and crystalline apatite coating on diamond-like carbon films grown on 304 biomedical stainless steel and evaluated its antibacterial effect. For this purpose, films containing two different concentrations of titanium dioxide (0.1 and 0.3g/L) were obtained by chemical vapor deposition. To obtain the apatite layer, the samples were soaked in simulated body fluid solution for up to 21days. The antibacterial activity of the films was evaluated by bacterial eradication tests using Staphylococcus aureus biofilm. Scanning electron microscopy, X-ray diffraction, Raman scattering spectroscopy, and goniometry showed that homogeneous, crystalline, and hydrophilic apatite films were formed independently of the titanium dioxide concentration. Interestingly, the diamond-like films containing titanium dioxide and hydroxyapatite reduced the biofilm formation compared to controls. A synergism between hydroxyapatite and titanium dioxide that provided an antimicrobial effect against opportunistic pathogens was clearly observed. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioactive macroporous titanium implants highly interconnected.

PubMed

Caparrós, Cristina; Ortiz-Hernandez, Mónica; Molmeneu, Meritxell; Punset, Miguel; Calero, José Antonio; Aparicio, Conrado; Fernández-Fairén, Mariano; Perez, Román; Gil, Francisco Javier

2016-10-01

Intervertebral implants should be designed with low load requirements, high friction coefficient and low elastic modulus in order to avoid the stress shielding effect on bone. Furthermore, the presence of a highly interconnected porous structure allows stimulating bone in-growth and enhancing implant-bone fixation. The aim of this study was to obtain bioactive porous titanium implants with highly interconnected pores with a total porosity of approximately 57 %. Porous Titanium implants were produced by powder sintering route using the space holder technique with a binder phase and were then evaluated in an in vivo study. The size of the interconnection diameter between the macropores was about 210 μm in order to guarantee bone in-growth through osteblastic cell penetration. Surface roughness and mechanical properties were analyzed. Stiffness was reduced as a result of the powder sintering technique which allowed the formation of a porous network. Compression and fatigue tests exhibited suitable properties in order to guarantee a proper compromise between mechanical properties and pore interconnectivity. Bioactivity treatment effect in novel sintered porous titanium materials was studied by thermo-chemical treatments and were compared with the same material that had undergone different bioactive treatments. Bioactive thermo-chemical treatment was confirmed by the presence of sodium titanates on the surface of the implants as well as inside the porous network. Raman spectroscopy results suggested that the identified titanate structures would enhance in vivo apatite formation by promoting ion exchange for the apatite formation process. In vivo results demonstrated that the bioactive titanium achieved over 75 % tissue colonization compared to the 40 % value for the untreated titanium.

In Situ Materials Study in Hot Hydrothermal Vent Fluid

NASA Astrophysics Data System (ADS)

Holland, P. M.; Schindele, W. J.; Holland, C. E.; Lilley, M. D.; Olson, E. J.

2004-12-01

We are developing methods and technology for in situ sampling and analysis of volatiles from hot hydrothermal vent fluids inside the mixing boundary. These fluids can reach temperatures of up to 400° C and are known to be corrosive to most materials. While titanium has been the material of choice for contact with these fluids, we wanted to assess whether other materials, such as Hastelloy or nickel might be suitable for in situ sampling from hydrothermal vents. For the present study, small (1/16" o.d.) tubes of chemically pure titanium, Hastelloy C, and Nickel 200 were prepared, using 316 stainless steel as a control. These were placed in an assembly with other test items, and inserted into the hydrothermal vent Sully in the Main Endeavor Field on the Juan de Fuca Plate in June 2003 by the Jason II ROV operated from the R/V Thompson. The assembly was retrieved 46 days later after exposure to approximately 360° C hydrothermal vent fluid at a depth of 2200 m. Inspection showed the stainless steel to be completely eroded away and nickel to be extensively corroded, however both the Hastelloy and titanium tubes were in excellent condition with the 0.030" i.d. passages in the tubes remaining open. Other test items included a miniature titanium filtered inlet fitting containing an 80 mesh titanium screen made of 0.004" (0.1 mm) chemically pure titanium wire, an Inconel washer and a sapphire ball. Apart from some discoloration, there appeared to be no significant degradation in these materials apart from signs of etching on the sapphire.

Biological response of human bone marrow mesenchymal stem cells to fluoride-modified titanium surfaces.

PubMed

Guida, Luigi; Annunziata, Marco; Rocci, Antonio; Contaldo, Maria; Rullo, Rosario; Oliva, Adriana

2010-11-01

The aim of the present study was to examine the behaviour of human bone marrow-derived mesenchymal stem cells (BM-MSC) to fluoride-modified grit-blasted (F-TiO) titanium surfaces compared with grit-blasted ones (TiO). Implant surfaces were analysed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). BM-MSC were isolated from healthy donors and grown on the implant surfaces. Cell adhesion and proliferation, type I collagen (Col I) synthesis, osteoblastic differentiation (in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular matrix mineralization) were assessed. Furthermore, the ability to affect the osteoblastic/osteoclastic balance in terms of osteoprotegerin (OPG) and activator of nuclear factor κ B ligand (RANKL) ratio was investigated. F-TiO surface showed higher S(a) values (P<0.05) and the presence of nano-scale structures at the AFM and SEM analysis. Comparable cell morphology and similar adhesion values on both surfaces were detected at early time, whereas higher proliferation values on F-TiO samples were observed at 7 and 10 days. Increased Col I and OPG levels for cells grown on F-TiO were found, whereas RANKL was not detectable in any of the conditioned media. BM-MSC showed a similar expression of early and late osteogenic markers on both TiO and F-TiO surfaces. The results of the present study show that the chemical and micro/nano-scale modifications induced by fluoride treatment of TiO-grit blasted surfaces stimulate the proliferation and the extracellular matrix synthesis by BM-MSC, as well as the increase of OPG synthesis, thus preventing osteoclast activation and differentiation. © 2010 John Wiley & Sons A/S.

Sleeve Push Technique: A Novel Method of Space Gaining.

PubMed

Verma, Sanjeev; Bhupali, Nameksh Raj; Gupta, Deepak Kumar; Singh, Sombir; Singh, Satinder Pal

2018-01-01

Space gaining is frequently required in orthodontics. Multiple loops were initially used for space gaining and alignment. The most common used mechanics for space gaining is the use of nickel-titanium open coil springs. The disadvantage of nickel-titanium coil spring is that they cannot be used until the arches are well aligned to receive the stiffer stainless steel wires. Therefore, a new method of gaining space during initial alignment and leveling has been developed and named as sleeve push technique (SPT). The nickel-titanium wires, i.e. 0.012 inches and 0.014 inches along with archwire sleeve (protective tubing) can be used in a modified way to gain space along with alignment. This method helps in gaining space right from day 1 of treatment. The archwire sleeve and nickel-titanium wire in this new SPT act as a mutually synergistic combination and provide the orthodontist with a completely new technique for space opening.

Preparation of superhydrophobic titanium surfaces via electrochemical etching and fluorosilane modification

NASA Astrophysics Data System (ADS)

Lu, Yao; Xu, Wenji; Song, Jinlong; Liu, Xin; Xing, Yingjie; Sun, Jing

2012-12-01

The preparation of superhydrophobic surfaces on hydrophilic metal substrates depends on both surface microstructures and low surface energy modification. In this study, a simple and inexpensive electrochemical method for preparing robust superhydrophobic titanium surfaces is reported. The neutral sodium chloride solution is used as electrolyte. Fluoroalkylsilane (FAS) was used to reduce the surface energy of the electrochemically etched surface. Scanning electron microscopy (SEM) images, energy-dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR) spectra, and contact angle measurement are performed to characterize the morphological features, chemical composition, and wettability of the titanium surfaces. Stability and friction tests indicate that the prepared titanium surfaces are robust. The analysis of electrolyte, reaction process, and products demonstrates that the electrochemical processing is very inexpensive and environment-friendly. This method is believed to be easily adaptable for use in large-scale industry productions to promote the application of superhydrophobic titanium surfaces in aviation, aerospace, shipbuilding, and the military industry.

Corrosion resistance and biological activity of TiO2 implant coatings produced in oxygen-rich environments.

PubMed

Zhang, Rui; Wan, Yi; Ai, Xing; Liu, Zhanqiang; Zhang, Dong

2017-01-01

The physical and chemical properties of bio-titanium alloy implant surfaces play an important role in their corrosion resistance and biological activity. New turning and turning-rolling processes are presented, employing an oxygen-rich environment in order to obtain titanium dioxide layers that can both protect implants from corrosion and also promote cell adhesion. The surface topographies, surface roughnesses and chemical compositions of the sample surfaces were obtained using scanning electron microscopy, a white light interferometer, and the Auger electron spectroscopy, respectively. The corrosion resistance of the samples in a simulated body fluid was determined using electrochemical testing. Biological activity on the samples was also analyzed, using a vitro cell culture system. The results show that compared with titanium oxide layers formed using a turning process in air, the thickness of the titanium oxide layers formed using turning and turning-rolling processes in an oxygen-rich environment increased by 4.6 and 7.3 times, respectively. Using an oxygen-rich atmosphere in the rolling process greatly improves the corrosion resistance of the resulting samples in a simulated body fluid. On samples produced using the turning-rolling process, cells spread quickly and exhibited the best adhesion characteristics.

Modified surface of titanium dioxide nanoparticles-based biosensor for DNA detection

NASA Astrophysics Data System (ADS)

Nadzirah, Sh.; Hashim, U.; Rusop, M.

2018-05-01

A new technique was used to develop a simple and selective picoammeter DNA biosensor for identification of E. coli O157:H7. This biosensor was fabricated from titanium dioxide nanoparticles that was synthesized by sol-gel method and spin-coated on silicon dioxide substrate via spinner. 3-Aminopropyl triethoxy silane (APTES) was used to modify the surface of TiO2. Simple surface modification approach has been applied; which is single dropping of APTES onto the TiO2 nanoparticles surface. Carboxyl modified probe DNA has been bind onto the surface of APTES/TiO2 without any amplifier element. Electrical signal has been used as the indicator to differentiate each step (surface modification of TiO2 and probe DNA immobilization). The I-V measurements indicate extremely low current (pico-ampere) flow through the device which is 2.8138E-10 A for pure TiO2 nanoparticles, 2.8124E-10 A after APTES modification and 3.5949E-10 A after probe DNA immobilization.

[The influences of crystallized compositions in the porcelain on bonding strength of titanium to porcelain].

PubMed

Mo, A; Wang, J; Liao, Y; Cen, Y; Shi, X

2001-12-01

Sufficient porcelain-titanium bond is a vital factor determining the clinical performance of titanium-porcelain restorations. The purpose of this study was to investigate the effects of self-preparation La-porcelain composition on the porcelain-titanium bonding strength and to compare with the Vita Titankeramik. The present study examines 5 different recipes of porcelain by weight%: SiO2, 12%-17%; LaO2, 7%-10%; Al2O3, 9%-14%; B2O3, 23%-31%; CaO, 6%-8%; K2O, 2%-3%; SrO, 2%-4%; Na2O, 1%-3%; SnO2, 8%-10%; ZrO2, 3%-5%; TiO2, 6%-8%. Specimens were tested in push type shear with a universal testing machine. Scanning electron microscopy (SEM) and electron probe microanalyzer (EPMA) were employed to reveal the microstructures and diffusion of elements in the interfacial regions between the porcelain coating and titanium to the bond strength when fired at 800 degrees C. The ratios of crystallized compositions had significant influences on the porcelain-titanium bond strength (P < 0.05). La-porcelain had the highest shear bond strength (37.76 MPa). The shear bond strength of the Vita Titankeramik to titanium was 20.18 MPa. The results of SEM revealed integrity of porcelain-titanium joints in La-porcelain and a greater amount of porosity in the interface of Vita Titankeramik to titanium. EPMA analysis demonstrated the aggregation of Si and Sn in the interfacial regions and their diffusion into the titanium. Chemical compositions of porcelain and ratios of crystallized compositions play the important role in the titanium porcelain bond. La-porcelain had the highest shear bond strength and good porcelain-titanium joints. La-porcelain is a new-style low fusing porcelain/titanium system.

Hybrid Calcium Phosphate Coatings for Titanium Implants

NASA Astrophysics Data System (ADS)

Kharapudchenko, E.; Ignatov, V.; Ivanov, V.; Tverdokhlebov, S.

2017-01-01

Hybrid multilayer coatings were obtained on titanium substrates by the combination of two methods: the micro-arc oxidation in phosphoric acid solution with the addition of calcium compounds to high supersaturated state and RF magnetron sputtering of the target made of synthetic hydroxyapatite. 16 different groups of coatings were formed on titanium substrates and in vitro studies were conducted in accordance with ISO 23317 in the solution simulating body fluid. The studies using SEM, XRD of the coatings of the samples before and after exposure to SBF were performed. The features of morphology, chemical and phase composition of the studied coatings are shown.

Toxic effects of the interaction of titanium dioxide nanoparticles with chemicals or physical factors

PubMed Central

Liu, Kui; Lin, Xialu; Zhao, Jinshun

2013-01-01

Due to their chemical stability and nonallergic, nonirritant, and ultraviolet protective properties, titanium dioxide (TiO2) nanoparticles (NPs) have been widely used in industries such as electronics, optics, and material sciences, as well as architecture, medicine, and pharmacology. However, increasing concerns have been raised in regards to its ecotoxicity and toxicity on the aquatic environment as well as to humans. Although insights have been gained into the effects of TiO2 NPs on susceptible biological systems, there is still much ground to be covered, particularly in respect of our knowledge of the effects of the interaction of TiO2 NPs with other chemicals or physical factors. Studies suggest that interactions of TiO2 NPs with other chemicals or physical factors may result in an increase in toxicity or adverse effects. This review highlights recent progress in the study of the interactive effects of TiO2 NPs with other chemicals or physical factors. PMID:23901269

Fracture surface analysis in composite and titanium bonding: Part 1: Titanium bonding

NASA Technical Reports Server (NTRS)

Sanderson, K. A.; Wightman, J. P.

1985-01-01

Fractured lap shear Ti 6-4 adherends bonded with polyphenyquinoxaline (PPQ) and polysulfone were analyzed. The effects of adherend pretreatment, stress level, thermal aging, anodizing voltage, and modified adhesive of Ti 6-4 adherend bonded with PPQ on lap shear strength were studied. The effect of adherend pretreatment on lap shear strength was investigated for PS samples. Results of scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) used to study the surface topography and surface composition are also discussed.

Biofunctionalization of a “Clickable” Organic Layer Photochemically Grafted on Titanium Substrates

PubMed Central

Li, Yan; Zhao, Meirong; Wang, Jun; Liu, Kai; Cai, Chengzhi

2011-01-01

We have developed a general method combining photochemical grafting and copper-catalyzed click chemistry for biofunctionalization of titanium substrates. The UV-activated grafting of an α,ω-alkenyne onto TiO2/Ti substrates provided a “clickable” thin film platform. The selective attachment of the vinyl end of the molecule to the surface was achieved by masking the alkynyl end with a trimethylgermanyl (TMG) protecting group. Subsequently, various oligo(ethylene glycol) (OEG) derivatives terminated with an azido group were attached to the TMG-alkynyl modified titanium surface via a one-pot deprotection/click reaction. The films were characterized by X-ray photoelectron spectroscopy (XPS), contact angle goniometry, ellipsometry, and atomic force microscopy (AFM). We showed that the titanium surface presenting click-immobilized OEG substantially suppressed the nonspecific attachment of protein and cells as compared to the unmodified titanium substrate. Furthermore, glycine-arginine-glycine-aspartate (GRGD), a cell adhesion peptide, was coimmobilized with OEG on the platform. We demonstrated that the resultant GRGD-presenting thin film on Ti substrates can promote the specific adhesion and spreading of AsPC-1 cells. PMID:21417429

Mineral composition of lunar late mare volcanism revealed from Kaguya SP data

NASA Astrophysics Data System (ADS)

Kato, S.; Morota, T.; Yamaguchi, Y.; Watanabe, S.; Otake, H.; Ohtake, M.; Nimura, T.

2017-12-01

Lunar mare basalts provide insights into the composition and thermal history of the lunar mantle. According to previous studies of crater counting analysis using remote sensing data, the ages of mare basalts suggest a first peak of magma activity at 3.2-3.8 Ga and a second peak at 2 Ga. To understand the mechanism for causing the second peak and its magma source is essential to constrain the thermal history of the lunar mantle. In our previous study [Kato et al., 2017], we reassess the correlation between the titanium contents and the eruption ages of mare basalt units using the compositional and chronological data updated by SELENE (Kaguya). The results show a rapid increase in mean titanium content near 2.3 Ga in the Procellarum KREEP Terrane (PKT), where the latest eruptions are concentrated. Moreover, the high-titanium basaltic eruptions are correlated with the second peak in volcanic activity at 2 Ga. Here we designate volcanisms before and after 2.3 Ga as Phase-1 and Phase-2 volcanism. To understand the mechanism of Phase-2 mare volcanism and its magma source, determining the mineral components and elemental compositions of mare basalts in the PKT is important. Nimura [2011] improved the modified Gaussian model (MGM) [Sunshine et al., 1990] by obtaining the relations between chemical compositions of minerals (the ratio of Fe/(Fe+Mg) in olivine and the ratios of Ca/(Ca+Fe+Mg) and Fe/(Ca+Fe+Mg) in pyroxene) and absorption band parameters (center, width and strength ratio of Gaussian curves). In this study, we re-derived the relations using experimental spectral data and applied the method to spectral data of mare basalts obtained by Kaguya Spectral Profiler (SP) to estimate the mineral components and elemental compositions of lunar mare basalts.

Metal injection molding of titanium for medical and aerospace applications

NASA Astrophysics Data System (ADS)

Scharvogel, Matthias; Winkelmueller, Wendelin

2011-02-01

Mixing of titanium powder and thermoplastic binders creates a feedstock that is injection molded similar to plastic, has a chemical and thermal debinding process, and then is sintered to form a net-shape or near-net shape part. TiJet Medizintechnik GmbH (TiJet) developed and uses its own feedstock and powder processing technology to achieve desired mechanical properties. This paper explains the theory of the process and the possibilities that result from the development of this new powder processing technology, such as new alloys, design possibilities, etc. Discussed will be the microstructure, chemical composition, and mechanical properties of the manufactured parts.

Nanotextured titanium surfaces stimulate spreading, migration, and growth of rat mast cells.

PubMed

Marcatti Amarú Maximiano, William; Marino Mazucato, Vivian; Tambasco de Oliveira, Paulo; Célia Jamur, Maria; Oliver, Constance

2017-08-01

Titanium is a biomaterial widely used in dental and orthopedic implants. Since tissue-implant interactions occur at the nanoscale level, nanotextured titanium surfaces may affect cellular activity and modulate the tissue response that occurs at the tissue-implant interface. Therefore, the characterization of diverse cell types in response to titanium surfaces with nanotopography is important for the rational design of implants. Mast cells are multifunctional cells of the immune system that release a range of chemical mediators involved in the inflammatory response that occurs at the tissue-implant interface. Therefore, the aim of this study was to investigate the effects of the nanotopography of titanium surfaces on the physiology of mast cells. The results show that the nanotopography of titanium surfaces promoted the spreading of mast cells, which was accompanied by the reorganization of the cytoskeleton. Also, the nanotopography of titanium surfaces enhanced cell migration and cell growth, but did not alter the number of adherent cells in first hours of culture or affect focal adhesions and mediator release. Thus, the results show that nanotopography of titanium surfaces can affect mast cell physiology, and represents an improved strategy for the rational production of surfaces that stimulate tissue integration with the titanium implants. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2150-2161, 2017. © 2017 Wiley Periodicals, Inc.

The Growth Behavior of Titanium Boride Layers in α and β Phase Fields of Titanium

NASA Astrophysics Data System (ADS)

Lv, Xiaojun; Hu, Lingyun; Shuang, Yajing; Liu, Jianhua; Lai, Yanqing; Jiang, Liangxing; Li, Jie

2016-07-01

In this study, the commercially pure titanium was successfully electrochemical borided in a borax-based electrolyte. The process was carried out at a constant cathodic current density of 300 mA cm-2 and at temperatures of 1123 K and 1223 K (850 °C and 950 °C) for 0.5, 1, 2, 3, and 5 hours. The growth behavior of titanium boride layers in the α phase field of titanium was compared with that in the β phase field. After boriding, the presence of both the TiB2 top layer and TiB whisker sub-layer was confirmed by the X-ray diffraction (XRD) and scanning electron microscope. The relationship between the thickness of boride layers and boriding time was found to have a parabolic character in both α and β phase fields of titanium. The TiB whiskers showed ultra-fast growth rate in the β phase field. Its growth rate constant was found to be as high as 3.2002 × 10-13 m2 s-1. Besides, the chemical resistance of the TiB2 layer on the surface of titanium substrate was characterized by immersion tests in molten aluminum.

Environmental protection of titanium alloys at high temperatures

NASA Technical Reports Server (NTRS)

Wright, I. G.; Wood, R. A.; Seltzer, M. S.

1974-01-01

Various concepts were evaluated for protecting titanium alloys from oxygen contamination at 922 K (1200 F) and from hot-salt stress-corrosion at 755 K (900 F). It is indicated that oxygen-contamination resistance can be provided by a number of systems, but for hot-salt stress-corrosion resistance, factors such as coating integrity become very important. Titanium aluminides resist oxygen ingress at 922 K through the formation of alumina (on TiAl3) or modified TiO2 (on Ti3Al, TiAl) scales. TiAl has some resistance to attack by hot salt, but has limited ductility. Ductile Ti-Ni and Ti-Nb-Cr-Al alloys provide limited resistance to oxygen ingress, but are not greatly susceptible to hot-salt stress-corrosion cracking.

Effect of microstructure on the elasto-viscoplastic deformation of dual phase titanium structures

NASA Astrophysics Data System (ADS)

Ozturk, Tugce; Rollett, Anthony D.

2018-02-01

The present study is devoted to the creation of a process-structure-property database for dual phase titanium alloys, through a synthetic microstructure generation method and a mesh-free fast Fourier transform based micromechanical model that operates on a discretized image of the microstructure. A sensitivity analysis is performed as a precursor to determine the statistically representative volume element size for creating 3D synthetic microstructures based on additively manufactured Ti-6Al-4V characteristics, which are further modified to expand the database for features of interest, e.g., lath thickness. Sets of titanium hardening parameters are extracted from literature, and The relative effect of the chosen microstructural features is quantified through comparisons of average and local field distributions.

Fracture characteristics of structural aerospace alloys containing deep surface flaws. [aluminum-titanium alloys

NASA Technical Reports Server (NTRS)

Masters, J. N.; Bixler, W. D.; Finger, R. W.

1973-01-01

Conditions controlling the growth and fracture of deep surface flaws in aerospace alloys were investigated. Static fracture tests were performed on 7075-T651 and 2219-T87 aluminum, and 6Ai-4V STA titanium . Cyclic flaw growth tests were performed on the two latter alloys, and sustain load tests were performed on the titanium alloy. Both the cyclic and the sustain load tests were performed with and without a prior proof overload cycle to investigate possible growth retardation effects. Variables included in all test series were thickness, flaw depth-to-thickness ratio, and flaw shape. Results were analyzed and compared with previously developed data to determine the limits of applicability of available modified linear elastic fracture solutions.

Nanofibers grafted on titanium alloy: the effects of fiber alignment and density on osteoblast mineralization.

PubMed

Lin, Hsin-Yi; Peng, Zhao-Xiang

2017-08-17

The surface of medical implant alloy Ti-6Al-4V was chemically modified to allow it to covalently bond with collagen/PVA nanofibers. These nanofibers were successfully attached to the Ti-6Al-4V surface in three different morphologies: randomly oriented high-density fiber, COL(H); randomly oriented low-density fiber, COL(L); and aligned high-density fiber, COL(A). The effects of the morphology of these covalently-bound collagen nanofibers on the growth and differentiation of osteoblasts were studied for 21 days. The low-density nanofibers covered approximately 80% of the Ti64 surface, while the high-density nanofibers covered nearly 100%. These covalently attached fibrous coatings remained attached to the metal surface after 3 weeks of cell culture. In the first week the aligned fibers of COL(A) allowed the osteoblasts to stretch and elongate in the direction of the fibers. This directional elongation was not seen in the cells on the randomly-oriented samples. Cells proliferated and differentiated on all three surfaces over time. By the end of the test, the amount of type I collagen secreted by the cells on COL(H) was the highest, while the degree of mineralization was highest on COL(A) among the three samples (p < 0.05). Different nanofiber morphologies changed the cell morphology and the secretion of cellular products. The mechanisms remained to be investigated. The surface of medical implant alloy Ti-6Al-4V was chemically modified to allow it to covalently bond with collagen/PVA nanofibers. The SEM micrographs in the top row show the random and aligned morphology of the collagen-PVA nanofibers. The nanofibers on COL(A) were aligned in the general direction indicated by the arrow. The second row are images from EDX titanium element mapping. The location of the titanium elements are shown as bright dots. The low-density nanofibers, COL(L), covered approximately 80% of the Ti64 surface, while the high-density nanofibers, COL(H) and COL(A), covered nearly 100%. All three surfaces demonstrated good biocompatibility for the cultured osteoblasts. The fiber alignment seemed to have an effect on early cellular morphology (day 7), collagen secretion and calcium deposition, while the density of the fibers seemed to have no significant effect on cell behavior. SEM micrographs of osteoblasts after 7 and 14 days of cell culture are shown in the third and fourth rows. The surface of COL(L) has more cell-free spots indicated by (*) on day 7 as other two surfaces were covered by cells. The nanofibers could no longer be observed and were covered with mineralized granules (circles) after 14 days of cell culture. The cells appear stretched out on the mineralized granules.

Method for removing oxide contamination from titanium diboride powder

DOEpatents

Brynestad, J.; Bamberger, C.E.

A method for removing oxide contamination from titanium diboride powder involves the direct chemical treatment of TiB/sub 2/ powders with a gaseous boron halide, such as BCl/sub 3/, at temperatures in the range of 500 to 800/sup 0/C. The BCl/sub 3/ reacts with the oxides to form volatile species which are removed by the BCl/sub 3/ exit stream.

Method for removing oxide contamination from titanium diboride powder

DOEpatents

Brynestad, Jorulf; Bamberger, Carlos E.

1984-01-01

A method for removing oxide contamination from titanium diboride powder involves the direct chemical treatment of TiB.sub.2 powders with a gaseous boron halide, such as BCl.sub.3, at temperatures in the range of 500.degree.-800.degree. C. The BCl.sub.3 reacts with the oxides to form volatile species which are removed by the BCl.sub.3 exit stream.

Formation of an ascorbate-apatite composite layer on titanium.

PubMed

Ito, Atsuo; Sogo, Yu; Ebihara, Yuko; Onoguchi, Masahiro; Oyane, Ayako; Ichinose, Noboru

2007-09-01

An ascorbate-apatite composite layer was successfully formed on NaOH- and heat-treated titanium by coprecipitating L-ascorbic acid phosphate and low-crystalline apatite in a supersaturated calcium phosphate solution at 37 degrees C for 48 h. The supersaturated calcium phosphate solutions used have chemical compositions attainable by mixing infusion fluids officially approved for clinical use. The amount of immobilized L-ascorbic acid phosphate ranged from 1.0 to 2.3 microg mm(-2), which is most likely to be sufficient for the in vitro osteogenic differentiation of mesenchymal stem cells on titanium. Since ascorbate is important for the collagen synthesis and subsequent osteogenesis of mesenchymal stem cells, titanium coated with the ascorbate-apatite composite layer would be useful as a scaffold in bone tissue engineering and as a bone substitute.

Comparative Corrosion Behavior of Two Palladium Containing Titanium Alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lian, T; Yashiki, T; Nakayama, T

2006-02-05

The ASTM standard B 265 provides the requirements for the chemical composition of titanium (Ti) alloys. It is planned to use corrosion resistant and high strength titanium alloys to fabricate the drip shield at the proposed Yucca Mountain Repository. Titanium grade (Gr) 7 (R52400) and other Ti alloys are currently being characterized for this application. Ti Gr 7 contains 0.15% Palladium (Pd) to increase its corrosion performance. In this article we report results on the comparative short term corrosion behavior of Ti Gr 7 and a Ruthenium (Ru) containing alloy (Ti Gr 33). Ti Gr 33 also contains a smallmore » amount of Pd. Limited electrochemical testing such as polarization resistance and cyclic potentiodynamic curves showed that both alloys have a similar corrosion behavior in the tested environments.« less

COMPARATIVE CORROSION BEHAVIOR OF TWO PALLADIUM CONTAINING TITANIUM ALLOYS

DOE Office of Scientific and Technical Information (OSTI.GOV)

T. Lian, T. Yashiki, T. Nakayama, T. Nakanishi, R. B. Rebak

2006-07-23

The ASTM standard B 265 provides the requirements for the chemical composition of titanium (Ti) alloys. It is planned to use corrosion resistant and high strength titanium alloys to fabricate the drip shield at the proposed Yucca Mountain Repository. Titanium grade (Gr) 7 (R52400) and other Ti alloys are currently being characterized for this application. Ti Gr 7 contains 0.15% Palladium (Pd) to increase its corrosion performance. In this article we report results on the comparative short term corrosion behavior of Ti Gr 7 and a Ruthenium (Ru) containing alloy (Ti Gr 33). Ti Gr 33 also contains a smallmore » amount of Pd. Limited electrochemical testing such as polarization resistance and cyclic potentiodynamic curves showed that both alloys have a similar corrosion behavior in the tested environments.« less

Medical equipment bio-capability processes using the atmospheric plasma-sprayed titanium coating

NASA Astrophysics Data System (ADS)

Rezaei, F.; Saviz, S.; Ghoranneviss, M.

2017-12-01

Antibacterial surfaces such as titanium coatings are able to have capability in the human body environment. In this study, titanium coatings are deposited on the 316 stainless steel substrates by a handmade plasma spray system. Some mechanical, chemical properties and microstructure of the created titanium layer are determined to evaluate the quality of coating. The XRD, SEM, adhesion tests from cross cut and corrosion test by potentiodynamic are used. During the different stages, some of the parameters are changed in different samples to achieve the best quality in the coating. It is shown that by increasing the spray time, the production of nanoparticles begins. On the other hand, the best layers are created when the spray main gas flow rate has a certain amount.

Investigation of electrical and optical properties of low temperature titanium nitride grown by rf-magnetron sputtering

NASA Astrophysics Data System (ADS)

Sosnin, D.; Kudryashov, D.; Mozharov, A.

2017-11-01

Titanium nitride is a promising material due to its low resistivity, high hardness and chemical inertness. Titanium nitride (TiN) can be applied as an ohmic contact for n-GaN and rectifying contact for p-GaN and also as a part of perovskite solar cell. A technology of TiN low temperature reactive rf-magnetron sputtering has been developed. Electrical and optical properties of titanium nitride were studied as a function of the rf-power and gas mixture composition. Reflectance and transmittance spectra were measured. Cross-section and surface SEM image were obtained. 250 nm thin films of TiN with a resistivity of 23.6 μOm cm were obtained by rf-magnetron sputtering at low temperature.

Surface characteristics and biocompatibility of cranioplasty titanium implants following different surface treatments.

PubMed

Hatamleh, Muhanad M; Wu, Xiaohong; Alnazzawi, Ahmad; Watson, Jason; Watts, David

2018-04-01

Surface and mechanical properties of titanium alloys are integral for their use in restoring bone defects of skull and face regions. These properties are affected by the method of constructing and surface treatment of the titanium implant. This study aimed to investigate the effects of titanium finishing protocols on the surface morphology, hardness and biocompatibility of TiAl6V4. Square shaped TiAl6V4 specimens (ASTM F68) (10×10×0.5mm) were divided into seven groups of different surface treatments (n=10). The treatments included mechanical polishing, sandblasting with AL 2 O 3 (50μm), immersion in different acids, and/or electro-chemical anodization. Weight loss %; 3D micro-roughness; Knoop micro-hardness, and osteoblast cell attachment and proliferation (after 3 days) were determined for each specimen. Data was analysed using one way ANOVA and Dunett T3 post-hoc tests, and t-test (p<0.05). Weight loss % was in the range of 1.70-5.60 as mechanical polishing produced the highest weight loss, followed by sandblasting, and combined protocol of mechanical polishing and acid treatment (p<0.05). Micro-roughness values (μm) were in the range of 2.81-16.68. It was the highest for control specimens (p<0.05), and smoothest surfaces after combined mechanical polishing and acid treatment; or after electro-chemical treatment (p<0.05). Micro-hardness values (MPa) ranged 170.90-442.15 as sandblasting with/without acid treatment caused statically significantly the highest values (p<0.05) while control and mechanically polished specimens had the lowest values (p<0.05). All treatments produced equally biocompatible surfaces (p>0.05) after 1h or 3 days. Furthermore, osteoblast cell proliferation statistically significantly increased after 3days among each surface treatment (p<0.05). Different finishing treatments have variable effect on cranioplasty titanium surface loss, micro-roughness and micro-hardness but constant improved biocompatibility effect. Electro-chemical treatment caused less material loss and produced biocompatible smoothest surface of comparable hardness; hence it can be suitable for cranioplasty titanium surface finishing. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Synthesis of walnut shell modified with titanium dioxide and zinc oxide nanoparticles for efficient removal of humic acid from aqueous solutions.

PubMed

Naghizadeh, Ali; Shahabi, Habibeh; Ghasemi, Fatemeh; Zarei, Ahmad

2016-12-01

The main aim of this research was to study the efficiency of modified walnut shell with titanium dioxide (TiO 2 ) and zinc oxide (ZnO) in the adsorption of humic acid from aqueous solutions. This experimental study was carried out in a batch condition to determine the effects of factors such as contact time, pH, humic acid concentration, dose of adsorbents (raw walnut shell, modified walnut shell with TiO 2 and ZnO) on the removal efficiency of humic acid. pH zpc of raw walnut shell, walnut shell modified with TiO 2 and walnut shell modified with ZnO were 7.6, 7.5, and 8, respectively. The maximum adsorption capacity of humic acid at concentration of 30 mg/L, contact time of 30 min at pH = 3 in an adsorbent dose of 0.02 g of walnut shell and ZnO and TiO 2 modified walnut shell were found to be 35.2, 37.9, and 40.2 mg/g, respectively. The results showed that the studied adsorbents tended to fit with the Langmuir model. Walnut shell, due to its availability, cost-effectiveness, and also its high adsorption efficiency, can be proposed as a promising natural adsorbent in the removal of humic acid from aqueous solutions.

Modification of the Surface Topography and Composition of Ultrafine and Coarse Grained Titanium by Chemical Etching.

PubMed

Nazarov, Denis V; Zemtsova, Elena G; Solokhin, Alexandr Yu; Valiev, Ruslan Z; Smirnov, Vladimir M

2017-01-13

In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions) and the etching time on the morphology and surface relief of ultrafine grained (UFG) and coarse grained (CG) titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF) and X-ray Photoelectron Spectroscopy (XPS). Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed.

Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide.

PubMed

Riazanova, A V; Costanzi, B N; Aristov, A I; Rikers, Y G M; Mulders, J J L; Kabashin, A V; Dahlberg, E Dan; Belova, L M

2016-03-18

Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10(-6) in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm(-1). The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

Gas-assisted electron-beam-induced nanopatterning of high-quality titanium oxide

NASA Astrophysics Data System (ADS)

Riazanova, A. V.; Costanzi, B. N.; Aristov, A. I.; Rikers, Y. G. M.; Mulders, J. J. L.; Kabashin, A. V.; Dahlberg, E. Dan; Belova, L. M.

2016-03-01

Electron-beam-induced deposition of titanium oxide nanopatterns is described. The precursor is titanium tetra-isopropoxide, delivered to the deposition point through a needle and mixed with oxygen at the same point via a flow through a separate needle. The depositions are free of residual carbon and have an EDX determined stoichiometry of TiO2.2. High resolution transmission electron microscopy and Raman spectroscopy studies reveal an amorphous structure of the fabricated titanium oxide. Ellipsometric characterization of the deposited material reveals a refractive index of 2.2-2.4 RIU in the spectral range of 500-1700 nm and a very low extinction coefficient (lower than 10-6 in the range of 400-1700 nm), which is consistent with high quality titanium oxide. The electrical resistivity of the titanium oxide patterned with this new process is in the range of 10-40 GΩ cm and the measured breakdown field is in the range of 10-70 V μm-1. The fabricated nanopatterns are important for a variety of applications, including field-effect transistors, memory devices, MEMS, waveguide structures, bio- and chemical sensors.

Modification of the Surface Topography and Composition of Ultrafine and Coarse Grained Titanium by Chemical Etching

PubMed Central

Nazarov, Denis V.; Zemtsova, Elena G.; Solokhin, Alexandr Yu.; Valiev, Ruslan Z.; Smirnov, Vladimir M.

2017-01-01

In this study, we present the detailed investigation of the influence of the etching medium (acidic or basic Piranha solutions) and the etching time on the morphology and surface relief of ultrafine grained (UFG) and coarse grained (CG) titanium. The surface relief and morphology have been studied by means of scanning electron microscopy (SEM), atomic force microscopy (AFM), and the spectral ellipsometry. The composition of the samples has been determined by X-ray fluorescence analysis (XRF) and X-ray Photoelectron Spectroscopy (XPS). Significant difference in the etching behavior of UFG and CG titanium has been found. UFG titanium exhibits higher etching activity independently of the etching medium. Formed structures possess higher homogeneity. The variation of the etching medium and time leads to micro-, nano-, or hierarchical micro/nanostructures on the surface. Significant difference has been found between surface composition for UFG titanium etched in basic and acidic Piranha solution. Based on the experimental data, the possible reasons and mechanisms are considered for the formation of nano- and microstructures. The prospects of etched UFG titanium as the material for implants are discussed. PMID:28336849

77 FR 35112 - Petition To Modify an Exemption of a Previously Approved Antitheft Device; Ford Motor Company

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-12

... stated that the Fusion Titanium trim and Fusion Hybrid vehicles will be equipped with the IAwPB system as... Standard for the Ford Fusion vehicle line beginning with its model year (MY) 2012 vehicles. On February 16, 2012, Ford submitted a petition to modify its previously approved exemption for the Ford Fusion vehicle...

Chemical vapor deposition of silicon, silicon dioxide, titanium and ferroelectric thin films

NASA Astrophysics Data System (ADS)

Chen, Feng

Various silicon-based thin films (such as epitaxial, polycrystalline and amorphous silicon thin films, silicon dioxide thin films and silicon nitride thin films), titanium thin film and various ferroelectric thin films (such as BaTiO3 and PbTiO3 thin films) play critical roles in the manufacture of microelectronics circuits. For the past few years, there have been tremendous interests to search for cheap, safe and easy-to-use methods to develop those thin films with high quality and good step coverage. Silane is a critical chemical reagent widely used to deposit silicon-based thin films. Despite its wide use, silane is a dangerous material. It is pyrophoric, extremely flammable and may explode from heat, shock and/or friction. Because of the nature of silane, serious safety issues have been raised concerning the use, transportation, and storage of compressed gas cylinders of silane. Therefore it is desired to develop safer ways to deposit silicon-based films. In chapter III, I present the results of our research in the following fields: (1) Silane generator, (2) Substitutes of silane for deposition of silicon and silicon dioxide thin films, (3) Substitutes of silane for silicon dioxide thin film deposition. In chapter IV, hydropyridine is introduced as a new ligand for use in constructing precursors for chemical vapor deposition. Detachement of hydropyridine occurs by a low-temperature reaction leaving hydrogen in place of the hydropyridine ligands. Hydropyridine ligands can be attached to a variety of elements, including main group metals, such as aluminum and antimony, transition metals, such as titanium and tantalum, semiconductors such as silicon, and non-metals such as phosphorus and arsenic. In this study, hydropyridine-containing titanium compounds were synthesized and used as chemical vapor deposition precursors for deposition of titanium containing thin films. Some other titanium compounds were also studied for comparison. In chapter V, Chemical Vapor Depositions (CVD) of many oxide thin films including ferroelectric and high dielectric constant BaTiO3, SrTiO 3 and PbTiO3 films had been carried out under reduced pressure (30 torr--80 torr) using liquid precursors containing beta-diketone ligands. The relative reactivities of Ba(beta-diketonate)2, Sr(beta-diketonate) 2, Pb(beta-diketonate)2, Ti(beta-diketonate)3, TiO(beta-diketonate)2 and Ti(OiPr)2(beta-diketonate) 2 had been studied individually prior to the deposition of BaTiO 3, SrTiO3 and PbTiO3 thin films from the mixtures of corresponding precursors. By using multi-step deposition method, carbon free stoichiometric BaTiO3 thin films uniform in large area have been achieved.

Biosensing applications of titanium dioxide coated graphene modified disposable electrodes.

PubMed

Kuralay, Filiz; Tunç, Selma; Bozduman, Ferhat; Oksuz, Lutfi; Oksuz, Aysegul Uygun

2016-11-01

In the present work, preparation of titanium dioxide coated graphene (TiO2/graphene) and the use of this nanocomposite modified electrode for electrochemical biosensing applications were detailed. The nanocomposite was prepared with radio frequency (rf) rotating plasma method which serves homogeneous distribution of TiO2 onto graphene. TiO2/graphene was characterized with scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) analysis. Then, this nanocomposite was dissolved in phosphate buffer solution (pH 7.4) and modified onto disposable pencil graphite electrode (PGE) by dip coating for the investigation of the biosensing properties of the prepared electrode. TiO2/graphene modified PGE was characterized with SEM, EDS and cyclic voltammetry (CV). The sensor properties of the obtained surface were examined for DNA and DNA-drug interaction. The detection limit was calculated as 1.25mgL(-1) (n=3) for double-stranded DNA (dsDNA). RSD% was calculated as 2.4% for three successive determinations at 5mgL(-1) dsDNA concentration. Enhanced results were obtained compared to the ones obtained with graphene and unmodified (bare) electrodes. Copyright © 2016 Elsevier B.V. All rights reserved.

Antimicrobial and osteogenic properties of a hydrophilic-modified nanoscale hydroxyapatite coating on titanium.

PubMed

Murakami, Asuka; Arimoto, Takafumi; Suzuki, Dai; Iwai-Yoshida, Misato; Otsuka, Fukunaga; Shibata, Yo; Igarashi, Takeshi; Kamijo, Ryutaro; Miyazaki, Takashi

2012-04-01

Hydroxyapatite (HA)-coated titanium (Ti) is commonly used for implantable medical devices. This study examined in vitro osteoblast gene expression and antimicrobial activity against early and late colonizers of supra-gingival plaque on nanoscale HA-coated Ti prepared by discharge in a physiological buffered solution. The HA-coated Ti surface showed super-hydrophilicity, whereas the densely sintered HA and Ti surfaces alone showed lower hydrophilicity. The sintered HA and HA-coated Ti surfaces enhanced osteoblast phenotypes in comparison with the bare Ti surface. The HA-coated Ti enabled antimicrobial activity against early colonizers of supra-gingival plaques, namely Streptococcus mitis and Streptococcus gordonii. Such antimicrobial activity may be caused by the surface hydrophilicity, thereby leading to a repulsion force between the HA-coated Ti surface and the bacterial cell membranes. On the contrary, the sintered HA sample was susceptible to infection of microorganisms. Thus, hydrophilic-modified HA-coated Ti may have potential for use in implantable medical devices. From the Clinical Editor: This study establishes that Hydroxyapatite (HA)-coated titanium (Ti) surface of implanted devices may result in an optimal microenvironment to control and prevent infections and may have potential future clinical applications. Copyright © 2012 Elsevier Inc. All rights reserved.

Titanium compacts produced by the pulvimetallurgical hydride-dehydride method for biomedical applications.

PubMed

Barreiro, M M; Grana, D R; Kokubu, G A; Luppo, M I; Mintzer, S; Vigna, G

2010-04-01

Titanium powder production by the hydride-dehydride method has been developed as a non-expensive process. In this work, commercially pure grade two Ti specimens were hydrogenated. The hydrided material was milled in a planetary mill. The hydrided titanium powder was dehydrided and then sieved to obtain a particle size between 37 and 125 microm in order to compare it with a commercial powder produced by chemical reduction with a particle size lower than 150 microm. Cylindrical green compacts were obtained by uniaxial pressing of the powders at 343 MPa and sintering in vacuum. The powders and the density of sintered compacts were characterized, the oxygen content was measured and in vivo tests were performed in the tibia bones of Wistar rats in order to evaluate their biocompatibility. No differences were observed between the materials which were produced either with powders obtained by the hydride-dehydride method or with commercial powders produced by chemical reduction regarding modifications in compactation, sintering and biological behaviour.

pH sensitive core-shell magnetic nanoparticles for targeted drug delivery in cancer therapy.

PubMed

Lungu, Iulia Ioana; Rădulescu, Marius; Mogoşanu, George Dan; Grumezescu, Alexandru Mihai

2016-01-01

In the last decade, nanobiotechnology has evolved rapidly with an extensive impact on biomedical area. In order to improve bioavailability and minimize adverse effects, drug delivery systems based on magnetic nanocomposites are under development mainly for cancer imaging and antitumor therapy. In this regard, pH sensitive core-shell magnetic nanoparticles (NPs) with accurate controlled size and shape are synthesized by various modern methods, such as homogeneous precipitation, coprecipitation, microemulsion or polyol approaches, high temperature and hydrothermal reactions, sol-gel reactions, aerosol÷vapor processes and sonolysis. Due to their unique combined physico-chemical and biological properties (such as higher dispensability, chemical and thermal stability, biocompatibility), pH responsive core-shell magnetic NPs are widely investigated for controlled release of cytostatic drugs into the tumor site by means of pH change: magnetite@silicon dioxide (Fe3O4@SiO2), Fe3O4@titanium dioxide (TiO2), β-thiopropionate-polyethylene glycol (PEG)-modified Fe3O4@mSiO2, Fe3O4 NPs core coated with SiO2 with an imidazole group modified PEG-polypeptide (mPEG-poly-L-Asparagine), polyacrylic acid (PAA) and folic acid (FA) coating of the iron oxide NP core, methoxy polyethylene glycol-block-polymethacrylic acid-block-polyglycerol monomethacrylate (MPEG-b-PMAA-b-PGMA) attached by a PGMA block to a Fe3O4 core, PEG-modified polyamidoamine (PAMAM) dendrimer shell with Fe3O4 core and mesoporous silica coated on Fe3O4, mostly coated with an anticancer drug. This review paper highlights the modern research directions currently employed to demonstrate the utility of the pH responsive core-shell magnetic NPs in diagnosis and treatment of oncological diseases.

Attenuation of Neutron and Gamma Radiation by a Composite Material Based on Modified Titanium Hydride with a Varied Boron Content

NASA Astrophysics Data System (ADS)

Yastrebinskii, R. N.

2018-04-01

The investigations on estimating the attenuation of capture gamma radiation by a composite neutron-shielding material based on modified titanium hydride and Portland cement with a varied amount of boron carbide are performed. The results of calculations demonstrate that an introduction of boron into this material enables significantly decreasing the thermal neutron flux density and hence the levels of capture gamma radiation. In particular, after introducing 1- 5 wt.% boron carbide into the material, the thermal neutron flux density on a 10 cm-thick layer is reduced by 11 to 176 factors, and the capture gamma dose rate - from 4 to 9 times, respectively. The difference in the degree of reduction in these functionals is attributed to the presence of capture gamma radiation in the epithermal region of the neutron spectrum.

Surface treatment of a titanium implant using low temperature atmospheric pressure plasmas

NASA Astrophysics Data System (ADS)

Lee, Hyun-Young; Tang, Tianyu; Ok, Jung-Woo; Kim, Dong-Hyun; Lee, Ho-Jun; Lee, Hae June

2015-09-01

During the last two decades, atmospheric pressure plasmas(APP) are widely used in diverse fields of biomedical applications, reduction of pollutants, and surface treatment of materials. Applications of APP to titanium surface of dental implants is steadily increasing as it renders surfaces wettability and modifies the oxide layer of titanium that hinders the interaction with cells and proteins. In this study, we have treated the titanium surfaces of screw-shaped implant samples using a plasma jet which is composed of a ceramic coaxial tube of dielectrics, a stainless steel inner electrode, and a coper tube outer electrode. The plasma ignition occurred with Ar gas flow between two coaxial metal electrodes and a sinusoidal bias voltage of 3 kV with a frequency of 20 kHz. Titanium materials used in this study are screw-shaped implants of which diameter and length are 5 mm and 13 mm, respectively. Samples were mounted at a distance of 5 mm below the plasma source, and the plasma treatment time was set to 3 min. The wettability of titanium surface was measured by the moving speed of water on its surface, which is enhanced by plasma treatment. The surface roughness was also measured by atomic force microscopy. The optimal condition for wettability change is discussed.

Osteogenic activity and antibacterial effect of porous titanium modified with metal-organic framework films.

PubMed

Chen, Junyu; Zhang, Xin; Huang, Chao; Cai, He; Hu, Shanshan; Wan, Qianbing; Pei, Xibo; Wang, Jian

2017-03-01

As a new class of crystalline nanoporous materials, metal-organic frameworks (MOFs) have recently been used for biomedical applications due to their large surface area, high porosity, and theoretically infinite structures. To improve the biological performance of titanium, MOF films were applied to surface modification of titanium. Zn-based MOF films composed of zeolitic imidazolate framework-8 (ZIF-8) crystals with nanoscale and microscale sizes (nanoZIF-8 and microZIF-8) were prepared on porous titanium surfaces by hydrothermal and solvothermal methods, respectively. The ZIF-8 films were characterized by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The nanoZIF-8 film exhibited good biocompatibility, whereas the microZIF-8 film showed obvious cytotoxicity to MG63 cells. Compared to pure titanium and alkali- and heat-treated porous titanium, the nanoZIF-8 film not only enhanced alkaline phosphatase (ALP) activity, extracellular matrix mineralization, and expression of osteogenic genes (ALP, Runx2) in MG63 cells but also inhibited the growth of Streptococcus mutans. These results indicate that MOF films or coatings may be promising candidates for bone tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 834-846, 2017. © 2016 Wiley Periodicals, Inc.

Thermogravimetric feasibility study of argon purification using powders of titanium alloys with molybdenum and vanadium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eremeev, A.P.; Veselovskii, P.F.

1987-10-20

The high adsorption and chemical activity of titanium alloy powders (TiMo > TiV) having specific size and chemical compositions, and the nature of the surface and its specific energy characteristics permit one to use them effectively for the purification of argon and other inert gases from impurities such as water vapor, carbon dioxide gas, oxygen, and nitrogen. In agreement with the developed activity series the irreversible adsorption of impurities (1 vol. %) by the indicated powders can be controlled using powders or filters pressed from these powders by heating to temperatures of 500-700/sup 0/. The thickness of the filters canmore » be established on the basis of the rate constants of the chemical reactions of the impurities with the TiMo and TiV powders obtained in this study.« less

Water-soluble titanium alkoxide material

DOEpatents

Boyle, Timothy J.

2010-06-22

A water soluble, water stable, titanium alkoxide composition represented by the chemical formula (OC.sub.6H.sub.6N).sub.2Ti(OC.sub.6H.sub.2(CH.sub.2N(CH.sub.3).sub.2).sub- .3-2,4,6).sub.2 with a theoretical molecular weight of 792.8 and an elemental composition of 63.6% C, 8.1% H, 14.1% N, 8.1% O and 6.0% Ti.

A New Technique for Preparation of High-Grade Titanium Slag from Titanomagnetite Concentrate by Reduction-Melting-Magnetic Separation Processing

NASA Astrophysics Data System (ADS)

Lv, Chao; Yang, Kun; Wen, Shu-ming; Bai, Shao-jun; Feng, Qi-cheng

2017-10-01

This paper proposes a new technique for preparation of high-grade titanium slag from Panzhihua vanadium titanomagnetite concentrate by reduction-melting-magnetic separation processing. Chemical analysis, x-ray diffraction, and scanning electron microscopy in conjunction with energy-dispersive spectroscopy were used to characterize the samples. The effective separation of iron and titanium slag could be realized by melting metallized pellets at 1550°C for 60 min with the addition of 1% CaO (basicity of 1.1) and 2% graphite powder. The small iron particles embedded in the slag could be removed by fine grinding and magnetic separation process. The grade of TiO2 in the obtained high-grade titanium slag reached 60.68% and the total recovery of TiO2 was 91.25%, which could be directly applied for producing titanium white by the sulfuric acid process. This technique provides an alternative method to use vanadium titanomagnetite concentrate of the Panzhihua area in China.

Nucleophilic stabilization of water-based reactive ink for titania-based thin film inkjet printing

NASA Astrophysics Data System (ADS)

Gadea, C.; Marani, D.; Esposito, V.

2017-02-01

Drop on demand deposition (DoD) of titanium oxide thin films (<500 nm) is performed via a novel titanium-alkoxide-based solution that is tailored as a reactive ink for inkjet printing. The ink is developed as water-based solution by a combined use of titanium isopropoxide and n-methyldiethanolamine (MDEA) used as nucleophilic ligand. The function of the ligand is to control the fast hydrolysis/condensation reactions in water for the metal alkoxide before deposition, leading to formation of the TiO2 only after the jet process. The evolution of the titanium-ligand interactions at increasing amount of MDEA is here elucidated in terms of long term stability. The ink printability parameter (Z) is optimized, resulting in a reactive solution with printability, Z, >1, and chemical stability up to 600 h. Thin titanium oxide films (<500 nm) are proved on different substrates. Pure anatase phase is obtained after annealing at low temperature (ca. 400 °C).

Nanometer Scale Titanium Surface Texturing Are Detected by Signaling Pathways Involving Transient FAK and Src Activations

PubMed Central

Zambuzzi, Willian F.; Bonfante, Estevam A.; Jimbo, Ryo; Hayashi, Mariko; Andersson, Martin; Alves, Gutemberg; Takamori, Esther R.; Beltrão, Paulo J.; Coelho, Paulo G.; Granjeiro, José M.

2014-01-01

Background It is known that physico/chemical alterations on biomaterial surfaces have the capability to modulate cellular behavior, affecting early tissue repair. Such surface modifications are aimed to improve early healing response and, clinically, offer the possibility to shorten the time from implant placement to functional loading. Since FAK and Src are intracellular proteins able to predict the quality of osteoblast adhesion, this study evaluated the osteoblast behavior in response to nanometer scale titanium surface texturing by monitoring FAK and Src phosphorylations. Methodology Four engineered titanium surfaces were used for the study: machined (M), dual acid-etched (DAA), resorbable media microblasted and acid-etched (MBAA), and acid-etch microblasted (AAMB). Surfaces were characterized by scanning electron microscopy, interferometry, atomic force microscopy, x-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. Thereafter, those 4 samples were used to evaluate their cytotoxicity and interference on FAK and Src phosphorylations. Both Src and FAK were investigated by using specific antibody against specific phosphorylation sites. Principal Findings The results showed that both FAK and Src activations were differently modulated as a function of titanium surfaces physico/chemical configuration and protein adsorption. Conclusions It can be suggested that signaling pathways involving both FAK and Src could provide biomarkers to predict osteoblast adhesion onto different surfaces. PMID:24999733

Tailoring nanocrystalline diamond coated on titanium for osteoblast adhesion.

PubMed

Pareta, Rajesh; Yang, Lei; Kothari, Abhishek; Sirinrath, Sirivisoot; Xiao, Xingcheng; Sheldon, Brian W; Webster, Thomas J

2010-10-01

Diamond coatings with superior chemical stability, antiwear, and cytocompatibility properties have been considered for lengthening the lifetime of metallic orthopedic implants for over a decade. In this study, an attempt to tailor the surface properties of diamond films on titanium to promote osteoblast (bone forming cell) adhesion was reported. The surface properties investigated here included the size of diamond surface features, topography, wettability, and surface chemistry, all of which were controlled during microwave plasma enhanced chemical-vapor-deposition (MPCVD) processes using CH4-Ar-H2 gas mixtures. The hardness and elastic modulus of the diamond films were also determined. H2 concentration in the plasma was altered to control the crystallinity, grain size, and topography of the diamond coatings, and specific plasma gases (O2 and NH3) were introduced to change the surface chemistry of the diamond coatings. To understand the impact of the altered surface properties on osteoblast responses, cell adhesion tests were performed on the various diamond-coated titanium. The results revealed that nanocrystalline diamond (grain sizes <100 nm) coated titanium dramatically increased surface hardness, and the introduction of O2 and NH3 during the MPCVD process promoted osteoblast adhesion on diamond and, thus, should be further studied for improving orthopedic applications. Copyright 2010 Wiley Periodicals, Inc. J Biomed Mater Res Part A, 2010.

Molybdeno-Aluminizing of Powder Metallurgy and Wrought Ti and Ti-6Al-4V alloys by Pack Cementation process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tsipas, Sophia A., E-mail: stsipas@ing.uc3m.es; Go

Wear and high temperature oxidation resistance of some titanium-based alloys needs to be enhanced, and this can be effectively accomplished by surface treatment. Molybdenizing is a surface treatment where molybdenum is introduced into the surface of titanium alloys causing the formation of wear-resistant surface layers containing molybdenum, while aluminizing of titanium-based alloys has been reported to improve their high temperature oxidation properties. Whereas pack cementation and other surface modification methods have been used for molybdenizing or aluminizing of wrought and/or cast pure titanium and titanium alloys, such surface treatments have not been reported on titanium alloys produced by powder metallurgymore » (PM). Also a critical understanding of the process parameters for simultaneous one step molybdeno-aluminizing of titanium alloys by pack cementation and the predominant mechanism for this process have not been reported. The current research work describes the surface modification of titanium and Ti-6Al-4V prepared by PM by molybdeno-aluminizing and analyzes thermodynamic aspects of the deposition process. Similar coatings are also deposited to wrought Ti-6Al-4V and compared. Characterization of the coatings was carried out using scanning electron microscopy and x-ray diffraction. For both titanium and Ti-6Al-4V, the use of a powder pack containing ammonium chloride as activator leads to the deposition of molybdenum and aluminium into the surface but also introduces nitrogen causing the formation of a thin titanium nitride layer. In addition, various titanium aluminides and mixed titanium aluminium nitrides are formed. The appropriate conditions for molybdeno-aluminizing as well as the phases expected to be formed were successfully determined by thermodynamic equilibrium calculations. - Highlights: •Simultaneous co-deposition of Mo-Al onto powder metallurgy and wrought Ti alloy •Thermodynamic calculations were used to optimize deposition conditions •External TiN and internal a Mo-rich layer on all alloy substrates •Titanium aluminides and Ti-Al mixed nitrides are formed on Ti-6Al-4V •The presence of Al and V alloying elements modifies the diffusion of Mo.« less

Synergistic effects of fibronectin and bone morphogenetic protein on the bioactivity of titanium metal.

PubMed

Biao, M N; Chen, Y M; Xiong, S B; Wu, B Y; Yang, B C

2017-09-01

To improve the biological properties of bioactive titanium metal, recombinant human bone morphogenetic protein 2(rhBMP-2) and fibronectin (Fn) were adsorbed on its surface solely or contiguously to modify the anodic oxidized titanium (AO-Ti), acid-alkali-treated titanium (AA-Ti), and polished titanium (P-Ti). It is found that the different bioactive titanium surface structures had great influence on protein adsorption. The adsorption amounts of BMP adsorbed solely and Fn/BMP adsorbed contiguously were AA-Ti > P-Ti > AO-Ti, and that for Fn adsorbed solely was AA-Ti ≈ P-Ti > AO-Ti. The conformation of proteins was changed remarkably after the adsorption. For BMP, the α-helix decreased on AA-Ti and stabilized on P-Ti and AO-Ti. For Fn, the β-sheet on PT-Ti and AA-Ti increased significantly. For Fn/BMP, the percentage of β-sheet on AA-Ti increased, and that of α-helix on all samples was stable. MSCs showed greater adhesion and spreading on Fn/BMP groups. MTT and Elisa tests showed that the synergistic effects of proteins made the cells proliferate and differentiate faster. It indicated both the surface structure and the synergistic effects of proteins could influence the biological properties of titanium metals. It provides research foundation for improving the biological properties of bioactive titanium metals by simultaneous application of several proteins. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 2485-2498, 2017. © 2017 Wiley Periodicals, Inc.

Chemical Analysis of the Moon at the Surveyor VII Landing Site: Preliminary Results.

PubMed

Turkevich, A L; Franzgrote, E J; Patterson, J H

1968-10-04

The alpha-scattering experiment aboard Surveyor VII has provided a chemical analysis of the moon in the area of the crater Tycho. The preliminary results indicate a chemical composition similar to that already found at two mare sites, but with a lower concentration of elements of the iron group (titanium through copper).

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2011 CFR

2011-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2012 CFR

2012-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2013 CFR

2013-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2014 CFR

2014-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

Liquid Oxygen Rotating Friction Ignition Testing of Aluminum and Titanium with Monel and Inconel for Rocket Engine Propulsion System Contamination Investigation

NASA Technical Reports Server (NTRS)

Peralta, S.; Rosales, Keisa R.; Stoltzfus, Joel M.

2009-01-01

Metallic contaminant was found in the liquid oxygen (LOX) pre-valve screen of the shuttle main engine propulsion system on two orbiter vehicles. To investigate the potential for an ignition, NASA Johnson Space Center White Sands Test Facility performed (modified) rotating friction ignition testing in LOX. This testing simulated a contaminant particle in the low-pressure oxygen turbo pump (LPOTP) and the high-pressure oxygen turbo pump (HPOTP) of the shuttle main propulsion system. Monel(R) K-500 and Inconel(R) 718 samples represented the LPOTP and HPOTP materials. Aluminum foil tape and titanium foil represented the contaminant particles. In both the Monel(R) and Inconel(R) material configurations, the aluminum foil tape samples did not ignite after 30 s of rubbing. In contrast, all of the titanium foil samples ignited regardless of the rubbing duration or material configuration. However, the titanium foil ignitions did not propagate to the Monel and Inconel materials.

Bone-like apatite growth on controllable macroporous titanium scaffolds coated with microporous titania.

PubMed

Rao, Xi; Li, Jing; Feng, Xue; Chu, Chenglin

2018-01-01

In this study, a simple, cost-effective approach of polymeric foam replication was used to produce three-dimensionally macroporous titanium scaffolds with controllable porosities and mechanical properties. Two kinds of porous titanium scaffolds with different porosities (74.7% and 87.6%) and pore sizes (360µm and 750µm) were fabricated. Both of the scaffolds exhibit good compressive strength (24.5MPa and 13.5MPa) with a low elastic modulus (0.23GPa and 0.11GPa), approximating the mechanical properties of nature human cancellous bone (E = 10-50MPa, σ = 0.01-3.0GPa). Thereafter, the scaffolds were surface modified using plasma electrolyte oxidation (PEO) process to gain a bioactive porous titania ceramic coating. The SBF immersion test indicates PEO treated scaffolds show excellent bioactivity as the apatite rapidly nucleates and grows on the scaffold surface during 3-28 days. The results suggest that the highly porous titanium scaffolds with titania bioactive coatings are promising in cancellous bone replacement. Copyright © 2017 Elsevier Ltd. All rights reserved.

Anticorrosion efficiency of ultrasonically deposited silica coatings on titanium

NASA Astrophysics Data System (ADS)

Ertaş, Fatma Sinem; Kaş, Recep; Mikó, Annamária; Birer, Özgür

2013-07-01

We utilized high intensity ultrasound to prepare coatings of silica and organically modified silica composed of multiple layers of densely packed nanoparticles. Ultrasound was used to collide nanoparticles onto an activated titanium surface with high speed. Large areas could be homogeneously coated by this method. These coatings were characterized by spectroscopy and microscopy methods and the anticorrosion efficiency in NaCl solution was evaluated by electrochemical measurements. The results indicated that the composite coatings provided good quality barrier layer on bare titanium and decreased the anodic corrosion rate. It was found that increase in the organic content of the coating shifted the passivation potential towards more positive direction. The comparison of the impedance results recorded at the corrosion potential pointed out that in each case a good quality barrier layer was formed on the titanium surface. The outstanding corrosion resistance of the composite coatings with only ~200 nm thickness shows that ultrasound assisted deposition can be a competitive method to obtain corrosion protective layers.

Morphological characteristics of mechanochemically synthesized Fe/Ti composites

NASA Astrophysics Data System (ADS)

Grigor'eva, T. F.; Kovaleva, S. A.; Kiseleva, T. Yu.; Vosmerikov, S. V.; Devyatkina, E. T.; Pastukhov, E. A.; Lyakhov, N. Z.

2016-08-01

The joint mechanical activation of chemically interacting iron and titanium has been studied by X-ray diffraction and atomic force microscopy. It is shown that chemically interacting metals Fe and Ti do not form any intermetallic compounds or solid solutions upon intense mechanical activation in a high-energy planetary mill. The products of mechanical activation are Fe/Ti mechanocomposites, in which titanium is distributed over the iron grain surface. An increase in the mechanical activation time leads to the agglomeration of powders and the formation of particles with a wide size range (5-25 μm). The iron crystallite sizes and the level of microstresses are reduced, indicating a decrease in the particle strength.

Improving Osteoblast Response In Vitro by a Nanostructured Thin Film with Titanium Carbide and Titanium Oxides Clustered around Graphitic Carbon.

PubMed

Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d'Abusco, Anna; Superti, Fabiana; Misiano, Carlo; Zanoni, Robertino; Politi, Laura; Mazzola, Luca; Iosi, Francesca; Mura, Francesco; Scandurra, Roberto

2016-01-01

Recently, we introduced a new deposition method, based on Ion Plating Plasma Assisted technology, to coat titanium implants with a thin but hard nanostructured layer composed of titanium carbide and titanium oxides, clustered around graphitic carbon. The nanostructured layer has a double effect: protects the bulk titanium against the harsh conditions of biological tissues and in the same time has a stimulating action on osteoblasts. The aim of this work is to describe the biological effects of this layer on osteoblasts cultured in vitro. We demonstrate that the nanostructured layer causes an overexpression of many early genes correlated to proteins involved in bone turnover and an increase in the number of surface receptors for α3β1 integrin, talin, paxillin. Analyses at single-cell level, by scanning electron microscopy, atomic force microscopy, and single cell force spectroscopy, show how the proliferation, adhesion and spreading of cells cultured on coated titanium samples are higher than on uncoated titanium ones. Finally, the chemistry of the layer induces a better formation of blood clots and a higher number of adhered platelets, compared to the uncoated cases, and these are useful features to improve the speed of implant osseointegration. In summary, the nanostructured TiC film, due to its physical and chemical properties, can be used to protect the implants and to improve their acceptance by the bone.

Long term storage test of titanium material with liquid fluorine propellant

NASA Technical Reports Server (NTRS)

Denson, J. R.; English, W. D.; Roth, J.; Toy, A.

1979-01-01

The compatibility of 6AL-4V Ti with propellant grade GF2 and LF2 at 77 K for up to 3 years was investigated. Titanium double coupons, annealed or heat treated, with 16 or 64 RMS finishes, were immersed in F2 in individual Pyrex capsules and stored under LN2 for 29 and 39 months. Pre and post immersion tests were performed on the propellant and coupons. Chemical analysis of the propellant did not reveal any significant changes due to titanium corrosion. Gravimetric, visual, microscopic, and metallurgical examination with pitting analysis did not reveal gross corrosion of the titanium although pitting appears to be greater after 39 months exposure. The increase in pit size and number raises the possibility of unpredictable crack propagation instability. Fracture toughness tests are necessary to define this possibility.

Investigation of Ag-TiO2 nanostructures photocatalytic properties prepared by modified dip coating method

NASA Astrophysics Data System (ADS)

AlArfaj, Esam

2016-05-01

In this article, titanium dioxide and silver nanostructures were deposited on glass substrates using modified sol-gel methods and dip-coating technique. The films were characterised chemically and physically using different techniques (TLC, UV-Vis and XRD) and tested for environmental applications regarding degradation of aromatic hydrocarbons. The photocatalytic activity of the TiO2 nanostructures is tested with different small concentrations of phenol in water and reaction mechanisms discussed. Considerable enhancement is observed in the photodegradation activity of Ag-modified (3 wt.%) TiO2 compared to unmodified TiO2 nanostructures for phenol concentrations within the pseudo-first-order Langmuir-Hinshelwood (LH) model for reaction kinetics. The pseudo-first-order global degradation rate constant increased from <0.005 min-1 for TiO2 to 0.013 min-1 for 3 mol% Ag-modified TiO2. The enhancement is attributed to the incorporation of Ag which promotes the generation of reactive oxygen species and increases the carrier recombination life-time. In addition, Ag has been observed to extend the absorption to the visible region by its surface plasmon resonances and to suppress the anatase-rutile phase transformation. Moreover, TiO2 grain size prepared was found to be 10 nm which maximises the active surface area. For phenol initial concentrations as low as 0.0002 M, saturation trend in the degradation process occurred at 0.00014 M and the reaction rate can be fitted with half-order LH kinetics.

The effect of doping titanium dioxide nanoparticles on phase transformation, photocatalytic activity and anti-bacterial properties

NASA Astrophysics Data System (ADS)

Buzby, Scott Edward

Nanosized titanium dioxide has a variety of important applications in everyday life including a photocatalyst for pollution remediation, photovoltaic devices, sunscreen, etc. This study focuses on the various properties of titanium dioxide nanoparticles doped with various cation and anion species. Samples were produced by various methods including metalorganic chemical vapor deposition (MOCVD), plasma assisted metalorganic chemical vapor deposition (PA-MOCVD) and sol-gel. Numerous techniques such as X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), electron microscopy both scanning (SEM) and transmission (TEM) were used for physical characterization. Photocatalytic properties were determined by the oxidation of methylene blue dye and 2-chlorophenol in water as well as gaseous formic acid with results analyzed by high performance liquid chromatography (HPLC), Fourier transform infrared spectroscopy (FTIR) and ultra violet - visible spectroscopy (UV-VIS). For the purpose of enhancement of the photocatalytic activity of titanium dioxide nanoparticles, the effect of anion doping and the anatase-rutile phase ratio were studied. Although anatase, rutile and mixed crystallite phases all show some degree of activity in photocatalytic reactions, these results show that anatase is better suited for the degradation of organic compounds in an aqueous medium any advantage in photocatalytic activity gained through the enhancement in optical response from the smaller band gap by addition of rutile was overcome by the negatives associated with the rutile phase. Furthermore substitutional nitrogen doping showed significant improvement in UV photocatalysis as well as allowing for visible light activation of the catalyst. Further studies on the phase transitions in titanium dioxide nanoparticles were carried out by synthesizing various cation doped samples by sol-gel. Analysis of the phases by XRD showed an inverse relationship between dopant size and rutile percentage. Dopant ions with larger radii than titanium stress the crystal lattice promoting anatase formation, since it has a larger c/a ratio than rutile does. The cation dopants were also found to decrease the average particle size of the titanium dioxide nanoparticles. The defect sites caused by the doping prevent the nucleation and retard particle growth of titanium dioxide particles. Cation doping of titanium dioxide nanoparticles affect other properties of the nanoparticles besides the phase transitions. For example titanium dioxide doped with magnetic materials such as Fe, Ni, Co or Cr has been shown to display room temperature ferromagnetism which are currently being studied for use in spintronic devices. The antibacterial studies of silver doped titanium dioxide nanoparticles were carried out against Escherichia coli, both in nutrient solution and on agar-plates. Both studies show that while pure titanium dioxide has no antibacterial effect, when doped with as little as 0.72 atomic % silver becomes more effective than pure silver nanoparticles of similar size. It has been observed that with concentrations as low as 25mug/cm 2 of silver doped titanium dioxide, completely antibacterial surfaces may be synthesized.

Fabrication of anticoagulation layer on titanium surface by sequential immobilization of poly (ethylene glycol) and albumin.

PubMed

Pan, Chang-Jiang; Hou, Yan-Hua; Zhang, Bin-Bin; Zhang, Lin-Cai

2014-01-01

This paper presents a simple method to sequentially immobilize poly (ethylene glycol) (PEG) and albumin on titanium surface to enhance the blood compatibility. Attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR) analysis indicated that PEG and albumin were successfully immobilized on the titanium surface. Water contact angle results showed a better hydrophilic surface after the immobilization. The immobilized PEG or albumin can not only obviously prevent platelet adhesion and activation but also prolong activated partial thromboplastin time (APTT), leading to the improved anticoagulation. Moreover, immobilization of albumin on PEG-modified surface can further improve the anticoagulation. The approach in the present study provides an effective and efficient method to improve the anticoagulation of blood-contact biomedical devices such as coronary stents.

The Effects of Different Wavelength UV Photofunctionalization on Micro-Arc Oxidized Titanium

PubMed Central

Zhou, Lei; Guo, Zehong; Rong, Mingdeng; Liu, Xiangning; Lai, Chunhua; Ding, Xianglong

2013-01-01

Many challenges exist in improving early osseointegration, one of the most critical factors in the long-term clinical success of dental implants. Recently, ultraviolet (UV) light-mediated photofunctionalization of titanium as a new potential surface treatment has aroused great interest. This study examines the bioactivity of titanium surfaces treated with UV light of different wavelengths and the underlying associated mechanism. Micro-arc oxidation (MAO) titanium samples were pretreated with UVA light (peak wavelength of 360 nm) or UVC light (peak wavelength of 250 nm) for up to 24 h. UVC treatment promoted the attachment, spread, proliferation and differentiation of MG-63 osteoblast-like cells on the titanium surface, as well as the capacity for apatite formation in simulated body fluid (SBF). These biological influences were not observed after UVA treatment, apart from a weaker effect on apatite formation. The enhanced bioactivity was substantially correlated with the amount of Ti-OH groups, which play an important role in improving the hydrophilicity, along with the removal of hydrocarbons on the titanium surface. Our results showed that both UVA and UVC irradiation altered the chemical properties of the titanium surface without sacrificing its excellent physical characteristics, suggesting that this technology has extensive potential applications and merits further investigation. PMID:23861853

Chemical compatibility of cartridge materials

NASA Technical Reports Server (NTRS)

Wilcox, Roy C.; Zee, R. H.

1991-01-01

This twelve month progress report deals with the chemical compatibility of semiconductor crystals grown in zero gravity. Specifically, it studies the chemical compatibility between TZM, a molybdenum alloy containing titanium and zirconium, and WC 103, a titanium alloy containing Niobium and Hafnium, and Gallium arsenide (GaAs) and Cadmium Zinc Tellurite (CdZnTe). Due to the health hazards involved, three approaches were used to study the chemical compatibility between the semiconductor and cartridge materials: reaction retort, thermogravimetric analysis, and bulk cylindrical cartridge containers. A scanning electron microscope with an energy dispersive X-ray analyzer was used to examine all samples after testing. The first conclusion drawn is that reaction rates with TZM were not nearly as great as they were with WC 103. Second, the total reaction between GaAs and WC 103 was almost twice that with TZM. Therefore, even though WC 103 is easier to fabricate, at least half of the cartridge thickness will be degraded if contact is made with one of the semiconductor materials leading to a loss of strength properties.

Selective fibronectin adsorption against albumin and enhanced stem cell attachment on helium atmospheric pressure glow discharge treated titanium

NASA Astrophysics Data System (ADS)

Han, Inho; Vagaska, Barbora; Joo Park, Bong; Lee, Mi Hee; Jin Lee, Seung; Park, Jong-Chul

2011-06-01

Successful tissue integration of implanted medical devices depends on appropriate initial cellular response. In this study, the effect of helium atmospheric pressure glow discharge (He-APGD) treatment of titanium on selective protein adsorption and the initial attachment processes and focal adhesion formation of osteoprogenitor cells and stem cells were examined. Titanium disks were treated in a self-designed He-APGD system. Initial attachment of MC3T3-E1 mouse pre-osteoblasts and human mesenchymal stem cells (MSCs) was evaluated by MTT assay and plasma membrane staining followed by morphometric analysis. Fibronectin adsorption was investigated by Enzyme-Linked ImmunoSorbant Assay. MSCs cell attachment to treated and non-treated titanium disks coated with different proteins was verified also in serum-free culture. Organization of actin cytoskeleton and focal adhesions was evaluated microscopically. He-APGD treatment effectively modified the titanium surfaces by creating a super-hydrophilic surface, which promoted selectively higher adsorption of fibronectin, a protein of critical importance for cell/biomaterial interaction. In two different types of cells, the He-APGD treatment enhanced the number of attaching cells as well as their attachment area. Moreover, cells had higher organization of actin cytoskeleton and focal adhesions. Faster acceptance of the material by the progenitor cells in the early phases of tissue integration after the implantation may significantly reduce the overall healing time; therefore, titanium treatment with He-APGD seems to be an effective method of surface modification of titanium for improving its tissue inductive properties.

Sensitivity of titanium brackets to the corrosive influence of fluoride-containing toothpaste and tea.

PubMed

Harzer, W; Schröter, A; Gedrange, T; Muschter, F

2001-08-01

Titanium brackets are used in orthodontic patients with an allergy to nickel and other specific substances. In recent studies, the corrosive properties of fluoride-containing toothpastes with different pH values were investigated. The present in vivo study tested how the surfaces of titanium brackets react to the corrosive influence of acidic fluoride-containing toothpaste during orthodontic treatment. Molar bands were placed on 18 orthodontic patients. In these same patients, titanium brackets were bonded on the left quadrants and stainless steel brackets on the right quadrants of the upper and lower arches. Fifteen patients used Gel Kam containing soluble tin fluoride (pH 3.2), whereas 3 used fluoride-free toothpaste. The brackets were removed for evaluation by light microscopy and scanning microscopy 5.5 to 7.0 months and 7.5 to 17 months after bonding. The quality and quantity of elements present were measured by scanning microscopy. Macroscopic evaluation showed the matte gray color of titanium brackets dominating over the silver gleam of the steel brackets. The plaque accumulation on titanium brackets is high because of the very rough surface. Pitting and crevices were observed in only 3 of the 165 brackets tested. The present in vivo investigation confirms the results of in vitro studies, but the changes are so minor that titanium brackets can safely be used for up to 18 months. Wing surfaces should be improved by modifying the manufacturing process.

Physical and rheological properties of Titanium Dioxide modified asphalt

NASA Astrophysics Data System (ADS)

Buhari, Rosnawati; Ezree Abdullah, Mohd; Khairul Ahmad, Mohd; Chong, Ai Ling; Haini, Rosli; Khatijah Abu Bakar, Siti

2018-03-01

Titanium Dioxide (TiO2) has been known as a useful photocatalytic material that is attributed to the several characteristics includes high photocatalytic activity compared with other metal oxide photocatalysts, compatible with traditional construction materials without changing any original performance. This study investigates the physical and rheological properties of modified asphalt with TiO2. Five samples of asphalt with different concentration of TiO2 were studied, namely asphalt 2%, 4%, 6% 8% and 10% TiO2. The tests includes are penetration, softening point, ductility, rotational viscosity and dynamic shear rheometer (DSR) test. From the results of this study, it is noted that addition of TiO2 has significant effect on the physical properties of asphalt. The viscosity tests revealed that asphalt 10% TiO2 has good workability among with reducing approximately 15°C compared to base asphalt. Based on the results from DSR measurements, asphalt 10% TiO2 has reduced temperature susceptibility and increase stiffness and elastic behaviour in comparison to base asphalt. As a result, TiO2 can be considered to be an additive to modify the properties of asphalt.

Surface XPS characterization of NiTi shape memory alloy after advanced oxidation processes in UV/H 2O 2 photocatalytic system

NASA Astrophysics Data System (ADS)

Wang, R. M.; Chu, C. L.; Hu, T.; Dong, Y. S.; Guo, C.; Sheng, X. B.; Lin, P. H.; Chung, C. Y.; Chu, P. K.

2007-08-01

Surface structure of NiTi shape memory alloy (SMA) was modified by advanced oxidation processes (AOP) in an ultraviolet (UV)/H 2O 2 photocatalytic system, and then systematically characterized with x-ray photoelectron spectroscopy (XPS). It is found that the AOP in UV/H 2O 2 photocatalytic system leads to formation of titanium oxides film on NiTi substrate. Depth profiles of O, Ni and Ti show such a film possesses a graded interface structure to NiTi substrate and there is no intermediate Ni-rich layer like that produced in conventional high temperature oxidation. Except TiO 2 phase, some titanium suboxides (TiO, Ti 2O 3) may also exist in the titanium oxides film. Oxygen mainly presents in metal oxides and some chemisorbed water and OH - are found in titanium oxides film. Ni nearly reaches zero on the upper surface and relatively depleted in the whole titanium oxides film. The work indicates the AOP in UV/H 2O 2 photocatalytic system is a promising way to favor the widespread application of biomedical NiTi SMA by improving its biocompatibility.

Fabrication of the Ti5Si3/Ti composite inoculants and its refining mechanism on pure titanium

NASA Astrophysics Data System (ADS)

Li, Nuo; Cui, Chunxiang; Liu, Shaungjin; Zhao, Long; Liu, Shuiqing

2017-03-01

The in situ Ti5Si3/Ti inoculants were successfully prepared by vacuum arc-melting and melt-spinning method. An efficient route by adding a small quantity of Ti5Si3/Ti inoculants to Ti melt has been first proposed to modify the coarse grains of as cast microstructure of pure titanium in this paper. It was found that the microstructure of ribbon inoculants was cellular structure that composed of Ti5Si3 and α-Ti phases. The grain refining effect of the inoculants was significantly improved with the adding ratio range from 0.2% to 0.5% in weight. With the increase of addition amount of inoculants on Ti melt, the tensile strength, yield strength and microhardness of pure titanium are significantly improved except elongation. The excellent grain refining effect can be attributed to the heterogeneous nucleation of the titanium grain on the precipitated Ti5Si3 phases in the Si-rich regions and the constitutional supercooling of Si in the Si-poverty regions. It is suggested that the in situ Ti5Si3/Ti inoculants is a promising inoculants for titanium alloys.

Identification and binding mechanism of phage displayed peptides with specific affinity to acid-alkali treated titanium.

PubMed

Sun, Yuhua; Tan, Jing; Wu, Baohua; Wang, Jianxin; Qu, Shuxin; Weng, Jie; Feng, Bo

2016-10-01

Acid-alkali treatment is one of means widely used for preparing bioactive titanium surfaces. Peptides with specific affinity to titanium surface modified by acid-alkali two-steps treatment were obtained via phage display technology. Out of the eight new unique peptides, titanium-binding peptide 54 displayed by monoclonal M13 phage at its pIII coat protein (TBP54-M13 phage) was proved to have higher binding affinity to the substrate. The binding interaction occurred at the domain from phenylalanine at position 1 to arginine at position 6 in the sequences of TBP54 (FAETHRGFHFSF) mainly via the reaction of these residues with the Ti surface. Together the coordination and electrostatic interactions controlled the specific binding of the phage to the substrate. The binding affinity was dependent on the surface basic hydroxyl group content. In addition, the phage showed a different interaction way with the Ti surface without acid-alkali treatment along with an impaired affinity. This study could provide more understanding of the interaction mechanism between the selected peptide and its specific substrate, and develop a promising method for the biofunctionalization of titanium. Copyright © 2016 Elsevier B.V. All rights reserved.

Method of preparation of novel fiber reinforced titanium diboride composite bodies and uses therefor

DOEpatents

Newkirk, L.C.; Riley, R.E.; Valencia, F.A.; Wallace, T.C. Sr.

Cloth is coated with titanium diboride in a chemical vapor deposition reaction under particular coating conditions which result in a uniform coating on the individual filaments making up the cloth fiber bundles. The coated cloth can be used as deposited as electrodes, for example, or can be hot pressed to form highly spall-resistant structures having special utility in fusion reactors, for example, as wall armor.

Reduction behavior and kinetics of vanadium-titanium sinters under high potential oxygen enriched pulverized coal injection

NASA Astrophysics Data System (ADS)

Ma, Jin-fang; Wang, Guang-wei; Zhang, Jian-liang; Li, Xin-yu; Liu, Zheng-jian; Jiao, Ke-xin; Guo, Jian

2017-05-01

In this work, the reduction behavior of vanadium-titanium sinters was studied under five different sets of conditions of pulverized coal injection with oxygen enrichment. The modified random pore model was established to analyze the reduction kinetics. The results show that the reduction rate of sinters was accelerated by an increase of CO and H2 contents. Meanwhile, with the increase in CO and H2 contents, the increasing range of the medium reduction index (MRE) of sinters decreased. The increasing oxygen enrichment ratio played a diminishing role in improving the reduction behavior of the sinters. The reducing process kinetic parameters were solved using the modified random role model. The results indicated that, with increasing oxygen enrichment, the contents of CO and H2 in the reducing gas increased. The reduction activation energy of the sinters decreased to between 20.4 and 23.2 kJ/mol.

The effect of heat treatment simulating porcelain firing processes on titanium corrosion resistance.

PubMed

Sokołowski, Grzegorz; Rylska, Dorota; Sokołowski, Jerzy

2016-01-01

Corrosion resistance of titanium used in metal-ceramic restorations in manufacturing is based on the presence of oxide layer on the metal surface. The procedures used during combining metallic material with porcelain may affect the changes in oxide layers structure, and thus anticorrosive properties of metallic material. The aim of the study was an evaluation of potential changes in the structure and selected corrosion properties of titanium after sandblasting and thermal treatment applicable to the processes of ceramics fusion. Milled titanium elements were subjected to a few variants of the processes typical of ceramics fusion and studied in terms of resistance to electrochemical corrosion. The study included the OCP changes over time, measurements of Icorr, Ecorr and Rp as well as potentiodynamic examinations. Surface microstructure and chemical composition were analyzed using SEM and EDS methods. The results obtained allow us to conclude that the processes corresponding to ceramic oxidation and fusion on titanium in the variants used in the study do not cause deterioration of its anticorrosive properties, and partially enhance the resistance. This depends on the quality of oxide layers structure. Titanium elements treated by porcelain firing processes do not lose their corrosion resistance.

The Surface Chemical Composition of Lunar Samples and Its Significance for Optical Properties

NASA Technical Reports Server (NTRS)

Gold, T.; Bilson, E.; Baron, R. L.

1976-01-01

The surface iron, titanium, calcium, and silicon concentration in numerous lunar soil and rock samples was determined by Auger electron spectroscopy. All soil samples show a large increase in the iron to oxygen ratio compared with samples of pulverized rock or with results of the bulk chemical analysis. A solar wind simulation experiment using 2 keV energy alpha -particles showed that an ion dose corresponding to approximately 30,000 years of solar wind increased the iron concentration on the surface of the pulverized Apollo 14 rock sample 14310 to the concentration measured in the Apollo 14 soil sample 14163, and the albedo of the pulverized rock decreased from 0.36 to 0.07. The low albedo of the lunar soil is related to the iron + titanium concentration on its surface. A solar wind sputter reduction mechanism is discussed as a possible cause for both the surface chemical and optical properties of the soil.

Surface Functionalization of Orthopedic Titanium Implants with Bone Sialoprotein

PubMed Central

Ritz, Ulrike; Ackermann, Angelika; Anthonissen, Joris; Kaufmann, Kerstin B.; Brendel, Christian; Götz, Hermann; Rommens, Pol M.; Hofmann, Alexander

2016-01-01

Orthopedic implant failure due to aseptic loosening and mechanical instability remains a major problem in total joint replacement. Improving osseointegration at the bone-implant interface may reduce micromotion and loosening. Bone sialoprotein (BSP) has been shown to enhance bone formation when coated onto titanium femoral implants and in rat calvarial defect models. However, the most appropriate method of BSP coating, the necessary level of BSP coating, and the effect of BSP coating on cell behavior remain largely unknown. In this study, BSP was covalently coupled to titanium surfaces via an aminosilane linker (APTES), and its properties were compared to BSP applied to titanium via physisorption and untreated titanium. Cell functions were examined using primary human osteoblasts (hOBs) and L929 mouse fibroblasts. Gene expression of specific bone turnover markers at the RNA level was detected at different intervals. Cell adhesion to titanium surfaces treated with BSP via physisorption was not significantly different from that of untreated titanium at any time point, whereas BSP application via covalent coupling caused reduced cell adhesion during the first few hours in culture. Cell migration was increased on titanium disks that were treated with higher concentrations of BSP solution, independent of the coating method. During the early phases of hOB proliferation, a suppressive effect of BSP was observed independent of its concentration, particularly when BSP was applied to the titanium surface via physisorption. Although alkaline phosphatase activity was reduced in the BSP-coated titanium groups after 4 days in culture, increased calcium deposition was observed after 21 days. In particular, the gene expression level of RUNX2 was upregulated by BSP. The increase in calcium deposition and the stimulation of cell differentiation induced by BSP highlight its potential as a surface modifier that could enhance the osseointegration of orthopedic implants. Both physisorption and covalent coupling of BSP are similarly effective, feasible methods, although a higher BSP concentration is recommended. PMID:27111551

Self-Assembled Monolayers for Dental Implants

PubMed Central

Correa-Uribe, Alejandra

2018-01-01

Implant-based therapy is a mature approach to recover the health conditions of patients affected by edentulism. Thousands of dental implants are placed each year since their introduction in the 80s. However, implantology faces challenges that require more research strategies such as new support therapies for a world population with a continuous increase of life expectancy, to control periodontal status and new bioactive surfaces for implants. The present review is focused on self-assembled monolayers (SAMs) for dental implant materials as a nanoscale-processing approach to modify titanium surfaces. SAMs represent an easy, accurate, and precise approach to modify surface properties. These are stable, well-defined, and well-organized organic structures that allow to control the chemical properties of the interface at the molecular scale. The ability to control the composition and properties of SAMs precisely through synthesis (i.e., the synthetic chemistry of organic compounds with a wide range of functional groups is well established and in general very simple, being commercially available), combined with the simple methods to pattern their functional groups on complex geometry appliances, makes them a good system for fundamental studies regarding the interaction between surfaces, proteins, and cells, as well as to engineering surfaces in order to develop new biomaterials. PMID:29552036

Welding of a corrosion-resistant composite material based on VT14 titanium alloy obtained using an electron beam emitted into the atmosphere

NASA Astrophysics Data System (ADS)

Golkovski, M. G.; Samoylenko, V. V.; Polyakov, I. A.; Lenivtseva, O. G.; Chakin, I. K.; Komarov, P. N.; Ruktuev, A. A.

2017-01-01

The study investigates the possibility of inert gas arc welding of a double layer composite material on a titanium base with an anti-corrosive layer obtained by fused deposition of a powder mix containing tantalum and niobium over a titanium base using an electron beam emitted into the atmosphere. Butt welding and fillet welding options were tested with two types of edge preparation. Welds were subjected to a metallographic examination including a structural study and an analysis of the chemical and phase composition of the welds. A conclusion was made regarding the possibility of using welding for manufacturing of items from the investigated composite material.

47,49Ti NMR: hyperfine interactions in oxides and metals.

PubMed

Bastow, T J; Gibson, M A; Forwood, C T

1998-10-01

A 47,49Ti NMR characterisation is given of various polymorphs of TiO2 (anatase, rutile and brookite), Ti2O3, perovskites CaTiO3 and BaTiO3, FeTiO3, TiB2, titanium metal, the titanium aluminides Ti3Al, TiAl, TiAl2, TiAl3, and TiAg. Values of chemical or Knight shift, nuclear quadrupole coupling constant and asymmetry parameter were derived from the (1/2, -1/2) powder lineshapes. For TiB2, titanium metal, TiAl, and TiAl3, where +/- (1/2, 3/2), and higher satellite transitions were observed, a value for the axial component of the Knight shift was obtained.

Stabilizing the body centered cubic crystal in titanium alloys by a nano-scale concentration modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, H. L.; Shah, S. A. A.; Hao, Y. L.

It is well-known that the body centered cubic (bcc) crystal in titanium alloys reaches its stability limit as the electron-to-atom (e/a) ratio of the alloy drops down to ~4.24. This critical value, however, is much higher than that of a multifunctional bcc type alloy (e/a = 4.15). Here we demonstrate that a nano-scale concentration modulation created by spinodal decomposition is what stabilizes the bcc crystal of the alloy. Aided by such a nano-scale concentration heterogeneity, unexpected properties from its chemically homogeneous counterpart are obtained. This provides a new strategy to design functional titanium alloys by tuning the spinodal decomposition.

Improving Osteoblast Response In Vitro by a Nanostructured Thin Film with Titanium Carbide and Titanium Oxides Clustered around Graphitic Carbon

PubMed Central

Longo, Giovanni; Ioannidu, Caterina Alexandra; Scotto d’Abusco, Anna; Superti, Fabiana; Misiano, Carlo; Zanoni, Robertino; Politi, Laura; Mazzola, Luca; Iosi, Francesca; Mura, Francesco; Scandurra, Roberto

2016-01-01

Introduction Recently, we introduced a new deposition method, based on Ion Plating Plasma Assisted technology, to coat titanium implants with a thin but hard nanostructured layer composed of titanium carbide and titanium oxides, clustered around graphitic carbon. The nanostructured layer has a double effect: protects the bulk titanium against the harsh conditions of biological tissues and in the same time has a stimulating action on osteoblasts. Results The aim of this work is to describe the biological effects of this layer on osteoblasts cultured in vitro. We demonstrate that the nanostructured layer causes an overexpression of many early genes correlated to proteins involved in bone turnover and an increase in the number of surface receptors for α3β1 integrin, talin, paxillin. Analyses at single-cell level, by scanning electron microscopy, atomic force microscopy, and single cell force spectroscopy, show how the proliferation, adhesion and spreading of cells cultured on coated titanium samples are higher than on uncoated titanium ones. Finally, the chemistry of the layer induces a better formation of blood clots and a higher number of adhered platelets, compared to the uncoated cases, and these are useful features to improve the speed of implant osseointegration. Conclusion In summary, the nanostructured TiC film, due to its physical and chemical properties, can be used to protect the implants and to improve their acceptance by the bone. PMID:27031101

More About Cutting Tool For Shaving Weld Beads

NASA Technical Reports Server (NTRS)

Oelgoetz, Peter A.; Davis, William M.

1996-01-01

Report describes modification and testing of proposed tool discussed in "Cutting Tool For Shaving Weld Beads" (MFS-30056). Modified version of commercial pneumatically driven rotary cutting tool removes such hard metals as nickel alloys, titanium, and stainless steels.

The Inhibition of Escherichia coli Biofilm Formation by Gallium Nitrate-Modified Titanium.

PubMed

Zhu, Yuanyuan; Qiu, Yan; Chen, Ruiqi; Liao, Lianming

2015-08-01

Periprosthetic infections are notoriously difficult to treat due to biofilm formation. Previously, we reported that gallium-EDTA attached to PVC (polyvinyl chloride) surface could prevent bacterial colonization. Herein we examined the effect of this gallium-EDTA complex on Escherichia coli biofilm formation on titanium. It was clearly demonstrated that gallium nitrate significantly inhibited the growth and auto-aggregation of Escherichia coli. Furthermore, titanium with gallium-EDTA coating resisted bacterial colonization as indicated by crystal violet staining. When the chips were immersed in human serum and incubated at 37 °C, they demonstrated significant antimicrobial activity after more than 28 days of incubation. These findings indicate that gallium-EDTA coating of implants can result in a surface that can resist bacterial colonization. This technology holds great promise for the prevention and treatment of periprosthetic infections.

Repairing a Facial Cleft by Polyether-Ether-Ketone Implant Combined With Titanium Mesh.

PubMed

Deng, Yuan; Tang, Weiwei; Li, Zhengkang

2018-05-15

The Tessier Number 4 cleft is one of the rarest, most complex craniofacial anomalies that presents difficulties in surgical treatment. In this article, we report a case of simultaneous facial depression, eye displacement, and medial canthus deformity. In this case, the maxillary bony defect was reconstructed using computer-assisted design computer-assisted manufacturing (CAD-CAM) polyether-ether-ketone (PEEK) material, and the orbital floor defect was repaired with AO prefabricated titanium mesh. Additionally, the medial canthus was modified with canthopexy and a single Z-plasty flap. Owing to its relative rarity and varied clinical presentations, no definitive operative methods have been accepted for Tessier No. 4 facial cleft. This study presents the combination of CAD-CAM manufactured PEEK material and titanium mesh as an alternative approach for reconstructing the bony defect of Tessier No. 4 facial clefts.

Morphological and chemical characteristics of different titanium surfaces treated by bicarbonate and glycine powder air abrasive systems.

PubMed

Menini, Maria; Piccardo, Paolo; Baldi, Domenico; Dellepiane, Elena; Pera, Paolo

2015-02-01

This in vitro study investigated possible morphological and chemical changes induced by glycine or sodium bicarbonate powder air polishing on machined and acid-etched titanium surfaces. The glycine powder (granulometry <65 μm) and sodium bicarbonate powder (granulometry <150 μm) were applied on 2 machined healing abutments and on 2 acid-etched healing abutments. The samples were characterized by scanning electron microscopy coupled with energy dispersive x-ray spectroscopy. The analyses were performed at different steps: (1) as received, right after opening the abutment packaging; (2) after 20 minutes air exposure; (3) after aging in artificial saliva; (4) after glycine or sodium bicarbonate powder air polishing for 5 seconds; (5) after repetition of steps 3 and 4 with longer time of polishing (20 seconds). Air polishing using glycine and sodium bicarbonate powder seemed to be safe for professional oral hygiene of titanium dental implants, although acid-etched abutments and abutments treated with bicarbonate harbored more salts. This might indicate a greater plaque accumulation in a clinical situation. However, this result has to be investigated in vivo to understand its clinical relevance.

Effect of Air-Polishing on Titanium Surfaces, Biofilm Removal, and Biocompatibility: A Pilot Study

PubMed Central

Bennani, Vincent; Hwang, Linda; Tawse-Smith, Andrew; Dias, George J.; Cannon, Richard D.

2015-01-01

Purpose. The aims of this in vitro study were to evaluate morphological changes induced by glycine powder air-polishing on titanium surfaces, biofilm removal, and biocompatibility. Material and Methods. Titanium grade IV discs were allocated into two groups: (1) discs without biofilm and (2) discs for Streptococcus mutans biofilm formation. Discs in each group were further subdivided into (a) no treatment and (b) air-polishing treatment with glycine powder. Discs were characterized by scanning electron microscopy (SEM), electron-dispersive spectroscopy (EDS), and confocal microscopy. Bacterial biofilms were quantified using a crystal violet dye-binding assay. Biocompatibility was evaluated by measuring the coverage and viability of L929 fibroblast cells cultured on the discs. Results. Air-polishing increased the roughness of treated discs (P < 0.05). EDS analysis did not show significant differences in the chemical composition of treated and nontreated discs. The amount of residual biofilm on treated discs was 8.6-fold lower than untreated controls (P < 0.05). Coverage of treated discs by fibroblasts was half that of untreated discs (P < 0.05) although both groups had the same cell viability. Conclusions. Air-polishing removed a significant amount of biofilm from titanium surfaces. The “polishing” was accompanied by increased surface roughness, but there were no changes in chemical and elemental compositions, nor the biocompatibility. PMID:26881198

Surface texture and composition of titanium brushed with toothpaste slurries of different pHs.

PubMed

Hossain, Awlad; Okawa, Seigo; Miyakawa, Osamu

2007-02-01

This in vitro study characterized the surface texture and composition of titanium brushed with toothpaste slurries of different pHs, and thereby elucidated mechanochemical interactions between the metal and abrasive material in dentifrice. Two fluoride-free toothpastes, which contained crystalline CaHPO(4).2H(2)O and amorphous SiO(2) particles as abrasive, were mixed with acidic buffers to provide slurries of pH 6.8 and 4.8. Specimens were cast from CP Ti, mirror-polished, and then toothbrushed at 120strokes/min for 350,400 strokes under a load of 2.45N. Specimen surfaces were characterized by means of SPM and EPMA. The obtained data were compared with the already reported results of water-diluted alkaline slurries. SPM data of each paste were analyzed using one-way ANOVA, followed by post hoc Tukey test. Irrespective of toothpaste, neutral slurries, as with alkaline slurries, yielded a chemically altered surface with rough texture, whereas acidic slurries formed a chemically clean surface with relatively smooth texture. Mechanochemical polishing effect might be mainly responsible for the cleanness and smoothness. Acidic slurry-induced smooth surface may minimize plaque formation. However, the augmentation of released titanium ions may be adverse to the human body. For evaluation of toothpaste abrasion effects on titanium, paste slurry pH should be taken into account.

Post Processing and Biological Evaluation of the Titanium Scaffolds for Bone Tissue Engineering.

PubMed

Wysocki, Bartłomiej; Idaszek, Joanna; Szlązak, Karol; Strzelczyk, Karolina; Brynk, Tomasz; Kurzydłowski, Krzysztof J; Święszkowski, Wojciech

2016-03-15

Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds fabricated by additive manufacturing (AM) methods from metallic powders. However, the partially melted powder particles must be removed in a post-process chemical treatment. The aim of this study was to investigate the effect of the chemical polishing with various acid baths on novel scaffolds' morphology, porosity and mechanical properties. In the first stage, Magics software (Materialise NV, Leuven, Belgium) was used to design a porous scaffolds with pore size equal to (A) 200 µm, (B) 500 µm and (C) 200 + 500 µm, and diamond cell structure. The scaffolds were fabricated from commercially pure titanium powder (CP Ti) using a SLM50 3D printing machine (Realizer GmbH, Borchen, Germany). The selective laser melting (SLM) process was optimized and the laser beam energy density in range of 91-151 J/mm³ was applied to receive 3D structures with fully dense struts. To remove not fully melted titanium particles the scaffolds were chemically polished using various HF and HF-HNO₃ acid solutions. Based on scaffolds mass loss and scanning electron (SEM) observations, baths which provided most uniform surface cleaning were proposed for each porosity. The pore and strut size after chemical treatments was calculated based on the micro-computed tomography (µ-CT) and SEM images. The mechanical tests showed that the treated scaffolds had Young's modulus close to that of compact bone. Additionally, the effect of pore size of chemically polished scaffolds on cell retention, proliferation and differentiation was studied using human mesenchymal stem cells. Small pores yielded higher cell retention within the scaffolds, which then affected their growth. This shows that in vitro cell performance can be controlled to certain extent by varying pore sizes.

Post Processing and Biological Evaluation of the Titanium Scaffolds for Bone Tissue Engineering

PubMed Central

Wysocki, Bartłomiej; Idaszek, Joanna; Szlązak, Karol; Strzelczyk, Karolina; Brynk, Tomasz; Kurzydłowski, Krzysztof J.; Święszkowski, Wojciech

2016-01-01

Nowadays, post-surgical or post-accidental bone loss can be substituted by custom-made scaffolds fabricated by additive manufacturing (AM) methods from metallic powders. However, the partially melted powder particles must be removed in a post-process chemical treatment. The aim of this study was to investigate the effect of the chemical polishing with various acid baths on novel scaffolds’ morphology, porosity and mechanical properties. In the first stage, Magics software (Materialise NV, Leuven, Belgium) was used to design a porous scaffolds with pore size equal to (A) 200 µm, (B) 500 µm and (C) 200 + 500 µm, and diamond cell structure. The scaffolds were fabricated from commercially pure titanium powder (CP Ti) using a SLM50 3D printing machine (Realizer GmbH, Borchen, Germany). The selective laser melting (SLM) process was optimized and the laser beam energy density in range of 91–151 J/mm3 was applied to receive 3D structures with fully dense struts. To remove not fully melted titanium particles the scaffolds were chemically polished using various HF and HF-HNO3 acid solutions. Based on scaffolds mass loss and scanning electron (SEM) observations, baths which provided most uniform surface cleaning were proposed for each porosity. The pore and strut size after chemical treatments was calculated based on the micro-computed tomography (µ-CT) and SEM images. The mechanical tests showed that the treated scaffolds had Young’s modulus close to that of compact bone. Additionally, the effect of pore size of chemically polished scaffolds on cell retention, proliferation and differentiation was studied using human mesenchymal stem cells. Small pores yielded higher cell retention within the scaffolds, which then affected their growth. This shows that in vitro cell performance can be controlled to certain extent by varying pore sizes. PMID:28773323

Low-temperature ({<=}200 Degree-Sign C) plasma enhanced atomic layer deposition of dense titanium nitride thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Samal, Nigamananda; Du Hui; Luberoff, Russell

Titanium nitride (TiN) has been widely used in the semiconductor industry for its diffusion barrier and seed layer properties. However, it has seen limited adoption in other industries in which low temperature (<200 Degree-Sign C) deposition is a requirement. Examples of applications which require low temperature deposition are seed layers for magnetic materials in the data storage (DS) industry and seed and diffusion barrier layers for through-silicon-vias (TSV) in the MEMS industry. This paper describes a low temperature TiN process with appropriate electrical, chemical, and structural properties based on plasma enhanced atomic layer deposition method that is suitable for themore » DS and MEMS industries. It uses tetrakis-(dimethylamino)-titanium as an organometallic precursor and hydrogen (H{sub 2}) as co-reactant. This process was developed in a Veeco NEXUS Trade-Mark-Sign chemical vapor deposition tool. The tool uses a substrate rf-biased configuration with a grounded gas shower head. In this paper, the complimentary and self-limiting character of this process is demonstrated. The effects of key processing parameters including temperature, pulse time, and plasma power are investigated in terms of growth rate, stress, crystal morphology, chemical, electrical, and optical properties. Stoichiometric thin films with growth rates of 0.4-0.5 A/cycle were achieved. Low electrical resistivity (<300 {mu}{Omega} cm), high mass density (>4 g/cm{sup 3}), low stress (<250 MPa), and >85% step coverage for aspect ratio of 10:1 were realized. Wet chemical etch data show robust chemical stability of the film. The properties of the film have been optimized to satisfy industrial viability as a Ruthenium (Ru) preseed liner in potential data storage and TSV applications.« less

Improved Mechanical Compatibility and Cytocompatibility of Ta/Ti Double-Layered Composite Coating

NASA Astrophysics Data System (ADS)

Ding, Ding; Xie, Youtao; Li, Kai; Huang, Liping; Zheng, Xuebin

2017-08-01

In order to improve the mechanical compatibility and cytocompatibility of titanium implants, a composite coating with double layers composed of tantalum and titanium was designed and prepared using plasma spraying technology. In the composite coating, the upper tantalum layer provides a good biocompatibility, and the sublayer of titanium with a porous structure ensures the low elastic modulus. Results show that the fabricated composite coating exhibits a relatively low elastic modulus of 26.7 GPa, which is close to the elastic modulus of human cortical bone. In vitro cytocompatibility evaluation of the composite coating shows that the human bone marrow stromal cells exhibit enhanced adhesion and spreading performance on the double-layered composite coating in comparison with the single-layered titanium coating. In order to eliminate the misgivings of chemical stability of the composite coating in clinical application, electrochemical corrosion of the coating was examined. The results obtained revealed a very weak galvanic corrosion between the tantalum and titanium in the composite coating, which would ensure the safety of the coating in vivo.

Investigation of the mechanical and chemical characteristics of nanotubular and nano-pitted anodic films on grade 2 titanium dental implant materials.

PubMed

Weszl, Miklós; Tóth, Krisztián László; Kientzl, Imre; Nagy, Péter; Pammer, Dávid; Pelyhe, Liza; Vrana, Nihal E; Scharnweber, Dieter; Wolf-Brandstetter, Cornelia; Joób F, Árpád; Bognár, Eszter

2017-09-01

The objective of this study was to investigate the reproducibility, mechanical integrity, surface characteristics and corrosion behavior of nanotubular (NT) titanium oxide arrays in comparison with a novel nano-pitted (NP) anodic film. Surface treatment processes were developed to grow homogenous NT and NP anodic films on the surface of grade 2 titanium discs and dental implants. The effect of process parameters on the surface characteristics and reproducibility of the anodic films was investigated and optimized. The mechanical integrity of the NT and NP anodic films were investigated by scanning electron microscopy, surface roughness measurement, scratch resistance and screwing tests, while the chemical and physicochemical properties were investigated in corrosion tests, contact angle measurement and X-ray photoelectron spectroscopy (XPS). The growth of NT anodic films was highly affected by process parameters, especially by temperature, and they were apt to corrosion and exfoliation. In contrast, the anodic growth of NP film showed high reproducibility even on the surface of 3-dimensional screw dental implants and they did not show signs of corrosion and exfoliation. The underlying reason of the difference in the tendency for exfoliation of the NT and NP anodic films is unclear; however the XPS analysis revealed fluorine dopants in a magnitude larger concentration on NT anodic film than on NP surface, which was identified as a possible causative. Concerning other surface characteristics that are supposed to affect the biological behavior of titanium implants, surface roughness values were found to be similar, whereas considerable differences were revealed in the wettability of the NT and NP anodic films. Our findings suggest that the applicability of NT anodic films on the surface of titanium bone implants may be limited because of mechanical considerations. In contrast, it is worth to consider the applicability of nano-pitted anodic films over nanotubular arrays for the enhancement of the biological properties of titanium implants. Copyright © 2017 Elsevier B.V. All rights reserved.

Bioengineered titanium surfaces affect the gene-expression and phenotypic response of osteoprogenitor cells derived from mouse calvarial bones.

PubMed

Isaac, J; Galtayries, A; Kizuki, T; Kokubo, T; Berda, A; Sautier, J-M

2010-09-28

This study investigated the in vitro effects of bioactive titanium surfaces on osteoblast differentiation. Three titanium substrates were tested: a commercially pure titanium (Cp Ti), an alkali- and heat-treated titanium (AH Ti), and an apatite-formed titanium (Ap Ti) generated by soaking AH Ti in a simulated body fluid. Chemical evaluation of the surface reactivity was analysed at nanometre scale by X-ray photoelectron spectroscopy (XPS), and at micrometre scale by energy dispersive X-ray microanalysis (EDX). It showed that the estimated proportion of the surface covered by adsorbed serum proteins differed between the three substrates and confirmed the bioactivity of AH Ti, illustrated by surface calcium and phosphate deposition when immersed in biological fluids. Mouse calvaria osteoblasts were cultured on the substrates for 15 days with no sign of cytotoxicity. Enzyme immunoassay and Real-Time RT-PCR were used to follow osteoblast differentiation through the production of osteocalcin (OC) and expression of several bone markers. At day 15, a significant up-regulation of Runx2, Osx, Dlx5, ALP, BSP, OC and DMP1 mRNA levels associated with an increase of OC production were observed on AH Ti and Ap Ti when compared to Cp Ti. These results suggest that bioengineered titanium has a great potential for dental applications in enhancing osseointegration.

Chemically Layered Porous Solids

NASA Technical Reports Server (NTRS)

Koontz, Steve

1991-01-01

Aerogels and other porous solids in which surfaces of pores have chemical properties varying with depth below macroscopic surfaces prepared by sequences of chemical treatments. Porous glass or silica bead treated to make two depth zones having different chemical properties. Beads dropped along tube filled with flowing gas containing atomic oxygen, generated in microwave discharge. General class of materials treatable include oxides of aluminum, silicon, zirconium, tin, titanium, and nickel, and mixtures of these oxides. Potential uses of treated materials include chromatographic separations, membrane separations, controlled releases of chemicals, and catalysis.

Chemical Processing Manual

NASA Technical Reports Server (NTRS)

Beyerle, F. J.

1972-01-01

Chemical processes presented in this document include cleaning, pickling, surface finishes, chemical milling, plating, dry film lubricants, and polishing. All types of chemical processes applicable to aluminum, for example, are to be found in the aluminum alloy section. There is a separate section for each category of metallic alloy plus a section for non-metals, such as plastics. The refractories, super-alloys and titanium, are prime candidates for the space shuttle, therefore, the chemical processes applicable to these alloys are contained in individual sections of this manual.

Carbon or boron modified titanium silicide

DOEpatents

Thom, A.J.; Akinc, M.

1998-07-14

A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

Carbon or boron modified titanium silicide

DOEpatents

Thom, A.J.; Akinc, M.

1997-12-02

A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

Carbon or boron modified titanium silicide

DOEpatents

Thom, Andrew J.; Akinc, Mufit

1996-12-03

A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

Carbon or boron modified titanium silicide

DOEpatents

Thom, Andrew J.; Akinc, Mufit

1997-12-02

A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

Carbon or boron modified titanium silicide

DOEpatents

Thom, A.J.; Akinc, M.

1996-12-03

A titanium silicide material based on Ti{sub 5}Si{sub 3} intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000 C. Boron is added to a Ti{sub 5}Si{sub 3} base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end. 3 figs.

Carbon or boron modified titanium silicide

DOEpatents

Thom, Andrew J.; Akinc, Mufit

1998-07-14

A titanium silicide material based on Ti.sub.5 Si.sub.3 intermetallic compound exhibits substantially improved oxidative stability at elevated temperatures. In particular, carbon is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.6 weight % C) effective to impart substantially improved oxidative stability at elevated temperatures, such as about 1000.degree. C. Boron is added to a Ti.sub.5 Si.sub.3 base material in an amount (e.g. about 0.3 to about 3.3 weight % B) to this same end.

Average chemical composition of the lunar surface

NASA Technical Reports Server (NTRS)

Turkevich, A. L.

1973-01-01

The available data on the chemical composition of the lunar surface at eleven sites (3 Surveyor, 5 Apollo and 3 Luna) are used to estimate the amounts of principal chemical elements (those present in more than about 0.5% by atom) in average lunar surface material. The terrae of the moon differ from the maria in having much less iron and titanium and appreciably more aluminum and calcium.

Visible light-harvesting photoanodes for solar energy conversion: A comparison of anchoring groups to titanium dioxide

NASA Astrophysics Data System (ADS)

Martini, Lauren A.

Environmental concerns related to climate change and geopolitical issues related to energy security have led to a widespread pursuit of alternative, non-fossil fuel energy sources capable of meeting our increasing global energy demands. Solar energy, which strikes the earth's surface at a rate vastly exceeding our current worldwide power demand, presents itself as a promising source of clean, abundant and renewable energy. The capture and conversion of solar energy into electricity as well as storable, transportable chemical fuels has therefore become major area of chemical research. Inspired by photosynthesis in nature, in which plants and algae convert sunlight, water, and carbon dioxide into oxygen and stored chemical fuel in the form of sugars, recent work has focused on visible light-driven water-splitting technologies for the production of solar fuels. Honda and Fujishima reported the first example of photoelectrochemical water oxidation in 1972. In their system, an inexpensive titanium dioxide semiconductor irradiated with ultraviolet light produced oxygen at the photoanode surface and hydrogen at the surface of a platinum counter electrode. In attempt to harness visible light instead, titanium dioxide and other inexpensive wide band gap photoanodes have been functionalized with visible light-absorbing molecular dyes. These dye-sensitized photoanodes have been used successfully to convert solar energy into electrical current, as in dye-sensitized solar cells, and to drive chemical processes like water oxidation, as in photocatalytic cells. In both systems, a long-lived charge separation is established upon illumination of the photoanode surface when a photoexcited molecular chromophore transfers an electron to the semiconductor conduction band. Following this electron injection process, a nearby redox-active species is oxidized and refills the hole left behind on the molecular chromophore. While the steps of this scheme are relatively straightforward, the integration of efficient visible-light absorption, ultrafast forward electron transfer, and stable charge separation is quite complicated. The work presented here is devoted to the design, synthesis, spectroscopy, and computational study of dye-sensitized photoanodes. In particular, we explore the relative stability and performance of different anchoring groups for the surface attachment of light-harvesting molecular dyes to titanium dioxide. Here we present the first systematic study that directly compares carboxylate, phosphonate, acetylacetonate, and hydroxamate anchors using the same molecular chromophore framework. We discuss a number of novel methods for the incorporation of anchoring group functionalities on each chromophore framework. We also assess the relative water stability of each of the anchoring groups on titanium dioxide as well as the relative efficiency of electron transfer from photoexcited molecular chromophores through each anchoring group into the conduction band of titanium dioxide. We hope that the work presented here will contribute to the rational design of better photoanodes for light-driven water splitting.

Nano-engineered titanium for enhanced bone therapy

NASA Astrophysics Data System (ADS)

Gulati, Karan; Atkins, Gerald J.; Findlay, David M.; Losic, Dusan

2013-09-01

Current treatment of a number of orthopaedic conditions, for example fractures, bone infection, joint replacement and bone cancers, could be improved if mechanical support could be combined with drug delivery. A very challenging example is that of infection following joint replacement, which is very difficult to treat, can require multiple surgeries and compromises both the implant and the patient's wellbeing. An implant capable of providing appropriate biomechanics and releasing drugs/proteins locally might ensure improved healing of the traumatized bone. We propose fabrication of nanoengineered titanium bone implants using bioinert titanium wires in order to achieve this goal. Titanium in the form of flat foils and wires were modified by fabrication of titania nanotubes (TNTs), which are hollow self-ordered cylindrical tubes capable of accommodating substantial drug amounts and releasing them locally. To further control the release of drug to over a period of months, a thin layer of biodegradable polymer PLGA poly(lactic-coglycolic acid) was coated onto the drug loaded TNTs. This delayed release of drug and additionally the polymer enhanced bone cell adhesion and proliferation.

Fatigue Damage Mechanisms in Advanced Hybrid Titanium Composite Laminates

NASA Technical Reports Server (NTRS)

Johnson, W. Steven; Rhymer, Donald W.; St.Clair, Terry L. (Technical Monitor)

2000-01-01

Hybrid Titanium Composite Laminates (HTCL) are a type of hybrid composite laminate with promise for high-speed aerospace applications, specifically designed for improved damage tolerance and strength at high-temperature (350 F, 177 C). However, in previous testing, HTCL demonstrated a propensity to excessive delamination at the titanium/PMC interface following titanium cracking. An advanced HTCL has been constructed with an emphasis on strengthening this interface, combining a PETI-5/IM7 PMC with Ti-15-3 foils prepared with an alkaline-perborate surface treatment. This paper discusses how the fatigue capabilities of the "advanced" HTCL compare to the first generation HTCL which was not modified for interface optimization, in both tension-tension (R = 0.1) and tension-compression (R=-0.2). The advanced HTCL under did not demonstrate a significant improvement in fatigue life, in either tension-tension or tension-compression loading. However, the advanced HTCL proved much more damage tolerant. The R = 0.1 tests revealed the advanced HTCL to increase the fatigue life following initial titanium ply damage up to 10X that of the initial HTCL at certain stress levels. The damage progression following the initial ply damage demonstrated the effect of the strengthened PMC/titanium interface. Acetate film replication of the advanced HTCL edges showed a propensity for some fibers in the adjacent PMC layers to fail at the point of titanium crack formation, suppressing delamination at the Ti/PMC interface. The inspection of failure surfaces validated these findings, revealing PMC fibers bonded to the majority of the titanium surfaces. Tension compression fatigue (R = -0.2) demonstrated the same trends in cycles between initial damage and failure, damage progression, and failure surfaces. Moreover, in possessing a higher resistance to delamination, the advanced HTCL did not exhibit buckling following initial titanium ply cracking under compression unlike the initial HTCL.

The Effect of Water or Wax-based Binders on the Chemical and Morphological Characteristics of the Margin Ceramic-Framework Interface.

PubMed

Güler, Umut; de Queiroz, José Renato Cavalcanti; de Oliveira, Luiz Fernando Cappa; Canay, Senay; Ozcan, Mutlu

2015-09-01

This study evaluated the effect of binder choice in mixing ceramic powder on the chemical and morphological features between the margin ceramic-framework interfaces. Titanium and zirconia frameworks (15 x 5 x 0.5 mm3) were veneered with margin ceramics prepared with two different binders, namely a) water/conventional or b) wax-based. For each zirconia framework material, four different margin ceramics were used: a- Creation Zi (Creation Willi Geller International); b- GC Initial Zr (GC America); Triceram (Dentaurum); and d- IPS emax (voclar Vivadent). For the titanium framework, three different margin ceramics were used: a- Creation Ti (Creation Willi Geller International); b- Triceram (Dentaurum); and c- VITA Titaniumkeramik (Vita Zahnfabrik). The chemical composition of the framework-margin ceramic interface was analyzed using Energy Dispersive X-ray Spectroscopy (EDS) and porosity level was quantified within the margin ceramic using an image program (ImageJ) from four random areas (100 x 100 pixels) on each SEM image. EDS analysis showed the presence of Carbon at the margin ceramic-framework interface in the groups where wax-based binder technique was used with the concentration being the highest for the IPS emax ZirCAD group. While IPS system (IPS ZirCAD and IPS Emax) presented higher porosity concentration using wax binder, in the other groups wax-based binder reduced the porosity of margin ceramic, except for Titanium - Triceram combination.

Nucleation Studies under the Conditions of Carbon-rich AGB Star Envelopes: TiC

NASA Astrophysics Data System (ADS)

Patzer, A. B. C.; Wendt, M.; Chang, C.; Sülzle, D.

2011-09-01

Many studies of dust nucleation in winds of carbon-rich AGB stars consider primarily carbon as the dust forming material. But dust grains formed in such circumstellar envelopes are rather a mixture of several chemical elements such as titanium or silicon in addition to carbon, as verified by many investigations of pre-solar grains enclosed in meteorites, for example. In this contribution we focus on the study of the nucleation of titanium carbide particles from the gas phase. The necessary properties of molecular titanium carbide clusters have been estimated by the density functional approach, and the first implications for the homogeneous nucleation of TiC are studied for conditions representative of circumstellar dust shells around carbon-rich AGB stars.

LARC-13 adhesive development

NASA Technical Reports Server (NTRS)

Hill, S. G.; Sheppard, C. H.; Johnson, J. C.

1980-01-01

A LARC-13 type adhesive system was developed and property data obtained that demonstrated improved thermomechanical properties superior to base LARC-13 adhesive. An improved adhesive for 589 K (600 F) use was developed by physical or chemical modification of LARC-13. The adhesive was optimized for titanium and composite bonding, and a compatible surface preparation for titanium and composite substrates was identified. The data obtained with the improved adhesive system indicated it would meet the 589 K (600 F) properties desired for application on space shuttle components. Average titanium lap shear data were: (1) 21.1 MPa (3355 psi) at RT, (2) 13.0 MPa (1881 psi) at 600 F, and (3) 16.4 MPa (2335) after aging 125 hours at 600 F and tested at 600 F.

Silicone azide fireproof material

NASA Technical Reports Server (NTRS)

1978-01-01

Finely powdered titanium oxide was added to silicone azide as the sintering agent to produce a nonflammable material. Mixing proportions, physical properties, and chemical composition of the fireproofing material are included.

Titanium diboride ceramic fiber composites for Hall-Heroult cells

DOEpatents

Besmann, Theodore M.; Lowden, Richard A.

1990-01-01

An improved cathode structure for Hall-Heroult cells for the electrolytic production of aluminum metal. This cathode structure is a preform fiber base material that is infiltrated with electrically conductive titanium diboride using chemical vapor infiltration techniques. The structure exhibits good fracture toughness, and is sufficiently resistant to attack by molten aluminum. Typically, the base can be made from a mat of high purity silicon carbide fibers. Other ceramic or carbon fibers that do not degrade at temperatures below about 1000 deg. C can be used.

Electro-Chemical-Mechanical, Low Stress, Automatic Polishing (ECMP) Device (Preprint)

DTIC Science & Technology

2010-01-01

into models that predict mechanical response [ 4 - 6 ]. In addition, surface preparation steps are critical to the imaging of ceramic and hybrid...2p 3/2 peak in the spectral data found in Figure 4 . The Ti 2p 3/2 peak is initially observed at 458.4 eV indicating that titanium is present in its...above 6 acceptable limits for both (average IQ values were higher than 2000). For the titanium samples, the samples processed without applied

Characterization of Mechanical, Thermal and Wear Properties of Titanium Rich Metallic Glasses.

DTIC Science & Technology

1982-12-20

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Analysis of x-ray diffraction pattern and complex plane impedance plot of polypyrrole/titanium dioxide nanocomposite: A simulation study

NASA Astrophysics Data System (ADS)

Ravikiran, Y. T.; Vijaya Kumari, S. C.

2013-06-01

To innovate the properties of Polypyrrole/Titanium dioxide (PPy/TiO2) nanocomposite further, it has been synthesized by chemical polymerization technique. The nanostructure and monoclinic phase of the prepared composite have been confirmed by simulating the X-ray diffraction pattern (XRD). Also, complex plane impedance plot of the composite has been simulated to find equivalent resistance capacitance circuit (RC circuit) and numerical values of R and C have been predicted.

Temperature dependence and P/Ti ratio in phosphoric acid treatment of titanium dioxide and powder properties.

PubMed

Onoda, H; Matsukura, A

2015-02-01

Titanium dioxide has photocatalytic activity and is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium dioxide was shaken with phosphoric acid to synthesize a white pigment for cosmetics. Titanium dioxide was treated with 0.1 mol/L of phosphoric acid at various P/Ti molar ratios, and then shaken in hot water for 1 h. The chemical composition, powder properties, photocatalytic activity, colour phase, and smoothness of the obtained powder were studied. The obtained materials indicated XRD peaks of titanium dioxide, however the peaks diminished subsequent to phosphoric acid treatment. The samples included small particles with sub-micrometer size. The photocatalytic activity of the obtained powders decreased, decomposing less sebum on the skin. Samples prepared at high P/Ti ratio with high shaking temperature indicated low whiteness in in L*a*b* colour space. The shaking and heating temperature and P/Ti ratio had influence on the smoothness of the obtained materials. Phosphoric acid treatment of titanium dioxide is an effective method to inhibit photocatalytic activity for a white pigment. © 2014 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

Topographic and chemical surface modifications to metal brackets after a period in the mouth.

PubMed

Houb-Dine, Afaf; Bahije, Loubna; Oualalou, Youssef; Benyahia, Hicham; Zaoui, Fatima

2017-09-01

In the current state of our knowledge, the effects of corrosion on the performance of orthodontic appliances and on patient health are far from clear. Awareness of these problems has led to a growing demand for nickel-free products. Titanium brackets were recently launched on the market as an alternative to stainless-steel brackets. However, the use of fluorides for caries prevention creates a risk of corrosion of these titanium appliances. The aim of this study is to examine the corrosion of stainless-steel and titanium brackets in clinical orthodontic use, focusing on the impact of fluorine. After approval by the ethics committee and the informed consent of the patients, 30 candidates for multi-bracket treatment were selected on the basis of certain exclusion criteria. The patients were divided into 4 groups: group 1: titanium brackets and fluorine protection; group 2: titanium brackets without fluorine protection; group 3: stainless-steel brackets and fluorine protection; group 4: stainless-steel brackets without fluorine protection. Analysis of the brackets removed after 4months in the mouth, using scanning electron microscopy (SEM) with phase contrast, revealed a difference in the surface topography of the metal brackets and the presence of chromium coating on the surface of the titanium appliances. Copyright © 2017 CEO. Published by Elsevier Masson SAS. All rights reserved.

Proteome Profiling Reveals Potential Toxicity and Detoxification Pathways Following Exposure of BEAS-2B Cells to Engineered Nanoparticle Titanium Dioxide

EPA Science Inventory

Identification of toxicity pathways linked to chemical -exposure is critical for a better understanding of biological effects of the exposure, toxic mechanisms, and for enhancement of the prediction of chemical toxicity and adverse health outcomes. To identify toxicity pathways a...

Hand and nickel-titanium root canal instrumentation performed by dental students: a micro-computed tomographic study.

PubMed

Peru, M; Peru, C; Mannocci, F; Sherriff, M; Buchanan, L S; Pitt Ford, T R

2006-02-01

The aim of this study was to evaluate root canals instrumented by dental students using the modified double-flared technique, nickel-titanium (NiTi) rotary System GT files and NiTi rotary ProTaper files by micro-computed tomography (MCT). A total of 36 root canals from 18 mesial roots of mandibular molar teeth were prepared; 12 canals were prepared with the modified double-flared technique, using K-flexofiles and Gates-Glidden burs; 12 canals were prepared using System GT and 12 using ProTaper rotary files. Each root was scanned using MCT preoperatively and postoperatively. At the coronal and mid-root sections, System GT and ProTaper files produced significantly less enlarged canal cross-sectional area, volume and perimeter than the modified double-flared technique (P < 0.05). In the mid-root sections there was significantly less thinning of the root structure towards the furcation with System GT and ProTaper (P < 0.05). The rotary techniques were both three times faster than the modified double-flared technique (P < 0.05). Qualitative evaluation of the preparations showed that both ProTaper and System GT were able to prepare root canals with little or no procedural error compared with the modified double-flared technique. Under the conditions of this study, inexperienced dental students were able to prepare curved root canals with rotary files with greater preservation of tooth structure, low risk of procedural errors and much quicker than with hand instruments.

Modified Goel’s Methods for Basilar Impression: A Case Report with Literature

PubMed Central

Asamoto, Shunji; Fukui, Yasuyuki; Nishiyama, Makoto; Ishikawa, Masayuki; Nakamura, Satoshi; Nagashima, Masaki; Muto, Jun; Jimbo, Hiroyuki

2016-01-01

We report the case of a 57-year-old woman who had basilar impression manifesting as severe myelopathy and occipital neuralgia and was treated by distraction and fixation performed using a modification of Goel’s method. Magnetic resonance imaging (MRI) and computed tomography (CT) scans showed severe myelocompression by the dens of the axis from the ventral side and occipitalization of the atlas. After traction using a Halo vest, C1–2 facet distraction and fixation was performed in one stage using a modified Goel’s method. Although Goel et al. used a custom-made spacer to distract the facet joints, we used a threaded titanium cylindrical cage that was inserted into the joint to fix the C1–2 facet joint with posterior fixation from occipital bone to C5. Postoperatively, gradual symptomatic and neurological amelioration were observed. The atlantoaxial joints were bone-fused at 3 years post-operation. Distraction and fixation performed using this modified version of Goel’s method was effective for treating basilar invagination. The threaded titanium cylindrical cage provided adequate C1–2 space and strong initial fixation. PMID:28663991

Direct electrochemistry of hemoglobin on graphene and titanium dioxide nanorods composite modified electrode and its electrocatalysis.

PubMed

Sun, Wei; Guo, Yaqing; Ju, Xiaomei; Zhang, Yuanyuan; Wang, Xiuzhen; Sun, Zhenfan

2013-04-15

A biocompatible sensing platform based on graphene (GR) and titanium dioxide (TiO₂) nanorods for the immobilization of hemoglobin (Hb) was adopted in this paper. The GR-TiO₂-Hb composite-modified carbon ionic liquid electrode was constructed through a simple casting method with Nafion as the film forming material. UV-Vis and FT-IR spectra confirmed that Hb retained its native structure in the composite film. Direct electron transfer of Hb incorporated into the composite was realized with a pair of quasi-reversible redox waves appeared, indicating that the presence of GR-TiO₂ nanocomposite on the electrode surface could facilitate the electron transfer rate between the electroactive center of Hb and the substrate electrode. Hb modified electrode showed excellent electrocatalytic activity to the reduction of trichloroacetic acid in the concentration range from 0.6 to 21.0 mmol L⁻¹. These results indicated that GR-TiO₂ nanocomposite could be a friendly biocompatible interface for immobilizing biomolecules and keeping their native structure. The fabricated biosensor displayed the advantages such as high sensitivity, good reproducibility and long-term stability. Copyright © 2012 Elsevier B.V. All rights reserved.

The effects of titanium nitride-coating on the topographic and biological features of TPS implant surfaces.

PubMed

Annunziata, Marco; Oliva, Adriana; Basile, Maria Assunta; Giordano, Michele; Mazzola, Nello; Rizzo, Antonietta; Lanza, Alessandro; Guida, Luigi

2011-11-01

Titanium nitride (TiN) coating has been proposed as an adjunctive surface treatment aimed to increase the physico-mechanical and aesthetic properties of dental implants. In this study we investigated the surface characteristics of TiN-coated titanium plasma sprayed (TiN-TPS) and uncoated titanium plasma sprayed (TPS) surfaces and their biological features towards both primary human bone marrow mesenchymal stem cells (BM-MSC) and bacterial cultures. 15 mm×1 mm TPS and TiN-TPS disks (P.H.I. s.r.l., San Vittore Olona, Milano, Italy) were topographically analysed by confocal optical profilometry. Primary human BM-MSC were obtained from healthy donors, isolated and expanded. Cells were seeded on the titanium disks and cell adhesion, proliferation, protein synthesis and osteoblastic differentiation in terms of alkaline phosphatase activity, osteocalcin synthesis and extracellular mineralization, were evaluated. Furthermore, adhesion and proliferation of Streptococcus pyogenes and Streptococcus sanguinis on both surfaces were also analysed. TiN-TPS disks showed a decreased roughness (about 50%, p < 0.05) and a decreased bacterial adhesion and proliferation compared to TPS ones. No difference (p > 0.05) in terms of BM-MSC adhesion, proliferation and osteoblastic differentiation between TPS and TiN-TPS surfaces was found. TiN coating showed to modify the topographical characteristics of TPS titanium surfaces and to significantly reduce bacterial adhesion and proliferation, although maintaining their biological affinity towards bone cell precursors. Copyright © 2011 Elsevier Ltd. All rights reserved.

Surface characteristics of anodized and hydrothermally treated titatnium with an increasing concentration of calcium ion

NASA Astrophysics Data System (ADS)

Park, Il Song; Bae, Tae Sung; Seol, Kyeong Won

2006-10-01

Titanium is widely used as an implant material due to its good mechanical properties and the excellent biocompatibility of the oxide film on the surface. To modify the unstable oxide surface of pure titanium, plasma electrolytic oxidation was applied in this study. The electrolyte used for anodizing was a mixture of GP (glycerophosphate disodium salt) and CA (calcium acetate). In addition, a hydrothermal treatment was performed to precipitate a calcium phosphate crystal on the titanium oxide layer for bioactivity. The effect of the CA concentration of the electrolyte on the surface of titanium was investigated, with CA concentrations at 0.1 M, 0.2 M, and 0.3 M. A high concentration of CA results in a low breakdown voltage; hence many large micropores were formed on the anodized surface. Moreover, the size of the HA crystals was more minute in proportion to the increasing concentration of CA. The crystal phase of titanium dioxide was mainly anatase, and a rutile phase was also observed. As the size and/or amount of HA crystals increased, the surface roughness increased. However, the surface roughness could be decreased by fully and uniformly covering the surface with HA crystals. The corrosion resistance in the saline solution was increased by anodic spark oxidation. In addition, it was slightly increased by a hydrothermal treatment. It is considered that a more stable and thicker titanium oxide layer is formed by anodic oxidation and a hydrothermal treatment.

Carbothermal reduction of Ti-modified IRMOF-3: an adaptable synthetic method to support catalytic nanoparticles on carbon.

PubMed

Kim, Jongsik; McNamara, Nicholas D; Her, Theresa H; Hicks, Jason C

2013-11-13

This work describes a novel method for the preparation of titanium oxide nanoparticles supported on amorphous carbon with nanoporosity (Ti/NC) via the post-synthetic modification of a Zn-based MOF with an amine functionality, IRMOF-3, with titanium isopropoxide followed by its carbothermal pyrolysis. This material exhibited high purity, high surface area (>1000 m(2)/g), and a high dispersion of metal oxide nanoparticles while maintaining a small particle size (~4 nm). The material was shown to be a promising catalyst for oxidative desulfurization of diesel using dibenzothiophene as a model compound as it exhibited enhanced catalytic activity as compared with titanium oxide supported on activated carbon via the conventional incipient wetness impregnation method. The formation mechanism of Ti/NC was also proposed based on results obtained when the carbothermal reduction temperature was varied.

Study of advanced composite structural design concepts for an arrow wing supersonic cruise configuration

NASA Technical Reports Server (NTRS)

Turner, M. J.; Grande, D. L.

1978-01-01

Based on estimated graphite and boron fiber properties, allowable stresses and strains were established for advanced composite materials. Stiffened panel and conventional sandwich panel concepts were designed and analyzed, using graphite/polyimide and boron/polyimide materials. The conventional sandwich panel was elected as the structural concept for the modified wing structure. Upper and lower surface panels of the arrow wing structure were then redesigned, using high strength graphite/polyimide sandwich panels, retaining the titanium spars and ribs from the prior study. The ATLAS integrated analysis and design system was used for stress analysis and automated resizing of surface panels. Flutter analysis of the hybrid structure showed a significant decrease in flutter speed relative to the titanium wing design. The flutter speed was increased to that of the titanium design by selective increase in laminate thickness and by using graphite fibers with properties intermediate between high strength and high modulus values.

Grain-resolved analysis of localized deformation in nickel-titanium wire under tensile load.

PubMed

Sedmák, P; Pilch, J; Heller, L; Kopeček, J; Wright, J; Sedlák, P; Frost, M; Šittner, P

2016-08-05

The stress-induced martensitic transformation in tensioned nickel-titanium shape-memory alloys proceeds by propagation of macroscopic fronts of localized deformation. We used three-dimensional synchrotron x-ray diffraction to image at micrometer-scale resolution the grain-resolved elastic strains and stresses in austenite around one such front in a prestrained nickel-titanium wire. We found that the local stresses in austenite grains are modified ahead of the nose cone-shaped buried interface where the martensitic transformation begins. Elevated shear stresses at the cone interface explain why the martensitic transformation proceeds in a localized manner. We established the crossover from stresses in individual grains to a continuum macroscopic internal stress field in the wire and rationalized the experimentally observed internal stress field and the topology of the macroscopic front by means of finite element simulations of the localized deformation. Copyright © 2016, American Association for the Advancement of Science.

Treatment of a textile effluent by adsorption with cork granules and titanium dioxide nanomaterial.

PubMed

Castro, Margarida; Nogueira, Verónica; Lopes, Isabel; Vieira, Maria N; Rocha-Santos, Teresa; Pereira, Ruth

2018-05-12

This study aimed to explore the efficiency of two adsorbents, cork granules with different granulometry and titanium dioxide nanomaterial, in the removal of chemical oxygen demand (COD), colour and toxicity from a textile effluent. The adsorption assays with cork were unsatisfactory in the removal of chemical parameters however they eliminated the acute toxicity of the raw effluent to Daphnia magna. The assay with TiO 2 NM did not prove to be efficient in the removal of colour and COD even after 240 min of contact; nevertheless it also reduced the raw effluent toxicity. The best approach for complete remediation of the textile effluent has not yet been found however promising findings were achieved, which may be an asset in future adsorption assays.

Chemical Engineering of Photoactivity in Heterometallic Titanium-Organic Frameworks by Metal Doping.

PubMed

Castells-Gil, Javier; Padial, Natalia M; Almora-Barrios, Neyvis; Albero, Josep; Ruiz-Salvador, A Rabdel; González-Platas, Javier; García, Hermenegildo; Martí-Gastaldo, Carlos

2018-06-06

We report a new family of titanium-organic frameworks that enlarges the limited number of crystalline, porous materials available for this metal. They are chemically robust and can be prepared as single crystals at multi-gram scale from multiple precursors. Their heterometallic structure enables engineering of their photoactivity by metal doping rather than by linker functionalization. Compared to other methodologies based on the post-synthetic metallation of MOFs, our approach is well-fitted for controlling the positioning of dopants at an atomic level to gain more precise control over the band-gap and electronic properties of the porous solid. Changes in the band-gap are also rationalized with computational modelling and experimentally confirmed by photocatalytic H 2 production. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Titanium-based silicide quantum dot superlattices for thermoelectrics applications.

PubMed

Savelli, Guillaume; Stein, Sergio Silveira; Bernard-Granger, Guillaume; Faucherand, Pascal; Montès, Laurent; Dilhaire, Stefan; Pernot, Gilles

2015-07-10

Ti-based silicide quantum dot superlattices (QDSLs) are grown by reduced-pressure chemical vapor deposition. They are made of titanium-based silicide nanodots scattered in an n-doped SiGe matrix. This is the first time that such nanostructured materials have been grown in both monocrystalline and polycrystalline QDSLs. We studied their crystallographic structures and chemical properties, as well as the size and the density of the quantum dots. The thermoelectric properties of the QDSLs are measured and compared to equivalent SiGe thin films to evaluate the influence of the nanodots. Our studies revealed an increase in their thermoelectric properties-specifically, up to a trifold increase in the power factor, with a decrease in the thermal conductivity-making them very good candidates for further thermoelectric applications in cooling or energy-harvesting fields.

Chemically functionalized two-dimensional titanium carbide MXene by in situ grafting-intercalating with diazonium ions to enhance supercapacitive performance

NASA Astrophysics Data System (ADS)

Wang, Hongbing; Zhang, Jianfeng; Wu, Yuping; Huang, Huajie; Jiang, Quanguo

2018-04-01

Two-dimensional Ti3C2 MXene nanosheets were functionalized with phenylsulfonic groups derived from in situ generated diazonium ions by the corresponding amine. During the functionalization process, the aryl groups were attached onto the MXene surfaces in the form of strong MXene-aryl (Tisbnd Osbnd C) linkages. Simultaneously, the intercalation of diazonium ions enabled Ti3C2 multi-layers to be delaminated into separate few-layer nanosheets via weak sonication with low energy. As a result of chemical functionalization for MXene Ti3C2, the dispersibility was greatly improved and the specific surface area increased significantly. The grafted functional groups are still stable up to at least 200 °C upon thermogravimetric analysis measurements. With diazonium ions intercalating and electroactive groups grafting between-in MXene layers, the chemically functionalized Ti3C2 electrodes exhibited an enhanced supercapacitive performance, which acquired a specific capacitance more than double that of pristine Ti3C2 samples and excellent cycling stability (91% capacity retention after 10,000 cycles at 3 A g-1). This feasible modification scheme can be also extended to functionalize other types of MXenes materials with this or other aryl diazonium ions as surface modifiers and intercalants, thus offering scope for full potential applications of the new 2D materials.

In vitro fibroblast and pre-osteoblastic cellular responses on laser surface modified Ti-6Al-4V.

PubMed

Chikarakara, Evans; Fitzpatrick, Patricia; Moore, Eric; Levingstone, Tanya; Grehan, Laura; Higginbotham, Clement; Vázquez, Mercedes; Bagga, Komal; Naher, Sumsun; Brabazon, Dermot

2014-12-29

The success of any implant, dental or orthopaedic, is driven by the interaction of implant material with the surrounding tissue. In this context, the nature of the implant surface plays a direct role in determining the long term stability as physico-chemical properties of the surface affect cellular attachment, expression of proteins, and finally osseointegration. Thus to enhance the degree of integration of the implant into the host tissue, various surface modification techniques are employed. In this work, laser surface melting of titanium alloy Ti-6Al-4V was carried out using a CO2 laser with an argon gas atmosphere. Investigations were carried out to study the influence of laser surface modification on the biocompatibility of Ti-6Al-4V alloy implant material. Surface roughness, microhardness, and phase development were recorded. Initial knowledge of these effects on biocompatibility was gained from examination of the response of fibroblast cell lines, which was followed by examination of the response of osteoblast cell lines which is relevant to the applications of this material in bone repair. Biocompatibility with these cell lines was analysed via Resazurin cell viability assay, DNA cell attachment assay, and alamarBlue metabolic activity assay. Laser treated surfaces were found to preferentially promote cell attachment, higher levels of proliferation, and enhanced bioactivity when compared to untreated control samples. These results demonstrate the tremendous potential of this laser surface melting treatment to significantly improve the biocompatibility of titanium implants in vivo.

Palladium-directed self-assembly of multi-titanium(IV)-porphyrin arrays on the substrate surface as sensitive ultrathin films for hydrogen peroxide sensing, photocurrent generation, and photochromism of viologen

NASA Astrophysics Data System (ADS)

He, Wen-Li; Fang, Fang; Ma, Dong-Mei; Chen, Meng; Qian, Dong-Jin; Liu, Minghua

2018-01-01

Multiporphyrin arrays are large, π-conjugated chromophores with high absorption efficiency and strong chemical stability that play an important role in supramolecular and advanced material sciences. Palladium-directed self-assembly of multiporphyrin array ultrathin films was achieved on substrate surfaces using oxo[5,10,15,20-tetra(4-pyridyl)porphyrinato]titanium (IV) complex [TiO(TPyP)] as a linker and sodium tetrachloropalladate (Na2PdCl4) as a connector. The Pd-TiOTPyP films as prepared were characterized by using UV-vis absorption and X-ray photoelectron spectroscopy, as well as by atomic force and scanning electron microscopy. The Soret absorption band of TiOTPyP was observed to red shift by 6 nm when the Pd-TiOTPyP multilayer-modified quartz substrate was immersed in an aqueous solution containing hydrogen peroxide. This was attributed to the formation of a TiO2TPyP monoperoxo complex. This oxidation reaction could be accelerated in an acidic solution. Furthermore, the immobilized Pd-TiOTPyP multilayers could act as light-harvesting units for photocurrent generation and photochromism of viologens, with strong stability, reproducibility, and recyclability. The photocurrent density could be enhanced in electrolyte solutions containing electron donors such as triethanolamine, or electron acceptors such as viologens. Finally, photoinduced reduction (photochromism) of viologens was investigated using the Pd-TiOTPyP multilayers as light sensitizers and EDTA as the electron donors.

Characterization of stainless steel surface processed using electrolytic oxidation and titanium complex ion solution

NASA Astrophysics Data System (ADS)

Kang, Yubin; Choi, Jaeyoung; Park, Jinju; Kim, Woo-Byoung; Lee, Kun-Jae

2017-09-01

This study attempts to improve the physical and chemical adhesion between metals and ceramics by using electrolytic oxidation and a titanium organic/inorganic complex ion solution on the SS-304 plate. Surface analysis confirmed the existence of the Tisbnd Osbnd Mx bonds formed by the bonding between the metal ions and the Ti oxide at the surface of the pre-processed SS plate, and improved chemical adhesion during ceramic coating was expected by confirming the presence of the carboxylic group. The adhesion was evaluated by using the ceramic coating solution in order to assess the improved adhesion of the SS plate under conditions. The results showed that both the adhesion and durability were largely improved in the sample processed with all the pre-processing steps, thus confirming that the physical and chemical adhesion between metals and ceramics can be improved by enhancing the physical roughness via electrolytic oxidation and pre-processing using a Ti complex ion solution.

Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study.

PubMed

Stanec, Zlatko; Halambek, Jasna; Maldini, Krešimir; Balog, Martin; Križik, Peter; Schauperl, Zdravko; Ćatić, Amir

2016-03-01

The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested.

Modification of Titanium Substrates with Chimeric Peptides Comprising Antimicrobial and Titanium-Binding Motifs Connected by Linkers To Inhibit Biofilm Formation.

PubMed

Liu, Zihao; Ma, Shiqing; Duan, Shun; Xuliang, Deng; Sun, Yingchun; Zhang, Xi; Xu, Xinhua; Guan, Binbin; Wang, Chao; Hu, Meilin; Qi, Xingying; Zhang, Xu; Gao, Ping

2016-03-02

Bacterial adhesion and biofilm formation are the primary causes of implant-associated infection, which is difficult to eliminate and may induce failure in dental implants. Chimeric peptides with both binding and antimicrobial motifs may provide a promising alternative to inhibit biofilm formation on titanium surfaces. In this study, chimeric peptides were designed by connecting an antimicrobial motif (JH8194: KRLFRRWQWRMKKY) with a binding motif (minTBP-1: RKLPDA) directly or via flexible/rigid linkers to modify Ti surfaces. We evaluated the binding behavior of peptides using quartz crystal microbalance (QCM) and atomic force microscopy (AFM) techniques and investigated the effect of the modification of titanium surfaces with these peptides on the bioactivity of Streptococcus gordonii (S. gordonii) and Streptococcus sanguis (S. sanguis). Compared with the flexible linker (GGGGS), the rigid linker (PAPAP) significantly increased the adsorption of the chimeric peptide on titanium surfaces (p < 0.05). Concentration-dependent adsorption is consistent with a single Langmuir model, whereas time-dependent adsorption is in line with a two-domain Langmuir model. Additionally, the chimeric peptide with the rigid linker exhibited more effective antimicrobial ability than the peptide with the flexible linker. This finding was ascribed to the ability of the rigid linker to separate functional domains and reduce their interference to the maximum extent. Consequently, the performance of chimeric peptides with specific titanium-binding motifs and antimicrobial motifs against bacteria can be optimized by the proper selection of linkers. This rational design of chimeric peptides provides a promising alternative to inhibit the formation of biofilms on titanium surfaces with the potential to prevent peri-implantitis and peri-implant mucositis.

Deposition of phosphate coatings on titanium within scaffold structure.

PubMed

Trybuś, Bartłomiej; Zieliński, Andrzej; Beutner, Rene; Seramak, Tomasz; Scharnweber, Dieter

2017-01-01

Existing knowledge about the appearance, thickness, and chemical composition of phosphate coatings on titanium inside porous structures is insufficient. Such knowledge is important for the design and fabrication of porous implants. Metallic scaffolds were fabricated by selective laser melting of 316L stainless steel powder. Phosphate coatings were deposited on Ti sensors placed either outside the scaffolds or in the holes in the scaffolds. The electrochemically-assisted cathodic deposition of phosphate coatings was performed under galvanostatic conditions in an electrolyte containing the calcium and phosphate ions. The phosphate deposits were microscopically investigated; this included the performance of mass weight measurements and chemical analyses of the content of Ca2+ and  24 PO ions after the dissolution of deposits. The thicknesses of the calcium phosphate coatings were about 140 and 200 nm for isolated titanium sensors and 170 and 300 nm for titanium sensors placed inside pores. Deposition of calcium phosphate occurred inside the pores up to 150 mm below the scaffold surface. The deposits were rich in Ca, with a Ca/P ratio ranging from 2 to 2.5. Calcium phosphate coatings can be successfully deposited on a Ti surface inside a model scaffold. An increase in cathodic current results in an increase in coating thickness. Any decrease in the cathodic current inside the porous structure is slight. The calcium phosphate inside the pores has a much higher Ca/P ratio than that of stoichiometric HAp, likely due to a gradual increase in Ca fraction with distance from the surface.

Controlled synthesis of titania using water-soluble titanium complexes: A review

NASA Astrophysics Data System (ADS)

Truong, Quang Duc; Dien, Luong Xuan; Vo, Dai-Viet N.; Le, Thanh Son

2017-07-01

The development of human society has led to the increase in energy and resources consumption as well as the arising problems of environmental damage and the toxicity to the human health. The development of novel synthesis method which tolerates utilization of toxic solvents and chemicals would fulfill the demand of the society for safer, softer, and environmental friendly technologies. For the past decades, a remarkable progress has been attained in the development of new water-soluble titanium complexes (WSTC) and their use for the synthesis of nanocrystalline titanium dioxide materials by aqueous solution-based approaches. The progress of synthesis of nanocrystalline titanium dioxide using such WSTCs is reviewed in this work. The key structural features responsible for the successfully controlled synthesis of TiO2 are discussed to provide guidelines for the morphology-controlled synthesis. Finally, this review ends with a summary and some perspectives on the challenges as well as new directions in this fascinating research.

Tribocorrosion behavior of beta titanium biomedical alloys in phosphate buffer saline solution.

PubMed

Pina, V Guiñón; Dalmau, A; Devesa, F; Amigó, V; Muñoz, A Igual

2015-06-01

The tribo-electrochemical behavior of different β titanium alloys for biomedical applications sintered by powder metallurgy has been investigated. Different mechanical, electrochemical and optical techniques were used to study the influence of the chemical composition, Sn content, and the electrochemical conditions on the tribocorrosion behavior of those alloys Ti30NbxSn alloys (where "x" is the weight percentage of Sn content, 2% and 4%). Sn content increases the active and passive dissolution rate of the titanium alloys, thus increasing the mechanically activated corrosion under tribocorrosion conditions. It also increases the mechanical wear of the alloy. Prevailing electrochemical conditions between -1 and 2V influences the wear accelerated corrosion by increasing it with the applied potential and slightly increases the mechanical wear of Ti30Nb4Sn. Wear accelerated corrosion can be predicted by existing models as a function of electrochemical and mechanical parameters of the titanium alloys. Copyright © 2015 Elsevier Ltd. All rights reserved.

Influence of pH-control in phosphoric acid treatment of titanium oxide and their powder properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Onoda, Hiroaki, E-mail: onoda@kpu.ac.jp; Matsukura, Aki

Highlights: • The photocatalytic activity was suppressed by phosphoric acid treatment. • The obtained pigment had small particles with sub-micrometer size. • By phosphoric acid treatment, the smoothness of samples improved. - Abstract: Titanium oxide that has the photocatalytic activity is used as a white pigment for cosmetics. A certain degree of sebum on the skin is decomposed by the ultraviolet radiation in sunlight. In this work, titanium oxide was shaken with phosphoric acid at various pH to synthesize a novel white pigment for cosmetics. Their chemical composition, powder properties, photocatalytic activity, color phase, and smoothness were studied. The obtainedmore » materials indicated XRD peaks of titanium oxide, however, these peak intensity became weak by phosphoric acid treatment. These samples without heating and heated at 100 °C included the small particles with sub-micrometer size. The photocatalytic activity of the obtained powders became weak by phosphoric acid treatment at pH 4 and 5 to protect the sebum on the skin.« less

Fabrication of dopamine-modified hyaluronic acid/chitosan multilayers on titanium alloy by layer-by-layer self-assembly for promoting osteoblast growth

NASA Astrophysics Data System (ADS)

Zhang, Xinming; Li, Zhaoyang; Yuan, Xubo; Cui, Zhenduo; Yang, Xianjin

2013-11-01

The bare inert surface of titanium (Ti) alloy typically causes early failures in implants. Layer-by-layer self-assembly is one of the simple methods for fabricating bioactive multilayer coatings on titanium implants. In this study, a dopamine-modified hyaluronic acid/chitosan (DHA/CHI) bioactive multilayer was built on the surface of Ti-24Nb-2Zr (TNZ) alloy. Zeta potential oscillated between -2 and 17 mV for DHA- and CHI-ending layers during the assembly process, respectively. The DHA/CHI multilayer considerably decreased the contact angle and dramatically improved the wettability of TNZ alloy. Atomic force microscopy results revealed a rough surface on the original TNZ alloy, while the surface became smoother and more homogeneous after the deposition of approximately 5 bilayers (TNZ/(DHA/CHI)5). X-ray photoelectron spectroscopy analysis indicated that the TNZ/(DHA/CHI)5 sample was completely covered by polyelectrolytes. Pre-osteoblast MC3T3-E1 cells were cultured on the original TNZ alloy and TNZ/(DHA/CHI)5 to evaluate the effects of DHA/CHI multilayer on osteoblast proliferation in vitro. The proliferation of osteoblasts on TNZ/(DHA/CHI)5 was significantly higher than that on the original TNZ alloy. The results of this study indicate that the proposed technique improves the biocompatibility of TNZ alloy and can serve as a potential modification method in orthopedic applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meisner, Ludmila L.; Semin, Viktor O.; Gudimova, Ekaterina Y.

By transmission electron microscopy method the evolution of structural-phase states on a depth of close to equiatomic NiTi modified layer has been studied. Modification performed by pulse impact on its surface low-energy high-current electron beam (beam energy density 10 J/sm{sup 2}, 10 pulses, pulse duration 50mks). It is established that during the treatment in the layer thickness of 8–10 μm, the melting of primary B2 phase and contained therein as Ti2Ni phase particles occurs. The result is change in the concentration ratio of titanium and nickel in the direction of increasing titanium content, which was confirmed by X-ray analysis in themore » form of increased unit cell parameter B2 phase. Analysis of the electron diffraction pattern showed that the modified layer is characterized as a highly distorted structure on the basis of bcc lattice. Lattice distortions are maximal near the surface and extends to a depth of melt. In subjacent layer there is gradual decline lattice distortions is observed.« less

Self-assembled monolayers of alendronate on Ti6Al4V alloy surfaces enhance osteogenesis in mesenchymal stem cells

NASA Astrophysics Data System (ADS)

Rojo, Luis; Gharibi, Borzo; McLister, Robert; Meenan, Brian J.; Deb, Sanjukta

2016-07-01

Phosphonates have emerged as an alternative for functionalization of titanium surfaces by the formation of homogeneous self-assembled monolayers (SAMs) via Ti-O-P linkages. This study presents results from an investigation of the modification of Ti6Al4V alloy by chemisorption of osseoinductive alendronate using a simple, effective and clean methodology. The modified surfaces showed a tailored topography and surface chemistry as determined by SEM microscopy and RAMAN spectroscopy. X-ray photoelectron spectroscopy revealed that an effective mode of bonding is created between the metal oxide surface and the phosphate residue of alendronate, leading to formation of homogenous drug distribution along the surface. In-vitro studies showed that alendronate SAMs induce differentiation of hMSC to a bone cell phenotype and promote bone formation on modified surfaces. Here we show that this novel method for the preparation of functional coatings on titanium-based medical devices provides osseoinductive bioactive molecules to promote enhanced integration at the site of implantation.

Self-assembled monolayers of alendronate on Ti6Al4V alloy surfaces enhance osteogenesis in mesenchymal stem cells

PubMed Central

Rojo, Luis; Gharibi, Borzo; McLister, Robert; Meenan, Brian J.; Deb, Sanjukta

2016-01-01

Phosphonates have emerged as an alternative for functionalization of titanium surfaces by the formation of homogeneous self-assembled monolayers (SAMs) via Ti-O-P linkages. This study presents results from an investigation of the modification of Ti6Al4V alloy by chemisorption of osseoinductive alendronate using a simple, effective and clean methodology. The modified surfaces showed a tailored topography and surface chemistry as determined by SEM microscopy and RAMAN spectroscopy. X-ray photoelectron spectroscopy revealed that an effective mode of bonding is created between the metal oxide surface and the phosphate residue of alendronate, leading to formation of homogenous drug distribution along the surface. In-vitro studies showed that alendronate SAMs induce differentiation of hMSC to a bone cell phenotype and promote bone formation on modified surfaces. Here we show that this novel method for the preparation of functional coatings on titanium-based medical devices provides osseoinductive bioactive molecules to promote enhanced integration at the site of implantation. PMID:27468811

Design of titanium nitride- and wolfram carbide-doped RGO/GC electrodes for determination of gallic acid.

PubMed

Stanković, Dalibor M; Ognjanović, Miloš; Martin, Fabian; Švorc, Ľubomir; Mariano, José F M L; Antić, Bratislav

2017-12-15

In the present paper, the electrochemical behavior and the properties of two modified glassy carbon (GC) electrodes used for quantification of gallic acid in sweet wines were compared. A comparative study was conducted between titanium nitride- or wolfram carbide-doped reduced graphene oxide, labeled as TNrGO and WCrGO, respectively, modified GC electrodes, which are promising composite nanomaterials for electroanalytical applications. For the first time, WCrGO was synthesized and its electroanalytical properties compared with those of TNrGO. Results showed that the proposed materials exhibited enhanced characteristics, e.g., low limits of detection (1.1 μM and 3.1 μM for TNrGO and WCrGO, respectively), wide linear ranges (for TNrGO 4.5-76 μM and for WCrGO 10-100 μM), low adsorption, and low background current, which make them promising candidates for electrochemical sensing applications. Copyright © 2017 Elsevier Inc. All rights reserved.

Fabrication of graphene/titanium carbide nanorod arrays for chemical sensor application.

PubMed

Fu, Chong; Li, Mingji; Li, Hongji; Li, Cuiping; Qu, Changqing; Yang, Baohe

2017-03-01

Vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium (graphene/TiC nanorod array) wires were fabricated using a direct current arc plasma jet chemical vapor deposition (DC arc plasma jet CVD) method. The graphene/TiC nanorod arrays were characterized by scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, and X-ray diffraction spectroscopy. The TiO 2 nanotube array was reduced to the TiC nanorod array, and using those TiC nanorods as nucleation sites, the vertical graphene layer was formed on the TiC nanorod surface. The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid (AA), dopamine (DA), uric acid (UA), and hydrochlorothiazide (HCTZ). The vertically stacked graphene sheets facilitated the electron transfer and reactant transport with a unique porous surface, high surface area, and high electron transport network of CVD graphene sheets. The TiC nanorod array facilitated the electron transfer and firmly held the graphene layer. Thus, the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

A study of the physical, chemical and biological properties of TiO2 coatings produced by micro-arc oxidation in a Ca-P-based electrolyte.

PubMed

dos Santos, Amanda; Araujo, Joyce R; Landi, Sandra M; Kuznetsov, Alexei; Granjeiro, José M; de Sena, Lidia Ágata; Achete, Carlos Alberto

2014-07-01

In this work, a porous and homogeneous titanium dioxide layer was grown on commercially pure titanium substrate using a micro-arc oxidation (MAO) process and Ca-P-based electrolyte. The structure and morphology of the TiO2 coatings were characterized by X-ray diffraction, scanning electron microscopy (SEM), transmission electron microscopy, and profilometry. The chemical properties were studied using electron dispersive X-ray spectroscopy (SEM-EDS) and X-ray photoelectron spectroscopy. The wettability of the coating was evaluated using contact angle measurements. During the MAO process, Ca and P ions were incorporated into the oxide layer. The TiO2 coating was composed of a mixture of crystalline and amorphous structures. The crystalline part of the sample consisted of a major anatase phase and a minor rutile phase. A cross-sectional image of the coating-substrate interface reveals the presence of voids elongated along the interface. An osteoblast culture was performed to verify the cytocompatibility of the anodized surface. The results of the cytotoxicity tests show satisfactory cell viability of the titanium dioxide films produced in this study.

Synthesis of TiO2 nano-powders prepared from purified sulphate leach liquor of red mud.

PubMed

Tsakiridis, P E; Oustadakis, P; Katsiapi, A; Perraki, M; Agatzini-Leonardou, S

2011-10-30

The research work presented in this paper is focused on the development of a purification process of red mud sulphate leach liquor for the recovery of titanium oxide (TiO(2)) nano-powders in the form of anatase. Initially, titanium was extracted over iron and aluminium from the leach liquor by solvent extraction using Cyanex 272 in toluene, at pH: 0.3 and T: 25°C, with 40% extractant concentration. Stripping of the loaded, with titanium, organic phase was carried out by diluted HCl (3 mol/L) at ambient temperature. Finally, the recovery of titanium nano-powder, in the form of anatase, was performed by chemical precipitation at pH: 6 and T: 95°C, using 10 wt% MgO pulp as neutralizing agent. The produced precipitates were characterized by X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric/differential thermal analysis (TGA/DTA). Their morphological characteristics and microstructure were studied by scanning electron microscopy (SEM). High grade titanium white precipitate, in the form of anatase, was obtained. Iron concentration in the precipitate did not exceed 0.3%, whereas no aluminium was detected. Copyright © 2011 Elsevier B.V. All rights reserved.

The Development of Titanium Alloys for Application in the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Halchak, John A.; Jerman, Gregory A.; Zimmerman, Frank R.

2010-01-01

The high-strength-to-weight ratio of titanium alloys, particularly at cryogenic temperatures, make them attractive for application in rocket engines - offering the potential of superior performance while minimizing component weight. This was particularly attractive for rotating components, such as pump impellers, where titanium alloys presented the potential to achieve a major advance in rotational tip speed, with a reduction in stages and resultant saving in pump weight and complexity. The investigation into titanium alloys for application in cryogenic turbopumps began in the early 1960's. However, it was found that the reactivity of titanium limited applications and produced unique processing challenges. Specialized chemical compositions and processing techniques had to be developed. A substantial amount of material properties testing and trials in experimental turbopumps occurred, ultimately leading to application in the Space Shuttle Main Engine. One particular alloy stood out for use at liquid hydrogen temperatures, Ti-5Al-2.5Sn ELI. This alloy was employed for several critical components. This presentation deals with the development effort, the challenges that were encountered and operational experiences with Ti-5Al-2.5Sn ELI in the SSME.

Laser engineered multilayer coating of biphasic calcium phosphate/titanium nanocomposite on metal substrates.

PubMed

Zhang, Martin Yi; Ye, Chang; Erasquin, Uriel Joseph; Huynh, Toan; Cai, Chengzhi; Cheng, Gary J

2011-02-01

In this work, laser coating of biphasic calcium phosphate/titanium (BCP/Ti) nanocomposite on Ti-6Al-4 V substrates was developed. A continuous wave neodymium-doped yttrium aluminium garnet (Nd:YAG) laser was used to form a robust multilayer of BCP/Ti nanocomposite starting from hydroxyapatite and titanium nanoparticles. In this process, low power coating is realized because of the strong laser-nanoparticle interaction and good sinterability of nanosized titanium. To guide the optimization of laser processing conditions for the coating process, a multiphysics model coupling electromagnetic module with heat transfer module was developed. This model was validated by laser coating experiments. Important features of the coated samples, including microstructures, chemical compositions, and interfacial bonding strength, were characterized. We found that a multilayer of BCP, consisting of 72% hydroxyapatite (HA) and 28% beta-tricalcium phosphate (β-TCP), and titanium nanocomposite was formed on Ti-6Al-4 V substrates. Significantly, the coating/substrate interfacial bonding strength was found to be two times higher than that of the commercial plasma sprayed coatings. Preliminary cell culture studies showed that the resultant BCP/Ti nanocomposite coating supported the adhesion and proliferation of osteoblast-like UMR-106 cells.

Interactions between graphene oxide and wide band gap semiconductors

NASA Astrophysics Data System (ADS)

Kawa, M.; Podborska, A.; Szaciłowski, K.

2016-09-01

The graphene oxide (GO) and GO@TiO2 nanocomposite have been synthesised by using modified Hummers method and ultrasonics respectively. The materials were characterized by using X-ray diffraction, Fourier transform infrared spectroscopy and UV-Vis absorption spectroscopy. It was found that the interaction between GO and TiO2 affects the average interlayer spacing in carbonaceous material. The formation of bonds between various oxygen-containing functional groups and surface of titanium dioxide was investigated. One of them formed between the quinone structures (occur in graphene oxide) and titanium atoms exhibited 1.5 bond order. Furthermore the charge-transfer processes in GO@TiO2 composite were observed.

Physical and Mechanical Properties of W-Ni-Fe-Co Metal Foam Modified by Titanium Tungsten Carbide Alloying

NASA Astrophysics Data System (ADS)

Ishchenko, A. N.; Tabachenko, A. N.; Afanas'eva, S. A.; Belov, N. N.; Biryukov, Yu. A.; Burkin, V. V.; D'yachkovskii, A. S.; Rogaev, K. S.; Skosyrskii, A. B.; Yugov, N. T.

2018-02-01

The paper studies physical and mechanical properties of tungsten-nickel-iron-cobalt metal foam alloyed with titanium tungsten carbide. Test specimens are obtained by the liquid phase sintering of powder materials, including those containing tungsten nanopowders. High porosity metal foams are prepared through varying the porosity of powder specimens and the content of filling material. The penetration capability of cylinder projectiles made of new alloys is explored in this paper. It is shown that their penetration depth exceeds that of the prototype with relevant weight and size, made of tungsten-nickel-iron alloy, other factors being equal.

Attachment of Porphyromonas gingivalis to corroded commercially pure titanium and titanium-aluminum-vanadium alloy.

PubMed

Barão, Valentim A R; Yoon, Cheon Joo; Mathew, Mathew T; Yuan, Judy Chia-Chun; Wu, Christine D; Sukotjo, Cortino

2014-09-01

Titanium dental material can become corroded because of electrochemical interaction in the oral environment. The corrosion process may result in surface modification. It was hypothesized that a titanium surface modified by corrosion may enhance the attachment of periodontal pathogens. This study evaluates the effects of corroded titanium surfaces on the attachment of Porphyromonas gingivalis. Commercially pure titanium (cp-Ti) and titanium-aluminum-vanadium alloy (Ti-6Al-4V) disks were used. Disks were anodically polarized in a standard three-electrode setting in a simulated oral environment with artificial saliva at pH levels of 3.0, 6.5, or 9.0. Non-corroded disks were used as controls. Surface roughness was measured before and after corrosion. Disks were inoculated with P. gingivalis and incubated anaerobically at 37°C. After 6 hours, the disks with attached P. gingivalis were stained with crystal violet, and attachment was expressed based on dye absorption at optical density of 550 nm. All assays were performed independently three times in triplicate. Data were analyzed by two-way analysis of variance, the Tukey honestly significant difference test, t test, and Pearson's correlation test (α = 0.05). Both cp-Ti and Ti-6Al-4V alloy-corroded disks promoted significantly more bacterial attachment (11.02% and 41.78%, respectively; P <0.0001) than did the non-corroded controls. Significantly more (11.8%) P. gingivalis attached to the cp-Ti disks than to the Ti-6Al-4V alloy disks (P <0.05). No significant difference in P. gingivalis attachment was noted among the corroded groups for both cp-Ti and Ti-6Al-4V alloy (P >0.05). There was no significant correlation between surface roughness and P. gingivalis attachment. A higher degree of corrosion on the titanium surface may promote increased bacterial attachment by oral pathogens.

Strong attachment of circadian pacemaker neurons on modified ultrananocrystalline diamond surfaces.

PubMed

Voss, Alexandra; Wei, HongYing; Zhang, Yi; Turner, Stuart; Ceccone, Giacomo; Reithmaier, Johann Peter; Stengl, Monika; Popov, Cyril

2016-07-01

Diamond is a promising material for a number of bio-applications, including the fabrication of platforms for attachment and investigation of neurons and of neuroprostheses, such as retinal implants. In the current work ultrananocrystalline diamond (UNCD) films were deposited by microwave plasma chemical vapor deposition, modified by UV/O3 treatment or NH3 plasma, and comprehensively characterized with respect to their bulk and surface properties, such as crystallinity, topography, composition and chemical bonding nature. The interactions of insect circadian pacemaker neurons with UNCD surfaces with H-, O- and NH2-terminations were investigated with respect to cell density and viability. The fast and strong attachment achieved without application of adhesion proteins allowed for advantageous modification of dispersion protocols for the preparation of primary cell cultures. Centrifugation steps, which are employed for pelletizing dispersed cells to separate them from dispersing enzymes, easily damage neurons. Now centrifugation can be avoided since dispersed neurons quickly and strongly attach to the UNCD surfaces. Enzyme solutions can be easily washed off without losing many of the dispersed cells. No adverse effects on the cell viability and physiological responses were observed as revealed by calcium imaging. Furthermore, the enhanced attachment of the neurons, especially on the modified UNCD surfaces, was especially advantageous for the immunocytochemical procedures with the cell cultures. The cell losses during washing steps were significantly reduced by one order of magnitude in comparison to controls. In addition, the integration of a titanium grid structure under the UNCD films allowed for individual assignment of physiologically characterized neurons to immunocytochemically stained cells. Thus, employing UNCD surfaces free of foreign proteins improves cell culture protocols and immunocytochemistry with cultured cells. The fast and strong attachment of neurons was attributed to a favorable combination of topography, surface chemistry and wettability. Copyright © 2016 Elsevier B.V. All rights reserved.

Thermo-stable carbon nanotube-TiO₂ nanocompsite as electron highways in dye-sensitized solar cell produced by bio-nano-process.

PubMed

Inoue, Ippei; Yamauchi, Hirofumi; Okamoto, Naofumi; Toyoda, Kenichi; Horita, Masahiro; Ishikawa, Yasuaki; Yasueda, Hisashi; Uraoka, Yukiharu; Yamashita, Ichiro

2015-07-17

We produced a thermostable TiO2-(anatase)-coated multi-walled-carbon-nanotube (MWNT) nanocomposite for use in dye-sensitized solar cells (DSSCs) using biological supuramolecules as catalysts. We synthesized two different sizes of iron oxide nanoparticles (NPs) and arrayed the NPs on a silicon substrate utilizing two kinds of genetically modified cage-shaped proteins with silicon-binding peptide aptamers on their outer surfaces. Chemical vapor deposition (CVD) with the vapor-liquid-solid phase (VLS) method was applied to the substrate, and thermostable MWNTs with a diameter of 6 ± 1 nm were produced. Using a genetically modified cage-shaped protein with carbon-nanomaterials binding and Ti-mineralizing peptides as a catalyst, we were able to mineralize a titanium compound around the surface of the MWNT. The products were sintered, and thin TiO2-layer-coated MWNTs nanocomoposites were successfully produced. Addition of a 0.2 wt% TiO2-coated MWNT nanocomposite to a DSSC photoelectrode improved current density by 11% and decreased electric resistance by 20% compared to MWNT-free reference DSSCs. These results indicate that a nanoscale TiO2-layer-coated thermostable MWNT structure produced by our mutant proteins works as a superior electron transfer highway within TiO2 photoelectrodes.

Thermo-stable carbon nanotube-TiO2 nanocompsite as electron highways in dye-sensitized solar cell produced by bio-nano-process

NASA Astrophysics Data System (ADS)

Inoue, Ippei; Yamauchi, Hirofumi; Okamoto, Naofumi; Toyoda, Kenichi; Horita, Masahiro; Ishikawa, Yasuaki; Yasueda, Hisashi; Uraoka, Yukiharu; Yamashita, Ichiro

2015-07-01

We produced a thermostable TiO2-(anatase)-coated multi-walled-carbon-nanotube (MWNT) nanocomposite for use in dye-sensitized solar cells (DSSCs) using biological supuramolecules as catalysts. We synthesized two different sizes of iron oxide nanoparticles (NPs) and arrayed the NPs on a silicon substrate utilizing two kinds of genetically modified cage-shaped proteins with silicon-binding peptide aptamers on their outer surfaces. Chemical vapor deposition (CVD) with the vapor-liquid-solid phase (VLS) method was applied to the substrate, and thermostable MWNTs with a diameter of 6 ± 1 nm were produced. Using a genetically modified cage-shaped protein with carbon-nanomaterials binding and Ti-mineralizing peptides as a catalyst, we were able to mineralize a titanium compound around the surface of the MWNT. The products were sintered, and thin TiO2-layer-coated MWNTs nanocomoposites were successfully produced. Addition of a 0.2 wt% TiO2-coated MWNT nanocomposite to a DSSC photoelectrode improved current density by 11% and decreased electric resistance by 20% compared to MWNT-free reference DSSCs. These results indicate that a nanoscale TiO2-layer-coated thermostable MWNT structure produced by our mutant proteins works as a superior electron transfer highway within TiO2 photoelectrodes.

Silica-supported, single-site titanium catalysts for olefin epoxidation. A molecular precursor strategy for control of catalyst structure.

PubMed

Jarupatrakorn, Jonggol; Don Tilley, T

2002-07-17

A molecular precursor approach involving simple grafting procedures was used to produce site-isolated titanium-supported epoxidation catalysts of high activity and selectivity. The tris(tert-butoxy)siloxy titanium complexes Ti[OSi(O(t)Bu)(3)](4) (TiSi4), ((i)PrO)Ti[OSi(O(t)Bu)(3)](3) (TiSi3), and ((t)BuO)(3)TiOSi(O(t)Bu)(3) (TiSi) react with the hydroxyl groups of amorphous Aerosil, mesoporous MCM-41, and SBA-15 via loss of HO(t)Bu and/or HOSi(O(t)Bu)(3) and introduction of titanium species onto the silica surface. Powder X-ray diffraction, nitrogen adsorption/desorption, infrared, and diffuse reflectance ultraviolet spectroscopies were used to investigate the structures and chemical natures of the surface-bound titanium species. The titanium species exist mainly in isolated, tetrahedral coordination environments. Increasing the number of siloxide ligands in the molecular precursor decreases the amount of titanium that can be introduced this way, but also enhances the catalytic activity and selectivity for the epoxidation of cyclohexene with cumene hydroperoxide as oxidant. In addition, the high surface area mesoporous silicas (MCM-41 and SBA-15) are more effective than amorphous silica as supports for these catalysts. Supporting TiSi3 on the SBA-15 affords highly active cyclohexene epoxidation catalysts (0.25-1.77 wt % Ti loading) that provide turnover frequencies (TOFs) of 500-1500 h(-1) after 1 h (TOFs are reduced by about half after calcination). These results demonstrate that oxygen-rich siloxide complexes of titanium are useful as precursors to supported epoxidation catalysts.

Controlled functionalization of nanoparticles & practical applications

NASA Astrophysics Data System (ADS)

Rashwan, Khaled

With the increasing use of nanoparticles in both science and industry, their chemical modification became a significant part of nanotechnology. Unfortunately, most commonly used procedures provide just randomly functionalized materials. The long-term objective of our work is site- and stoichiometrically-controlled functionalization of nanoparticles with the utilization of solid supports and other nanostructures. On the examples of silica nanoparticles and titanium dioxide nanorods, we have obtained results on the solid-phase chemistry, method development, and modeling, which advanced us toward this goal. At the same time, we explored several applications of nanoparticles that will benefit from the controlled functionalization: imaging of titanium-dioxide-based photocatalysts, bioimaging by fluorescent nanoparticles, drug delivery, assembling of bone implants, and dental compositions. Titanium dioxide-based catalysts are known for their catalytic activity and their application in solar energy utilization such as photosplitting of water. Functionalization of titanium dioxide is essential for enhancing bone-titanium dioxide nanotube adhesion, and, therefore, for its application as an interface between titanium implants and bones. Controlled functionalization of nanoparticles should enhance sensitivity and selectivity of nanoassemblies for imaging and drug delivery applications. Along those lines, we studied the relationship between morphology and surface chemistry of nanoparticles, and their affinity to organic molecules (salicylic and caffeic acid) using Langmuir adsorption isotherms, and toward material surfaces using SEM- and TEM-imaging. We focused on commercial samples of titanium dioxide, titanium dioxide nanorods with and without oleic acid ligands, and differently functionalized silica nanoparticles. My work included synthesis, functionalization, and characterization of several types of nanoparticles, exploring their application in imaging, dentistry, and bone implant construction. Significant part of my experimental efforts was devoted to the solid-phase method development using model organic molecules, as well as affinity of nanoparticles to the functional groups and surfaces that can be used as linkages for constructing functional nanodevices.

Surface chemical study on the covalent attachment of hydroxypropyltrimethyl ammonium chloride chitosan to titanium surfaces

NASA Astrophysics Data System (ADS)

Xu, Xiaofen; Wang, Ling; Guo, Shengrong; Lei, Lei; Tang, Tingting

2011-10-01

An anti-microbial and bioactive coating could not only reduce the probability of infection related to titanium implants but also support the growth of surrounding osteogenic cells. Our previous study has showed that hydroxypropyltrimethyl ammonium chloride chitosan (HACC) with a DS (degrees of substitution) of 18% had improved solubility and significantly higher antibacterial activities against three bacteria which were usually associated with infections in orthopaedics. In the current study, HACC with a DS of 18% coating was bonded to titanium surface by a three-step process. The titanium surface after each individual reaction step was analyzed by X-ray photoelectron spectroscopy (XPS) and attenuated total reflection (ATR) of Fourier-transformed infrared (FT-IR) spectroscopy. The XPS results demonstrated that there were great changes in the atomic ratios of C/Ti, O/Ti, and N/Ti after each reaction step. The XPS high resolution and corresponding devolution spectra of carbon, oxygen, nitrogen, and titanium were also in good coordination with the anticipated reaction steps. Additionally, the absorption bands around 3365 cm -1 (-OH vibration), 1664 cm -1 (Amide I), 1165 cm -1 ( νas, C-O-C bridge), and the broad absorption bands between 958 cm -1 and 1155 cm -1 (skeletal vibrations involving the C-O stretching of saccharide structure of HACC) verified that HACC was successfully attached to titanium surface.

Adherence of oral streptococci to nanostructured titanium surfaces.

PubMed

Narendrakumar, Krunal; Kulkarni, Mukta; Addison, Owen; Mazare, Anca; Junkar, Ita; Schmuki, Patrik; Sammons, Rachel; Iglič, Aleš

2015-12-01

Peri-implantitis and peri-mucositis pose a severe threat to the success of dental implants. Current research focuses on the development of surfaces that inhibit biofilm formation while not inferring with tissue integration. This study compared the adherence of two oral bacterial species, Streptococcus sanguinis and Streptococcus mutans to nanostructured titanium surfaces. The samples included TiO2 nanotubes formed by anodization of titanium foil of 100, 50 and 15nm diameter (NT15, NT50, NT100), a nanoporous (15nm pore diameter) surface and compact TiO2 control. Adherent surviving bacteria were enumerated after 1h in an artificial saliva medium containing bovine mucin. Lowest numbers of adherent bacteria of both species were recovered from the original titanium foil and nanoporous surface and highest numbers from the Ti100 nanotubes. Numbers of attached S. sanguinis increased in the order (NT15

Atomic force microscopy analysis of different surface treatments of Ti dental implant surfaces

NASA Astrophysics Data System (ADS)

Bathomarco, Ti R. V.; Solorzano, G.; Elias, C. N.; Prioli, R.

2004-06-01

The surface of commercial unalloyed titanium, used in dental implants, was analyzed by atomic force microscopy. The morphology, roughness, and surface area of the samples, submitted to mechanically-induced erosion, chemical etching and a combination of both, were compared. The results show that surface treatments strongly influence the dental implant physical and chemical properties. An analysis of the length dependence of the implant surface roughness shows that, for scan sizes larger than 50 μm, the average surface roughness is independent of the scanning length and that the surface treatments lead to average surface roughness in the range of 0.37 up to 0.48 μm. It is shown that the implant surface energy is sensitive to the titanium surface area. As the area increases there is a decrease in the surface contact angle.

Surface force analysis of glycine adsorption on different crystal surfaces of titanium dioxide (TiO2).

PubMed

Ganbaatar, Narangerel; Imai, Kanae; Yano, Taka-Aki; Hara, Masahiko

2017-01-01

Surface force analysis with atomic force microscope (AFM) in which a single amino acid residue was mounted on the tip apex of AFM probe was carried out for the first time at the molecular level on titanium dioxide (TiO 2 ) as a representative mineral surface for prebiotic chemical evolution reactions. The force analyses on surfaces with three different crystal orientations revealed that the TiO 2 (110) surface has unique characteristics for adsorbing glycine molecules showing different features compared to those on TiO 2 (001) and (100). To examine this difference, we investigated thermal desorption spectroscopy (TDS) and the interaction between the PEG cross-linker and the three TiO 2 surfaces. Our data suggest that the different single crystal surfaces would provide different chemical evolution field for amino acid molecules.

Cadmium removal from water using thiolactic acid-modified titanium dioxide nanoparticles.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Skubal, L. R.; Meshkov, N. K.; Rajh, T.

2002-05-31

This study investigated the use of titanium dioxide (TiO{sub 2}) nanoparticles to remove aqueous cadmium from simulated wastewaters. Nanosized (45 A) colloids of anatase TiO{sub 2} were synthesized through the controlled hydrolysis of TiCl4 and their surfaces modified with the bidental chelating agent thiolactic acid (TLA). Colloids were introduced into 65 ppm cadmium-laden waters, and the suspensions were purged aerobically, anoxically with an inert gas, or by a sequential aerobic/anoxic purge. Suspensions were illuminated with 253.7 nm light. In each experiment, samples were taken from the reactor, filtered, and the filtrates analyzed by atomic absorption spectroscopy for residual cadmium. Resultsmore » from the aerobic experiments exhibited minimal (approximately 10%) removal of the cadmium from solution and no reduction of the metal on either the modified or the unmodified colloid. Anoxic results were more promising, showing no cadmium reduction on the unmodified colloid but a 40% adsorption and reduction (from a +2 valence state to elemental cadmium as determined by methyl viologen tests) of cadmium on TLA-modified colloid in the presence of light. Results from the mixed atmospheric conditions fared the best and demonstrated that in the absence of light, approximately 20% of aqueous cadmium was sorbed to the modified colloid via a Freundlich adsorption isotherm. Upon illumination, greater than 90% of cadmium was removed by both adsorption and reduction processes onto the TLA-modified TiO{sub 2}. These removal and reduction processes were catalytic in nature. Results from this study are significant because to date, no other research in the literature has been able to accomplish cadmium removal and reduction using TiO{sub 2}.« less

Titanium diboride ceramic fiber composites for Hall-Heroult cells

DOEpatents

Besmann, T.M.; Lowden, R.A.

1990-05-29

An improved cathode structure is described for Hall-Heroult cells for the electrolytic production of aluminum metal. This cathode structure is a preform fiber base material that is infiltrated with electrically conductive titanium diboride using chemical vapor infiltration techniques. The structure exhibits good fracture toughness, and is sufficiently resistant to attack by molten aluminum. Typically, the base can be made from a mat of high purity silicon carbide fibers. Other ceramic or carbon fibers that do not degrade at temperatures below about 1000 C can be used.

A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [titanium alloys

NASA Technical Reports Server (NTRS)

Chen, W.; Dwight, D. W.; Wightman, J. P.

1978-01-01

Various surface preparations for titanium 6-4 alloy were studied. An anodizing method was investigated, and compared with the results of other chemical treatments, namely, phosphate/fluoride, Pasa-Jell and Turco. The relative durability of the different surface treatments was assessed by monitoring changes in surface chemistry and morphology occasioned by aging at 505 K (450 F). Basic electron spectroscopic data were collected for polyimide and polyphenylquinoxaline adhesives and synthetic precursors. Fractographic studies were completed for several combinations of adherend, adhesive, and testing conditions.

A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [acid-base properties of titanium 6-4 surfaces

NASA Technical Reports Server (NTRS)

Siriwardane, R.; Wightman, J. P.

1980-01-01

The acid-base properties of titanium 6-4 plates (low surface area) were investigated after three different pretreatments, namely Turco, phosphate-fluoride and Pasa-Jell. A series of indicators was used and color changes were detected using diffuse reflectance visible spectroscopy. Electron spectroscopy for chemical analysis was used to examine the indicator on the Ti 6-4 surface. Specular reflectance infra-red spectroscopy was used to study the adsorption of stearic acid from cyclohexane solutions on the Ti 6-4 surface.

Osteoconductive phosphoserine-modified poly(ε-lysine) dendrons: synthesis, titanium oxide surface functionalization and response of osteoblast-like cell lines

PubMed Central

Meikle, S. T.; Bianchi, G.; Olivier, G.; Santin, M.

2013-01-01

The lack of direct bonding between the surface of an implant and the mineralized bony tissue is among the main causes of aseptic loosening in titanium-based implants. Surface etching and ceramic coatings have led to improved osteointegration, but their clinical performance is still limited either by partial bonding or by coating delamination. In this work, a solid-phase synthesis method has been optimized to produce poly(ε-lysine) dendrons, the outermost branching generation of which is functionalized by phosphoserine (PS), a known catalyst of the biomineralization process. The dendrons were deposited onto etched titanium oxide surfaces as a near-to-monolayer film able to induce the formation of a homogeneous calcium phosphate phase in a simulated body fluid over 3 days. The dendron films also stimulated MG63 and SAOS-2 osteoblast-like cells to proliferate at a rate significantly higher than etched titanium, with SAOS-2 also showing a higher degree of differentiation over 14 days. PS-tethered dendron films were not affected by various sterilization methods and UV treatment appeared to improve the cell substrate potential of these films, thus suggesting their potential as a surface functionalization method for bone implants. PMID:23193106

Development of Modified Titanium Nitride Nanoparticles as Potential Contrast Material for Photoacoustic Imaging

DTIC Science & Technology

2014-05-10

based on modified fullerenes , carbon nanotubes and gold nanoparticles (including nanocages and nanorods) were very recently reported.4 Nevertheless, this...ratios of 1:1.6 and 1:16, in order to form an onion- like core-shell structure, containing TiN core and shells of TPP (inner shell) and chitosan (outer...These results nicely correlate with the cells viability results and the formation of the ROS is most likely the cause of the cells death (Figure 24

Photofunctionalization and non-thermal plasma activation of titanium surfaces.

PubMed

Henningsen, Anders; Smeets, Ralf; Hartjen, Philip; Heinrich, Oliver; Heuberger, Roman; Heiland, Max; Precht, Clarissa; Cacaci, Claudio

2018-03-01

The aim of this study was to compare UV light and non-thermal plasma (NTP) treatment regarding the improvement of physical material characteristics and cell reaction on titanium surfaces in vitro after short-term functionalization. Moderately rough (Ra 1.8-2.0 μm) sandblasted and acid-etched titanium disks were treated by UV light (0.05 mW/cm 2 at λ = 360 nm and 2 mW/cm 2 at λ = 250 nm) or by NTP (24 W, -0.5 mbar) of argon or oxygen for 12 min each. Surface structure was investigated by scanning electron microscopy, confocal microscopy and X-ray photoelectron spectroscopy (XPS). Hydrophilicity was assessed by dynamic contact angle measurement. Cell attachment, viability, cell proliferation and cytotoxicity were assessed in vitro using murine osteoblast-like cells. UV irradiation or NTP treatment of titanium surfaces did not alter the surface structure. XPS analysis revealed a significantly increased oxidation of the surface and a decrease of carbon after the use of either method. NTP and UV light led to a significant better cell attachment of murine osteoblasts; significantly more osteoblasts grew on the treated surfaces at each time point (p < 0.001). UV light as well as NTP modified the surface of titanium and significantly improved the conditions for murine osteoblast cells in vitro. However, results indicate a slight advantage for NTP of argon and oxygen in a short time interval of surface functionalization compared to UV. UV light and NTP are able to improve surface conditions of dental implants made of titanium.

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings

PubMed Central

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-01-01

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating. PMID:23546301

Core-shell VO2@TiO2 nanorods that combine thermochromic and photocatalytic properties for application as energy-saving smart coatings.

PubMed

Li, Yamei; Ji, Shidong; Gao, Yanfeng; Luo, Hongjie; Kanehira, Minoru

2013-01-01

Vanadium dioxide (VO2) is a Mott phase transition compound that can be applied as a thermochromic smart material for energy saving and comfort, and titanium dioxide (TiO2) is a well-known photocatalyst for self-cleaning coatings. In this paper, we report a VO2@TiO2 core-shell structure, in which the VO2 nanorod core exhibits a remarkable modulation ability for solar infrared light, and the TiO2 anatase shell exhibits significant photocatalytic degradation of organic dye. In addition, the TiO2 overcoating not only increased the luminous transmittance of VO2 based on an antireflection effect, but also modified the intrinsic colour of VO2 films from yellow to light blue. The TiO2 also enhanced the chemical stability of VO2 against oxidation. This is the first report of such a single nanoparticle structure with both thermochromic and photocatalytic properties that offer significant potential for creating a multifunctional smart coating.

Evaluation of effect of galvanic corrosion between nickel-chromium metal and titanium on ion release and cell toxicity

PubMed Central

Choi, Jung-Yun

2015-01-01

PURPOSE The purpose of this study was to evaluate cell toxicity due to ion release caused by galvanic corrosion as a result of contact between base metal and titanium. MATERIALS AND METHODS It was hypothesized that Nickel (Ni)-Chromium (Cr) alloys with different compositions possess different corrosion resistances when contacted with titanium abutment, and therefore in this study, specimens (10×10×1.5 mm) were fabricated using commercial pure titanium and 3 different types of Ni-Cr alloys (T3, Tilite, Bella bond plus) commonly used for metal ceramic restorations. The specimens were divided into 6 groups according to the composition of Ni-Cr alloy and contact with titanium. The experimental groups were in direct contact with titanium and the control groups were not. After the samples were immersed in the culture medium - Dulbecco's modified Eagle's medium[DMEM] for 48 hours, the released metal ions were detected using inductively coupled plasma mass spectrometer (ICP-MS) and analyzed by the Kruskal-Wallis and Mann-Whitney test (P<.05). Mouse L-929 fibroblast cells were used for cell toxicity evaluation. The cell toxicity of specimens was measured by the 3-{4,5-dimethylthiazol-2yl}-2,5-diphenyltetrazolium bromide (MTT) test. Results of MTT assay were statistically analyzed by the two-way ANOVA test (P<.05). Post-hoc multiple comparisons were conducted using Tukey's tests. RESULTS The amount of metal ions released by galvanic corrosion due to contact between the base metal alloy and titanium was increased in all of the specimens. In the cytotoxicity test, the two-way ANOVA showed a significant effect of the alloy type and galvanic corrosion for cytotoxicity (P<.001). The relative cell growth rate (RGR) was decreased further on the groups in contact with titanium (P<.05). CONCLUSION The release of metal ions was increased by galvanic corrosion due to contact between base metal and titanium, and it can cause adverse effects on the tissue around the implant by inducing cytotoxicity. PMID:25932317

Titanium Ions Release from an Innovative Titanium-Magnesium Composite: an in Vitro Study

PubMed Central

Halambek, Jasna; Maldini, Krešimir; Balog, Martin; Križik, Peter; Schauperl, Zdravko; Ćatić, Amir

2016-01-01

Background The innovative titanium-magnesium composite (Ti-Mg) was produced by powder metallurgy (P/M) method and is characterized in terms of corrosion behavior. Material and methods Two groups of experimental material, 1 mass% (Ti-1Mg) and 2 mass% (Ti-2Mg) of magnesium in titanium matrix, were tested and compared to commercially pure titanium (CP Ti). Immersion test and chemical analysis of four solutions: artificial saliva; artificial saliva pH 4; artificial saliva with fluoride and Hank balanced salt solution were performed after 42 days of immersion, using inductively coupled plasma mass spectrometry (ICP-MS) to detect the amount of released titanium ions (Ti). SEM and EDS analysis were used for surface characterization. Results The difference between the results from different test solutions was assessed by ANOVA and Newman-Keuls test at p<0.05. The influence of predictor variables was found by multiple regression analysis. The results of the present study revealed a low corrosion rate of titanium from the experimental Ti-Mg group. Up to 46 and 23 times lower dissolution of Ti from Ti-1Mg and Ti-2Mg, respectively was observed compared to the control group. Among the tested solutions, artificial saliva with fluorides exhibited the highest corrosion effect on all specimens tested. SEM micrographs showed preserved dual phase surface structure and EDS analysis suggested a favorable surface bioactivity. Conclusion In conclusion, Ti-Mg produced by P/M as a material with better corrosion properties when compared to CP Ti is suggested. PMID:27688425

Titanium nitride formation by a dual-stage femtosecond laser process

NASA Astrophysics Data System (ADS)

Hammouti, S.; Holybee, B.; Zhu, W.; Allain, J. P.; Jurczyk, B.; Ruzic, D. N.

2018-06-01

Formation of TiN by femtosecond laser processing in controlled gas atmosphere is reported. A dual-stage process was designed and aimed to first remove and restructure the native oxide layer of titanium surface through laser irradiation under an argon-controlled atmosphere, and then to maximize titanium nitride formation through an irradiation under a nitrogen reactive environment. An extensive XPS study was performed to identify and quantify laser-induced titanium surface chemistry modifications after a single-stage laser process (Ar and N2 individually), and a dual-stage laser process. The importance of each step that composes the dual-stage laser process was demonstrated and leads to the dual-stage laser process for the formation of TiO, Ti2O3 and TiN. In this study, the largest nitride formation occurs for the dual stage process with laser conditions at 4 W/1.3 J cm-2 under argon and 5 W/1.6 J cm-2 under nitrogen, yielding a total TiN composition of 8.9%. Characterization of both single-stage and dual-stage laser process-induced surface morphologies has been performed as well, leading to the observation of a wide range of hierarchical surface structures such as high-frequency ripples, grooves, protuberances and pillow-like patterns. Finally, water wettability was assessed by means of contact angle measurements on untreated titanium surface, and titanium surfaces resulting from either single-stage laser process or dual-stage laser process. Dual-stage laser process allows a transition of titanium surface, from phobic (93°) to philic (35°), making accessible both hydrophilic and chemically functionalized hierarchical surfaces.

Characterization of plastic deformation and chemical reaction in titanium-polytetrafluoroethylene mixture

NASA Astrophysics Data System (ADS)

Davis, Jeffery Jon

1998-09-01

The subject of this dissertation is the deformation process of a single metal - polymer system (titanium - polytetrafluoroethylene) and how this process leads to initiation of chemical reaction. Several different kinds of experiments were performed to characterize the behavior of this material to shock and impact. These mechanical conditions induce a rapid plastic deformation of the sample. All of the samples tested had an initial porosity which increased the plastic flow condition. It is currently believed that during the deformation process two important conditions occur: removal of the oxide layer from the metal and decomposition of the polymer. These conditions allow for rapid chemical reaction. The research from this dissertation has provided insight into the complex behavior of plastic deformation and chemical reactions in titanium - polytetrafluoroethylene (PTFE, Teflon). A hydrodynamic computational code was used to model the plastic flow for correlation with the results from the experiments. The results from this work are being used to develop an ignition and growth model for metal/polymer systems. Three sets of experiments were used to examine deformation of the 80% Ti and 20% Teflon materials: drop- weight, gas gun, and split-Hopkinson pressure bar. Recovery studies included post shot analysis of the samples using x-ray diffraction. Lagrangian hydrocode DYNA2D modeling of the drop-weight tests was performed for comparison with experiments. One of the reactions know to occur is Ti + C → TiC (s) which results in an exothermic release. However, the believed initial reactions occur between Ti and fluorine which produces TixFy gases. The thermochemical code CHEETAH was used to investigate the detonation products and concentrations possible during Ti - Teflon reaction. CHEETAH shows that the Ti - fluorine reactions are thermodynamically favorable. This research represents the most comprehensive to date study of deformation induced chemical reaction in metal/polymers.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eremenko, V.N.; Kosolapova, T.Ya.

Metallographic studies and chemical phase analysis of carbon-free nickel with titanium carbide, prepared by powder metallurgy and treated under various thermal conditions, showed no separation of free carbon and indicated that the TiC--Ni system is quasi-binary. (R.V.J.)

Safety and efficacy of nano lamellar TiN coatings on nitinol atrial septal defect occluders in vivo.

PubMed

Zhang, Zhi xiong; Fu, Bu fang; Zhang, De yuan; Zhang, Zhi wei; Cheng, Yan; Sheng, Li yuan; Lai, Chen; Xi, Ting fei

2013-04-01

Atrial septal defect (ASD) occlusion devices made of nickel-titanium (NiTi) have a major shortcoming in that they release nickel into the body. We modified NiTi occluders using Arc Ion Plating technology. Nano lamellar titanium-nitrogen (TiN) coatings were formed on the surfaces of the occluders. The safety and efficacy of the modified NiTi occluders were evaluated in animal model. The results showed that 38 out of 39 rams (97%) survived at the end of the experiment. Fibrous capsules formed on the surfaces of the devices. Gradual endothelialization took place through the attachment of endothelial progenitor cells from the blood and the migration of endothelial cells from adjacent endocardium. The neo-endocardium formed more quickly in the coated group than in the uncoated group, as indicated by the evaluation of the six month study group. After TiN coating, there was no significant difference in endothelial cell cycle. TiN coating significantly reduced the release of nickel in both in vivo and in vitro indicating an improved biocompatibility of the nitinol ASD occluders. Superior and modified ASD occluders may provide a good choice for people with nickel allergies after sFDA registration, which is expected in one to two years. Copyright © 2012 Elsevier B.V. All rights reserved.

An in vitro assessment of titanium functionalized with polysaccharides conjugated with vascular endothelial growth factor for enhanced osseointegration and inhibition of bacterial adhesion.

PubMed

Hu, Xuefeng; Neoh, Koon-Gee; Shi, Zhilong; Kang, En-Tang; Poh, Chyekhoon; Wang, Wilson

2010-12-01

The long-term success of orthopedic implants may be compromised by defective osseointegration and bacterial infection. An effective approach to minimize implant failure would be to modify the surface of the implant to make it habitable for bone-forming cells and anti-infective at the same time. In this in vitro study, the surfaces of titanium (Ti) substrates were functionalized by first covalently grafting either dopamine followed by carboxymethyl chitosan (CMCS) or hyaluronic acid-catechol (HAC). Vascular endothelial growth factor (VEGF) was then conjugated to the polysaccharide-grafted surface. Antibacterial assay with Staphylococcus aureus (S. aureus) showed that the polysaccharide-modified substrates significantly decrease bacterial adhesion. The CMCS-functionalized Ti demonstrated better antibacterial property than the HAC-functionalized Ti since CMCS is bactericidal while HA only inhibits the adhesion of bacteria without killing them. Osteoblast attachment, as well as alkaline phosphatase (ALP) activity and calcium deposition were enhanced by the immobilized VEGF on the polysaccharide-grafted Ti. Thus, Ti substrates modified with polysaccharides conjugated with VEGF can promote osteoblast functions and concurrently reduce bacterial adhesion. Since VEGF is also known to enhance angiogenesis, the VEGF-polysaccharide functionalized substrates will have promising applications in the orthopedic field. Copyright © 2010 Elsevier Ltd. All rights reserved.

Highly sensitive and selective hyphenated technique (molecularly imprinted polymer solid-phase microextraction-molecularly imprinted polymer sensor) for ultra trace analysis of aspartic acid enantiomers.

PubMed

Prasad, Bhim Bali; Srivastava, Amrita; Tiwari, Mahavir Prasad

2013-03-29

The present work is related to combination of molecularly imprinted solid-phase microextraction and complementary molecularly imprinted polymer-sensor. The molecularly imprinted polymer grafted on titanium dioxide modified silica fiber was used for microextraction, while the same polymer immobilized on multiwalled carbon nanotubes/titanium dioxide modified pencil graphite electrode served as a detection tool. In both cases, the surface initiated polymerization was found to be advantageous to obtain a nanometer thin imprinted film. The modified silica fiber exhibited high adsorption capacity and enantioselective diffusion of aspartic acid isomers into respective molecular cavities. This combination enabled double preconcentrations of d- and l-aspartic acid that helped sensing both isomers in real samples, without any cross-selectivity and matrix complications. Taking into account 6×10(4)-fold dilution of serum and 2×10(3)-fold dilution of cerebrospinal fluid required by the proposed method, the limit of detection for l-aspartic acid is 0.031ngmL(-1). Also, taking into account 50-fold dilution required by the proposed method, the limit of detection for d-aspartic acid is 0.031ngmL(-1) in cerebrospinal fluid. Copyright © 2013 Elsevier B.V. All rights reserved.

Processing and problems in manufacturing a Ti-modified Nb/sub 3/Sn MJR billet. Volume 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

McDonald, W.K.; Smathers, D.; Geno, J.D.

1985-06-18

This report is submitted to complete Task II of University of California Order Number 4321405. Task I had Teledyne Wah Chang Albany (TWCA) assemble and process by the Modified Jelly Roll (MJR) method a Ti-modified Nb/sub 3/Sn superconductor billet. This billet was identified as M103 by TWCA. The billet matrix is nominally composed of copper 13.5 wt % tin bronze sheet and niobium 1.2 wt % titanium expanded metal with a volume ratio of three parts bronze to one part niobium alloy. All processing steps and problems encountered in manufacturing billet M103 are described in this report.

Deployment of titanium thermal barrier for low-temperature carbon nanotube growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, G.Y.; Poa, C.H.P.; Henley, S.J.

2005-12-19

Chemical vapor-synthesized carbon nanotubes are typically grown at temperatures around 600 deg. C. We report on the deployment of a titanium layer to help elevate the constraints on the substrate temperature during plasma-assisted growth. The growth is possible through the lowering of the hydrocarbon content used in the deposition, with the only source of heat provided by the plasma. The nanotubes synthesized have a small diameter distribution, which deviates from the usual trend that the diameter is determined by the thickness of the catalyst film. Simple thermodynamic simulations also show that the quantity of heat, that can be distributed, ismore » determined by the thickness of the titanium layer. Despite the lower synthesis temperature, it is shown that this technique allows for high growth rates as well as better quality nanotubes.« less

Structural characteristics and sorption properties of lithium-selective composite materials based on TiO2 and MnO2

NASA Astrophysics Data System (ADS)

Chaban, M. O.; Rozhdestvenska, L. M.; Palchyk, O. V.; Dzyazko, Y. S.; Dzyazko, O. G.

2018-04-01

A number of nanomaterials containing titanium dioxide and manganese dioxide were synthesized. The effect of synthesis conditions on structural and sorption characteristics for the selective extraction of lithium ions from solutions was studied. The ion-exchange materials were investigated with the methods of electron microscopy, thermogravimetric and X-ray analyses. During thermal synthesis phases of lithium manganese titanium spinel and TiO2 are being formed. Replacing a part of manganese with titanium ions leads to a decrease in the dissolution of Mn and to an increase in chemical stability. Composites with optimal values of selectivity and sorption rates were used to remove lithium ions from solutions with high salt background. The recovery degree of lithium ions under dynamic conditions reached 99%, the highest sorption capacity was found at pH 10.

Chlorination Kinetics of Titanium Nitride for Production of Titanium Tetrachloride from Nitrided Ilmenite

NASA Astrophysics Data System (ADS)

Ahmadi, Eltefat; Rezan, Sheikh Abdul; Baharun, Norlia; Ramakrishnan, Sivakumar; Fauzi, Ahmad; Zhang, Guangqing

2017-10-01

The kinetics of chlorination of titanium nitride (TiN) was investigated in the temperature range of 523 K to 673 K (250 °C to 400 °C). The results showed that the extent of chlorination slightly increased with increasing temperature and decreasing particle size of titanium nitride at constant flow rate of N2-Cl2 gas mixture. At 523 K (250 °C), the extent of chlorination was 85.6 pct in 60 minutes whereas at 673 K (400 °C), it was 97.7 pct investigated by weight loss measurement and confirmed by ICP analyses. The experimental results indicated that a shrinking unreacted core model with mixed-control mechanism governed the chlorination rate. It was observed that the surface chemical reaction of chlorine gas on the surface of TiN particles was rate controlling in the initial stage and, during later stage, internal (pore) diffusion through the intermediate product layer was rate controlling step. Overall the process follows the mixed-control model incorporating both chemical reaction and internal diffusion control. The activation energy for the chlorination of TiN was found to be about 10.97 kJ mol-1. In processing TiCl4 from TiN and TiO0.02C0.13N0.85, the solids involved in the chlorination process were characterized by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy-dispersive X-ray spectrometer (EDX). The SEM/EDX results demonstrated the consumption of TiN particles with extent of chlorination that showed shrinking core behavior.

The influence of mineral particles on fibroblast behaviour: A comparative study.

PubMed

Soto Veliz, Diosangeles; Luoto, Jens C; Pulli, Ilari; Toivakka, Martti

2018-07-01

Minerals are versatile tools utilised to modify and control the physical-chemical and functional properties of substrates. Those properties include ones directing cell fate; thus, minerals can potentially provide a direct and inexpensive method to manipulate cell behaviour. This paper shows how different minerals influence human dermal fibroblast behaviour depending on their properties. Different calcium carbonates, calcium sulphates, silica, silicates, and titanium dioxide were characterised using TEM, ATR-FTIR, and zeta potential measurements. Mineral-cell interactions were analysed through MTT assay, LDH assay, calcein AM staining, live cell imaging, immunofluorescence staining, western blot, and extra/intracellular calcium measurements. Results show that the interaction of the fibroblasts with the minerals was governed by a shared period of adaptation, followed by increased proliferation, growth inhibition, or increased toxicity. Properties such as size, ion release and chemical composition had a direct influence on the cells leading to cell agglomeration, morphological changes, and the possible formation of protein-mineral complexes. In addition, zeta potential and FTIR measurements of the minerals showed adsorption of the cell culture media onto the particles. This article provides fundamental insight into the mineral-fibroblast interactions, and makes it possible to arrange the minerals according to the time-dependent cellular response. Copyright © 2018 Elsevier B.V. All rights reserved.

Surface Modifications with Laser Synthesized Mo Modified Coating

NASA Astrophysics Data System (ADS)

Sun, Lu; Chen, Hao; Liu, Bo

2013-01-01

Mg-Cu-Al was first used to improve the surface performance of TA15 titanium alloys by means of laser cladding technique. The synthesis of hard composite coating on TA15 titanium alloy by laser cladding of Mg-Cu-Al-B4C/Mo pre-placed powders was investigated by means of scanning electron microscope, energy dispersive spectrometer and high resolution transmission electron microscope. Experimental results indicated that such composite coating mainly consisted of TiB2, TiB, TiC, Ti3Al and AlCuMg. Compared with TA15 alloy substrate, an improvement of wear resistance was observed for this composite coating due to the actions of fine grain, amorphous and hard phase strengthening.

Visible-Light Responsive Catalysts Using Quantum Dot-Modified TiO2 for Air and Water Purification

NASA Technical Reports Server (NTRS)

Coutts, Janelle L.; Hintze, Paul E.; Clausen, Christian A.; Richards, Jeffrey T.

2014-01-01

Photocatalysis, the oxidation or reduction of contaminants by light-activated catalysts, utilizing titanium dioxide (TiO2) as the catalytic substrate has been widely studied for trace contaminant control in both air and water applications. The interest in this process is due primarily to its low energy consumption and capacity for catalyst regeneration. Titanium dioxide requires ultraviolet light for activation due to its relatively large band gap energy of 3.2 eV. Traditionally, Hg-vapor fluorescent light sources are used in PCO reactors; however, the use of mercury precludes the use of this PCO technology in a spaceflight environment due to concerns over crew Hg exposure.

Surface Modification Enhanced Reflection Intensity of Quartz Crystal Microbalance Sensors upon Molecular Adsorption.

PubMed

Kojima, Taisuke

2018-01-01

Molecular adsorption on a sensing surface involves molecule-substrate and molecule-molecule interactions. Combining optical systems and a quartz crystal microbalance (QCM) on the same sensing surface allows the quantification of such interactions and reveals the physicochemical properties of the adsorbed molecules. However, low sensitivity of the current reflection-based techniques compared to the QCM technique hinders the quantitative analysis of the adsorption events. Here, a layer-by-layer surface modification of a QCM sensor is studied to increase the optical sensitivity. The intermediate layers of organic-inorganic molecules and metal-metal oxide were explored on a gold (Au) surface of a QCM sensor. First, polyhedral oligomeric silsesquioxane-derivatives that served as the organic-inorganic intermediate layer were synthesized and modified on the Au-QCM surface. Meanwhile, titanium oxide, fabricated by anodic oxidation of titanium, was used as a metal-metal oxide intermediate layer on a titanium-coated QCM surface. The developed technique enabled interrogation of the molecular adsorption owing to the enhanced optical sensitivity.

Scanning electron microscopy of heat treated TiO2 nanotubes arrays obtained by anodic oxidation

NASA Astrophysics Data System (ADS)

Naranjo, D. I.; García-Vergara, S. J.; Blanco, S.

2017-12-01

Scanning electron microscopy was used to investigate the anatase-rutile transformation of self-organized TiO2 nanotubes obtained on titanium foil by anodizing and subsequent heat treatment. The anodizing was carried out at 20V in an 1% v/v HF acid and ethylene glycol:water (50:50) electrolyte at room temperature. The anodized samples were initially pre-heat treated at 450°C for 4 hours to modify the amorphous structure of TiO2 nanotubes into anatase structure. Then, the samples were heated between 600 to 800°C for different times, in order to promote the transformation to rutile structure. The formation of TiO2 nanotubes is evident by SEM images. Notably, when the samples are treated at high temperature, the formation of rutile crystals starts to become evident at the nanotubes located on the originally grain boundaries of the titanium. Thus, the anatase - rutile transformation has a close relationship with the microstructure of the titanium, more exactly with grain boundaries.

Marangoni Convection during Free Electron Laser Nitriding of Titanium

NASA Astrophysics Data System (ADS)

Höche, Daniel; Müller, Sven; Rapin, Gerd; Shinn, Michelle; Remdt, Elvira; Gubisch, Maik; Schaaf, Peter

2009-08-01

Pure titanium was treated by free electron laser (FEL) radiation in a nitrogen atmosphere. As a result, nitrogen diffusion occurs and a TiN coating was synthesized. Local gradients of interfacial tension due to the local heating lead to a Marangoni convection, which determines the track properties. Because of the experimental inaccessibility of time-dependent occurrences, finite element calculations were performed, to determine the physical processes such as heat transfer, melt flow, and mass transport. In order to calculate the surface deformation of the gas-liquid interface, the level set approach was used. The equations were modified and coupled with heat-transfer and diffusion equations. The process was characterized by dimensionless numbers such as the Reynolds, Peclet, and capillary numbers, to obtain more information about the acting forces and the coating development. Moreover, the nitrogen distribution was calculated using the corresponding transport equation. The simulations were compared with cross-sectional micrographs of the treated titanium sheets and checked for their validity. Finally, the process presented is discussed and compared with similar laser treatments.

Effects of Electric Discharge Plasma Treatment on the Thermal Conductivity of Polymer-Metal Nitride/Carbide Composites

NASA Astrophysics Data System (ADS)

Parali, Levent; Kurbanov, Mirza A.; Bayramov, Azad A.; Tatardar, Farida N.; Sultanakhmedova, Ramazanova I.; Xanlar, Huseynova Gulnara

2015-11-01

High-density polymer composites with semiconductor or dielectric fillers such as aluminum nitride (AIN), aluminum oxide (Al2O3), titanium carbide (TiC), titanium nitride (TiN), boron nitride (BN), silicon nitride (Si3N4), and titanium carbonitride (TiCN) were prepared by the hot pressing method. Each powder phase of the composites was exposed to an electric discharge plasma process before composite formation. The effects of the electric discharge plasma process and the filler content (volume fraction) on the thermal conductivity, volt-ampere characteristics, thermally stimulated depolarization current, as well as electrical and mechanical strength were investigated. The results of the study indicate that, with increasing filler volume fraction, the thermal conductivity of the samples also increased. Furthermore, the thermal conductivity, and electrophysical and mechanical properties of the high-density polyethylene + 70% BN composite modified using the electric discharge plasma showed improvement when compared with that without electric discharge plasma treatment.

Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites

PubMed Central

Li, Feng; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

2018-01-01

Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca3(PO4)2, TixPy, and Ti3O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed. PMID:29659504

Microstructure and Mechanical Properties of Graphene-Reinforced Titanium Matrix/Nano-Hydroxyapatite Nanocomposites.

PubMed

Li, Feng; Jiang, Xiaosong; Shao, Zhenyi; Zhu, Degui; Zhu, Minhao

2018-04-16

Biomaterial composites made of titanium and hydroxyapatite (HA) powder are among the most important biomedicalmaterials due to their good mechanical properties and biocompatibility. In this work, graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites were prepared by vacuum hot-pressing sintering. The microstructure and mechanical properties of graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were systematically investigated. Microstructures of the nanocomposites were examined by X-ray diffraction (XRD), back scattered electron imaging (BSE), scanning electron microscope (SEM) equipped with energy dispersive spectrometer (EDS), electron probe microanalyzer (EPMA), and transmission electron microscope (TEM). The mechanical properties were determined from microhardness, shear strength, and compressive strength. Results showed that during the high-temperature sintering process, complex chemical reactions occurred, resulting in new phases of nucleation such as Ca₃(PO₄)₂, Ti x P y , and Ti₃O.The new phases, which easily dropped off under the action of external force, could hinder the densification of sintering and increase the brittleness of the nanocomposites. Results demonstrated that graphene had an impact on the microstructure and mechanical properties of the nanocomposites. Based on the mechanical properties and microstructure of the nanocomposites, the strengthening and fracture mechanisms of the graphene-reinforced titanium matrix/nano-hydroxyapatite nanocomposites with different graphene content were analyzed.

Tuning the reactivity of semiconductor surfaces by functionalization with amines of different basicity

PubMed Central

Bent, Stacey F.; Kachian, Jessica S.; Rodríguez-Reyes, Juan Carlos F.; Teplyakov, Andrew V.

2011-01-01

Surface functionalization of semiconductors has been the backbone of the newest developments in microelectronics, energy conversion, sensing device design, and many other fields of science and technology. Over a decade ago, the notion of viewing the surface itself as a chemical reagent in surface reactions was introduced, and adding a variety of new functionalities to the semiconductor surface has become a target of research for many groups. The electronic effects on the substrate have been considered as an important consequence of chemical modification. In this work, we shift the focus to the electronic properties of the functional groups attached to the surface and their role on subsequent reactivity. We investigate surface functionalization of clean Si(100)-2 × 1 and Ge(100)-2 × 1 surfaces with amines as a way to modify their reactivity and to fine tune this reactivity by considering the basicity of the attached functionality. The reactivity of silicon and germanium surfaces modified with ethylamine (CH3CH2NH2) and aniline (C6H5NH2) is predicted using density functional theory calculations of proton attachment to the nitrogen of the adsorbed amine to differ with respect to a nucleophilic attack of the surface species. These predictions are then tested using a model metalorganic reagent, tetrakis(dimethylamido)titanium (((CH3)2N)4Ti, TDMAT), which undergoes a transamination reaction with sufficiently nucleophilic amines, and the reactivity tests confirm trends consistent with predicted basicities. The identity of the underlying semiconductor surface has a profound effect on the outcome of this reaction, and results comparing silicon and germanium are discussed. PMID:21068370

Investigation of tool wear and surface roughness on machining of titanium alloy with MT-CVD cutting tool

NASA Astrophysics Data System (ADS)

Maity, Kalipada; Pradhan, Swastik

2018-04-01

In this study, machining of titanium alloy (grade 5) is carried out using MT-CVD coated cutting tool. Titanium alloys possess superior strength-to-weight ratio with good corrosion resistance. Most of the industries used titanium alloy for the manufacturing of various types of lightweight components. The parts made from Ti-6Al-4V largely used in aerospace, biomedical, automotive and marine sectors. The conventional machining of this material is very difficult, due to low thermal conductivity and high chemical reactivity properties. To achieve a good surface finish with minimum tool wear of cutting tool, the machining is carried out using MT-CVD coated cutting tool. The experiment is carried out using of Taguchi L27 array layout with three cutting variables and levels. To find out the optimum parametric setting desirability function analysis (DFA) approach is used. The analysis of variance is studied to know the percentage contribution of each cutting variables. The optimum parametric setting results calculated from DFA were validated through the confirmation test.

Preparation of Copper and Chromium Alloyed Layers on Pure Titanium by Plasma Surface Alloying Technology

NASA Astrophysics Data System (ADS)

He, Xiaojing; Li, Meng; Wang, Huizhen; Zhang, Xiangyu; Tang, Bin

2015-05-01

Cu-Cr alloyed layers with different Cu and Cr contents on pure titanium were obtained by means of plasma surface alloying technology. The microstructure, chemical composition and phase composition of Cu-Cr alloyed layers were analyzed by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS) and X-ray diffraction (XRD), respectively. The experimental results demonstrate that the alloyed layers are bonded strongly to pure titanium substrate and consist of unbound Ti, CuTi, Cu3Ti, CuTi3 and Cr2Ti. The thickness of Cu5Cr5 and Cu7Cr3 alloyed layer are about 18 μm and 28 μm, respectively. The antibacterial properties against gram-negative Escherichia coli (E.coli, ATCC10536) and gram-positive Staphylococcus aureus (S. aureus, ATCC6538) of untreated pure titanium and Cu-Cr alloyed specimen were investigated by live/dead fluorescence staining method. The study shows that Cu-Cr alloyed layers exhibit excellent antibacterial activities against both E.coli and S.aureus within 24 h, which may be attributed to the formation of Cu-containing phases.

Tribological performance of titanium samples oxidized by fs-laser radiation, thermal heating, or electrochemical anodization

NASA Astrophysics Data System (ADS)

Kirner, S. V.; Slachciak, N.; Elert, A. M.; Griepentrog, M.; Fischer, D.; Hertwig, A.; Sahre, M.; Dörfel, I.; Sturm, H.; Pentzien, S.; Koter, R.; Spaltmann, D.; Krüger, J.; Bonse, J.

2018-04-01

Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms.

Catalytic Efficiency of Titanium Dioxide (TiO2) and Zeolite ZSM-5 Catalysts in the in-situ Epoxidation of Palm Olein

NASA Astrophysics Data System (ADS)

Yunus, M. Z. Mohd; Jamaludin, S. K.; Abd. Karim, S. F.; Gani, A. Abd; Sauki, A.

2018-05-01

Titanium dioxide and zeolite ZSM-5 are the commonly used heterogeneous catalysts in many chemical reactions. They have several advantages such as low cost and environmental friendly. In this study, titanium dioxide and zeolite ZSM-5 act as catalyst in the in-situ epoxidation of palm olein. Epoxidation of palm olein was carried out by using in-situ generated performic acid to produce epoxidized palm olein in a semi-batch reactor at different temperatures (45°C and 60°C) and agitation speed of 400 rpm. The effects of both catalysts are studied to compare their efficiency in catalyzing the in-situ epoxidation. Epoxidized palm olein was analyzed by using percent of relative conversion to oxirane (RCO%) and fourier transform infrared spectroscopy (FTIR). Surface area of the catalysts used were then characterized by using BET. The results indicated that titanium dioxide is a better catalyst in the in-situ epoxidation of palm olein since it provides higher RCO% compared to Zeolite ZSM-5 at 45°C.

Production and characterization of a novel carbon nanotube/titanium nitride nanocomposite

NASA Astrophysics Data System (ADS)

Baddour, Carole Emilie; Das, Kaushik; Vengallatore, Srikar; Meunier, Jean-Luc

2016-12-01

A novel titanium nitride (TiN)/carbon nanotube (CNT) nanocomposite is produced with the purpose to mechanically, structurally and chemically stabilize a ‘felt-like’ CNT growth structure. The CNTs are grown on stainless steel (SS) 304 by chemical vapor deposition using the direct growth method previously developed, which does not require the use of an additional catalyst precursor. The TiN coating is achieved by physical vapor deposition and is shown here to generate a nanocomposite with a porous three-dimensional architecture. The contact stiffness is evaluated using nanoindentation, and wetting properties of the TiN/CNT nanocomposites are determined from contact angle measurements. An increase in contact stiffness and effective elastic modulus with TiN coating time was observed. The TiN coating on the non-wetting CNT felt results in a wetting nanocomposite surface. The wetting property is found to be a function of the TiN coating thickness on the CNT structure.

Methods for chemical recovery of non-carrier-added radioactive tin from irradiated intermetallic Ti-Sb targets

DOEpatents

Lapshina, Elena V [Troitsk, RU; Zhuikov, Boris L [Troitsk, RU; Srivastava, Suresh C [Setauket, NY; Ermolaev, Stanislav V [Obninsk, RU; Togaeva, Natalia R [Obninsk, RU

2012-01-17

The invention provides a method of chemical recovery of no-carrier-added radioactive tin (NCA radiotin) from intermetallide TiSb irradiated with accelerated charged particles. An irradiated sample of TiSb can be dissolved in acidic solutions. Antimony can be removed from the solution by extraction with dibutyl ether. Titanium in the form of peroxide can be separated from tin using chromatography on strong anion-exchange resin. In another embodiment NCA radiotin can be separated from iodide solution containing titanium by extraction with benzene, toluene or chloroform. NCA radiotin can be finally purified from the remaining antimony and other impurities using chromatography on silica gel. NCA tin-117m can be obtained from this process. NCA tin-117m can be used for labeling organic compounds and biological objects to be applied in medicine for imaging and therapy of various diseases.

Effect of the chemical composition and the structural and phases states of materials on hydrogen retention

NASA Astrophysics Data System (ADS)

Chernov, I. I.; Stal'tsov, M. S.; Kalin, B. A.; Bogachev, I. A.; Guseva, L. Yu.; Korshunov, S. N.

2017-07-01

The results of investigation of the effect of chemical composition and structural and phase states of reactor steels and vanadium alloys on their capture and retention of hydrogen introduced into the materials in various ways are presented. It is shown that, in the case of identical conditions of hydrogen introduction, the amount of hydrogen captured by austenitic steels is substantially higher than that captured by ferritic/ martensitic steels. At the same time, the EP450 ODS ferritic/martensitic steel dispersion-strengthened with nanosized yttrium oxide particles retains a substantially higher amount of hydrogen as compared to that retained in the EP450 matrix steel. The alloying of vanadium with tungsten, zirconium, and titanium leads to an increase in the amount of retained hydrogen. The effect of titanium content on hydrogen retention is found to be nonmonotonic; the phenomenon is explained from a physical view point.

Mechanical Grinding Preparation and Characterization of TiO2-Coated Wollastonite Composite Pigments

PubMed Central

Chen, Wanting; Liang, Yu; Hou, Xifeng; Zhang, Jing; Ding, Hao; Sun, Sijia; Cao, Hu

2018-01-01

TiO2-coated wollastonite composite pigments were prepared by the mechano-chemical grinding of wollastonite and TiO2 powder together in a wet ultrafine stirred mill. X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy and infrared spectra were used to investigate the microstructures and morphologies of the composite and the reaction mechanism. The results indicate that the TiO2-coated wollastonite composite pigments have similar properties to titanium dioxide pigment, showing much better properties than dry and wet mixing of wollastonite and TiO2. The hiding power of TiO2-coated wollastonite composite pigments (45% TiO2) is 17.97 g/m2, reaching 81.08% of titanium dioxide. A firm combination between wollastonite and TiO2 is obtained through a surface dehydroxylation reaction during the mechano-chemical method. PMID:29649116

Treatment of Candida albicans biofilms with low-temperature plasma induced by dielectric barrier discharge and atmospheric pressure plasma jet

NASA Astrophysics Data System (ADS)

Koban, Ina; Matthes, Rutger; Hübner, Nils-Olaf; Welk, Alexander; Meisel, Peter; Holtfreter, Birte; Sietmann, Rabea; Kindel, Eckhard; Weltmann, Klaus-Dieter; Kramer, Axel; Kocher, Thomas

2010-07-01

Because of some disadvantages of chemical disinfection in dental practice (especially denture cleaning), we investigated the effects of physical methods on Candida albicans biofilms. For this purpose, the antifungal efficacy of three different low-temperature plasma devices (an atmospheric pressure plasma jet and two different dielectric barrier discharges (DBDs)) on Candida albicans biofilms grown on titanium discs in vitro was investigated. As positive treatment controls, we used 0.1% chlorhexidine digluconate (CHX) and 0.6% sodium hypochlorite (NaOCl). The corresponding gas streams without plasma ignition served as negative treatment controls. The efficacy of the plasma treatment was determined evaluating the number of colony-forming units (CFU) recovered from titanium discs. The plasma treatment reduced the CFU significantly compared to chemical disinfectants. While 10 min CHX or NaOCl exposure led to a CFU log10 reduction factor of 1.5, the log10 reduction factor of DBD plasma was up to 5. In conclusion, the use of low-temperature plasma is a promising physical alternative to chemical antiseptics for dental practice.

Skeletal stem cell and bone implant interactions are enhanced by LASER titanium modification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sisti, Karin E., E-mail: karinellensisti@gmail.com; Biomaterials Group, Institute of Chemistry, São Paulo State University; Federal University of Mato Grosso do Sul

Purpose: To evaluate the osteo-regenerative potential of Titanium (Ti) modified by Light Amplification by Stimulated Emission of Radiation (LASER) beam (Yb-YAG) upon culture with human Skeletal Stem Cells (hSSCs{sup 1}). Methods: Human skeletal cell populations were isolated from the bone marrow of haematologically normal patients undergoing primary total hip replacement following appropriate consent. STRO-1{sup +} hSSC{sup 1} function was examined for 10 days across four groups using Ti discs: i) machined Ti surface group in basal media (Mb{sup 2}), ii) machined Ti surface group in osteogenic media (Mo{sup 3}), iii) LASER-modified Ti group in basal media (Lb{sup 4}) and, iv)more » LASER-modified Ti group in osteogenic media (Lo{sup 5}). Molecular analysis and qRT-PCR as well as functional analysis including biochemistry (DNA, Alkaline Phosphatase (ALP{sup 6}) specific activity), live/dead immunostaining (Cell Tracker Green (CTG{sup 7})/Ethidium Homodimer-1 (EH-1{sup 8})), and fluorescence staining (for vinculin and phalloidin) were undertaken. Inverted, confocal and Scanning Electron Microscopy (SEM) approaches were used to characterise cell adherence, proliferation, and phenotype. Results: Enhanced cell spreading and morphological rearrangement, including focal adhesions were observed following culture of hSSCs{sup 1} on LASER surfaces in both basal and osteogenic conditions. Biochemical analysis demonstrated enhanced ALP{sup 6} specific activity on the hSSCs{sup 1}-seeded on LASER-modified surface in basal culture media. Molecular analysis demonstrated enhanced ALP{sup 6} and osteopontin expression on titanium LASER treated surfaces in basal conditions. SEM, inverted microscopy and confocal laser scanning microscopy confirmed extensive proliferation and migration of human bone marrow stromal cells on all surfaces evaluated. Conclusions: LASER-modified Ti surfaces modify the behaviour of hSSCs.{sup 1} In particular, SSC{sup 1} adhesion, osteogenic gene expression, cell morphology and cytoskeleton structure were affected. The current studies show Ti LASER modification can enhance the osseointegration between Ti and skeletal cells, with important implications for orthopaedic application. - Highlights: • Bone stem cells on LASER Ti surface display enhanced cell growth and viability. • Bone stem cells on LASER Ti surface exhibit marked biocompatibility. • Human bone stem cells on LASER Ti surface exhibit altered morphology. • LASER Ti enhance osteogenic differentiation of human bone skeletal stem cells. • LASER Ti provides a unique approach to enhance osseointegration with the material.« less

On the influence of DC electric fields on the aerosol assisted chemical vapor deposition growth of photoactive titanium dioxide thin films.

PubMed

Romero, Luz; Binions, Russell

2013-11-05

Titanium dioxide thin films were deposited on fluorine doped tin oxide glass substrate from the electric field assisted aerosol chemical vapor deposition (EACVD) reaction of titanium isopropoxide (TTIP, Ti(OC3H7)4) in toluene on glass substrates at a temperature of 450 °C. DC electric fields were generated by applying a potential difference between the electrodes of the transparent coated oxide coated glass substrates during the deposition. The deposited films were characterized using scanning electron microscopy, X-ray diffraction, atomic force microscopy, Raman spectroscopy, and UV-vis spectroscopy. The photoactivity and hydrophilicity of the deposited films were also analyzed using a dye-ink test and water-contact angle measurements. The characterization work revealed that the incorporation of DC electric fields produced significant reproducible changes in the film microstructure, preferred crystallographic orientation, roughness, and film thickness. Photocatalytic activity was calculated from the half-time (t1/2) or time taken to degrade 50% of the initial resazurin dye concentration. A large improvement in photocatalytic activity was observed for films deposited using an electric field with a strong orientation in the (004) direction (t1/2 17 min) as compared to a film deposited with no electric field (t1/2 40 min).

Influence of microstructure and chemical composition of sputter deposited TiO2 thin films on in vitro bioactivity.

PubMed

Lilja, Mirjam; Genvad, Axel; Astrand, Maria; Strømme, Maria; Enqvist, Håkan

2011-12-01

Functionalisation of biomedical implants via surface modifications for tailored tissue response is a growing field of research. Crystalline TiO(2) has been proven to be a bone bioactive, non-resorbable material. In contact with body fluids a hydroxyapaptite (HA) layer forms on its surface facilitating the bone contact. Thus, the path of improving biomedical implants via deposition of crystalline TiO(2) on the surface is interesting to follow. In this study we have evaluated the influence of microstructure and chemical composition of sputter deposited titanium oxide thin films on the in vitro bioactivity. We find that both substrate bias, topography and the flow ratio of the gases used during sputtering affect the HA layer formed on the films after immersion in simulated body fluid at 37°C. A random distribution of anatase and rutile crystals, formed at negative substrate bias and low Ar to O(2) gas flow ratios, are shown to favor the growth of flat HA crystal structures whereas higher flow ratios and positive substrate bias induced growth of more spherical HA structures. These findings should provide valuable information when optimizing the bioactivity of titanium oxide coatings as well as for tailoring process parameters for sputtered-based production of bioactive titanium oxide implant surfaces.

Magnesium ion implantation on a micro/nanostructured titanium surface promotes its bioactivity and osteogenic differentiation function

PubMed Central

Wang, Guifang; Li, Jinhua; Zhang, Wenjie; Xu, Lianyi; Pan, Hongya; Wen, Jin; Wu, Qianju; She, Wenjun; Jiao, Ting; Liu, Xuanyong; Jiang, Xinquan

2014-01-01

As one of the important ions associated with bone osseointegration, magnesium was incorporated into a micro/nanostructured titanium surface using a magnesium plasma immersion ion-implantation method. Hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 30 minutes (Mg30) and hierarchical hybrid micro/nanostructured titanium surfaces followed by magnesium ion implantation for 60 minutes (Mg60) were used as test groups. The surface morphology, chemical properties, and amount of magnesium ions released were evaluated by field-emission scanning electron microscopy, energy dispersive X-ray spectroscopy, field-emission transmission electron microscopy, and inductively coupled plasma-optical emission spectrometry. Rat bone marrow mesenchymal stem cells (rBMMSCs) were used to evaluate cell responses, including proliferation, spreading, and osteogenic differentiation on the surface of the material or in their medium extraction. Greater increases in the spreading and proliferation ability of rBMMSCs were observed on the surfaces of magnesium-implanted micro/nanostructures compared with the control plates. Furthermore, the osteocalcin (OCN), osteopontin (OPN), and alkaline phosphatase (ALP) genes were upregulated on both surfaces and in their medium extractions. The enhanced cell responses were correlated with increasing concentrations of magnesium ions, indicating that the osteoblastic differentiation of rBMMSCs was stimulated through the magnesium ion function. The magnesium ion-implanted micro/nanostructured titanium surfaces could enhance the proliferation, spreading, and osteogenic differentiation activity of rBMMSCs, suggesting they have potential application in improving bone-titanium integration. PMID:24940056

Chemically modified carbonic anhydrases useful in carbon capture systems

DOEpatents

Novick, Scott; Alvizo, Oscar

2013-01-15

The present disclosure relates to chemically modified carbonic anhydrase polypeptides and soluble compositions, homogenous liquid formulations comprising them. The chemically modified carbonic anhydrase polypeptides have improved properties relative to the same carbonic anhydrase polypeptide that is not chemically modified including the improved properties of increased activity and/or stability in the presence of amine compounds, ammonia, or carbonate ion. The present disclosure also provides methods of preparing the chemically modified polypeptides and methods of using the chemically modified polypeptides for accelerating the absorption of carbon dioxide from a gas stream into a solution as well as for the release of the absorbed carbon dioxide for further treatment and/or sequestering.

Chemically modified carbonic anhydrases useful in carbon capture systems

DOEpatents

Novick, Scott J; Alvizo, Oscar

2013-10-29

The present disclosure relates to chemically modified carbonic anhydrase polypeptides and soluble compositions, homogenous liquid formulations comprising them. The chemically modified carbonic anhydrase polypeptides have improved properties relative to the same carbonic anhydrase polypeptide that is not chemically modified including the improved properties of increased activity and/or stability in the presence of amine compounds, ammonia, or carbonate ion. The present disclosure also provides methods of preparing the chemically modified polypeptides and methods of using the chemically modified polypeptides for accelerating the absorption of carbon dioxide from a gas stream into a solution as well as for the release of the absorbed carbon dioxide for further treatment and/or sequestering.

Influence of titanium implant surface characteristics on bone regeneration in dehiscence-type defects: an experimental study in dogs.

PubMed

Schwarz, Frank; Sager, Martin; Kadelka, Ines; Ferrari, Daniel; Becker, Jürgen

2010-05-01

The aim of the present study was to compare bone regeneration in dehiscence-type defects at titanium implants with chemically modified sandblasted/acid-etched (modSLA) or dual acid-etched surfaces with a calcium phosphate nanometre particle modification (DCD/CaP). Buccal dehiscence-type defects were surgically created following implant site preparation in both the upper and the lower jaws of 12 fox hounds. Both types of implants were randomly allocated in a split-mouth design and left to heal in a submerged position for 2 and 8 weeks. Dissected blocks were processed for histomorphometrical analysis [e.g. new bone height (NBH), percentage of bone-to-implant contact (BIC), area of new bone fill (BF), and area of mineralized tissue (MT) within BF]. At 2 and 8 weeks, both groups revealed comparable mean BF (2.3+/-0.6 to 2.5+/-0.6 mm(2)versus 2.0+/-0.6 to 1.4+/-0.5 mm(2)) and MT (31.1+/-14.3-83.2+/-8.2%versus 38.9+/-15.9-84.4+/-6.3%) values. However, modSLA implants revealed significantly higher mean NBH (2.4+/-0.8 to 3.6+/-0.3 mm versus 0.9+/-0.8 to 1.8+/-1.4 mm) and BIC (53.3+/-11.3-79.5+/-6.6%versus 19.3+/-16.4-47.2+/-30.7%) values than DCD/CaP implants. ModSLA implants may have a higher potential to support osseointegration in dehiscence-type defects than DCD/CaP implants.

Structural analysis and corrosion studies on an ISO 5832-9 biomedical alloy with TiO2 sol-gel layers.

PubMed

Burnat, B; Dercz, G; Blaszczyk, T

2014-03-01

The aim of this study was to demonstrate the relationship between the structural and corrosion properties of an ISO 5832-9 biomedical alloy modified with titanium dioxide (TiO2) layers. These layers were obtained via the sol-gel method by acid-catalyzed hydrolysis of titanium isopropoxide in isopropanol solution. To obtain TiO2 layers with different structural properties, the coated samples were annealed at temperatures of 200, 300, 400, 450, 500, 600 and 800 °C for 2 h. For all the prepared samples, accelerated corrosion measurements were performed in Tyrode's physiological solution using electrochemical methods. The most important corrosion parameters were determined: corrosion potential, polarization resistance, corrosion rate, breakdown and repassivation potentials. Corrosion damage was analyzed using scanning electron microscopy. Structural analysis was carried out for selected TiO2 coatings annealed at 200, 400, 600 and 800 °C. In addition, the morphology, chemical composition, crystallinity, thickness and density of the deposited TiO2 layers were determined using suitable electron and X-ray measurement methods. It was shown that the structure and character of interactions between substrate and deposited TiO2 layers depended on annealing temperature. All the obtained TiO2 coatings exhibit anticorrosion properties, but these properties are related to the crystalline structure and character of substrate-layer interaction. From the point of view of corrosion, the best TiO2 sol-gel coatings for stainless steel intended for biomedical applications seem to be those obtained at 400 °C.

The importance of particle size in porous titanium and nonporous counterparts for surface energy and its impact on apatite formation.

PubMed

Chen, Xiao-Bo; Li, Yun-Cang; Hodgson, Peter D; Wen, Cuie

2009-07-01

The importance of particle size in titanium (Ti) fabricated by powder metallurgy for the surface energy and its impact on the apatite formation was investigated. Four sorts of Ti powders of different mean particle size were realized through 20min, 2h, 5h and 8h of ball milling, respectively. Each sort of Ti powder was used to fabricate porous Ti and its nonporous counterparts sharing similar surface morphology, grain size and chemical composition, and then alkali-heat treatment was conducted on them. Surface energy was measured on the surfaces of the nonporous Ti counterparts due to the difficulty in measuring the porous surfaces directly. The surface energy increase on the alkali-heat-treated porous and nonporous Ti was observed due to the decrease in the particle size of the Ti powders and the presence of Ti-OH groups brought by the alkali-heat treatment. The apatite-inducing ability of the alkali-heat-treated porous and nonporous Ti with different surface energy values was evaluated in modified simulated body fluid and results indicated that there was a strong correlation between the apatite-inducing ability and the surface energy. The alkali-heat-treated porous and nonporous Ti discs prepared from the powders with an average particle size of 5.89+/-0.76microm possessed the highest surface energy and the best apatite-inducing ability when compared to the samples produced from the powders with the average particle size varying from 19.79+/-0.31 to 10.25+/-0.39microm.

Understanding long-term silver release from surface modified porous titanium implants.

PubMed

Shivaram, Anish; Bose, Susmita; Bandyopadhyay, Amit

2017-08-01

Prevention of orthopedic device related infection (ODRI) using antibiotics has met with limited amount of success and is still a big concern during post-surgery. As an alternative, use of silver as an antibiotic treatment to prevent surgical infections is being used due to the well-established antimicrobial properties of silver. However, in most cases silver is used in particulate form with wound dressings or with short-term devices such as catheters but not with load-bearing implants. We hypothesize that strongly adherent silver to load-bearing implants can offer longer term solution to infection in vivo. Keeping that in mind, the focus of this study was to understand the long term release study of silver ions for a period of minimum 6months from silver coated surface modified porous titanium implants. Implants were fabricated using a LENS™ system, a powder based additive manufacturing technique, with at least 25% volume porosity, with and without TiO 2 nanotubes in phosphate buffer saline (pH 7.4) to see if the total release of silver ions is within the toxic limit for human cells. Considering the fact that infection sites may reduce the local pH, silver release was also studied in acetate buffer (pH 5.0) for a period of 4weeks. Along with that, the osseointegrative properties as well as cytotoxicity of porous titanium implants were assessed in vivo for a period of 12weeks using a rat distal femur model. In vivo results indicate that porous titanium implants with silver coating show comparable, if not better, biocompatibility and bonding at the bone-implant interface negating any concerns related to toxicity related to silver to normal cells. The current research is based on our recently patented technology, however focused on understanding longer-term silver release to mitigate infection related problems in load-bearing implants that can even arise several months after the surgery. Prevention of orthopedic device related infection using antibiotics has met with limited success and is still a big concern during post-surgery. Use of silver as an antibiotic treatment to prevent surgical infections is being explored due to the well-established antimicrobial properties of silver. However, in most cases silver is used in particulate form with wound dressings or with short-term devices such as catheters but not with load-bearing implants. We hypothesize that strongly adherent silver to load-bearing implants can offer longer-term solution towards infection in vivo. Keeping that in mind, the focus of this study was to understand the long-term release of silver ions, for a period of minimum 6months, from silver coated surface modified porous titanium implants. Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Mechanical design optimization of bioabsorbable fixation devices for bone fractures.

PubMed

Lovald, Scott T; Khraishi, Tariq; Wagner, Jon; Baack, Bret

2009-03-01

Bioabsorbable bone plates can eliminate the necessity for a permanent implant when used to fixate fractures of the human mandible. They are currently not in widespread use because of the low strength of the materials and the requisite large volume of the resulting bone plate. The aim of the current study was to discover a minimally invasive bioabsorbable bone plate design that can provide the same mechanical stability as a standard titanium bone plate. A finite element model of a mandible with a fracture in the body region is subjected to bite loads that are common to patients postsurgery. The model is used first to determine benchmark stress and strain values for a titanium plate. These values are then set as the limits within which the bioabsorbable bone plate must comply. The model is then modified to consider a bone plate made of the polymer poly-L/DL-lactide 70/30. An optimization routine is run to determine the smallest volume of bioabsorbable bone plate that can perform and a titanium bone plate when fixating fractures of this considered type. Two design parameters are varied for the bone plate design during the optimization analysis. The analysis determined that a strut style poly-L-lactide-co-DL-lactide plate of 690 mm2 can provide as much mechanical stability as a similar titanium design structure of 172 mm2. The model has determined a bioabsorbable bone plate design that is as strong as a titanium plate when fixating fractures of the load-bearing mandible. This is an intriguing outcome, considering that the polymer material has only 6% of the stiffness of titanium.

Low-Temperature Nitriding of Pure Titanium by using Hollow Cathode RF-DC Plasma

NASA Astrophysics Data System (ADS)

Windajanti, J. M.; S, D. J. Djoko H.; Abdurrouf

2017-05-01

Pure titanium is widely used for the structures and mechanical parts due to its high strength, low density, and high corrosion resistance. Unfortunately, titanium products suffer from low hardness and low wear resistance. Titanium’s surface can be modified by nitriding process to overcome such problems, which is commonly conducted at high temperature. Here, we report the low-temperature plasma nitriding process, where pure titanium was utilized by high-density RF-DC plasma combined with hollow cathode device. To this end, a pure titanium plate was set inside a hollow tube placed on the cathode plate. After heating to 450 °C, a pre-sputtering process was conducted for 1 hour to remove the oxide layer and activate the surface for nitriding. Plasma nitriding using N2/H2 gasses was performed in 4 and 8 hours with the RF voltage of 250 V, DC bias of -500 to -600 V, and gas pressure of 75 to 30 Pa. To study the nitriding mechanism as well as the role of hollow cathode, the nitrided specimen was characterized by SEM, EDX, XRD, and micro-hardness equipment. The TiN compound was obtained with the diffusion zone of nitrogen until 5 μm thickness for 4 hours nitriding process, and 8 μm for 8 hours process. The average hardness also increased from 300 HV in the untreated specimen to 624 HV and 792 HV for 4 and 8 hours nitriding, respectively.

Effects of anodic oxidation parameters on a modified titanium surface.

PubMed

Park, Il Song; Lee, Min Ho; Bae, Tae Sung; Seol, Kyeong Won

2008-02-01

Anodic oxidation is an electrochemical treatment that can be used to control the thickness of an oxide layer formed on a titanium surface. This procedure has the advantage of allowing the ions contained in an electrolyte to deposit onto the oxide layer. The characteristics of a layer treated with anodic oxidation can vary according to the type and concentration of the electrolytes as well as the processing variables used during anodic oxidation. In this study, the constant electrolyte for anodic oxidation was a mixed solution containing 0.02 M DL-alpha-glycerophosphate disodium salt and 0.2M calcium acetate. Anodic oxidation was carried out at different voltages, current densities, and duration of anodic oxidation. The results showed that the current density and variation in the duration of anodic oxidation did not have a large effect on the change in the characteristics of the layer. On the other hand, the size of the micropores was increased with increasing voltage of anodic oxidation, and anatase and rutile phases were found to co-exist in the porous titanium dioxide layer. In addition, the thickness of the oxide layer on titanium and the characteristic of corrosion resistance increased with increasing voltage. The MTT test showed that the cell viability was increased considerably as a result of anodic oxidation. The anodizing voltage is an important parameter that determines the characteristics of the anodic oxide layer of titanium. (c) 2007 Wiley Periodicals, Inc.

One-Step Hydrothermal-Electrochemical Route to Carbon-Stabilized Anatase Powders

NASA Astrophysics Data System (ADS)

Tao, Ying; Yi, Danqing; Zhu, Baojun

2013-04-01

Black carbon-stabilized anatase particles were prepared by a simple one-step hydrothermal-electrochemical method using glucose and titanium citrate as the carbon and titanium source, respectively. Morphological, chemical, structural, and electrochemical characterizations of these powders were carried out by Raman spectroscopy, Fourier-transform infrared spectroscopy, x-ray diffraction, scanning electron microscopy, and cyclic voltammetry. It was revealed that 200-nm carbon/anatase TiO2 was homogeneously dispersed, and the powders exhibited excellent cyclic performance at high current rates of 0.05 V/s. The powders are interesting potential materials that could be used as anodes for lithium-ion batteries.

Generation of highly N-type, defect passivated transition metal oxides using plasma fluorine insertion

DOEpatents

Baker, L. Robert; Seo, Hyungtak; Hervier, Antoine; Somorjai, Gabor A.

2016-04-12

A new composition of matter is disclosed wherein oxygen vacancies in a semiconducting transition metal oxide such as titanium dioxide are filled with a halogen such as Fluorine, whereby the conductivity of the composition is greatly enhanced, while at the same time the chemical stability of the composition is greatly improved. Stoichiometric titanium dioxide having less than 3 % oxygen vacancies is subject to fluorine insertion such that oxygen vacancies are filled, limited amounts of fluorine replace additional oxygen atoms and fluorine interstitially inserts into the body of the TiO.sub.2 composition.

Surgical treatment of chronic mandibular dislocation--report of a case.

PubMed

Bakardjiev, Angel G; Atanasov, Dimitar T

2002-01-01

Chronic dislocation of the temporomandibular jaw (TMJ) can result from lax joint ligaments and parafunctioning joints; it can also be a consequence of a systemic connective tissue disorder. The authors report a case of hypermobile joint syndrome in combination with mitral valve prolapse. The case was managed by osteosynthesis using modified titanium plate.

Targeted sonocatalytic cancer cell injury using avidin-conjugated titanium dioxide nanoparticles.

PubMed

Ninomiya, Kazuaki; Fukuda, Aya; Ogino, Chiaki; Shimizu, Nobuaki

2014-09-01

In this study, we applied sonodynamic therapy to cancer cells based on the delivery of titanium dioxide (TiO2) nanoparticles (NPs) modified with avidin protein, which preferentially discriminated cancerous cells from healthy cells. Subsequently, hydroxyl radicals were generated from the TiO2 NPs after activation by external ultrasound irradiation (TiO2/US treatment). Although 30% of the normal breast cells (human mammary epithelial cells) exhibited the uptake of avidin-modified TiO2 NPs, over 80% of the breast cancer cells (MCF-7) exhibited the uptake of avidin-TiO2 NPs. Next the effect of the TiO2/US treatment on MCF-7 cell growth was examined for up to 96 h after 1-MHz ultrasound was applied (0.1 W/cm(2), 30 s) to cells that incorporated the TiO2 NPs. No apparent cell injury was observed until 24h after the treatment, but the viable cell concentration declined to 68% compared with the control at 96 h. Copyright © 2014 Elsevier B.V. All rights reserved.

Effect of Atmospheric Plasma Treatment to Titanium Surface on Initial Osteoblast-Like Cell Spreading. .

PubMed

Kim, In-Hye; Son, Jun-Sik; Kwon, Tae-Yub; Kim, Kyo-Han

2015-01-01

Plasma treatments are becoming a popular method for modifying the characteristics of a range of substrate surfaces. Atmospheric pressure plasma is cost-efficient, safe and simple compared to high-pressure plasma. This study examined the effects of atmospheric pressure plasma to a titanium (Ti) surface on osteoblast-like cell (osteoblast) spreading and cellular networks. The characteristics of the Ti surface before and after the atmospheric plasma treatment were analyzed by X-ray photoemission spectroscopy (XPS), scanning electron microscopy (SEM), contact angle measurements, and an optical 3D profiling system. The morphology of osteoblasts attached to the Ti surfaces was observed by SEM and confocal laser scanning microscopy. The atmospheric pressure plasma made the Ti surfaces more hydrophilic. The osteoblasts that adhered to the untreated surface were round and spherical, whereas the cells covered a larger surface area on the plasma-treated surface. The plasma-treated Ti surface showed enhanced cell spreading and migration with more developed cellular networks. In conclusion, an atmospheric plasma treatment is a potential surface modifying method that can enhance the initial the cell affinity at the early stages in vitro.

Inclusion of Ti and Zr species on clay surfaces and their effect on the interaction with organic molecules

NASA Astrophysics Data System (ADS)

Rangel-Rivera, Pedro; Bachiller-Baeza, María Belén; Galindo-Esquivel, Ignacio; Rangel-Porras, Gustavo

2018-07-01

The interactions between the clay surface and the organic molecules play an important role in the efficient of these materials in adsorption and catalytic processes. These materials are often modified with the inclusion of other catalytic particles for the purpose of enhancing the activity. In this study, commercial clay K10 was modified with the particles inclusion of titanium and zirconium. The solid surfaces were examined by infrared spectroscopy, scanning electron microscopy (SEM) coupled to an energy-dispersive X-ray spectroscopy device (EDS), and X-ray photoelectron spectroscopy (XPS). Temperature programmed desorption of ammonia (TPD-NH3) and propan-2-ol decomposition test reaction were performed to probe the acid properties. The adsorption of acetic acid, ethanol, and propan-2-ol on the surface of each solid and their thermal stability were studied by diffuse reflectance infrared Fourier transform spectroscopy (DRIFT). Finally, these materials were used in the esterification of acetic acid with penta-1-ol. The real effect over the incorporation of titanium species and zirconium species on clay surface for interacting with the organic molecules was discussed.

Construction of a multifunctional coating consisting of phospholipids and endothelial progenitor cell-specific peptides on titanium substrates

NASA Astrophysics Data System (ADS)

Chen, Huiqing; Li, Xiaojing; Zhao, Yuancong; Li, Jingan; Chen, Jiang; Yang, Ping; Maitz, Manfred F.; Huang, Nan

2015-08-01

A phospholipid/peptide polymer (PMMDP) with phosphorylcholine groups, endothelial progenitor cell (EPC)-specific peptides and catechol groups was anchored onto a titanium (Ti) surface to fabricate a biomimetic multifunctional surface. The PMMDP coating was characterized by X-ray photoelectron spectroscopy (XPS), water contact angle measurements and atomic force microscopy (AFM), respectively. The amount of PMMDP coating on the Ti surface was quantified by using the quartz crystal microbalance with dissipation (QCM-D). Interactions between blood components and the coated and bare Ti substrates were evaluated by platelet adhesion and activation assays and fibrinogen denaturation test using platelet rich plasma (PRP). The results revealed that the PMMDP-modified surface inhibited fibrinogen denaturation and reduced platelet adhesion and activation. EPC cell culture on the PMMDP-modified surface showed increased adhesion and proliferation of EPCs when compared to the cells cultured on untreated Ti surface. The inhibition of fibrinogen denaturation and platelet adhesion and support of EPCs attachment and proliferation indicated that this coating might be beneficial for future applications in blood-contacting implants, such as vascular stents.

Titanium Implant Osseointegration Problems with Alternate Solutions Using Epoxy/Carbon-Fiber-Reinforced Composite

PubMed Central

Petersen, Richard C.

2014-01-01

The aim of the article is to present recent developments in material research with bisphenyl-polymer/carbon-fiber-reinforced composite that have produced highly influential results toward improving upon current titanium bone implant clinical osseointegration success. Titanium is now the standard intra-oral tooth root/bone implant material with biocompatible interface relationships that confer potential osseointegration. Titanium produces a TiO2 oxide surface layer reactively that can provide chemical bonding through various electron interactions as a possible explanation for biocompatibility. Nevertheless, titanium alloy implants produce corrosion particles and fail by mechanisms generally related to surface interaction on bone to promote an inflammation with fibrous aseptic loosening or infection that can require implant removal. Further, lowered oxygen concentrations from poor vasculature at a foreign metal surface interface promote a build-up of host-cell-related electrons as free radicals and proton acid that can encourage infection and inflammation to greatly influence implant failure. To provide improved osseointegration many different coating processes and alternate polymer matrix composite (PMC) solutions have been considered that supply new designing potential to possibly overcome problems with titanium bone implants. Now for important consideration, PMCs have decisive biofunctional fabrication possibilities while maintaining mechanical properties from addition of high-strengthening varied fiber-reinforcement and complex fillers/additives to include hydroxyapatite or antimicrobial incorporation through thermoset polymers that cure at low temperatures. Topics/issues reviewed in this manuscript include titanium corrosion, implant infection, coatings and the new epoxy/carbon-fiber implant results discussing osseointegration with biocompatibility related to nonpolar molecular attractions with secondary bonding, carbon fiber in vivo properties, electrical semiconductors, stress transfer, additives with low thermal PMC processing and new coating possibilities. PMID:25635227

Titanium nitride thin films for minimizing multipactoring

DOEpatents

Welch, Kimo M.

1979-01-01

Applying a thin film coating to the surface of a workpiece, in particular, applying a coating of titanium nitride to a klystron window by means of a crossed-field diode sputtering array. The array is comprised of a cohesive group of numerous small hollow electrically conducting cylinders and is mounted so that the open ends of the cylinders on one side of the group are adjacent a titanium cathode plate. The workpiece is mounted so as to face the open ends of the other side of the group. A magnetic field is applied to the array so as to be coaxial with the cylinders and a potential is applied across the cylinders and the cathode plate, the cylinders as an anode being positive with respect to the cathode plate. The cylinders, the cathode plate and the workpiece are situated in an atmosphere of nitrogen which becomes ionized such as by field emission because of the electric field between the cylinders and cathode plate, thereby establishing an anode-cathode discharge that results in sputtering of the titanium plate. The sputtered titanium coats the workpiece and chemically combines with the nitrogen to form a titanium nitride coating on the workpiece. Gas pressure, gas mixtures, cathode material composition, voltages applied to the cathode and anode, the magnetic field, cathode, anode and workpiece spacing, and the aspect ratio (ratio of length to inner diameter) of the anode cylinders, all may be controlled to provide consistent optimum thin film coatings of various compositions and thicknesses. Another facet of the disclosure is the coating of microwave components per se with titanium nitride to reduce multipactoring under operating conditions of the components.

High-intensity low energy titanium ion implantation into zirconium alloy

NASA Astrophysics Data System (ADS)

Ryabchikov, A. I.; Kashkarov, E. B.; Pushilina, N. S.; Syrtanov, M. S.; Shevelev, A. E.; Korneva, O. S.; Sutygina, A. N.; Lider, A. M.

2018-05-01

This research describes the possibility of ultra-high dose deep titanium ion implantation for surface modification of zirconium alloy Zr-1Nb. The developed method based on repetitively pulsed high intensity low energy titanium ion implantation was used to modify the surface layer. The DC vacuum arc source was used to produce metal plasma. Plasma immersion titanium ions extraction and their ballistic focusing in equipotential space of biased electrode were used to produce high intensity titanium ion beam with the amplitude of 0.5 A at the ion current density 120 and 170 mA/cm2. The solar eclipse effect was used to prevent vacuum arc titanium macroparticles from appearing in the implantation area of Zr sample. Titanium low energy (mean ion energy E = 3 keV) ions were implanted into zirconium alloy with the dose in the range of (5.4-9.56) × 1020 ion/cm2. The effect of ion current density, implantation dose on the phase composition, microstructure and distribution of elements was studied by X-ray diffraction, scanning electron microscopy and glow-discharge optical emission spectroscopy, respectively. The results show the appearance of Zr-Ti intermetallic phases of different stoichiometry after Ti implantation. The intermetallic phases are transformed from both Zr0.7Ti0.3 and Zr0.5Ti0.5 to single Zr0.6Ti0.4 phase with the increase in the implantation dose. The changes in phase composition are attributed to Ti dissolution in zirconium lattice accompanied by the lattice distortions and appearance of macrostrains in intermetallic phases. The depth of Ti penetration into the bulk of Zr increases from 6 to 13 μm with the implantation dose. The hardness and wear resistance of the Ti-implanted zirconium alloy were increased by 1.5 and 1.4 times, respectively. The higher current density (170 mA/cm2) leads to the increase in the grain size and surface roughness negatively affecting the tribological properties of the alloy.

40 CFR 415.224 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 30 2012-07-01 2012-07-01 false [Reserved] 415.224 Section 415.224 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production Subcategory § 415.224...

40 CFR 415.224 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 30 2013-07-01 2012-07-01 true [Reserved] 415.224 Section 415.224 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production Subcategory § 415.224...

40 CFR 415.224 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 29 2011-07-01 2009-07-01 true [Reserved] 415.224 Section 415.224 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production Subcategory § 415.224...

40 CFR 415.224 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 28 2010-07-01 2010-07-01 true [Reserved] 415.224 Section 415.224 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production Subcategory § 415.224...

40 CFR 415.224 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 29 2014-07-01 2012-07-01 true [Reserved] 415.224 Section 415.224 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS INORGANIC CHEMICALS MANUFACTURING POINT SOURCE CATEGORY Titanium Dioxide Production Subcategory § 415.224...

LASER APPLICATIONS AND OTHER TOPICS IN QUANTUM ELECTRONICS: Study of photoinduced absorption by the method of modified laser photothermal radiometry

NASA Astrophysics Data System (ADS)

Skvortsov, L. A.; Maksimov, E. M.; Tuchkov, A. A.

2008-10-01

The application of the method of modified laser photothermal radiometry for studying the photoinduced absorption in thin films is considered. The sensitivity of the method is estimated. The mechanism of induced near-IR absorption in titanium dioxide films is proposed and the nature of surface defects responsible for this process is explained. It is shown that kinetic equations describing monomolecular recombination are consistent with the experimental dependences for the thermal activation energy of defects equal to 0.17±0.04 eV.

Ti4+ to Ti3+ conversion of TiO2 uppermost layer by low-temperature vacuum annealing: interest for titanium biomedical applications.

PubMed

Guillemot, F; Porté, M C; Labrugère, C; Baquey, Ch

2002-11-01

Because of the Ti(3+) defects responsibility for dissociative adsorption of water onto TiO(2) surfaces and due to the hydroxyls influence on the biological behavior of titanium, controlling the Ti(3+) surface defects density by means of low-temperature vacuum annealing is proposed to improve the bone/implant interactions. Experiments have been carried out on Ti-6Al-4V alloys exhibiting a porous surface generated primarily by chemical treatment. XPS investigations have shown that low-temperature vacuum annealing can create a controlled number of Ti(3+) defects (up to 21% Ti(3+)/Ti(4+) at 573 K). High Ti(3+) defect concentration is linked to surface porosity. Such surfaces, exhibiting high hydrophilicity and microporosity, would confer to titanium biomaterials a great ability to interact with surrounding proteins and cells and hence would favor the bone anchorage of as-treated implants.

The photoelectrocatalytic activity, long term stability and corrosion performance of NiMo deposited titanium oxide nano-tubes for hydrogen production in alkaline medium

NASA Astrophysics Data System (ADS)

Mert, Mehmet Erman; Mert, Başak Doğru; Kardaş, Gülfeza; Yazıcı, Birgül

2017-11-01

In this study, titanium oxide nano-tubes are doped with Ni and Mo particles with various chemical compositions, in order to put forth the efficiency of single and binary coatings on hydrogen evolution reaction (HER) in 1 M KOH. The characterization was achieved by cyclic voltammetry, scanning electron microscopy and energy dispersive X-ray analysis. The water wettability characteristics of electrode surfaces were investigated using contact angle. The long-term catalyst stability and corrosion performance were determined by current-potential curves and electrochemical impedance spectroscopy. Furthermore, photoelectrochemical behavior was determined via linear sweep voltammetry. Results showed that, nano-structured Ni and Mo deposited titanium oxide nano-tubes decrease the hydrogen over potential and increase HER efficiency, it is stable over 168 h electrolysis and it exhibits higher corrosion performance.

Spectroscopic studies on some fluorescent mixed-ligand titanium(IV) complexes.

PubMed

Baranwal, Balram Prasad; Singh, Alok Kumar; Varma, Anand

2011-12-15

A novel route to synthesize some titanium(IV) complexes containing acetylacetone, straight chain carboxylic acid and hydroxycarboxylic acid ligands has been investigated. Complexes with the general formula [Ti(acac)Cl(2-n)(OOCR*)(n)(OOCC(15)H(31))] (where Hacac=acetylacetone, R*COOH=hydroxycarboxylic acids and n=1 or 2) have been isolated and characterized. Molecular weight determinations indicated mononuclear nature of the complexes. LMCT bands were observed in the electronic spectra. Infrared spectra suggested bidentate nature of the ligands. Fluorescent behaviour of the complexes was noticed on the basis of fluorescence spectra. Powder XRD indicated them to be semi-crystalline having the crystallite size in 136-185 nm range. Transmission electron microscopy (TEM) indicated spherical particles of ~ 200 nm diameter. On the basis of physico-chemical studies, it is suggested that titanium is having coordination number 7 or 8 in these complexes. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of high power ultrasonic vibration on the cold compaction of titanium.

PubMed

Fartashvand, Vahid; Abdullah, Amir; Ali Sadough Vanini, Seyed

2017-05-01

Titanium has widely been used in chemical and aerospace industries. In order to overcome the drawbacks of cold compaction of titanium, the process was assisted by an ultrasonic vibration system. For this purpose, a uniaxial ultrasonic assisted cold powder compaction system was designed and fabricated. The process variables were powder size, compaction pressure and initial powder compact thickness. Density, friction force, ejection force and spring back of the fabricated samples were measured and studied. The density was observed to improve under the action of ultrasonic vibration. Fine size powders showed better results of consolidation while using ultrasonic vibration. Under the ultrasonic action, it is thought that the friction forces between the die walls and the particles and those friction forces among the powder particles are reduced. Spring back and ejection force didn't considerably change when using ultrasonic vibration. Copyright © 2016 Elsevier B.V. All rights reserved.

Thickness Influence on In Vitro Biocompatibility of Titanium Nitride Thin Films Synthesized by Pulsed Laser Deposition

PubMed Central

Duta, Liviu; Stan, George E.; Popa, Adrian C.; Husanu, Marius A.; Moga, Sorin; Socol, Marcela; Zgura, Irina; Miculescu, Florin; Urzica, Iuliana; Popescu, Andrei C.; Mihailescu, Ion N.

2016-01-01

We report a study on the biocompatibility vs. thickness in the case of titanium nitride (TiN) films synthesized on 410 medical grade stainless steel substrates by pulsed laser deposition. The films were grown in a nitrogen atmosphere, and their in vitro cytotoxicity was assessed according to ISO 10993-5 [1]. Extensive physical-chemical analyses have been carried out on the deposited structures with various thicknesses in order to explain the differences in biological behavior: profilometry, scanning electron microscopy, atomic force microscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction and surface energy measurements. XPS revealed the presence of titanium oxynitride beside TiN in amounts that vary with the film thickness. The cytocompatibility of films seems to be influenced by their TiN surface content. The thinner films seem to be more suitable for medical applications, due to the combined high values of bonding strength and superior cytocompatibility. PMID:28787846

Synthesis of nano-titanium dioxide by sol-gel route

NASA Astrophysics Data System (ADS)

Kaler, Vandana; Duchaniya, R. K.; Pandel, U.

2016-04-01

Nanosized titanium dioxide powder was synthesised via sol-gel route by hydrolysis of titanium tetraisopropoxide with ethanol and water mixture in high acidic medium. The synthesized nanopowder was further characterized by X-ray Diffraction, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, and Ultraviolet Visible Spectroscopy in order to determine size, morphology and crystalline structure of the material. The synthesis of nano-TiO2 powder in anatase phase was realized by XRD. The optical studies of nano-TiO2 powder was carried out by UV-Vis spectroscopy and band gap was calculated as 3.5eV, The SEM results with EDAX confirmed that prepared nano-TiO2 particles were in nanometer range with irregular morphology. The FTIR analysis showed that only desired functional groups were present in sample. These nano-TiO2 particles have applications in solar cells, chemical sensors and paints, which are thrust areas these days.

Application of gas-fluid atomization technology in ultrosonic vibration cutting titanium alloy workpiece

NASA Astrophysics Data System (ADS)

Zhou, Zhimin; Zhang, Yuangliang; Li, Xiaoyan; Sun, Baoyuan

2009-11-01

To further improve machined surface quality of diamond cutting titanium workpiece and reduce diamond tool wear, it puts forward a kind of machining technology with mixture of carbon dioxide gas, water and vegetable oil atomized mist as cooling media in the paper. The cooling media is sprayed to cutting area through gas-liquid atomizer device to achieve purpose of cooling, lubricating, and protecting diamond tool. Experiments indicate that carbon dioxide gas can touch cutting surface more adequately through using gas-liquid atomization technology, which makes iron atoms of cutting surface cause a chemical reaction directly with carbon in carbon dioxide gas and reduce graphitizing degree of diamond tool. Thus, this technology of using gas-liquid atomization and ultrasonic vibration together for cutting Titanium Alloy is able to improve machined surface quality of workpiece and slow of diamond tool wear.