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Sample records for 2-cm thick titanium

  1. An X-ray monitor for measurement of a titanium tritide target thickness.

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Steinberg, R.

    1972-01-01

    An X-ray device capable of measuring titanium tritide film thickness from 0.1 to 30 microns has been built and tested. The monitor was designed for use in a rotating target system which used thick targets and incorporated a sputtering electrode to remove depleted layers from the target surface. The thickness measurement can be done in the presence of an intense background of bremsstrahlung and characteristic titanium X-radiation. A measurement can be accomplished in situ in two hours with reasonable accuracy.

  2. An X-ray monitor for measurement of a titanium tritide target thickness

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Steinberg, R.

    1972-01-01

    An X-ray device capable of measuring titanium tritide film thickness from 0.1 to 30 micrometers has been built and tested. The monitor was designed for use in a rotating target system which used thick targets and incorporated a sputtering electrode to remove depleted layers from the target surface. The thickness measurement can be done in the presence of an intense background of bremsstrahlung and characteristic titanium X-radiation. A measurement can be accomplished in situ in two hours with reasonable accuracy.

  3. Phased Arrays Techniques and Split Spectrum Processing for Inspection of Thick Titanium Casting Components

    NASA Astrophysics Data System (ADS)

    Banchet, J.; Sicard, R.; Zellouf, D. E.; Chahbaz, A.

    2003-03-01

    In aircraft structures, titanium parts and engine members are critical structural components, and their inspection crucial. However, these structures are very difficult to inspect ultrasonically because of their large grain structure that increases noise drastically. In this work, phased array inspection setups were developed to detected small defects such as simulated inclusions and porosity contained in thick titanium casting blocks, which are frequently used in the aerospace industry. A Cut Spectrum Processing (CSP)-based algorithm was then implemented on the acquired data by employing a set of parallel bandpass filters with different center frequencies. This process led in substantial improvement of the signal to noise ratio and thus, of detectability.

  4. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    PubMed Central

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-01-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices. PMID:26899567

  5. Nano-thick calcium oxide armed titanium: boosts bone cells against methicillin-resistant Staphylococcus aureus

    NASA Astrophysics Data System (ADS)

    Cao, Huiliang; Qin, Hui; Zhao, Yaochao; Jin, Guodong; Lu, Tao; Meng, Fanhao; Zhang, Xianlong; Liu, Xuanyong

    2016-02-01

    Since the use of systemic antibiotics for preventing acute biomaterial-associated infections (BAIs) may build up bacterial resistance and result in huge medical costs and unpredictable mortality, new precaution strategies are required. Here, it demonstrated that titanium armed with a nano-thick calcium oxide layer was effective on averting methicillin-resistant Staphylococcus aureus (MRSA) infections in rabbits. The calcium oxide layer was constructed by, firstly, injecting of metallic calcium into titanium via a plasma immersion ion implantation process, and then transforming the outer most surface into oxide by exposing to the atmosphere. Although the calcium oxide armed titanium had a relative low reduction rate (~74%) in growth of MRSA in vitro, it could markedly promote the osteogenic differentiation of bone marrow stem cells (BMSCs), restore local bone integration against the challenge of MRSA, and decrease the incidence of MRSA infection with a rate of 100% (compared to the titanium control). This study demonstrated for the first time that calcium, as one of the major elements in a human body, could be engineered to avert MRSA infections, which is promising as a safe precaution of disinfection for implantable biomedical devices.

  6. Determination of thicknesses of oxide films grown on titanium under argon irradiation by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    Do, Ngoc-Long; Garcia-Caurel, Enric; Bérerd, Nicolas; Moncoffre, Nathalie; Gorse-Pomonti, Dominique

    2014-04-01

    In this article we present a study of the oxidation of pure titanium bulk samples under argon ion irradiation at 500 °C under rarefied air. In particular we follow the dependence of the oxide thickness as a function of the energy of argon ions. The novelty of this study consists in the range of ion energy explored, from 1 to 9 MeV. Until very recently it was commonly accepted that metal surfaces were transparent to ion beams in this low energy range (few MeV), and no surface modifications were expected. In a previous paper by the authors of this work, the formation of shallow craters in the surface of titanium was reported as a result of argon ion bombardment with energies of 2, 4 and 9 MeV under the same environmental conditions. We show here that around 3 MeV the oxide growth is unexpectedly enhanced. We think that an interplay of electronic excitations and nuclear ballistic collisions could possibly explain this enhanced oxide growth. We have used spectroscopic visible ultraviolet ellipsometry and XPS to determine the thickness of the oxide layers and characterize their optical properties. From the optical properties of the oxides we observed that for ion energies below 3-4 MeV the oxides show a dielectric-like behavior, whereas for ion energies above 3-4 MeV the oxides show a metal-like behavior. These findings indicate also that ion bombardment in this energy range may change substantially the oxygen-to-titanium ratio in the oxide films grown under irradiation leading to the formation of titanium sub-oxides.

  7. CaTiO(3) coating on titanium for biomaterial application--optimum thickness and tissue response.

    PubMed

    Ohtsu, Naofumi; Sato, Kenji; Yanagawa, Aya; Saito, Kesami; Imai, Yoshio; Kohgo, Takao; Yokoyama, Atsuro; Asami, Katsuhiko; Hanawa, Takao

    2007-08-01

    The objectives of this study were to determine the optimum thickness of a CaTiO(3) film for biomaterial applications and to investigate the biocompatibility and bone formation of titanium with a CaTiO(3) film. First, CaTiO(3) films of 10, 20, 30, and 50 nm in thickness were deposited on titanium substrates using radiofrequency magnetron sputtering followed by annealing at 873 K in air for 7.2 ks. The optimum thickness of the CaTiO(3) film for bone formation was determined by comparison with its performance regarding calcium phosphate formation in Hanks' balanced saline solution (HBSS). Regarding calcium phosphate formation, the performance of the specimen with a 50-nm-thick CaTiO(3) film was superior to those of specimens with other thicknesses. A titanium prism with a CaTiO(3) film of 50-nm in thickness was surgically inserted in both soft and hard rat tissues. The biocompatibility of CaTiO(3)-deposited titanium and bone formation on it was investigated by histological observations. A slight inflammatory reaction was observed around the titanium with the 50-nm-thick CaTiO(3) film, while no severe response, such as degeneration and necrosis, was observed in either soft or hard rat tissue. New bone formation on the titanium plate with the CaTiO(3) film was more active than that without the film. The 50-nm-thick CaTiO(3) film has biocompatibility and can facilitate new bone formation in vivo, and, consequently, it is an excellent surface modification method for biomaterial applications. PMID:17279562

  8. Effect of oxide coated thickness on thermal ignition of titanium-based pyrotechnics

    SciTech Connect

    Erickson, K.L.

    1984-01-01

    The effect which variations in oxide coating thickness can have on thermal ignition of titanium-based pyrotechnics was examined theoretically. The analyses were developed using previously published experimental studies of ignition mechanisms. Those studies indicated that ignition is controlled by the rate at which an already existing oxide coating dissolves in the bulk metal. The specific case of hot-wire ignition at near minimum energy was considered. It was assumed that oxide dissolution occurs by molecular diffusion, and an approximate ignition model was developed to examine the relative variations in ignition times which result from variations in oxide coating thickness. The model consists of a heat conduction equation for the wire and pyrotechnic and a Fick's-law diffusion equation, with Arrhenius-type diffusion coefficient, for the oxygen in the titanium particles. Calculations showed that the ratio of ignition times t/sub i/sub 2///t/sub i/sub 1// could be estimated from t/sub i/sub 2///t/sub i/sub 1// approx. = (h/sub 2//h/sub 1/)/sup y/, where y = 2/(1 + Q/6 kcal mole/sup -1/); h/sub 2//h/sub 1/ is the respective ratio of oxide coating thicknesses, and Q is the oxygen-diffusion activation energy. Literature values for Q vary from 16 to 75 kcal/mole, while the exponent y varies from 0.6 to 0.2, respectively. At lower activation energies, moderate variations in oxide coating thickness could cause significant variations in ignition time.

  9. Titanium

    SciTech Connect

    Fox, G.J.

    1997-01-01

    The article contains a summary of factors pertinent to titanium use. Geology and exploitation, production processes, global production, titanium dioxide and alloy applications, and the titanium market are reviewed. Potential applications outlined are for oil and gas equipment and for the automotive industry. Titanium alloys were selected for drilling risers for North Sea oil and gas drilling platforms due to a high strength-to-weight ratio and corrosion resistance. These properties also make titanium alloys attractive for auto parts, although the cost is currently prohibitive.

  10. Titanium

    USGS Publications Warehouse

    Bedinger, G.M.

    2013-01-01

    Titanium is the ninth most abundant element in the earth’s crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  11. The influence of nickel layer thickness on microhardness and hydrogen sorption rate of commercially pure titanium alloy

    NASA Astrophysics Data System (ADS)

    Kudiiarov, V. N.; Kashkarov, E. B.; Syrtanov, M. S.; Yugova, I. S.

    2016-02-01

    The influence of nickel coating thickness on microhardness and hydrogen sorption rate by commercially pure titanium alloy was established in this work. Coating deposition was carried out by magnetron sputtering method with prior ion cleaning of surface. It was shown that increase of sputtering time from 10 to 50 minutes leads to increase coating thickness from 56 to 3.78 μm. It was established that increase of nickel coating thickness leads to increase of microhardness at loads less than 0.5 kg. Microhardness values for all samples are not significantly different at loads 1 kg. Hydrogen content in titanium alloy with nickel layer deposited at 10 and 20 minutes exceeds concentration in initial samples on one order of magnitude. Further increasing of deposition time of nickel coating leads to decreasing of hydrogen concentration in samples due to coating delamination in process of hydrogenation.

  12. Effect of titanium oxide nanoparticle incorporation into nm thick coatings deposited using an atmospheric pressure plasma.

    PubMed

    Denis, Dowling P; Barry, Twomey; Gerry, Byrne

    2010-04-01

    This study reports on the use of an atmospheric plasma technique to incorporate metal oxide nanoparticles into nm thick siloxane coatings. Titanium dioxide (TiO2) particles with diameters of 30-80 nm, were mixed with a number of different siloxanes-polydimethylsiloxane, hexamethyldisiloxane and tetraethylorthosilicate (TEOS). The TiO2/TEOS mixture was found to give the most stable suspension, possibly due to the higher surface tension of TEOS compared with the other siloxanes. TiO2/TEOS mixtures with 2 to 10% by weight of the metal oxide were prepared and were then nebulised into a helium/oxygen atmospheric plasma. Polyethylene terepthalate (PET) and silicon wafer substrates were passed through this plasma using a reel-to-reel substrate manipulation system. SEM combined with EDX was used to examine the distribution of the metal oxide particles in the resultant coatings. The TEOS coating thickness without TiO2 addition was 9 nm. The composite coating consisted of a relatively homogeneous distribution of small agglomerates of the TiO2 nanoparticles in TEOS. A linear increase in the titanium surface concentration was observed with increase in the quantity of TiO2 added into the siloxane precursor. The chemical functionality of the siloxane coating was examined using FTIR spectroscopy and no significant spectrum differences was observed with the incorporation of the different concentrations of TiO2 into the polymer. There were also no changes observed in coating surface energy with TiO2 incorporation. Coating morphology was examined using optical profilometry and surface roughness (Ra) values increased from typical values of 0.8 nm for the TEOS coating to 4.1 nm for the TiO2/TEOS coating. The adhesion of the deposited coatings was compared using fragmentation tests. These were carried out through uniaxial tensile loading. The coating cracking pattern after applied strain of 20% was not observed to change significantly with the addition of TiO2 into the siloxane. PMID

  13. Effect of Thickness on the Structure, Composition and Properties of Titanium Nitride Nano-Coatings

    SciTech Connect

    Martinez, Gustavo; Shutthanandan, V.; Thevuthasan, Suntharampillai; Chessa, J. F.; Ramana, C.V.

    2014-05-05

    Titanium nitride (TiNx) coatings were grown by magnetron sputtering onto Si(1 0 0) substrates by varying time of deposition to produce coatings with variable thickness (dTiN) in the range of 20-120 nm. TiNx coatings were characterized by studying their structure, composition, and mechanical properties. Nuclear reaction analysis (NRA) combined with Rutherford backscattering spectrometry (RBS) analyses indicate that the grown coatings were stoichiometric TiN. Grazing incidence X-ray diffraction (GIXRD) measurements indicate that the texturing of TiN coatings changes as a function of dTiN. The (1 1 1) and (0 0 2) peaks appear initially; (1 1 1) becomes intense while (0 0 2) disappears with increasing dTiN. Dense, columnar grain structure was evident for all the coatings in electron microscopy analyses. The residual stress for TiN coatings with dTiN~120 nm was 1.07 GPa in compression while thinner samples exhibit higher values of stress.

  14. An investigation into the optimum thickness of titanium dioxide thin films synthesized by using atmospheric pressure chemical vapour deposition for use in photocatalytic water oxidation.

    PubMed

    Hyett, Geoffrey; Darr, Jawwad A; Mills, Andrew; Parkin, Ivan P

    2010-09-10

    Twenty eight films of titanium dioxide of varying thickness were synthesised by using atmospheric pressure chemical vapour deposition (CVD) of titanium(IV) chloride and ethyl acetate onto glass and titanium substrates. Fixed reaction conditions at a substrate temperature of 660 °C were used for all depositions, with varying deposition times of 5-60 seconds used to control the thickness of the samples. A sacrificial electron acceptor system composed of alkaline sodium persulfate was used to determine the rate at which these films could photo-oxidise water in the presence of 365 nm light. The results of this work showed that the optimum thickness for CVD films on titanium substrates for the purposes of water oxidation was ≈200 nm, and that a platinum coating on the reverse of such samples leads to a five-fold increase in the observed rate of water oxidation. PMID:20645333

  15. Electron beam welding of titanium and Ti-6AL-4V Thick plates

    NASA Astrophysics Data System (ADS)

    Kohyama, Akira; Arata, Yoshiaki; Tomie, Michio; Igata, Naohiro

    1984-05-01

    This paper reports work as thick weld process development for Ti and Ti alloys in fusion reactor applications. The materials used are pure Ti and Ti-6A1-4V with a maximum plate thickness of 56 mm I-butt welded by a 100KW electron beam welding facility at Osaka University. Optimum welding conditions produced sound welded I-butt joints without detectable defects by X-ray when evaluated with tensile test and micro-Vickers hardness test. The microstructures of the welded joints were investigated with TEM and SEM. These results showed that welded joints were quite sound and were possibly acceptable as structural components of fusion reactor even in as welded state.

  16. Dependence of Sheet Resistance of CoSi2 with Gate Length of 30 nm on Thickness of Titanium Nitride Capping Layer in Co-Salicide Process

    NASA Astrophysics Data System (ADS)

    Kawamura, Kazuo; Inagaki, Satoshi; Saiki, Takashi; Nakamura, Ryo; Kataoka, Yuji; Kase, Masataka

    2007-11-01

    Since the distribution of gate resistance using cobalt silicide (CoSi2) increases markedly for gate lengths of 30 nm or less, CoSi2 is now being replaced by NiSi. However, CoSi2 still has the advantages of a high thermal stability and a low degree of roughness at the interface between the silicide and silicon layers owing to the low degree of mismatch (1.2%) of between their lattice constants. We have achieved excellent sheet resistance (Rs) with a gate length Lg=30 nm by optimizing the thickness of a cobalt capping layer of titanium nitride. The results shows an abnormal Rs behavior, in which one σ of Rs increases with capping layer thickness in the range of 10-50 nm, while it decreases with increasing capping layer thickness in the range of 0-10 nm. Unlike the results of a previous report [K. Goto et al.: IEDM Tech. Dig., 1995, p. 449], the variation in the Rs with a gate length Lg=30 nm is small, even without a TiN capping layer thickness down to 5-10 nm. We suggest that the uniformity of Rs is determined by the thickness of the CoSi layer after selective etching and the titanium concentration in the CoSi layer for capping TiN thicknesses of 10-50 nm, while the uniformity is determined by the titanium concentration and the damage sustained during selective etching for TiN thickness of 0-10 nm. For this optimization, CoSi2 is applicable to the 65 nm node technology node or beyond.

  17. Remote quantitative temperature and thickness measurements of plasma-deposited titanium nitride thin coatings on steel using a laser interferometric thermoreflectance optical thermometer

    SciTech Connect

    Liu Yue; Mandelis, Andreas; Choy, Mervyn; Wang, Chinhua; Segal, Lee

    2005-08-15

    An optical thermometer based on the principle of laser thermoreflectance has been introduced to monitor the surface temperature of thin coatings on steel parts undergoing an industrial titanium nitride (TiN) alloy deposition process. To study the feasibility of the optical thermometer, various thermo-optical parameters of TiN affected by the deposition process have been investigated; namely, the reflectance-temperature relation, the thermoreflectance coefficient, and the coating thickness dependence of thermoreflectance and of total reflectance. A theory of interferometric thermoreflectance has been introduced to model the total reflectance variations during the coating process. An inverse reflectance-temperature relation for the TiN-D2 steel substrate system has been found and a first-order Taylor series expansion used to model thermoreflectance has been shown to yield a thermoreflectance coefficient which is independent of temperature. Both results are in quantitative agreement with the Drude-Zener theory of conductors and semi-conductors. An empirical formula has been derived to effectively model the experimental thermoreflectance coefficient dependence of the TiN-D2 steel system on TiN coating thickness, in qualitative agreement with scattering mechanisms of the Boltzmann transport theory in conductors and semiconductors. The good agreement of theoretical interferometric thermoreflectance simulations with in situ measurements during a specific industrial TiN sputter-coating growth process and the independence of the thermoreflectance and thin-coating-thickness reflectance coefficients from temperature show the potential of using this nonintrusive noncontacting technique as an optical thermometer to determine surface temperatures of physically inaccessible samples undergoing industrial coating deposition processes.

  18. Photoluminescence of dense nanocrystalline titanium dioxide thin films: effect of doping and thickness and relation to gas sensing.

    PubMed

    Mercado, Candy; Seeley, Zachary; Bandyopadhyay, Amit; Bose, Susmita; McHale, Jeanne L

    2011-07-01

    The photoluminescence (PL) of dense nanocrystalline (anatase) TiO(2) thin films is reported as a function of calcination temperature, thickness, and tungsten and nickel doping. The dependence of the optical absorption, Raman spectra, and PL spectra on heat treatment and dopants reveals the role of oxygen vacancies, crystallinity, and phase transformation in the performance of TiO(2) films used as gas sensors. The broad visible PL from defect states of compact and undoped TiO(2) films is found to be much brighter and less sensitive to the presence of oxygen than that of mesoporous films. The dense nanocrystalline grains and the nanoparticles comprising the mesoporous film are comparable in size, demonstrating the importance of film morphology and carrier transport in determining the intensity of defect photoluminescence. At higher calcination temperatures, the transformation to rutile results in the appearance of a dominant near-infrared peak. This characteristic change in the shape of the PL spectra demonstrates efficient capture of conduction band electrons by the emerging rutile phase. The W-doped samples show diminished PL with quenching on the red side of the emission spectrum occurring at lower concentration and eventual disappearance of the PL at higher W concentration. The results are discussed within the context of the performance of the TiO(2) thin films as CO gas sensors and the chemical nature of luminescent defects. PMID:21702459

  19. Detection of Thermal 2 cm and 1 cm Formaldehyde Emission in NGC 7538

    NASA Astrophysics Data System (ADS)

    Yuan, Liang; Araya, E. D.; Hofner, P.; Kurtz, S.; Pihlstrom, Y.

    2011-05-01

    Formaldehyde is a tracer of high density gas in massive star forming regions. The K-doublet lines from the three lowest rotational energy levels of ortho-formaldehyde correspond to wavelengths of 6, 2 and 1 cm. Thermal emission of these transitions is rare, and maser emission has only been detected in the 6 cm line. NGC 7538 is an active site of massive star formation in the Galaxy, and one of only a few regions known to harbor 6 cm formaldehyde (H2CO) masers. Using the NRAO 100 m Green Bank Telescope (GBT), we detected 2 cm H2CO emission toward NGC 7538 IRS1. The velocity of the 2 cm H2CO line is very similar to the velocity of one of the 6 cm H2CO masers but the linewidth is greater. To investigate the nature of the 2 cm emission, we conducted observations of the 1 cm H2CO transition, and obtained a cross-scan map of the 2 cm line. We detected 1 cm emission and found that the 2 cm emission is extended (greater than 30"), which implies brightness temperatures of ˜0.2 K. Assuming optically thin emission, LTE, and that the 1 cm and 2 cm lines originate from the same volume of gas, both these detections are consistent with thermal emission of gas at ˜30 K. We conclude that the 1 cm and 2 cm H2CO lines detected with the GBT are thermal, which implies molecular densities above ˜105 cm-3. LY acknowledges support from WIU. PH acknowledges partial support from NSF grant AST-0908901.

  20. Examination of Organic Carryover from 2-cm Contactors to Support the Modular CSSX Unit

    SciTech Connect

    Nash, Charles A.; Norato, Michael A.; Walker; D. Douglas; Pierce, Robert A.; Eubanks, Ronnye A.; Clark, James D.; Smith, Wilson M. Jr.; Crump, Stephen L.; Nelson, D. Zane; Fink, Samuel D.; Peters, Thomas B.; May, Cecil G.; Herman, David T.; Bolton, Henry L.

    2005-04-29

    A bank of four 2-cm centrifugal contactors was operated in countercurrent fashion to help address questions about organic carryover for the Modular Caustic Side Solvent Extraction (CSSX) Unit (MCU). The contactors, having weirs sized for strip operation, were used to examine carryover for both strip effluent (SE) and decontaminated salt solution (DSS). Since only one bank of contactors was available in the short time frame of this work, the organic phase and only one aqueous phase were present in the flow loops at a time. Personnel maintained flowsheet-typical organic phase to aqueous phase (O:A) flow ratios when varying flow rates. Solvent from two different batches were tested with strip solution. In addition, potential mitigations of pH adjustment and coalescing media were examined. The experiment found that organic carryover after decanting averaged 220 ppm by mass with a range of 74 to 417 ppm of Isopar{reg_sign} L for strip effluent (SE)/organic solvent contacts. These values are based on measured modifier. Values were bounded by a value of 95 ppm based upon Isopar{reg_sign} L values as reported. The higher modifier-based numbers are considered more reliable at this time. Carryover of Isopar{reg_sign} L in DSS simulant averaged 77 ppm by mass with a range of 70 to 88 ppm of Isopar{reg_sign} L based on modifier content. The carryover was bounded by a value of 19 ppm based upon Isopar{reg_sign} L values as reported. More work is needed to resolve the discrepancy between modifier and Isopar{reg_sign} L values. The work did not detect organic droplets greater than 18 microns in SE. Strip output contained droplets down to 0.5 micron in size. Droplets in DSS were almost monodisperse by comparison, having a size range 4.7 +/- 1.6 micron in one test and 5.2 +/- 0.8 micron in the second demonstration. Optical microscopy provided qualitative results confirming the integrity of droplet size measurements in this work. Acidic or basic adjustments of aqueous strip solution

  1. A search for periodic structure in solar 2 cm microwave radiation. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Sentman, D. D.

    1973-01-01

    A power spectral analysis of 285 hr of 2 cm microwave intensity data showed no statistically significant ( 96% confidence) periodicities in the frequency range 1 to 15 mHz. No correlation was found between 2 cm periodicities and solar activity in H alpha, X-ray, and several microwave frequencies. A small shift of power toward higher frequencies in the power spectrum of the 2 cm data was found to be correlated with solar H alpha and X-ray activity. Using the statistical properties of power spectra, an expression for the ratio of the minimum detectable peak-to-peak to ambient temperature at chromospheric heights may be derived. Applied to a model for oscillation bursts in quiescent supergranules, and using the most significant results of experiments to detect the microwave periodicities, this expression yields an upper limit of approximately .0015.

  2. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, II, George T.; Hansen, Jeffrey S.; Oden, Laurance L.; Turner, Paul C.; Ochs, Thomas L.

    1998-01-01

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  3. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, G.T. II; Hansen, J.S.; Oden, L.L.; Turner, P.C.; Ochs, T.L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body followed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet. 3 figs.

  4. Method of making multilayered titanium ceramic composites

    DOEpatents

    Fisher, George T., II; Hansen; Jeffrey S.; Oden; Laurance L.; Turner; Paul C.; Ochs; Thomas L.

    1998-08-25

    A method making a titanium ceramic composite involves forming a hot pressed powder body having a microstructure comprising at least one titanium metal or alloy layer and at least one ceramic particulate reinforced titanium metal or alloy layer and hot forging the hot pressed body follwed by hot rolling to substantially reduce a thickness dimension and substantially increase a lateral dimension thereof to form a composite plate or sheet that retains in the microstructure at least one titanium based layer and at least one ceramic reinforced titanium based layer in the thickness direction of the composite plate or sheet.

  5. Titanium/gold process characterization

    SciTech Connect

    Fajardo, L.S.

    1991-11-01

    Characterization of the titanium/gold (Ti/Au) deposition process used at the Allied-Signal Inc., Albuquerque Microelectronics Operation (AMO) was performed. Tests were conducted to set up evaporation parameters, correlate titanium and gold thicknesses to sheet resistance, improve thickness uniformity, and reduce frontside contamination of deposit material on product wafers. The Ti/Au process is the final step in the production of integrated circuits (ICs) at the AMO wafer fabrication facility. 3 figs.

  6. Single-Polarisation, Single-Frequency, 2 cm Ytterbium-Doped Fibre Laser

    SciTech Connect

    Guan, W.; Marciante, J.R.

    2007-05-23

    A single-polarisation, single-frequency, ytterbium-doped silica fibre laser has been demonstrated in a 2 cm linear cavity. The output power reaches 35 mW with an optical signal-to-noise ratio greater than 65 dB. A polarisation-maintaining fibre Bragg grating is used as the polarisation-dependent reflector to generate the single-polarisation output with the polarisation extinction ratio greater than 20 dB. The laser works stably for two hours under laboratory conditions.

  7. Titan's surface properties inferred from the seasonal brightness variation at 2-cm wavelength

    NASA Astrophysics Data System (ADS)

    Janssen, M.; Le Gall, A.; Lopes, R.; Lorenz, R.; Malaska, M.; Neish, C.; Solomonidou, A.

    2015-10-01

    A comprehensive calibration and mapping of the thermal microwave emission from Titan's surface at 2.2-cm wavelength has been completed by the passive radiometer included in the Cassini RADAR instrument. A seasonal brightness temperature variation has been determined that is comparable to but slightly smaller than that obtained by Cassini's Composite Infrared Spectrometer (CIRS). This difference has implications for the composition and structure of Titan's surface; namely, that most of Titan's surface is covered by the deposition and possible redistribution of tholin-like atmospheric photochemical products to a depth of at least a meter.

  8. Lightweight Protective Coatings For Titanium Alloys

    NASA Technical Reports Server (NTRS)

    Wiedemann, Karl E.; Taylor, Patrick J.; Clark, Ronald K.

    1992-01-01

    Lightweight coating developed to protect titanium and titanium aluminide alloys and titanium-matrix composite materials from attack by environment when used at high temperatures. Applied by sol-gel methods, and thickness less than 5 micrometers. Reaction-barrier and self-healing diffusion-barrier layers combine to protect titanium alloy against chemical attack by oxygen and nitrogen at high temperatures with very promising results. Can be extended to protection of other environmentally sensitive materials.

  9. Thick target D-T neutron yield measurements using metal occluders of scandium, titanium, yttrium, zirconium, gadolinium, erbium, hafnium, and tantalum at energies from 25 to 200 keV

    SciTech Connect

    Malbrough, D.J.; Molloy, J.T. Jr.; Becker, R.H.

    1990-11-19

    Deuterium-Tritium (D-T) neutron yields from thick films of scandium, titanium, yttrium, zirconium, gadolinium, erbium, hafnium, and tantalum were measured by the associated particle technique using the 200-keV accelerator at the Pinellas Plant. The neutron yields were measured for all targets at energies from 25 to 200 keV in 5-keV steps with an average uncertainty of {plus_minus}6.8%. Tabulated results are presented with yield versus energy curves for each target. Yield curves for D-D neutrons from earlier measurements are also presented with the D-T neutron yield curves. Good fits to the data were found for both D-D and D-T with theoretical calculations that were adjusted by smooth functions of the form: A{sub 0} + A{sub 1}E + A{sub 2}E{sup 2}. The results of the fits strongly suggest that disagreement between measurement and theory is due mainly to inaccuracies in currently available stopping power data. Comparisons with earlier theoretical calculations for titanium and erbium are also presented. 27 refs., 10 figs., 4 tabs.

  10. Improved effectiveness and safety of flexible ureteroscopy for renal calculi (<2 cm): A retrospective study

    PubMed Central

    Chen, Shuqiu; Xu, Bin; Liu, Ning; Jiang, Hua; Zhang, Xiaowen; Yang, Yu; Liu, Jing; Sha, Guozhu; Zhu, Weidong; Chen, Ming

    2015-01-01

    Introduction: We discuss the efficacy and safety of flexible ureteroscopy for renal calculi with a burden of <2 cm, as well as the prevention and treatment of complications. Methods: A total of 108 renal calculi with flexible ureteroscopy and holmium laser treatment were retrospectively analyzed. The stone-free rate was evaluated. The effectiveness, safety, surgical technique, incidence of complications, and relevant treatments were analyzed. Results: All patients underwent only one lithotripsy procedure. The success rate of flexible ureteroscopy was 97.2% (105/108). Among the 105 cases, the total lithotripsy success rate was 97.1% (101/105). The total stone-free rate after 8 weeks post-operation was 94.3% (99/105), the stone-free rate of the lower calyx was 85.7% (30/35); it was 98.6% (69/70) in the middle–upper calyceal and renal pelvis. The incidence of complications was 12.9% (14/108). None of the patients had serious adverse outcomes. Conclusion: Flexible ureteroscopy represents an optimal treatment option for selected renal calculi with burden of <2 cm. The effectiveness and safety of flexible ureteroscopy can be further improved through reasonable preoperative evaluation and advances in surgical techniques, as well as a better understanding of the inducement and treatment of complications. PMID:26029294

  11. Analysis of Saturn's Thermal Emission at 2.2-cm Wavelength: Spatial Distribution of Ammonia Vapor

    NASA Technical Reports Server (NTRS)

    Laraia, A. L.; Ingersoll, A. P.; Janssen, Michael A.; Gulkis, Samuel; Oyafuso, Fabiano A.; Allison, Michael D.

    2013-01-01

    This work focuses on determining the latitudinal structure of ammonia vapor in Saturn's cloud layer near 1.5 bars using the brightness temperature maps derived from the Cassini RADAR (Elachi et al., 2004) instrument, which works in a passive mode to measure thermal emission from Saturn at 2.2-cm wavelength. We perform an analysis of five brightness temperature maps that span epochs from 2005 to 2011, which are presented in a companion paper by Janssen et al. (2013a, this issue). The brightness temperature maps are representative of the spatial distribution of ammonia vapor, since ammonia gas is the only effective opacity source in Saturn's atmosphere at 2.2-cm wavelength. Relatively high brightness temperatures indicate relatively low ammonia relative humidity (RH), and vice versa. We compare the observed brightness temperatures to brightness temperatures computed using the Juno atmospheric microwave radiative transfer (JAMRT) program which includes both the means to calculate a tropospheric atmosphere model for Saturn and the means to carry out radiative transfer calculations at microwave frequencies. The reference atmosphere to which we compare has a 3x solar deep mixing ratio of ammonia (we use 1.352x10(exp -4) for the solar mixing ratio of ammonia vapor relative to H2; see Atreya, 2010) and is fully saturated above its cloud base. The maps are comprised of residual brightness temperatures-observed brightness temperature minus the model brightness temperature of the saturated atmosphere.

  12. Saturns Thermal Emission at 2.2-cm Wavelength as Imaged by the Cassini RADAR Radiometer

    NASA Technical Reports Server (NTRS)

    Janssen, M. A.; Ingersoll, A. P.; Allison, M. D.; Gulkis, S.; Laraia, A. L.; Baines, K. H.; Edgington, S. G.; Anderson, Y. Z.; Kelleher, K.; Oyafuso, F. A.

    2013-01-01

    We present well-calibrated, high-resolution maps of Saturn's thermal emission at 2.2-cm wavelength obtained by the Cassini RADAR radiometer through the Prime and Equinox Cassini missions, a period covering approximately 6 years. The absolute brightness temperature calibration of 2% achieved is more than twice better than for all previous microwave observations reported for Saturn, and the spatial resolution and sensitivity achieved each represent nearly an order of magnitude improvement. The brightness temperature of Saturn in the microwave region depends on the distribution of ammonia, which our radiative transfer modeling shows is the only significant source of absorption in Saturn's atmosphere at 2.2-cm wavelength. At this wavelength the thermal emission comes from just below and within the ammonia cloud-forming region, and yields information about atmospheric circulations and ammonia cloud-forming processes. The maps are presented as residuals compared to a fully saturated model atmosphere in hydrostatic equilibrium. Bright regions in these maps are readily interpreted as due to depletion of ammonia vapor in, and, for very bright regions, below the ammonia saturation region. Features seen include the following: a narrow equatorial band near full saturation surrounded by bands out to about 10deg planetographic latitude that demonstrate highly variable ammonia depletion in longitude; narrow bands of depletion at -35deg latitude; occasional large oval features with depleted ammonia around -45deg latitude; and the 2010-2011 storm, with extensive saturated and depleted areas as it stretched halfway around the planet in the northern hemisphere. Comparison of the maps over time indicates a high degree of stability outside a few latitudes that contain active regions.

  13. Intrarenal Surgery vs Percutaneous Nephrolithotomy in the Management of Lower Pole Stones Greater than 2 cm

    PubMed Central

    Koyuncu, Hakan; Yencilek, Faruk; Kalkan, Mehmet; Bastug, Yavuz; Yencilek, Esin; Ozdemir, Ahmet Tunc

    2015-01-01

    Purpose To compare the efficacy of RIRS and PNL in lower pole stones ≥2 cm. Materials and and Methods: A total of 109 patients who underwent PNL or RIRS for solitary lower pole stone between April 2009 and December 2012, were retrospectively analyzed. Lower pole stone was diagnosed with CT scan. Stone size was assessed as the longest axis of the stone. All patients were informed about the advantages, disadvantages and probable complications of both PNL and RIRS before the selection of the procedure. Patients decided the surgery type by themselves without being under any influences and written informed consent was obtained from all patients prior to the surgery. Patients were divided into two groups according to the patients’ preference of surgery type. Group 1 consisted of 77 patients who underwent PNL and Group 2 consisted of 32 patients treated with RIRS. Stone free statuses, postoperative complications, operative time and hospitalization time were compared in both groups. Results There was no statistical significance between the two groups in mean age, stone size, stone laterality, mean follow-up periods and mean operative times. In PNL group, stone-free rate was 96.1% at first session and 100% after the additional procedure. In Group 2, stone-free rate was 90.6% at the first procedure and 100% after the additional procedure. The final stone-free rates and operative times were similar in both groups. Conclusions RIRS should be an effective treatment alternative to PNL in lower pole stones larger than 2 cm, especially in selected patients. PMID:26005965

  14. Design considerations and initial performance of a 1.2 cm{sup 2} beta imaging intra-operative probe

    SciTech Connect

    Tornai, M.P.; MacDonald, L.R.; Levin, C.S.; Siegel, S.; Hoffman, E.J.

    1996-08-01

    A novel small area beta ({beta}{sup {+-}}) detector is under development for nuclear emission imaging of surgically exposed, radiolabeled tumor beds. The imaging device front-end consists of a 0.5 mm thick by 1.25 cm diameter CaF{sub 2}(Eu) scintillator disk coupled to a rapid bundle of 2 mm diameter double clad optical fibers through a polystyrene light diffuser. The detector area (1.2 cm{sup 2}) was determined by the requirement of introducing the probe into small cavities, e.g. during neuro-surgical lesion resection, but large enough to produce images of clinical significance. Flexible back-end optical fibers (1.9 m long) were coupled to the front-end components allowing {approximately} 75 photoelectrons to e detected for mean beta energies of 250 keV, indicating that sufficient signal can be obtained with clinical beta emitters (e.g. {sup 18}F, {sup 131}I). The long flexible fibers guide the scintillation light to a Philips XP1700 series, fiber optical faceplate, Multi-Channel PMT. The parallel MC-PMT outputs re fed into a variable gain, charge divider network and an i-V pre-amplifier/line driver network, whose resulting four outputs are digitized and histogrammed with standard Anger positioning logic. The various components in the imaging chain were evaluated and optimized by both simulations and measurements. Line spread functions measured in the 10.8 mm FOV were 0.50 mm {+-} 0.038 mm and 0.55 mm {+-} 0.065 mm FWHM in X and Y, respectively. A 20% variation in pulse height and minimal variation in spatial resolution was observed. The differential image uniformity was measured to be {+-}15.6% with {approximately} 150 cts/pixel. Preliminary images show excellent reproduction of phantom activity distributions.

  15. Titanium 2013

    USGS Publications Warehouse

    2014-01-01

    Titanium is the ninth most abundant element in the earth's crust and can be found in nearly all rocks and sediments. It is a lithophile element with a strong affinity for oxygen and is not found as a pure metal in nature. Titanium was first isolated as a pure metal in 1910, but it was not until 1948 that the metal was produced commercially using the Kroll process (named after its developer, William Kroll) to reduce titanium tetrachloride with magnesium to produce titanium metal.

  16. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, R.; Glatzmaier, G.C.

    1995-05-23

    A process is disclosed for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  17. Process for synthesizing titanium carbide, titanium nitride and titanium carbonitride

    DOEpatents

    Koc, Rasit; Glatzmaier, Gregory C.

    1995-01-01

    A process for synthesizing titanium carbide, titanium nitride or titanium carbonitride. The process comprises placing particles of titanium, a titanium salt or titanium dioxide within a vessel and providing a carbon-containing atmosphere within the vessel. The vessel is heated to a pyrolysis temperature sufficient to pyrolyze the carbon to thereby coat the particles with a carbon coating. Thereafter, the carbon-coated particles are heated in an inert atmosphere to produce titanium carbide, or in a nitrogen atmosphere to produce titanium nitride or titanium carbonitride, with the heating being of a temperature and time sufficient to produce a substantially complete solid solution.

  18. Thermal Stir Welds in Titanium

    NASA Astrophysics Data System (ADS)

    Fonda, Richard W.; Knipling, Keith E.; Pilchak, Adam L.

    2016-01-01

    Although conventional friction stir welding (FSW) has proven unsuccessful in joining thick sections of alpha and near-alpha titanium alloys, thermal stir welding, a variant of the FSW process in which an external heat source is used to preheat the workpiece, is demonstrated to be able to reliably join 12.3-mm-thick plates of CP titanium. This paper describes the microstructures and textures that develop in these thermal stir welds. The observed microstructure was used to reconstruct the high-temperature microstructure and texture present during the welding process and therefore reveal the genesis of the welding structures.

  19. Method for the production of strongly adhesive films on titanium and titanium alloys with a metallization process

    NASA Technical Reports Server (NTRS)

    Hahn, H. J.

    1986-01-01

    A process for the spray-application of a strongly adhesive, thick antifriction layer on titanium and titanium alloys is proposed. The titanium/titanium alloy component to be coated is first subjected to cleaning in a pickling bath with reducing additives and sand-blasting, then coated with an intermediate layer of nickel, after which the final layer is applied. The formation of TiNi at the interface ensures strong bonding of the antifriction layer.

  20. Cell response of anodized nanotubes on titanium and titanium alloys.

    PubMed

    Minagar, Sepideh; Wang, James; Berndt, Christopher C; Ivanova, Elena P; Wen, Cuie

    2013-09-01

    Titanium and titanium alloy implants that have been demonstrated to be more biocompatible than other metallic implant materials, such as Co-Cr alloys and stainless steels, must also be accepted by bone cells, bonding with and growing on them to prevent loosening. Highly ordered nanoporous arrays of titanium dioxide that form on titanium surface by anodic oxidation are receiving increasing research interest due to their effectiveness in promoting osseointegration. The response of bone cells to implant materials depends on the topography, physicochemistry, mechanics, and electronics of the implant surface and this influences cell behavior, such as adhesion, proliferation, shape, migration, survival, and differentiation; for example the existing anions on the surface of a titanium implant make it negative and this affects the interaction with negative fibronectin (FN). Although optimal nanosize of reproducible titania nanotubes has not been reported due to different protocols used in studies, cell response was more sensitive to titania nanotubes with nanometer diameter and interspace. By annealing, amorphous TiO2 nanotubes change to a crystalline form and become more hydrophilic, resulting in an encouraging effect on cell behavior. The crystalline size and thickness of the bone-like apatite that forms on the titania nanotubes after implantation are also affected by the diameter and shape. This review describes how changes in nanotube morphologies, such as the tube diameter, the thickness of the nanotube layer, and the crystalline structure, influence the response of cells. PMID:23436766

  1. [Clinicopathological study of small lung cancer (diameter of 2 cm or less) by uptake value of 18F-fluorodeoxyglucose].

    PubMed

    Nakano, Tomoyuki; Endo, Shunsuke; Mitsuda, Sayaka; Endo, Tetsuya; Tezuka, Yasuhiro; Kanai, Yoshihiko; Otani, Shin-ichi; Yamamoto, Shin-ichi; Tetsuka, Kenji; Hasegawa, Tsuyoshi; Ishikawa, Shigemi; Saito, Noriko

    2012-01-01

    18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) for lung cancer may be a biomarker for malignancy as well as a useful tool for detection of nodal involvement and distant metastasis. The goal of this study was to clarify a relationship between clinicopathological findings and maximum standardized uptake value( SUVmax) obtained by preoperative PET in patients with non-small cell lung cancer in diameter of 2 cm or less. Between January 2008 and April 2011, 124 patients( 54 men and 70 women) with non-small cell lung cancer in diameter of 2 cm or less undergoing lobectomy or segmentectomy were enrolled. The relationship between SUVmax and clinicopathological findings as tumor diameter, histological type, pleural invasion, vascular invasion, lymphatic permeation and nodal involvement were analyzed. Correlation between SUVmax and findings such as vascular invasion and lymphatic permeation showed relatively strong in the patients with adenocarcinoma, on the contrary to the correlation in the patients with non-adenocarcinoma. No tumor showing SUVmax of 2 or less showed vascular invasion and/or lymphatic permeation as well as nodal involvement in any patients with adenocarcinoma. SUVmax of the primary tumor in diameter of 2 cm or less, can be a useful biomarker which indicates a surgical candidate for sublobar pulmonary resection as well as mediastinal nodal dissection, especially in patients with adenocarcinoma. PMID:22314152

  2. A Prospective, Multi-Institutional Study of Flexible Ureteroscopy for Proximal Ureteral Stones Smaller than 2 cm

    PubMed Central

    Hyams, Elias S.; Monga, Manoj; Pearle, Margaret S.; Antonelli, Jodi A.; Semins, Michelle J.; Assimos, Dean G.; Lingeman, James E.; Pais, Vernon M.; Preminger, Glenn M.; Lipkin, Michael E.; Eisner, Brian H.; Shah, Ojas; Sur, Roger L; Mufarrij, Patrick W.; Matlagak, Brian R.

    2015-01-01

    Purpose Flexible ureteroscopy is rapidly becoming a first line therapy for many patients with renal and ureteral stones. However, current understanding of treatment outcomes in patients with isolated proximal ureteral stones is limited. Therefore, we performed a prospective, multi-institutional study of ureteroscopic management of proximal ureteral stones smaller than 2 cm to better define clinical outcomes associated with this approach. Materials and Methods Adult patients with proximal ureteral calculi smaller than 2 cm were prospectively identified. Patients with concomitant ipsilateral renal calculi or prior ureteral stenting were excluded from study. Flexible ureteroscopy, holmium laser lithotripsy and ureteral stent placement was performed. Ureteral access sheath use, laser settings and other details of perioperative and postoperative management were based on individual surgeon preference. Stone clearance was determined by the results of renal ultrasound and plain x-ray of the kidneys, ureters and bladder 4 to 6 weeks postoperatively. Results Of 71 patients 44 (62%) were male and 27 (38%) were female. Mean age was 48.2 years. ASA® score was 1 in 12 cases (16%), 2 in 41 (58%), 3 in 16 (23%) and 4 in 2 (3%). Mean body mass index was 31.8 kg/m2, mean stone size was 7.4 mm (range 5 to 15) and mean operative time was 60.3 minutes (range 15 to 148). Intraoperative complications occurred in 2 patients (2.8%), including mild ureteral trauma. Postoperative complications developed in 6 patients (8.7%), including urinary tract infection in 3, urinary retention in 2 and flash pulmonary edema in 1. The stone-free rate was 95% and for stones smaller than 1 cm it was 100%. Conclusions Flexible ureteroscopy is associated with excellent clinical outcomes and acceptable morbidity when applied to patients with proximal ureteral stones smaller than 2 cm. PMID:25014576

  3. Preparation of titanium diboride powder

    DOEpatents

    Brynestad, Jorulf; Bamberger, Carlos E.

    1985-01-01

    Finely-divided titanium diboride or zirconium diboride powders are formed by reacting gaseous boron trichloride with a material selected from the group consisting of titanium powder, zirconium powder, titanium dichloride powder, titanium trichloride powder, and gaseous titanium trichloride.

  4. Comparison of flexible ureterorenoscopy and mini-percutaneous nephrolithotomy in treatment of lower calyceal stones smaller than 2 cm.

    PubMed

    Akbulut, Fatih; Kucuktopcu, Onur; Kandemir, Emre; Sonmezay, Erkan; Simsek, Abdulmuttalip; Ozgor, Faruk; Binbay, Murat; Muslumanoglu, Ahmet Yaser; Gurbuz, Gokhan

    2016-01-01

    To compare the outcomes of flexible ureterorenoscopy (F-URS) and mini-percutaneous nephrolithotomy (mini-PNL) in the treatment of lower calyceal stones smaller than 2 cm. Patients who underwent F-URS and mini-PNL for the treatment of lower calyceal stones smaller than 2 cm between March 2009 and December 2014 were retrospectively evaluated. Ninety-four patients were divided into two groups by treatment modality: F-URS (Group 1: 63 patients) and mini-PNL (Group 2: 31 patients). All patients were preoperatively diagnosed with intravenous pyelography or computed tomography. Success rates for F-URS and mini-PNL at postoperative first month were 85.7% and 90.3%, respectively. Operation time, fluoroscopy time, and hospitalization time for F-URS and mini-PNL patients were 44.40 min, 2.9 min, 22.4 h, and 91.9 min, 6.4 min, and 63.8 h, respectively. All three parameters were significantly shorter among the F-URS group (p < 0.001). Postoperative hemoglobin drop was significantly lower in F-URS group compared to mini-PNL group (0.39 mg/dL vs. 1.15 mg/dL, p = 0.001). A comparison of complications according to the Clavien classification demonstrated significant differences between the groups (p = 0.001). More patients in the F-URS groups require antibiotics due to urinary tract infection, and more patients in the mini-PNL group required ureteral double J catheter insertion under general anesthesia. Although both F-URS and mini-PNL have similar success rates for the treatment of lower calyceal stones, F-URS appears to be more favorable due to shorter fluoroscopy and hospitalization times; and lower hemoglobin drops. Multicenter and studies using higher patient volumes are needed to confirm these findings. PMID:26727075

  5. Predictive factors for flexible ureterorenoscopy requirement after rigid ureterorenoscopy in cases with renal pelvic stones sized 1 to 2 cm

    PubMed Central

    Gülpinar, Ömer; Özcan, Cihat; Göğüş, Çağatay; Kerimov, Seymur; Şafak, Mut

    2015-01-01

    Purpose To evaluate the outcomes of rigid ureterorenoscopy (URS) for renal pelvic stones (RPS) sized 1 to 2 cm and to determine the predictive factors for the requirement for flexible URS (F-URS) when rigid URS fails. Materials and Methods A total of 88 patients were included into the study. In 48 patients, the RPS were totally fragmented with rigid URS and F-URS was not required (group 1). In 40 patients, rigid URS was not able to access the renal pelvis or fragmentation of the stones was not completed owing to stone position or displacement and F-URS was utilized for retrograde intrarenal surgery (RIRS) (group 2). The predictive factors for F-URS requirement during RIRS for RPS were evaluated. Both groups were compared regarding age, height, sex, body mass index, stone size, stone opacity, hydronephrosis, and previous treatments. Results The mean patient age was 48.6±16.5 years and the mean follow-period was 39±11.5 weeks. The overall stone-free rate in the study population was 85% (75 patients). In groups 1 and 2, the overall stone-free rates were 83% (40 patients) and 87% (35 patients), respectively (p>0.05). The independent predictors of requirement for F-URS during RIRS were male gender, patient height, and higher degree of hydronephrosis. Conclusions Rigid URS can be utilized in selected patients for the fragmentation of RPS sized 1 to 2 cm with outcomes similar to that of F-URS. In case of failure of rigid URS, F-URS can be performed successfully in this group of patients. PMID:25685301

  6. Titan's surface at 2.2-cm wavelength imaged by the Cassini RADAR radiometer: Calibration and first results

    USGS Publications Warehouse

    Janssen, M.A.; Lorenz, R.D.; West, R.; Paganelli, F.; Lopes, R.M.; Kirk, R.L.; Elachi, C.; Wall, S.D.; Johnson, W.T.K.; Anderson, Y.; Boehmer, R.A.; Callahan, P.; Gim, Y.; Hamilton, G.A.; Kelleher, K.D.; Roth, L.; Stiles, B.; Le, Gall A.

    2009-01-01

    The first comprehensive calibration and mapping of the thermal microwave emission from Titan's surface is reported based on radiometric data obtained at 2.2-cm wavelength by the passive radiometer included in the Cassini Radar instrument. The data reported were accumulated from 69 separate observational segments in Titan passes from Ta (October 2004) through T30 (May 2007) and include emission from 94% of Titan's surface. They are diverse in the key observing parameters of emission angle, polarization, and spatial resolution, and their reduction into calibrated global mosaic maps involved several steps. Analysis of the polarimetry obtained at low to moderate resolution (50+ km) enabled integration of the radiometry into a single mosaic of the equivalent brightness temperature at normal incidence with a relative precision of about 1 K. The Huygens probe measurement of Titan's surface temperature and radiometry obtained on Titan's dune fields allowed us to infer an absolute calibration estimated to be accurate to a level approaching 1 K. The results provide evidence for a surface that is complex and varied on large scales. The radiometry primarily constrains physical properties of the surface, where we see strong evidence for subsurface (volume) scattering as a dominant mechanism that determines the emissivity, with the possibility of a fluffy or graded-density surface layer in many regions. The results are consistent with, but not necessarily definitive of a surface composition resulting from the slow deposition and processing of organic compounds from the atmosphere. ?? 2008 Elsevier Inc.

  7. Titan's Surface at 2.2-Cm Wavelength: Results and Interpretations through the First Ten Years of Observation By Cassini

    NASA Astrophysics Data System (ADS)

    Janssen, M. A.; Le Gall, A. A.; Hayes, A. G., Jr.; Lopes, R. M. C.; Malaska, M. J.

    2014-12-01

    A comprehensive calibration and mapping of the thermal microwave emission from Titan's surface will be presented, based on radiometric data obtained at 2.2-cm wavelength by the passive radiometer in the Cassini Radar instrument through the nearly ten years following Saturn Orbit Insertion. The data reported were accumulated from Titan passes Ta (October 2004) through T98 (February 2014) and now incorporate emission from all of Titan's surface. The mapping will eventually include data at both low and high spatial resolution, while for the present we concentrate on only the low-resolution data that provide thermal polarization. These data are sufficient to examine not only surface effective dielectric constant but seasonal and diurnal surface temperature variations, which we compare with current CIRS results. The map of effective dielectric constant allows us to explore possible regional variations in surface properties and composition. Finally, these data allow us to understand the nature and magnitude of systematic errors in the map-making process, essential to interpreting both the present maps and the forthcoming high-resolution maps based on these. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration.

  8. Opportunities in the electrowinning of molten titanium from titanium dioxide

    NASA Astrophysics Data System (ADS)

    van Vuuren, D. S.; Engelbrecht, A. D.; Hadley, T. D.

    2005-10-01

    The value chain of titanium products shows that the difference between the cost of titanium ingot and titanium dioxide is about 9/kg titanium. In contrast, the price of aluminum, which is produced in a similar way, is only about 1.7/kg. Electrowinning of molten titanium from titanium dioxide is therefore believed to have significant potential to reduce the cost of titanium products. The process is hampered by the high operating temperatures and sophisticated materials of construction required; the high affinity of titanium for carbon, oxygen, and nitrogen; and physical and chemical properties of the different titanium oxide species when reducing titanium from Ti4+ to metallic titanium.

  9. How useful are the "other" semipermeable membrane devices (SPMDs); the mini-unit (15.2 cm long)?

    PubMed

    Goodbred, Steven L; Bryant, Wade L; Rosen, Michael R; Alvarez, David; Spencer, Terri

    2009-06-15

    Mini (15.2 cm) semipermeable membrane devices (SPMDs) were used successfully in 169 streams from six metropolitan areas of the US to sequester hydrophobic organic compounds (HOCs) that are indicative of urbanization. A microscale assay the P450RGS, which responds to compounds that bind to the aryl hydrocarbon receptor (AhR), and the Fluoroscan, a chemical screen for polycyclic aromatic hydrocarbons (PAHs), were performed on each mini SPMD extract. Results show both tests were sensitive enough to respond in streams with low urbanization and responded exponentially in a predictable way to a gradient of urbanization. Mini SPMDs had sufficient sampling rates to detect HOCs using gas chromatography with mass spectrometric detection (GC/MS) in streams with low levels of urbanization. The total number of HOCs in streams had a linear response to a gradient of urbanization, where 73 of 140 targeted compounds were detected. A diverse group of compounds was found in urban streams including, PAHs, insecticides, herbicides, musk fragrances, waste water treatment compounds and flame retardants. Pentachloroanisole (PCA), a breakdown product of pentachlorophenol (wood preservative), was the most ubiquitous HOC, and was detected in 71% of streams. An evaluation of mini SPMD performance showed they can detect concentrations in water below toxicity benchmarks for many HOCs with the exception of 2,3,7,8 tetrachlorodibenzo-p-dioxin. A comparison of mini SPMDs with full sized (91.4 cm) SPMDs showed they have several distinct advantages. The most notable advantages are their low cost, small size, and reduced chance of vandalism. The greatest limitation is the inability to detect compounds at low concentrations (pg/L). Mini SPMDs perform quite well in a wide array of environmental settings and applications and should be considered as an option in environmental studies. PMID:19328522

  10. Composition, seasonal change and bathymetry of Ligeia Mare, Titan, derived from its 2.2-cm thermal emission

    NASA Astrophysics Data System (ADS)

    Le Gall, A. A.; Malaska, M.; Lorenz, R. D.; Janssen, M. A.; Tokano, T.; Hayes, A.; Lunine, J. I.; Veyssière, G.; Mastrogiuseppe, M.; Karatekin, O.; Encrenaz, P.

    2015-12-01

    For the last 10 years, the Cassini RADAR has been exploring Saturn's moon Titan, the only planetary body besides Earth whose surface presently exhibits significant accumulations of liquids in the forms of lakes and seas. In particular, the passive Radiometer that is incorporated in this instrument has been recording the 2.2 cm-wavelength thermal emission from Titan's three seas. Radiometry observations provide new information beyond the active radar reflection data. In this paper, we analyze the radiometry observations collected from Feb. 2007 to July 2013 over one of these seas, Ligeia Mare, with the goal of providing constrains on its liquid composition, seafloor nature, bathymetry, and dynamics. In light of the two-layer model we have developed for this analysis, we find that the dielectric constant of the sea liquid is most likely smaller than 1.8, suggesting that the composition of Ligeia Mare is dominated by liquid methane rather than liquid ethane (although a ternary methane-ethane-nitrogen mixture cannot be ruled out). This result is further supported by the value we infer for the liquid loss tangent of 3-5×10-5. This value is in agreement with the one first published by Mastrogiuseppe et al. (2014) based on active radar observation. A high methane concentration suggests that Ligeia Mare is either a sea from which ethane has been removed by crustal interaction, or a sea primarely fed by methane-rich precipitation, or both. For the seafloor, a dielectric constant of 2.6-2.9±0.9 is determined. Though this result is not very constraining, we favor a scenario where the floor of Ligeia Mare is covered by a sludge of compacted and possibly nitrile-rich organic material formed by the deposition of photochemical haze or by rain-washing of the nearby shores. These results are then used to convert the radiometry mosaic of Ligeia Mare into a qualitative low-resolution bathymetry map. Lastly, we establish limits on the physical temperature variation of the sea

  11. Impact of Micropapillary Histologic Subtype in Selecting Limited Resection vs Lobectomy for Lung Adenocarcinoma of 2cm or Smaller

    PubMed Central

    2013-01-01

    Background We sought to analyze the prognostic significance of the new International Association for the Study of Lung Cancer (IASLC), American Thoracic Society (ATS), and European Respiratory Society (ERS) lung adenocarcinoma (ADC) classification for patients undergoing resection for small (≤2cm) lung ADC and to investigate whether histologic subtyping can predict recurrence after limited resection (LR) vs lobectomy (LO). Methods Comprehensive histologic subtyping was performed according to the IASLC/ATS/ERS classification on all consecutive patients who underwent LR or LO for small lung ADC between 1995 and 2009 at Memorial Sloan-Kettering Cancer Center. Clinical characteristics and pathologic data were retrospectively evaluated for 734 consecutive patients (LR: 258; LO: 476). Cumulative incidence of recurrence (CIR) was calculated using competing risks analysis and compared across groups using Grey’s test. All statistical tests were two-sided. Results Application of IASLC/ATS/ERS lung ADC histologic subtyping to predict recurrence demonstrates that, in the LR group but not in the LO group, micropapillary (MIP) component of 5% or greater was associated with an increased risk of recurrence, compared with MIP component of less than 5% (LR: 5-year CIR = 34.2%, 95% confidence interval [CI] = 23.5% to 49.7% vs 5-year CIR = 12.4%, 95% CI = 6.9% to 22.1%, P < .001; LO: 5-year CIR = 19.1%, 95% CI = 12.0% to 30.5% vs 15-year CIR = 12.9%, 95% CI = 7.6% to 21.9%, P = .13). In the LR group, among patients with tumors with an MIP component of 5% or greater, most recurrences (63.4%) were locoregional; MIP component of 5% or greater was statistically significantly associated with increased risk of local recurrence when the surgical margin was less than 1cm (5-year CIR = 32.0%, 95% CI = 18.6% to 46.0% for MIP ≥ 5% vs 5-year CIR = 7.6%, 95% CI = 2.3% to 15.6% for MIP < 5%; P = .007) but not when surgical margin was 1cm or greater (5-year CIR = 13.0%, 95% CI = 4.1% to 22

  12. Electroslag welding of titanium and its alloys

    SciTech Connect

    Malin, V.Y.

    1985-02-01

    The objective of this review is to examine the specific requirements of the electroslag welding process when applied to thick-wall components made from titanium or its various alloys. The review includes process variations, flux and equipment development requirements, specifics of the various techniques, wire and shielding gas supply problems, welding conditions, properties of the welds, quality control, and other topics.

  13. Producing Foils From Direct Cast Titanium Alloy Strip

    NASA Technical Reports Server (NTRS)

    Stuart, T. A.; Gaspar, T. A.; Sukonnik, I. M.; Semiatan, S. L.; Batawi, E.; Peters, J. A.; Fraser, H. L.

    1996-01-01

    This research was undertaken to demonstrate the feasibility of producing high-quality, thin-gage, titanium foil from direct cast titanium strip. Melt Overflow Rapid Solidification Technology (MORST) was used to cast several different titanium alloys into 500 microns thick strip, 10 cm wide and up to 3 m long. The strip was then either ground, hot pack rolled or cold rolled, as appropriate, into foil. Gamma titanium aluminide (TiAl) was cast and ground to approximately 100 microns thick foil and alpha-2 titanium aluminide (Ti3AI) was cast and hot pack rolled to approximately 70 microns thick foil. CP Ti, Ti6Al2Sn4Zr2Mo, and Ti22AI23Nb (Orthorhombic), were successfully cast and cold-rolled into good quality foil (less than 125 microns thick). The foils were generally fully dense with smooth surfaces, had fine, uniform microstructures, and demonstrated mechanical properties equivalent to conventionally produced titanium. By eliminating many manufacturing steps, this technology has the potential to produce thin gage, titanium foil with good engineering properties at significantly reduced cost relative to conventional ingot metallurgy processing.

  14. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-07-04

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  15. Titanium hermetic seals

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1995-01-01

    Titanium is prenitrided by being heated in a nitrogen environment under conditions which give rise to the formation of a titanium-nitride surface layer on the titanium. Titanium thus prenitrided may be used in electrical components which are hermetically sealed using silicate glasses and standard glass sealing techniques. According to the method of the invention, alkali volatilization and formation of deleterious interfacial silicide are inhibited.

  16. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; Watkins, R.D.

    1988-01-21

    Glass compositions containing CaO, Al/sub 2/O/sub 3/, B/sub 2/O/sub 3/, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  17. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; Watkins, Randall D.

    1992-01-01

    Glass compositions containing CaO, Al.sub.2 O.sub.3, B.sub.2 O.sub.3, SrO and BaO of various combinations of mole % are provided. These compositions are capable of forming stable glass-to-metal seals with titanium and titanium alloys, for use in components such as seals for battery headers.

  18. Osteogenic cell sheets reinforced with photofunctionalized micro-thin titanium.

    PubMed

    Ishijima, Manabu; Hirota, Makoto; Park, Wonhee; Honda, Masaki J; Tsukimura, Naoki; Isokawa, Keitaro; Ishigami, Tomohiko; Ogawa, Takahiro

    2015-05-01

    Cell sheet technology has been used to deliver cells in single-sheet form with an intact extracellular matrix for soft tissue repair and regeneration. Here, we hypothesized that titanium-reinforced cell sheets could be constructed for bone tissue engineering and regeneration. Fifty-µm-thick titanium plates containing apertures were prepared and roughened by acid etching, some of which were photofunctionalized with 12 min of UV light treatment. Cell sheets were prepared by culturing rat calvarial periosteum-derived cells on temperature-responsive culture dishes and attached to titanium plates. Titanium-reinforced osteogenic cell sheet construction was conditional on various technical and material factors: cell sheets needed to be double-sided and sandwich the titanium plate, and the titanium plates needed to be micro thin and contain apertures to allow close apposition of the two cell sheets. Critically, titanium plates needed to be UV-photofunctionalized to ensure adherence and retention of cell sheets. Single-sided cell sheets or double-sided cell sheets on as-made titanium contracted and deformed within 4 days of incubation. Titanium-reinforced cell sheets on photofunctionalized titanium were structurally stable at least up to 14 days, developed the expected osteogenic phenotypes (ALP production and mineralization), and maintained structural integrity without functional degradation. Successful construction of titanium-reinforced osteogenic cell sheets was associated with increased cell attachment, retention, and expression of vinculin, an adhesion protein by photofunctionalization. This study identified the technical and material requirements for constructing titanium-reinforced osteogenic cell sheets. Future in vivo studies are warranted to test these titanium-reinforced cell sheets as stably transplantable, mechanically durable, and shape controllable osteogenic devices. PMID:25604095

  19. Silicon nitride coating on titanium to enable titanium-ceramic bonding.

    PubMed

    Wang, R R; Welsch, G E; Monteiro, O

    1999-08-01

    Failures that occur in titanium-ceramic restorations are of concern to clinicians. The formation of poorly adhering oxide on titanium at dental porcelain sintering temperatures causes adherence problems between titanium and porcelain, which is the main limiting factor in the fabrication of titanium-ceramic restorations. To overcome this problem a 1-microm thick Si3N4 coating was applied to a titanium surface using a plasma-immersion implantation and deposition method. Such a coating serves as an oxygen diffusion barrier on titanium during the porcelain firings. The protective coating was characterized in the as-deposited condition and after thermal cycling. Cross sections of Ti/Si3N4-porcelain interface regions were examined by various electron microscopy methods and by energy dispersive analysis of X-rays to study the Si3N4 film's effectiveness in preventing titanium oxidation and in forming a bond with porcelain. The experiments have shown that this Si3N4 coating enables significant improvement in Ti-ceramic bonding. PMID:10380005

  20. Laser shock peening of titanium 6-4 alloy

    NASA Astrophysics Data System (ADS)

    Brar, N. S.; Hopkins, A.; Laber, M. W.

    2000-04-01

    Laser shock peening of titanium 6-4 has been shown to improve its high cycle fatigue life. Residual compressive stresses generated on the surface of titanium 6-4, as a result of laser shocking, have shown dramatic improvement in the performance of aircraft turbine blades. Laser shocking of titanium was carried out with a 20 ns pulse width, 50 joule pulsed laser, operated by LSP Technologies, Columbus, OH. Titanium disks, 20-mm in diameter, and ranging in thicknesses from zero (bare LiF) to 3-mm were subjected to laser shock to monitor amplitude and temporal stress profiles of the pulsed laser. Laser shock stress amplitudes on the back of titanium disks were monitored with VISAR using LiF as the window material. The peak shock stress produced in LiF (titanium thickness zero) was measured to be 16±1 GPa. The laser shock amplitude decays to about 2.7 GPa while propagating through 3-mm thick disk of titanium 6-4.

  1. Laser Shock Peening of Titanium 6-4 Alloy

    NASA Astrophysics Data System (ADS)

    Hopkins, Alan; Laber, Mark; Brar, Nachhatter S.

    1999-06-01

    shock 99 Laser shock peening of titanium 6-4 has been shown to improve its high cycle fatigue life. Residual compressive stresses generated on the surface of titanium 6-4, as a result of laser shocking, have shown dramatic improvement in the performance of aircraft turbine blades. Laser shocking of titanium was carried out with a 20 ns pulse width, 50 joule pulsed laser, operated by LSP Technologies, Columbus, OH. Disks of titanium, 0 to 3-mm thick and 20-mm in diameter, were subjected to the pulsed laser to monitor amplitude and temporal stress profiles of laser shock. Laser shock stress amplitudes on the back of titanium disks were monitored with VISAR using LiF as the window material. The peak shock stress produced in LiF (titanium thickness zero) was measured to be 16±1 GPa. The laser shock amplitude decays to about 2.6 GPa while propagating through 3-mm thick disk of titanium 6-4. *Supported by the U.S. Air Force Research Laboratory

  2. Thick Toenails

    MedlinePlus

    ... be seen in individuals with nail fungus (onychomycosis), psoriasis, and hypothyroidism. Those who have problems with the thickness of their toenails should consult a foot and ankle surgeon for proper diagnosis and treatment. and or or and or or, browse by ...

  3. Titanium oxidation by rf inductively coupled plasma

    NASA Astrophysics Data System (ADS)

    Valencia-Alvarado, R.; de la Piedad-Beneitez, A.; López-Callejas, R.; Barocio, S. R.; Mercado-Cabrera, A.; Peña-Eguiluz, R.; Muñoz-Castro, A. E.; Rodríguez-Méndez, B. G.; de la Rosa-Vázquez, J. M.

    2014-05-01

    The development of titanium dioxide (TiO2) films in the rutile and anatase phases is reported. The films have been obtained from an implantation/diffusion and sputtering process of commercially pure titanium targets, carried out in up to 500 W plasmas. The experimental outcome is of particular interest, in the case of anatase, for atmospheric pollution degradation by photocatalysis and, as to the rutile phase, for the production of biomaterials required by prosthesis and implants. The reactor employed consists in a cylindrical pyrex-like glass vessel inductively coupled to a 13.56 MHz RF source. The process takes place at a 5×10-2 mbar pressure with the target samples being biased from 0 to -3000 V DC. The anatase phase films were obtained from sputtering the titanium targets over glass and silicon electrically floated substrates placed 2 cm away from the target. The rutile phase was obtained by implantation/diffusion on targets at about 700 °C. The plasma was developed from a 4:1 argon/oxygen mixture for ~5 hour processing periods. The target temperature was controlled by means of the bias voltage and the plasma source power. The obtained anatase phases did not require annealing after the plasma oxidation process. The characterization of the film samples was conducted by means of x-ray diffraction, scanning electron microscopy, x-ray photoelectron spectroscopy and Raman spectroscopy.

  4. The biomimetic apatite-cefalotin coatings on modified titanium.

    PubMed

    Kang, Min-Kyung; Lee, Sang-Bae; Moon, Seung-Kyun; Kim, Kwang-Mahn; Kim, Kyoung-Nam

    2012-02-01

    Dental implant failure often occurs due to oral bacterial infection. The aim of this study was to demonstrate that antibiotic efficacy could be enhanced with modified titanium. First, the titanium was modified by anodization and heat-treatment. Then, a biomimetic coating process was completed in two steps. Surface characterization was performed with scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Release of antibiotic was evaluated by UV/VIS spectrometry, and the antibacterial effect was evaluated on Streptococcus mutans. After the second coating step, we observed a thick homogeneous apatite layer that contained the antibiotic, cefalotin. The titanium formed a rutile phase after the heat treatment, and a carbonated apatite phase appeared after biomimetic coating. We found that the modified titanium increased the loading of cefalotin onto the hydroxyapatite coated surface. The results suggested that modified titanium coated with a cefalotin using biomimetic coating method might be useful for preventing local post-surgical implant infections. PMID:22277612

  5. Laser Gas Nitriding of Titanium and Titanium Alloys

    NASA Astrophysics Data System (ADS)

    Dai, J. J.; Hou, S. Q.

    Titanium and titanium alloys are widely used in many fields due to some of their characteristics such as light density, high strength, and excellent corrosion resistance. However, poor mechanical performances limit their practical applications. Laser gas nitriding is a promising method used to improve the surface properties of components. Recent developments on laser gas nitriding of titanium and titanium alloys are reviewed. The processing parameters have important effects on the resulting characteristics of titanium and titanium alloys. The resulting microstructure and properties of laser gas nitrided specimens are presented. The problems to be solved and the prospects in the field of laser gas nitriding of titanium and titanium alloys are discussed.

  6. Dichloromethane photodegradation using titanium catalysts

    SciTech Connect

    Tanguay, J.F.; Suib, S.L.; Coughlin, R.W. )

    1989-06-01

    The use of titanium dioxide and titanium aluminosilicates in the photocatalytic destruction of chlorinated hydrocarbons is investigated. Titanium-exchanged clays, titanium-pillared clays, and titanium dioxide in the amorphous, anatase, and rutile forms are used to photocatalytically degrade dichloromethane to hydrochloric acid and carbon dioxide. Bentonite clays pillared by titanium dioxide are observed to be more catalytically active than titanium-exchanged clays. Clays pillared by titanium aluminum polymeric cations display about the same catalytic activity as that of titanium-exchanged clays. The rutile form of titanium dioxide is the most active catalyst studied for the dichloromethane degradation reaction. The anatase form of titanium dioxide supported on carbon felt was also used as a catalyst. This material is about five times more active than titanium dioxide-pillared clays. Degradation of dichloromethane using any of these catalysts can be enhanced by oxygen enrichment of the reaction solution or by preirradiating the catalyst with light.

  7. Method of measuring the thickness of radioactive thin films

    NASA Technical Reports Server (NTRS)

    Alger, D. L.; Steinberg, R.; Makinen, M. D.

    1974-01-01

    Thickness monitor consists of proportional X-ray counter coupled to pulse counting system, copper filter over face of counter, rotatable collimator containing radioactive source, and rotatable shutter. Monitor can be used as integral part of neutron generator. It has been used to measure titanium tritide film thicknesses from 0.1 to 30 micrometers.

  8. Silk electrogel coatings for titanium dental implants.

    PubMed

    Elia, Roberto; Michelson, Courtney D; Perera, Austin L; Harsono, Masly; Leisk, Gray G; Kugel, Gerard; Kaplan, David L

    2015-04-01

    The aim of this study was to develop biocompatible, biodegradable dental implant coatings capable of withstanding the mechanical stresses imparted during implant placement. Two techniques were developed to deposit uniform silk fibroin protein coatings onto dental implants. Two novel coating techniques were implemented to coat titanium shims, studs, and implants. One technique involved electrodeposition of the silk directly onto the titanium substrates. The second technique consisted of melting electrogels and dispensing the melted gels onto the titanium to form the coatings. Both techniques were tested for coating reproducibility using a stylus profilometer and a dial thickness gauge. The mechanical strength of adhered titanium studs was assessed using a universal mechanical testing machine. Uniform, controllable coatings were obtained from both the electrodeposition and melted electrogel coating techniques, tunable from 35 to 1654 µm thick under the conditions studied, and able to withstand delamination during implantation into implant socket mimics. Mechanical testing revealed that the adhesive strength of electrogel coatings, 0.369 ± 0.09 MPa, rivaled other biologically derived coating systems such as collagen, hydroxyapatite, and chitosan (0.07-4.83 MPa). These novel silk-based techniques offer a unique approach to the deposition of safe, simple, mechanically robust, biocompatible, and degradable implant coatings. PMID:25425563

  9. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-07-15

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B{sub 2}O{sub 3}), barium oxide (BaO), lanthanum oxide (La{sub 2}O{sub 3}), and at least one other oxide selected from the group consisting of aluminum oxide (Al{sub 2}O{sub 3}), calcium oxide (CaO), lithium oxide (Li{sub 2}O), sodium oxide (Na{sub 2}O), silicon dioxide (SiO{sub 2}), or titanium dioxide (TiO{sub 2}). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900 C, and generally about 700--800 C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 1 fig.

  10. Sealing glasses for titanium and titanium alloys

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Barium lanthanoborate sealing-glass compositions are provided comprising various combinations (in terms of mole-%) of boron oxide (B.sub.2 O.sub.3), barium oxide (BaO), lanthanum oxide (La.sub.2 O.sub.3), and at least one other oxide selected from the group consisting of aluminum oxide (Al.sub.2 O.sub.3), calcium oxide (CaO), lithium oxide (Li.sub.2 O), sodium oxide (Na.sub.2 O), silicon dioxide (SiO.sub.2), or titanium dioxide (TiO.sub.2). These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys having an improved aqueous durability and favorable sealing characteristics. Examples of the sealing-glass compositions are provided having coefficients of thermal expansion about that of titanium or titanium alloys, and with sealing temperatures less than about 900.degree. C., and generally about 700.degree.-800.degree. C. The barium lanthanoborate sealing-glass compositions are useful for components and devices requiring prolonged exposure to moisture or water, and for implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  11. 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.

  12. Laser reactive ablation deposition of titanium nitride and titanium carbide films

    NASA Astrophysics Data System (ADS)

    D'Anna, Emilia; Leggieri, Gilberto; Luches, Armando; Martino, Maurizio; Perrone, Alessio; Majni, Guiseppe; Mengucci, Paolo; Mihailescu, Ion N.

    1994-11-01

    Titanium nitride and titanium carbide films were deposited on silicon substrates by XeCl excimer laser reactive ablation of titanium in nitrogen and methane atmospheres, respectively. A series of 10,000 pulses at the fluence of approximately 5 J/cm2 and repetition rate of 10 Hz were directed to the target. The pressure in the chamber was fixed, during every irradiation series, at a given value within the range 6 X 10-4 - 10 mbar of N2 or CH4. Very flat films with thickness exceeding 1 micrometers were deposited. The structural characteristics of the deposited films were investigated by Rutherford backscattering spectrometry, scanning electron microscopy, and by x-ray diffraction. Under specific experimental conditions very pure nitride films were deposited.

  13. 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.

  14. Regulation of PP2Cm expression by miRNA-204/211 and miRNA-22 in mouse and human cells

    PubMed Central

    Pan, Bang-fen; Gao, Chen; Ren, Shu-xun; Wang, Yi-bin; Sun, Hai-peng; Zhou, Mei-yi

    2015-01-01

    Aim: The mitochondrial targeted 2C-type serine/threonine protein phosphatase (PP2Cm) is encoded by the gene PPM1K and is highly conserved among vertebrates. PP2Cm plays a critical role in branched-chain amino acid catabolism and regulates cell survival. Its expression is dynamically regulated by the nutrient environment and pathological stresses. However, little is known about the molecular mechanism underlying the regulation of PPM1K gene expression. In this study, we aimed to reveal how PPM1K expression is affected by miRNA-mediated post-transcriptional regulation. Methods: Computational analysis based on conserved miRNA binding motifs was applied to predict the candidate miRNAs that potentially affect PPM1K expression. Dual-luciferase reporter assay was performed to verify the miRNAs' binding sites in the PPM1K gene and their influence on PPM1K 3′UTR activity. We further over-expressed the mimics of these miRNAs in human and mouse cells to examine whether miRNAs affected the mRNA level of PPM1K. Results: Computational analysis identified numerous miRNAs potentially targeting PPM1K. Luciferase reporter assays demonstrated that the 3′UTR of PPM1K gene contained the recognition sites of miR-204 and miR-211. Overexpression of these miRNAs in human and mouse cells diminished the 3′UTR activity and the endogenous mRNA level of PPM1K. However, the miR-22 binding site was found only in human and not mouse PPM1K 3′UTR. Accordingly, PPM1K 3′UTR activity was suppressed by miR-22 overexpression in human but not mouse cells. Conclusion: These data suggest that different miRNAs contribute to the regulation of PP2Cm expression in a species-specific manner. miR-204 and miR-211 are efficient in both mouse and human cells, while miR-22 regulates PP2Cm expression only in human cells. PMID:26592513

  15. 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.

  16. 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

    2016-04-01

    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.

  17. Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

    DOEpatents

    Holcombe, C.E.; Dykes, N.L.

    1992-04-28

    A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness. No Drawings

  18. Process for making a titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition

    DOEpatents

    Holcombe, Cressie E.; Dykes, Norman L.

    1992-01-01

    A ceramic composition composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to aobut 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness.

  19. Electroplating on titanium alloy

    NASA Technical Reports Server (NTRS)

    Lowery, J. R.

    1971-01-01

    Activation process forms adherent electrodeposits of copper, nickel, and chromium on titanium alloy. Good adhesion of electroplated deposits is obtained by using acetic-hydrofluoric acid anodic activation process.

  20. Caracterisation of Titanium Nitride Layers Deposited by Reactive Plasma Spraying

    NASA Astrophysics Data System (ADS)

    Roşu, Radu Alexandru; Şerban, Viorel-Aurel; Bucur, Alexandra Ioana; Popescu, Mihaela; Uţu, Dragoş

    2011-01-01

    Forming and cutting tools are subjected to the intense wear solicitations. Usually, they are either subject to superficial heat treatments or are covered with various materials with high mechanical properties. In recent years, thermal spraying is used increasingly in engineering area because of the large range of materials that can be used for the coatings. Titanium nitride is a ceramic material with high hardness which is used to cover the cutting tools increasing their lifetime. The paper presents the results obtained after deposition of titanium nitride layers by reactive plasma spraying (RPS). As deposition material was used titanium powder and as substratum was used titanium alloy (Ti6Al4V). Macroscopic and microscopic (scanning electron microscopy) images of the deposited layers and the X ray diffraction of the coatings are presented. Demonstration program with layers deposited with thickness between 68,5 and 81,4 μm has been achieved and presented.

  1. Titanium Allergy: A Literature Review

    PubMed Central

    Goutam, Manish; Giriyapura, Chandu; Mishra, Sunil Kumar; Gupta, Siddharth

    2014-01-01

    Titanium has gained immense popularity and has successfully established itself as the material of choice for dental implants. In both medical and dental fields, titanium and its alloys have demonstrated success as biomedical devices. Owing to its high resistance to corrosion in a physiological environment and the excellent biocompatibility that gives it a passive, stable oxide film, titanium is considered the material of choice for intraosseous use. There are certain studies which show titanium as an allergen but the resources to diagnose titanium sensivity are very limited. Attention is needed towards the development of new and precise method for early diagnosis of titanium allergy and also to find out the alternative biomaterial which can be used in place of titanium. A review of available articles from the Medline and PubMed database was done to find literature available regarding titanium allergy, its diagnosis and new alternative material for titanium. PMID:25484409

  2. Modulated IR radiometry for determining thermal properties and basic characteristics of titanium thin films

    SciTech Connect

    Apreutesei, Mihai; Lopes, Claudia; Vaz, Filipe; Macedo, Francisco; Borges, Joel

    2014-07-01

    Titanium thin films of different thicknesses were prepared by direct current magnetron sputtering to study modulated infrared (IR) radiometry as a tool for analyzing film thickness. Thickness was varied by regularly increasing the deposition time, keeping all the other deposition parameters constant. The influence of film thickness on morphological, structural, and electrical properties of the titanium coatings also was investigated. The experimental results revealed a systematic grain growth with increasing film thickness, along with enhanced film crystallinity, which led to increased electrical conductivity. Using the results obtained by modulated IR radiometry, the thickness of each thin film was calculated. These thickness values were then compared with the coating thickness measurements obtained by scanning electron microscopy. The values confirmed the reliability of modulated IR radiometry as an analysis tool for thin films and coatings, and for determining thicknesses in the micrometer range, in particular.

  3. Titanium by design: TRIP titanium alloy

    NASA Astrophysics Data System (ADS)

    Tran, Jamie

    Motivated by the prospect of lower cost Ti production processes, new directions in Ti alloy design were explored for naval and automotive applications. Building on the experience of the Steel Research Group at Northwestern University, an analogous design process was taken with titanium. As a new project, essential kinetic databases and models were developed for the design process and used to create a prototype design. Diffusion kinetic models were developed to predict the change in phase compositions and microstructure during heat treatment. Combining a mobility database created in this research with a licensed thermodynamic database, ThermoCalc and DICTRA software was used to model kinetic compositional changes in titanium alloys. Experimental diffusion couples were created and compared to DICTRA simulations to refine mobility parameters in the titanium mobility database. The software and database were able to predict homogenization times and the beta→alpha plate thickening kinetics during cooling in the near-alpha Ti5111 alloy. The results of these models were compared to LEAP microanalysis and found to be in reasonable agreement. Powder metallurgy was explored using SPS at GM R&D to reduce the cost of titanium alloys. Fully dense Ti5111 alloys were produced and achieved similar microstructures to wrought Ti5111. High levels of oxygen in these alloys increased the strength while reducing the ductility. Preliminary Ti5111+Y alloys were created, where yttrium additions successfully gettered excess oxygen to create oxides. However, undesirable large oxides formed, indicating more research is needed into the homogeneous distribution of the yttrium powder to create finer oxides. Principles established in steels were used to optimize the beta phase transformation stability for martensite transformation toughening in titanium alloys. The Olson-Cohen kinetic model is calibrated to shear strains in titanium. A frictional work database is established for common alloying

  4. Preliminary evaluation of hybrid titanium composite laminates

    NASA Technical Reports Server (NTRS)

    Miller, J. L.; Progar, D. J.; Johnson, W. S.; St.clair, T. L.

    1994-01-01

    In this study, the mechanical response of hybrid titanium composite laminates (HTCL) was evaluated at room and elevated temperatures. Also, the use of an elastic-plastic laminate analysis program for predicting the tensile response from constituent properties was verified. The improvement in mechanical properties achieved by the laminates was assessed by comparing the results of static strength and constant amplitude fatigue tests to those for monolithic titanium sheet. Two HTCL were fabricated with different fiber volume fractions, resin layer thicknesses, and resins. One panel was thicker and was more poorly bonded in comparison to other. Consequently, the former had a lower tensile strength, while fewer cracks grew in this panel and at a slower rate. Both panels showed an improvement in fatigue life of almost two orders of magnitude. The model predictions were also in good agreement with the experimental results for both HTCL panels.

  5. Characterization of titanium alloys for cryogenic applications

    NASA Astrophysics Data System (ADS)

    Reytier, M.; Kircher, F.; Levesy, B.

    2002-05-01

    Titanium alloys are employed in the design of superconducting magnet support systems for their high mechanical strength associated with their low thermal conductivity. But their use requires a careful attention to their crack tolerance at cryogenic temperature. Measurements have been performed on two extra low interstitial materials (Ti-5Al-2.5Sn ELI and Ti-6Al-4V ELI) with different thickness and manufacturing process. The investigation includes the tensile properties at room and liquid helium temperatures using smooth and notched samples. Moreover, the fracture toughness has been determined at 4.2 K using Compact Tension specimens. The microstructure of the different alloys and the various fracture surfaces have also been studied. After a detailed description of the experimental procedures, practical engineering characteristics are given and a comparison of the different titanium alloys is proposed for cryogenic applications.

  6. Extracorporeal shock wave lithotripsy versus retrograde intrarenal surgery for treatment for renal stones 1-2 cm: a meta-analysis.

    PubMed

    Zheng, Changjian; Yang, Hongmei; Luo, Jun; Xiong, Bo; Wang, Hongzhi; Jiang, Qing

    2015-11-01

    This study is to evaluate the efficacy and safety of extracorporeal shock wave lithotripsy (ESWL) versus retrograde intrarenal surgery (RIRS) for the treatment for renal calculi 1-2 cm. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and the Chinese Biomedical Literature Database were researched and hand-searched for relevant congress abstracts and journals about RIRS and ESWL for the treatment for 1- to 2-cm renal stones. The retrieval time ended in September 2014. The related trials met the inclusion criteria were included in the meta-analysis. Two reviewers independently assessed the quality of all included studies, and meta-analysis was performed with RevMan 5.2. Seven literatures were retrieved, including 983 patients. The meta-analysis results showed that, compared to RIRS group, the patients in ESWL group had the following features:(1) the stone-free rate [relative risk (RR) 0.86; 95% confidence interval (CI) 0.77-0.95, P = 0.005] was significantly different between two groups; (2) The retreatment rate of RIRS group was lower (RR 8.12; 95% CI 4.77-13.83, P < 0.00); (3) The complications were not significantly different between two groups (Grade I RR 1.06; 95% CI 0.67-1.69, P = 0.80; Grade II RR 0.75; 95% CI 0.29-1.91, P = 0.54; Grade III RR 0.86; 95% CI 0.26-2.86, P = 0.80). Compared to ESWL, our results showed that RIRS provided significantly higher stone-free rate and lower retreatment rate and without increase in the incidence of complications. However, further randomized trials are needed to confirm these findings. PMID:26211003

  7. High-temperature oxidation of titanium silicide coatings on titanium

    SciTech Connect

    Abba, A.; Caillet, M.; Galerie, A.

    1982-02-01

    Coatings of Ti/sub 5/Si/sub 3/ on titanium have been prepared by means of decomposition of silane SiH/sub 4/ on heated titanium ribbons. Oxidation of the coated titanium specimens was much slower than that of the noncoated ones. Gravimetric and morphological experiments allowed to propose a mechanism describing the oxidation process.

  8. DEMONSTRATION OF THE NEXT-GENERATION CAUSTIC-SIDE SOLVENT EXTRACTION SOLVENT WITH 2-CM CENTRIFUGAL CONTRACTORS USING TANK 49H WASTE AND WASTE SIMULANT

    SciTech Connect

    Pierce, R.; Peters, T.; Crowder, M.; Caldwell, T.; Pak, D; Fink, S.; Blessing, R.; Washington, A.

    2011-09-27

    Researchers successfully demonstrated the chemistry and process equipment of the Caustic-Side Solvent Extraction (CSSX) flowsheet using MaxCalix for the decontamination of high level waste (HLW). The demonstration was completed using a 12-stage, 2-cm centrifugal contactor apparatus at the Savannah River National Laboratory (SRNL). This represents the first CSSX process demonstration of the MaxCalix solvent system with Savannah River Site (SRS) HLW. Two tests lasting 24 and 27 hours processed non-radioactive simulated Tank 49H waste and actual Tank 49H HLW, respectively. Conclusions from this work include the following. The CSSX process is capable of reducing {sup 137}Cs in high level radioactive waste by a factor of more than 40,000 using five extraction, two scrub, and five strip stages. Tests demonstrated extraction and strip section stage efficiencies of greater than 93% for the Tank 49H waste test and greater than 88% for the simulant waste test. During a test with HLW, researchers processed 39 liters of Tank 49H solution and the waste raffinate had an average decontamination factor (DF) of 6.78E+04, with a maximum of 1.08E+05. A simulant waste solution ({approx}34.5 liters) with an initial Cs concentration of 83.1 mg/L was processed and had an average DF greater than 5.9E+03, with a maximum DF of greater than 6.6E+03. The difference may be attributable to differences in contactor stage efficiencies. Test results showed the solvent can be stripped of cesium and recycled for {approx}25 solvent turnovers without the occurrence of any measurable solvent degradation or negative effects from minor components. Based on the performance of the 12-stage 2-cm apparatus with the Tank 49H HLW, the projected DF for MCU with seven extraction, two scrub, and seven strip stages operating at a nominal efficiency of 90% is {approx}388,000. At 95% stage efficiency, the DF in MCU would be {approx}3.2 million. Carryover of organic solvent in aqueous streams (and aqueous in organic

  9. Titanium Cold Spray Coatings

    NASA Astrophysics Data System (ADS)

    Ajaja, Jihane; Goldbaum, Dina; Chromik, Richard; Yue, Stephen; Rezaeian, Ahmad; Wong, Wilson; Irissou, Eric; Legoux, Jean-Gabriel

    Titanium Cold Spray Coatings Cold Spray is an emerging technology used for the deposition of coatings for many industries including aerospace. This technique allows the deposition of metallic materials at low temper-atures below their melting point. The aim of this research was to develop a test technique that can measure the degree to which a cold spray coating achieves mechanical properties similar to a traditional bulk material. Vickers hardness testing and nanoindentation were used as micro-and nano-scale measurement techniques to characterize the mechanical properties of titanium coatings, deposited at different deposition conditions, and bulk Ti. The mechanical properties of bulk titanium and titanium coatings were measured over a range of length scales, with the indentation size effect examined with Meyer's law. Hardness measurements are shown to be affected by material porosity, microstructure and coating particle bonding mechanism. Hard-ness measurements showed that Ti coatings deposited at higher gas pressures and temperatures demonstrate an indentation load response similar to bulk Ti. Key words: titanium, cold spray, Vickers hardness, nanoindentation, indentation size effect, microstructure, mechanical properties

  10. Titanium metal: extraction to application

    SciTech Connect

    Gambogi, Joseph; Gerdemann, Stephen J.

    2002-09-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium. In this paper, we discuss all aspects of the titanium industry from ore deposits through extraction to present and future applications. The methods of both primary (mining of ore, extraction, and purification) and secondary (forming and machining) operations will be analyzed. The chemical and physical properties of titanium metal will be briefly examined. Present and future applications for titanium will be discussed. Finally, the economics of titanium metal production also are analyzed as well as the advantages and disadvantages of various alternative extraction methods.

  11. 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.

  12. Weld-bonded titanium structures

    NASA Technical Reports Server (NTRS)

    Vaughan, R. W.; Creedon, J. F. (Inventor)

    1976-01-01

    Structurally stronger titanium articles are produced by a weld-bonding technique comprising fastening at least two plates of titanium together using spotwelding and curing an adhesive interspersed between the spot-weld nuggets. This weld-bonding may be employed to form lap joints or to stiffen titanium metal plates.

  13. Tensile and creep properties of titanium-vanadium, titanium-molybdenum, and titanium-niobium alloys

    NASA Technical Reports Server (NTRS)

    Gray, H. R.

    1975-01-01

    Tensile and creep properties of experimental beta-titanium alloys were determined. Titanium-vanadium alloys had substantially greater tensile and creep strength than the titanium-niobium and titanium-molybdenum alloys tested. Specific tensile strengths of several titanium-vanadium-aluminum-silicon alloys were equivalent or superior to those of commercial titanium alloys to temperatures of 650 C. The Ti-50V-3Al-1Si alloy had the best balance of tensile strength, creep strength, and metallurgical stability. Its 500 C creep strength was far superior to that of a widely used commercial titanium alloy, Ti-6Al-4V, and almost equivalent to that of newly developed commercial titanium alloys.

  14. Ballistic Limit Equation for Single Wall Titanium

    NASA Technical Reports Server (NTRS)

    Ratliff, J. M.; Christiansen, Eric L.; Bryant, C.

    2009-01-01

    Hypervelocity impact tests and hydrocode simulations were used to determine the ballistic limit equation (BLE) for perforation of a titanium wall, as a function of wall thickness. Two titanium alloys were considered, and separate BLEs were derived for each. Tested wall thicknesses ranged from 0.5mm to 2.0mm. The single-wall damage equation of Cour-Palais [ref. 1] was used to analyze the Ti wall's shielding effectiveness. It was concluded that the Cour-Palais single-wall equation produced a non-conservative prediction of the ballistic limit for the Ti shield. The inaccurate prediction was not a particularly surprising result; the Cour-Palais single-wall BLE contains shield material properties as parameters, but it was formulated only from tests of different aluminum alloys. Single-wall Ti shield tests were run (thicknesses of 2.0 mm, 1.5 mm, 1.0 mm, and 0.5 mm) on Ti 15-3-3-3 material custom cut from rod stock. Hypervelocity impact (HVI) tests were used to establish the failure threshold empirically, using the additional constraint that the damage scales with impact energy, as was indicated by hydrocode simulations. The criterion for shield failure was defined as no detached spall from the shield back surface during HVI. Based on the test results, which confirmed an approximately energy-dependent shield effectiveness, the Cour-Palais equation was modified.

  15. Titanium alkoxide compound

    DOEpatents

    Boyle, Timothy J.

    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.

  16. A functionally graded titanium/hydroxyapatite film obtained by sputtering.

    PubMed

    Ozeki, Kazuhide; Yuhta, Toshio; Fukui, Yasuhiro; Aoki, Hideki; Nishimura, Ikuya

    2002-03-01

    A functionally graded film of titanium/hydroxyapatite (HA) was prepared on a titanium substrate using a radio frequency magnetron sputtering. The ratio of titanium to HA was controlled by moving the target shutter. The film was composed of five layers, with overall film thickness of 1 microm. The HA was concentrated close to the surface, while the titanium concentration increased with proximity to the substrate. The bonding strength between the film and the substrate was 15.2 MPa in a pull-out test and the critical load from a scratch test was 58.85 mN. The corresponding values of a pure HA sputtered film were 8.0 MPa and 38.47 mN, respectively. The bonding strength of a pure HA plasma spray coating was 10.4 MPa in the pull-out test. The graded film and the pure HA film were sputter-coated to a thickness of 1 microm on titanium columns (10 mm in length and 4 mm in diameter). These columns were implanted in diaphyses of the femora of six adult dogs and a push-out test was carried out after 2, 4, and 12 weeks. After 12 weeks, the push-out strengths of the graded film, the pure HA film and the non-coated columns were 3.7, 3.5, and 1.0 MPa. PMID:15348621

  17. Effects of neurosurgical titanium mesh on radiation dose

    SciTech Connect

    Patone, Hassisen . E-mail: hash.patone@mail.mcgill.ca; Barker, Jennifer; Roberge, David

    2006-01-01

    The purpose of this study was to determine the dosimetric impact of a neurosurgical titanium mesh in patients treated with 6- and 18-MV photon beams. The effects of a 0.4-mm-thick titanium mesh on the dose profile at 3 regions within a solid water phantom were measured using extended dose range-2 (EDR2) film for 6- and 18-MV photon beams. All measurements were performed with the titanium mesh placed at a depth of 1.5 cm in the phantom. Films were exposed immediately above the mesh, immediately below the mesh, and at a depth of 5 cm from the surface of the phantom. The films were scanned using a scanning densitometer. In the region directly above the titanium mesh, there was an increase in dose of 7.1% for 6-MV photons and 4.9% for 18-MV photons. Directly below the titanium mesh, there was an average decrease in dose of 1.5% for 6-MV photons and an increase of 1.0% for 18-MV photons. At 5-cm depth, for 6- and 18-MV photons, there was a decrease in dose of 2.2% and 0.6%, respectively. We concluded that for cranial irradiation with high-energy photons, the dosimetric impact of a 0.4-mm titanium mesh is small and does not require modification in treatment parameters.

  18. DEMONSTRATION OF THE NEXT-GENERATION CAUSTIC-SIDE SOLVENT EXTRACTION SOLVENT WITH 2-CM CENTRIGUGAL CONTRACTORS USING TANK 49H WASTE AND WASTE SIMULANT

    SciTech Connect

    Pierce, R.; Peters, T.; Crowder, M.; Pak, D.; Fink, S.; Blessing, R.; Washington, A.; Caldwell, T.

    2011-11-29

    Researchers successfully demonstrated the chemistry and process equipment of the Caustic-Side Solvent Extraction (CSSX) flowsheet using MaxCalix for the decontamination of high level waste (HLW). The demonstration was completed using a 12-stage, 2-cm centrifugal contactor apparatus at the Savannah River National Laboratory (SRNL). This represents the first CSSX process demonstration of the MaxCalix solvent system with Savannah River Site (SRS) HLW. Two tests lasting 24 and 27 hours processed non-radioactive simulated Tank 49H waste and actual Tank 49H HLW, respectively. A solvent extraction system for removal of cesium from alkaline solutions was developed utilizing a novel solvent invented at the Oak Ridge National Laboratory (ORNL). This solvent consists of a calix[4]arene-crown-6 extractant dissolved in an inert hydrocarbon matrix. A modifier is added to the solvent to enhance the extraction power of the calixarene and to prevent the formation of a third phase. An additional additive is used to improve stripping performance and to mitigate the effects of any surfactants present in the feed stream. The process that deploys this solvent system is known as Caustic Side Solvent Extraction (CSSX). The solvent system has been deployed at the Savannah River Site (SRS) in the Modular CSSX Unit (MCU) since 2008.

  19. Performance of a 64-channel, 3.2×3.2 cm2 SiPM tile for TOF-PET application

    NASA Astrophysics Data System (ADS)

    Ferri, Alessandro; Acerbi, Fabio; Gola, Alberto; Piemonte, Claudio; Paternoster, Giovanni; Zorzi, Nicola

    2016-07-01

    In this work, we present a new 3.2×3.2 cm2 detector tile, composed of 8×8 single SiPMs, having a regular 4 mm pitch in both the X and Y directions. The tile fill factor is 85%. We produced two versions of the tile with different SiPM technologies: RGB-HD and NUV. The first one features square micro-cells with 25 μm pitch, a PDE peaked at 550 nm and a DCR of 300 kHz/mm2, at 20 °C and at maximum detection efficiency. The second one features micro-cells with 40 μm pitch and a PDE peaked in the blue part of the spectrum. The dark count rate at 20 °C and at maximum PDE is 100 kHz/mm2. In this work, we show the energy and timing resolution measurements at 511 keV obtained coupling the two tiles to an 8×8 LYSO array with a pixel size of 4×4×22 mm3, perfectly matching the photo-detector array.

  20. Characterization of hydrogen barrier coatings for titanium-base alloys

    NASA Astrophysics Data System (ADS)

    Leguey, T.; Baluc, N.; Jansen, F.; Victoria, M.

    2002-12-01

    The purpose of this study was to investigate the barrier efficiency of a thick thermal spray deposit on the α-titanium alloy, Ti-5Al-2.4Sn against hydrogen penetration. Therefore, a duplex coating has been applied by plasma spraying using a Sulzer Metco F4 gun. The selected duplex coating system consisted of a 0.1-0.2 mm thick tantalum bond layer and a chromium oxide top layer doped with 3 wt% titanium oxide. The achieved thickness of the top layer was about 0.6 mm. The coated specimens have been characterized with regard to bond strength, hardness and microstructure. Hydrogen charging experiments were performed in a Sievert's apparatus.

  1. Sorting Titanium Welding Rods

    NASA Technical Reports Server (NTRS)

    Ross, W. D., Jr.; Brown, R. L.

    1985-01-01

    Three types of titanium welding wires identified by their resistance to current flow. Welding-wire tester quickly identifies unknown titaniumalloy wire by touching wire with test probe, and comparing meter response with standard response. Before touching wire, tip of test probe dipped into an electrolyte.

  2. Sintering titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-09-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  3. Hydroxyapatite-titanium interface reaction induced by keV electron irradiation

    NASA Astrophysics Data System (ADS)

    Torrisi, L.; Foti, G.

    1992-03-01

    Thin films of hydroxyapatite bioceramic, 5-50 Å in thickness, have been deposited on ion cleaned titanium surfaces to study the chemical-physical adhesion of metal-ceramic interfaces of biomedical devices (orthopaedic and dentistry prosthesis). Film deposition was performed in ultrahigh vacuum condition (10 -10 mbar) using 5 keV argon sputtering of hydroxyapatite matrix; the film thickness was measured in situ with Auger electron spectroscopy. The hydroxyapatite-titanium interface was irradiated with an electron beam of 0.5-5 keV energy and 0.2-2 A/cm 2 current density. During electron irradiation, Auger spectra show chemical shifts of phosphorus, titanium and oxygen peaks. The released electron energy induces modifications in the tetraedric phosphorus-oxygen groups with production of new chemical bonds between phosphorus, oxygen and titanium. Oxygen, for example, diffuses into the titanium interface forming titanium oxide. Chemical reactions induced by electron irradiation are driven by the metal-ceramic interface. Near the interface a strong and fast effect is observed while far from the interface a weak and slow effect occurs. Chemical reactions depend on the electron irradiation dose showing an inhibition threshold at about 10 19 e/cm 2 and, near the interface, a saturation condition at about 5 × 10 20 e/cm 2. Titanium-ceramic chemical reactions are inhibited if the substrate titanium surface is rich in oxide.

  4. Design of 3D-Printed Titanium Compliant Mechanisms

    NASA Technical Reports Server (NTRS)

    Merriam, Ezekiel G.; Jones, Jonathan E.; Howell, Larry L.

    2014-01-01

    This paper describes 3D-printed titanium compliant mechanisms for aerospace applications. It is meant as a primer to help engineers design compliant, multi-axis, printed parts that exhibit high performance. Topics covered include brief introductions to both compliant mechanism design and 3D printing in titanium, material and geometry considerations for 3D printing, modeling techniques, and case studies of both successful and unsuccessful part geometries. Key findings include recommended flexure geometries, minimum thicknesses, and general design guidelines for compliant printed parts that may not be obvious to the first time designer.

  5. Osteoinductive hydroxyapatite-coated titanium implants.

    PubMed

    Ripamonti, Ugo; Roden, Laura C; Renton, Louise F

    2012-05-01

    Previous studies have shown that heterotopic induction of bone formation by calcium phosphate-based macroporous constructs is set into motion by the geometry of the implanted substrata, i.e. a sequence of repetitive concavities assembled within the macroporous spaces. The aim of this study was to construct osteoinductive titanium implants that per se, and without the exogenous application of the osteogenic soluble molecular signals of the transforming growth factor-β supergene family, would initiate the induction of bone formation. To generate intrinsically osteoinductive titanium implants for translation in clinical contexts, titanium grade Ti-6A1-4V cylinders of 15 mm in length and 3.85 mm in diameter, with or without concavities, were plasma sprayed with crystalline hydroxyapatite resulting in a uniform layer of 30 μm in thickness. Before coating, experimental titanium implants were prepared with a sequence of 36 repetitive concavities 1600 μm in diameter and 800 μm in depth, spaced a distance of 1000 μm apart. Mandibular molars and premolars were extracted to prepare edentulous mandibular ridges for later implantation. Planar and geometric hydroxyapatite-coated titanium constructs were implanted in the left and right edentulized hemi-mandibles, respectively, after a healing period of 7-8 months, 3 per hemi-mandible. Three planar and three geometric implants were implanted in the left and right tibiae, respectively; additionally, planar and geometric constructs were also inserted in the rectus abdominis muscle. Six animals were euthanized at 30 and 90 days after implantation; one animal had to be euthanized 5 days after surgery and the remaining animal was euthanized 31 months after implantation. Undecalcified longitudinal sections were precision-sawed, ground and polished to 40-60 μm; all sections were stained with a modified Goldner's trichrome. Undecalcified specimen block preparation was performed using the EXAKT precision cutting and grinding system

  6. The field evaporation of deuterated titanium as a neutron generator ion source

    NASA Astrophysics Data System (ADS)

    Reichenbach, B.; Johnson, B. Bargsten; Schwoebel, P. R.

    2010-11-01

    The field evaporation of deuterated titanium films is being investigated as a deuterium ion source for deuterium-tritium neutron generators. It has been found that titanium and deuterated titanium films having thicknesses of up to at least 70 layers assume a body-centered-cubic crystal structure when grown on ⟨110⟩ oriented tungsten substrates. Deuterated titanium films having thicknesses exceeding 50 atomic layers have been controllably field evaporated from the surface of tungsten tips in less than 20 ns. At ion current densities exceeding ˜106 A/cm2 and film thicknesses greater than ˜20 layers, space charge effects decrease the ratio of D to TiDx ions to less than 1. Decreasing the evaporation rate such that ion current densities are of the order of 105 A/cm2 increases the D to TiDx ratio for the evaporation of a film thickness of greater than ˜20 layers by the reduction in space charge effects that can inhibit the dissociation of titanium-deuterium complexes. Atomic deuterium ion yields of ˜10-7 μC of D+/tip have been observed and yields of >10-6 μC of D+/tip should be possible using larger tip radii. The field evaporation of titanium from an array of microfabricated tips has been demonstrated for the first time.

  7. Gas-phase hydrogen permeation through alpha-titanium - Surface film and dimensional effects

    NASA Technical Reports Server (NTRS)

    Shah, K. K.; Johnson, D. L.

    1976-01-01

    The two techniques normally used to determine diffusivity and permeability in metals are considered and a description is presented of experiments which had been conducted to determine the direct effect of oxide and nitride films on the membrane surface as a function of location and thickness. The test specimens used in the experiments has been machined from commercially pure titanium rod. The results of the experiments show that hydrogen transport in alpha-titanium is partially or completely controlled by surface reactions depending upon membrane wall thickness and the composition and thickness of the surface film.

  8. Rolling-induced Face Centered Cubic Titanium in Hexagonal Close Packed Titanium at Room Temperature

    NASA Astrophysics Data System (ADS)

    Wu, H. C.; Kumar, A.; Wang, J.; Bi, X. F.; Tomé, C. N.; Zhang, Z.; Mao, S. X.

    2016-04-01

    Combining transmission electron microscopes and density functional theory calculations, we report the nucleation and growth mechanisms of room temperature rolling induced face-centered cubic titanium (fcc-Ti) in polycrystalline hexagonal close packed titanium (hcp-Ti). Fcc-Ti and hcp-Ti take the orientation relation: <0001>hcp||<001>fcc and , different from the conventional one. The nucleation of fcc-Ti is accomplished via pure-shuffle mechanism with a minimum stable thickness of three atomic layers, and the growth via shear-shuffle mechanisms through gliding two-layer disconnections or pure-shuffle mechanisms through gliding four-layer disconnections. Such phase transformation offers an additional plastic deformation mode comparable to twinning.

  9. Rolling-induced Face Centered Cubic Titanium in Hexagonal Close Packed Titanium at Room Temperature

    PubMed Central

    Wu, H. C.; Kumar, A.; Wang, J.; Bi, X. F.; Tomé, C. N.; Zhang, Z.; Mao, S. X.

    2016-01-01

    Combining transmission electron microscopes and density functional theory calculations, we report the nucleation and growth mechanisms of room temperature rolling induced face-centered cubic titanium (fcc-Ti) in polycrystalline hexagonal close packed titanium (hcp-Ti). Fcc-Ti and hcp-Ti take the orientation relation: 〈0001〉hcp||〈001〉fcc and , different from the conventional one. The nucleation of fcc-Ti is accomplished via pure-shuffle mechanism with a minimum stable thickness of three atomic layers, and the growth via shear-shuffle mechanisms through gliding two-layer disconnections or pure-shuffle mechanisms through gliding four-layer disconnections. Such phase transformation offers an additional plastic deformation mode comparable to twinning. PMID:27067515

  10. Differences in the bone differentiation properties of MC3T3-E1 cells on polished bulk and sputter-deposited titanium specimens.

    PubMed

    Oya, Kei; Tanaka, Yuta; Moriyama, Yoshihisa; Yoshioka, Yuki; Kimura, Tsuyoshi; Tsutsumi, Yusuke; Doi, Hisashi; Nomura, Naoyuki; Noda, Kazuhiko; Kishida, Akio; Hanawa, Takao

    2010-08-01

    The roughness and cleanness of a titanium surface must be controlled in order to investigate the expression mechanism of hard tissue compatibility on titanium. In this study, osteogenic MC3T3-E1 cells were cultured and differentiation-induced on bulk and sputter-deposited titanium specimens, and the osteogenesis were investigated. For the preparation of bulk specimens, titanium discs were mirror-polished. On the other hand, titanium was sputter-deposited on smooth and clean cover glasses as sputter-deposited specimens. As a result, no significant difference was observed in the cell morphology and attached number. On the other hand, the time showing maximum activity in the alkaline phosphatase and gene expressions, which are related to bone differentiation on the bulk titanium, were superior to those on the sputter-deposited titanium. From the surface observation of the specimens with a scanning electron microscope and a scanning probe microscope, the surface on the sputter-deposited titanium was more uniform and cleaner than that on the bulk titanium. According to X-ray photoelectron spectroscopy, the thickness of surface oxide film on the sputter-deposited titanium was smaller than that on the bulk titanium. In addition, the proportions of TiO and Ti(2)O(3) in the surface oxide film on the sputter-deposited titanium were larger than those on the bulk titanium. These differences might influence the differentiation of osteoblastic cells. PMID:20198694

  11. Hydrothermal modification of titanium surface in calcium solutions.

    PubMed

    Hamad, Kenichi; Kon, Masayuki; Hanawa, Takao; Yokoyama, Ken'ichi; Miyamoto, Youji; Asaoka, Kenzo

    2002-05-01

    Hydrothermal modification of a titanium surface in calcium solutions was performed. The apatite precipitation on the modified surface in Hanks' solution, as a simulated body fluid, was evaluated and the surface microstructure changes after the modification were characterized by thin-film X-ray diffractometry (TF-XRD) and X-ray photoelectron spectroscopy (XPS). Hydrothermal modification in CaO solution enhanced the precipitation of apatite on the titanium surface. High pH, high pressure and high temperature of the CaO solution increased the thickness of the surface-modified layer and enhanced the synthesis of calcium titanate which possibly promoted the precipitation of apatite in Hanks' solution. Hydrothermal modification in CaCl2 solution, on the other hand, showed reverse effects. The modification of titanium in CaO solution with hydrothermal treatment is expected to result in excellent osteointegration and can be easily performed by using an autoclave, a clinical apparatus widely used. PMID:11962668

  12. Plasma electrolytic oxidation of Titanium Aluminides

    NASA Astrophysics Data System (ADS)

    Morgenstern, R.; Sieber, M.; Grund, T.; Lampke, T.; Wielage, B.

    2016-03-01

    Due to their outstanding specific mechanical and high-temperature properties, titanium aluminides exhibit a high potential for lightweight components exposed to high temperatures. However, their application is limited through their low wear resistance and the increasing high-temperature oxidation starting from about 750 °C. By the use of oxide ceramic coatings, these constraints can be set aside and the possible applications of titanium aluminides can be extended. The plasma electrolytic oxidation (PEO) represents a process for the generation of oxide ceramic conversion coatings with high thickness. The current work aims at the clarification of different electrolyte components’ influences on the oxide layer evolution on alloy TNM-B1 (Ti43.5Al4Nb1Mo0.1B) and the creation of compact and wear resistant coatings. Model experiments were applied using a ramp-wise increase of the anodic potential in order to show the influence of electrolyte components on the discharge initiation and the early stage of the oxide layer growth. The production of PEO layers with technically relevant thicknesses close to 100 μm was conducted in alkaline electrolytes with varying amounts of Na2SiO3·5H2O and K4P2O7 under symmetrically pulsed current conditions. Coating properties were evaluated with regard to morphology, chemical composition, hardness and wear resistance. The addition of phosphates and silicates leads to an increasing substrate passivation and the growth of compact oxide layers with higher thicknesses. Optimal electrolyte compositions for maximum coating hardness and thickness were identified by statistical analysis. Under these conditions, a homogeneous inner layer with low porosity can be achieved. The frictional wear behavior of the compact coating layer is superior to a hard anodized layer on aluminum.

  13. Corrosion of stainless steel, nickel-titanium, coated nickel-titanium, and titanium orthodontic wires.

    PubMed

    Kim, H; Johnson, J W

    1999-02-01

    Orthodontic wires containing nickel have been implicated in allergic reactions. The potential for orthodontic wires to cause allergic reactions is related to the pattern and mode of corrosion with subsequent release of metal ions, such as nickel, into the oral cavity. The purpose of this study was to determine if there is a significant difference in the corrosive potential of stainless steel, nickel titanium, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium orthodontic wires. At least two specimens of each wire were subjected to potentiostatic anodic dissolution in 0.9% NaCl solution with neutral pH at room temperature. Using a Wenking MP 95 potentiostat and an electrochemical corrosion cell, the breakdown potential of each wire was determined. Photographs were taken of the wire speci mens using a scanning electron microscope, and surface changes were qualitatively evaluated. The breakdown potentials of stainless steel, two nickel titanium wires, nitride-coated nickel titanium, epoxy-coated nickel titanium, and titanium were 400 mV, 300 mV, 750 mV, 300 mV, 1800 mV, and >2000 mV, respectively. SEM photographs revealed that some nickel titanium and stainless steel wires were susceptible to pitting and localized corrosion. The results indicate that corrosion occurred readily in stainless steel. Variability in breakdown potential of nickel titanium alloy wires differed across vendors' wires. The nitride coating did not affect the corrosion of the alloy, but epoxy coating decreased corrosion. Titanium wires and epoxy-coated nickel titanium wires exhibited the least corrosive potential. For patients allergic to nickel, the use of titanium or epoxy-coated wires during orthodontic treatment is recommended. PMID:10022183

  14. Machining of Aircraft Titanium with Abrasive-Waterjets for Fatigue Critical Applications

    SciTech Connect

    Liu, H. T.; Hovanski, Yuri; Dahl, Michael E.

    2012-02-01

    Laboratory tests were conducted to determine the fatigue performance of abrasive-waterjet- (AWJ-) machined aircraft titanium. Dog-bone specimens machined with AWJs were prepared and tested with and without sanding and dry-grit blasting with Al2O3 as secondary processes. The secondary processes were applied to remove the visual appearance of AWJ-generated striations and to clean up the garnet embedment. The fatigue performance of AWJ-machined specimens was compared with baseline specimens machined with CNC milling. Fatigue test results of the titanium specimens not only confirmed our previous findings in aluminum dog-bone specimens but in comparison also further enhanced the fatigue performance of the titanium. In addition, titanium is known to be difficult to cut, particularly for thick parts, however AWJs cut the material 34% faster han stainless steel. AWJ cutting and dry-grit blasting are shown to be a preferred ombination for processing aircraft titanium that is fatigue critical.

  15. Hydride precipitation in titanium

    SciTech Connect

    Numakura, H.; Kowia, M.

    1984-10-01

    The crystal structure and morphology of hydride (deuteride) precipitates are investigated on ..cap alpha..-titanium specimens containing 1-3 at.% H or D by transmission electron microscopy. The hydride is found to have a face-centered tetragonal structure (c/a = 1.09) with an ordered arrangement of hydrogen, being isomorphous to ..gamma..-zirconium hydride. Two types of precipitation mode are observed with the habit planes (0110) and near (0225).

  16. Titanium Honeycomb Panel Testing

    NASA Technical Reports Server (NTRS)

    Richards, W. Lance; Thompson, Randolph C.

    1996-01-01

    Thermal-mechanical tests were performed on a titanium honeycomb sandwich panel to experimentally validate the hypersonic wing panel concept and compare test data with analysis. Details of the test article, test fixture development, instrumentation, and test results are presented. After extensive testing to 900 deg. F, non-destructive evaluation of the panel has not detected any significant structural degradation caused by the applied thermal-mechanical loads.

  17. Titanium-boron mixtures as variable heat sources

    SciTech Connect

    Begeal, D.R. ); Munger, A.C. )

    1990-01-01

    The reaction between titanium and boron to form titanium diboride is one of the hottest pyrotechnic reactions in common usage and offers the advantage of being a solid state gasless reaction. Based on the work of Hart, a heat source with a variable output has been developed that utilizes this pyrotechnic. The device was designed to deliver the heat across a 0.26 inch inner diameter hemispherical bulkhead of a material and thickness that can be specified by the user. For evaluation purposes, the bulkhead was 0.036 inches thick stainless steel. The maximum temperature on the tip of the bulkhead was 950{degree}C for the pure reactants and 680{degree}C for blends diluted with 30 weight percent of alumina. Further, the temperature was uniform within {plus minus}20{degree}C across a 2 millimeter diameter on the tip of the bulkhead, and the temperature rise characteristics were repeatable. Ignition of the titanium/boron heat powder was accomplished by first igniting an adjacent charge of titanium subhydride/potassium perchlorate with a one ohm bridge wire. The header was constructed of inconel, a glass ceramic insulator, and hastelloy pins. The ignition and subsequent burn of the titanium/boron was nearly instantaneous, thus the thermal output was dependent only on the heat transfer properties of the materials and geometry involved. Therefore, the user can tailor the blend dilution and the bulkhead characteristics to provide a large range of precise heat outputs. Typical uses of this heat source include timely ignition of other materials, or heating confined gas to perform useful mechanical work. Achievement of the precise heat output required special attention to the purity of the titanium and boron and to the blending process. These aspects, as well as those described above will be described. 6 refs., 9 figs., 3 tabs.

  18. Interaction Between Titanium Implant Surfaces and Hydrogen Peroxide in Biologically Relevant Environments

    SciTech Connect

    Muyco, J; Ratto, T

    2004-04-21

    Titanium was exposed to dilute solutions of hydrogen peroxide (H2O2) to better characterize the interaction at the interface between the solution and metal. The intensity of light passing through films of known thickness of titanium on quartz was measured as a function of time in contact with H{sub 2}O{sub 2} in concentrations of 0.3% and 1.0%. An atomic force microscope (AFM) was used to record deflection-distance (force) curves as a probe approached the interface of titanium in contact with solution containing 0.3% of H{sub 2}O{sub 2}. The interaction layer measured using AFM techniques was much greater than the thickness of the titanium films used in this study. Raman spectroscopy taken during interaction shows the emergence of a Ti-peroxy gel and titania after 2 hours in contact with 0.3% H2O2 solution.

  19. Titanium fasteners. [for aircraft industry

    NASA Technical Reports Server (NTRS)

    Phillips, J. L.

    1972-01-01

    Titanium fasteners are used in large quantities throughout the aircraft industry. Most of this usage is in aluminum structure; where titanium structure exists, titanium fasteners are logically used as well. Titanium fasteners offer potential weight savings to the designer at a cost of approximately $30 per pound of weight saved. Proper and least cost usage must take into consideration type of fastener per application, galvanic couples and installation characteristics of protective coatings, cosmetic appearance, paint adhesion, installation forces and methods available and fatigue performance required.

  20. 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.

  1. INDUSTRIAL PROCESS PROFILES FOR ENVIRONMENTAL USE: CHAPTER 26. TITANIUM INDUSTRY

    EPA Science Inventory

    The titanium industry produces two principal products, titanium metal and titanium dioxide. For purposes of analyses, therefore, the industry is considered in two segments: titanium metal production and titanium dioxide production. Two industrial process flow diagrams and eleven ...

  2. Study on the Properties of Ionized Metal Plasma Methodology on Titanium

    SciTech Connect

    Leow, M. T.; Hassan, Z.; Lee, K. E.; Omar, G.; Lim, S. P.; Chan, C. F.; Siew, E. T.; Chuah, Z. M.

    2010-07-07

    Ionized Metal Plasma (IMP) deposition was used in depositing metal interconnection of titanium metal film. Inductively coupled plasma (ICP) was attached to chamber wall where it creates an electromagnetic field, thus, ionizing the sputtered metal atoms from target. The film morphology was observed by scanning electron microscope (SEM). Acoustic measurement of titanium film thickness showed that there was a comparable result with film resistance measured by 4-point probe. Results show that higher plasma density would cause tensile properties on the film stress.

  3. Influence of sulfide concentration on the corrosion behavior of titanium in a simulated oral environment.

    PubMed

    Harada, Rino; Takemoto, Shinji; Kinoshita, Hideaki; Yoshinari, Masao; Kawada, Eiji

    2016-05-01

    This study assessed the corrosion behavior of titanium in response to sulfide by determining the effects of sulfide concentration and pH over immersion period. Corrosion was evaluated through changes in color, glossiness, surface characterization, and titanium release. Sulfide solutions were prepared in 3 different concentrations with Na2S, each in pH unadjusted (sulfide-alkaline) and pH adjusted to 7.5 (sulfide-neutral). Titanium discoloration increased and glossiness decreased as sulfide concentration and immersion period increased in sulfide-alkaline solutions. Coral-like complexes were observed on the surface of these specimens, which became more pronounced as concentration increased. Small amounts of titanium release were detected in sulfide-alkaline solutions; however, this was not affected by immersion periods. Corrosion was indicated through considerable surface oxidation suggesting the formation of a thick oxide layer. No significant changes in color and glossiness, or titanium release were indicated for titanium specimens immersed in sulfide-neutral solutions indicating that pH had a significant effect on corrosion. Our findings suggest that a thick oxide layer on the titanium surface was formed in sulfide-alkaline solutions due to excessive oxidation. PMID:26952423

  4. Experimentally reproduced textures and mineral chemistries of high-titanium mare basalts

    NASA Technical Reports Server (NTRS)

    Usselman, T. M.; Lofgren, G. E.; Williams, R. J.; Donaldson, C. H.

    1975-01-01

    Many of the textures, morphologies, and mineral chemistries of the high-titanium mare basalts have been experimentally duplicated using single-stage cooling histories. Lunar high-titanium mare basalts are modeled in a 1 m thick gravitationally differentiating flow based on cooling rates, thermal models, and modal olivine contents. The low-pressure equilibrium phase relations of a synthetic high-titanium basalt composition were investigated as a function of oxygen fugacity, and petrographic criteria are developed for the recognition of phenocrysts which were present in the liquid at the time of eruption.

  5. 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. PMID:26964975

  6. Titanium Optics for Ion Thrusters

    NASA Technical Reports Server (NTRS)

    Soulas, George C.; Haag, Thomas W.; Patterson, Michael J.; Rawlin, Vincent K.

    1999-01-01

    Ion thruster total impulse capability is limited, in part, by accelerator grid sputter erosion. A development effort was initiated to identify a material with a lower accelerator grid volumetric sputter erosion rate than molybdenum, but that could utilize the present NSTAR thruster grid design and fabrication techniques to keep development costs low, and perform as well as molybdenum optics. After comparing the sputter erosion rates of several atomic materials to that of molybdenum at accelerator voltages, titanium was found to offer a 45% reduction in volumetric erosion rates. To ensure that screen grid sputter erosion rates are not higher at discharge chamber potentials, titanium and molybdenum sputter erosion rates were measured at these potentials. Preliminary results showed only a slightly higher volumetric erosion rate for titanium, so that screen grid erosion is insignificant. A number of material, thermal, and mechanical properties were also examined to identify any fabrication, launch environment, and thruster operation issues. Several titanium grid sets were successfully fabricated. A titanium grid set was mounted onto an NSTAR 30 cm engineering model ion thruster and tested to determine optics performance. The titanium optics operated successfully over the entire NSTAR power range of 0.5 to 2.3 kW. Differences in impingement-limited perveances and electron backstreaming limits were found to be due to a larger cold gap for the titanium optics. Discharge losses for titanium grids were lower than those for molybdenum, likely due to a slightly larger titanium screen grid open area fraction. Radial distributions of beam current density with titanium optics were very similar to those with molybdenum optics at all power levels. Temporal electron backstreaming limit measurements showed that titanium optics achieved thermal equilibrium faster than molybdenum optics.

  7. Titanium diboride-chromium diboride-yttrium titanium oxide ceramic composition and a process for making the same

    DOEpatents

    Holcombe, Cressie E.; Dykes, Norman L.

    1991-01-01

    A ceramic composition is described. The ceramic composition consists essentially of from about 84 to 96 w/o titanium diboride, from about 1 to 9 w/o chromium diboride, and from about 3 to about 15 w/o yttrium-titanium-oxide. A method of making the ceramic composition is also described. The method of making the ceramic composition comprises the following steps: Step 1--A consolidated body containing stoichiometric quantities of titanium diboride and chromium diboride is provided. Step 2--The consolidated body is enclosed in and in contact with a thermally insulated package of yttria granules having a thickness of at least 0.5 inches. Step 3--The consolidated body enclosed in the thermally insulated package of yttria granules is heated in a microwave oven with microwave energy to a temperature equal to or greater than 1,900 degrees centigrade to sinter and uniformly disperse yttria particles having a size range from about 1 to about 12 microns throughout the consolidated body forming a densified body consisting essentially of titanium diboride, chromium diboride, and yttrium-titanium-oxide. The resulting densified body has enhanced fracture toughness and hardness.

  8. Expression and prognostic value of GalNAc-T3 in patients with completely resected small (≤2 cm) peripheral lung adenocarcinoma after IASLC/ATS/ERS classification

    PubMed Central

    Zhao, Shilei; Guo, Tao; Li, Jinxiu; Uramoto, Hidetaka; Guan, Hongwei; Deng, Wuguo; Gu, Chundong

    2015-01-01

    cell lines was compared with normal bronchial epithelium cell line. Based on the univariate and multivariate analysis, poor TNM stage (P<0.001), pleural invasion (hazard ratio [HR]: 7.958, P=0.021), vascular invasion (HR: 2.403, P=0.040), and low GalNAc-T3 expression (HR: 3.317, P=0.016) were shown to be independently associated with an unfavorable prognosis. However, IASLC/ATS/ERS classification of risk groups and Sica score (P=0.034 and P=0.032, respectively) was correlated with overall survival on Kaplan–Meier method but not Cox regression model. Conclusion GalNAc-T3 expression was correlated with the IASLC/ATS/ERS classification and also associated with prognosis of patients with completely resected small (≤2 cm) peripheral lung adenocarcinoma. PMID:26604783

  9. Reactive sputtering of titanium diboride and titanium disilicide

    SciTech Connect

    Maya, L.; Vallet, C.E.; Fiedor, J.N.

    1997-07-01

    Nanocomposite films of titanium nitride in either boron nitride or silicon nitride matrices were prepared by reactive sputtering of titanium diboride or titanium disilicide targets in a nitrogen plasma. These films were expected to have high dielectric constants and in the case of the silicon nitride matrix high hardness. The films were characterized by a variety of physicochemical techniques including photoelectron spectroscopy, Rutherford backscattering spectroscopy, RBS, and transmission electron microscopy. The films derived from titanium diboride incorporated oxygen as an inadvertent impurity in the form of titanium monoxide and dioxide. A silicon oxynitride underlayer is suggested by the RBS analysis of the silicon nitride based film, apparently arising from exposure of the native oxide on silicon to the nitrogen plasma. Capacitance measurements of the films showed moderately high dielectric constants of about 30{endash}60 and a hardness of 11 GPa for the silicon nitride nanocomposite. {copyright} {ital 1997 American Vacuum Society.}

  10. Surface properties and biocompatibility of nitrided titanium for abrasion resistant implant materials.

    PubMed

    Tamura, Yutaka; Yokoyama, Atsuro; Watari, Fumio; Kawasaki, Takao

    2002-12-01

    Corrosion, other related properties and biocompatibility of surface nitrided titanium were investigated to examine its possible use as an abrasion resistant implant material. The nitrided layer about 2 microm thick composed of TiN and Ti2N was formed on titanium by a gas nitriding method. The dissolved amount of titanium ion in SBF was as low as the detection limit of ICP, and that in the 1% lactic acid showed no significant difference from titanium. The tissue reaction of the cylindrical implant in soft tissue of rats showed no inflammation, and fine particles of 1 microm induced phagocytosis, which was similar to titanium. The implantation in the femor showed the new bone formed in direct contact with implants. All the results suggested that the wettability, corrosion resistance, S. mutans adhesion and biocompatibility were nearly equivalent to those of titanium. The surface of nitrided titanium was promising, with biocompatibility comparable with titanium, as an implant material such as for an abutment part of a dental implant, which requires high abrasion resistance. PMID:12608425

  11. Titanium minerals for new materials

    NASA Astrophysics Data System (ADS)

    Kotova, O.; Ozhogina, E.; Ponaryadov, A.; Golubeva, I.

    2016-04-01

    The mineral composition of titanium minerals of modern coastal-marine placer in Stradbroke Island (Australia) and Pizhma paleoplacer in Middle Timan (Russia) has been presented. The physical features of titanium minerals and their modification methods were shown. Photocatalysts on the basis of the Pizhma leucoxene were developed for water purification.

  12. Refractory plasmonics with titanium nitride: broadband metamaterial absorber.

    PubMed

    Li, Wei; Guler, Urcan; Kinsey, Nathaniel; Naik, Gururaj V; Boltasseva, Alexandra; Guan, Jianguo; Shalaev, Vladimir M; Kildishev, Alexander V

    2014-12-17

    A high-temperature stable broadband plasmonic absorber is designed, fabricated, and optically characterized. A broadband absorber with an average high absorption of 95% and a total thickness of 240 nm is fabricated, using a refractory plasmonic material, titanium nitride. This absorber integrates both the plasmonic resonances and the dielectric-like loss. It opens a path for the interesting applications such as solar thermophotovoltaics and optical circuits. PMID:25327161

  13. Compaction of Titanium Powders

    SciTech Connect

    Stephen J. Gerdemann; Paul D. Jablonski

    2010-11-01

    Accurate modeling of powder densification has been an area of active research for more than 60 years. The earliest efforts were focused on linearization of the data because computers were not readily available to assist with curve-fitting methods. In this work, eight different titanium powders (three different sizes of sponge fines <150 μm, <75 μm, and < 45 μm; two different sizes of a hydride-dehydride [HDH] <75 μm and < 45 μm; an atomized powder; a commercially pure [CP] Ti powder from International Titanium Powder [ITP]; and a Ti 6 4 alloy powder) were cold pressed in a single-acting die instrumented to collect stress and deformation data during compaction. From these data, the density of each compact was calculated and then plotted as a function of pressure. The results show that densification of all the powders, regardless of particle size, shape, or chemistry, can be modeled accurately as the sum of an initial density plus the sum of a rearrangement term and a work-hardening term. These last two terms are found to be a function of applied pressure and take the form of an exponential rise.

  14. Electrorotation of titanium microspheres.

    PubMed

    Arcenegui, Juan J; Ramos, Antonio; García-Sánchez, Pablo; Morgan, Hywel

    2013-04-01

    Electrorotation (ROT) data for solid titanium micrometer-sized spheres in an electrolyte are presented for three different ionic conductivities, over the frequency range of 10 Hz to 100 kHz. The direction of rotation was found to be opposite to the direction of rotation of the electric field vector (counterfield electrorotation), with a single rotation peak. The maximum rotation rate occurs at a frequency of the order of the reciprocal RC time constant for charging the particle double layer capacitance through the resistor of the electrolyte bulk. A model for the electrical torque acting on a metallic sphere is presented, using a constant phase element impedance to describe the metal/electrolyte interface. The titanium spheres are much denser than the electrolyte and rest on the bottom substrate. Therefore, the electrical and viscous torques near a wall are considered in the analysis. Good agreement is found between the predicted and measured rotational speed as a function of frequency. Theory shows that there is no effect of induced charge electroosmotic flow on the ROT, as observed experimentally. PMID:23348799

  15. Biocompatibility of Titanium

    NASA Astrophysics Data System (ADS)

    Namavar, Fereydoon; Sabirianov, Renat; Marton, Denes; Rubinstein, Alexander; Garvin, Kevin

    2012-02-01

    Titanium is the material of choice for orthopaedic applications because of its known biocompatibility. In order to enhance osteogenic properties of the Ti implants, it is necessary to understand the origin of its biocompatibility. We addresses the origin of Ti biocompatibility through (1) theoretical modeling, (2) the precise determination of Ti surface chemistry by X-ray photoelectron spectroscopy (XPS), (3) and the study of fibronectin adsorption as a function of Ti (near) surface chemistry by Enzyme-linked immunosorbent assay (ELISA). We compare the protein adsorption on Ti with the native oxide layer and the one coated by TiO2 in anatase phase using ion beam assisted deposition (IBAD). We show that the thin native sub-stoichiometric titanium oxide layer is crucial for biocompatibility of Ti surface. This is due to the enhancement of the non-specific adsorption of proteins which mediate cell adhesion. Improving the surface oxide quality, i.e. fabricating stoichiometric TiO2 (using IBAD) as well as nanoengineering the surface topology that matches its dimensions to that of adhesive proteins, is crucial for increased protein adsorption and, as a result, further increases biocompatibility of Ti implant materials.

  16. Titanium in 1980

    NASA Astrophysics Data System (ADS)

    Minkler, Ward W.

    1981-04-01

    Much attention is being focused on the availability and use of non-fuel minerals in the United States. Because of the rapid increase in demand since 1978, titanium has been one of the much-publicized metals in this group. Sponge producers are now expanding sponge manufacturing plants to meet this greater demand, and it now appears that there could be a surplus of sponge in 1981. A delay in airplane purchases caused by severe operating losses of the airlines could have a significant effect on mill product shipments in 1981. However, there is no reason to believe that titanium has reached maturity as a structural aerospace or industrial metal. While it is unreasonable to anticipate that demand will continue to grow at the same rate experienced between 1978 and 1980, new greenfield capacity will nevertheless be required in the early 1980s. Two basic issues must be resolved before such ventures become reality: 1) choice of process; and 2) method for financing, either public or private. Both will be the subject of study and debate in 1981.

  17. 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

  18. Microstructure and biocompatibility of titanium oxides produced on nitrided surface layer under glow discharge conditions.

    PubMed

    Czarnowska, E; Morgiel, J; Ossowski, M; Major, R; Sowinska, A; Wierzchon, T

    2011-10-01

    The disadvantages of titanium implants are their low wear resistance and the release of titanium elements into surrounding tissue. These can be eliminated by modifying the surface by surface engineering methods, among them nitriding under glow discharge conditions which allow to produce diffusive surface layers. Their combining with an oxide layer might be valuable for biological events occurring at the bone implant interface. The aim of this study was to enhance the titanium biomaterial performance via combining nitriding and oxidizing treatments in one process under glow discharge conditions. The oxynitrided surface layers were produced at 680 degrees C. The obtained layer was TiO + TiN + Ti2N + alphaTi(N) type and about 4-microm thick and was of diffusive character. This layer significantly increased wear resistance and slightly corrosion resistance compared to that of the reference titanium alloy. The produced titanium oxide was about 400-nm thick and built from fine crystallites. This oxide exhibits bioactivity in SBF (simulated body fluid). Osteoblasts of Saos-2 line incubated on this surface exhibited good adhesion and proliferation and ALP release comparable with cells cultured on the reference titanium alloy and TiN + Ti2N + alphaTi(N) surface layers. A quantitative analysis of blood platelets adhering to this layer revealed their highest amount in comparison to that on both the nitrided surface layer and titanium alloy. The presented study provided a simple and reproducible method of combining oxidizing and nitriding under glow discharge in one process. Experimental data in vitro suggests that titanium alloy oxynitriding under low temperatures at glow discharge conditions improves titanium alloy properties and biocompatibility and tissue healing. Therefore, the layer of TiO + TiN +Ti2N + alphaTi(N) type could be valuable for long-term bone implants. PMID:22400281

  19. Ballistic Experiments with Titanium and Aluminum Targets

    SciTech Connect

    Gogolewski, R.; Morgan, B.R.

    1999-11-23

    During the course of the project we conducted two sets of fundamental experiments in penetration mechanics in the LLNL Terminal Ballistics Laboratory of the Physics Directorate. The first set of full-scale experiments was conducted with a 14.5mm air propelled launcher. The object of the experiments was to determine the ballistic limit speed of 6Al-4V-alloy titanium, low fineness ratio projectiles centrally impacting 2024-T3 alloy aluminum flat plates and the failure modes of the projectiles and the targets. The second set of one-third scale experiments was conducted with a 14.5mm powder launcher. The object of these experiments was to determine the ballistic limit speed of 6Al-4V alloy titanium high fineness ratio projectiles centrally impacting 6Al-4V alloy titanium flat plates and the failure modes of the projectiles and the target. We employed radiography to observe a projectile just before and after interaction with a target plate. Early on, we employed a non-damaging ''soft-catch'' technique to capture projectiles after they perforated targets. Once we realized that a projectile was not damaged during interaction with a target, we used a 4-inch thick 6061-T6-alloy aluminum witness block with a 6.0-inch x 6.0-inch cross-section to measure projectile residual penetration. We have recorded and tabulated below projectile impact speed, projectile residual (post-impact) speed, projectile failure mode, target failure mode, and pertinent comments for the experiments. The ballistic techniques employed for the experiments are similar to those employed in an earlier study.

  20. Surface characteristics of thermally treated titanium surfaces

    PubMed Central

    Lee, Yang-Jin; Cui, De-Zhe; Jeon, Ha-Ra; Chung, Hyun-Ju; Park, Yeong-Joon; Kim, Ok-Su

    2012-01-01

    Purpose The characteristics of oxidized titanium (Ti) surfaces varied according to treatment conditions such as duration time and temperature. Thermal oxidation can change Ti surface characteristics, which affect many cellular responses such as cell adhesion, proliferation, and differentiation. Thus, this study was conducted to evaluate the surface characteristics and cell response of thermally treated Ti surfaces. Methods The samples were divided into 4 groups. Control: machined smooth titanium (Ti-S) was untreated. Group I: Ti-S was treated in a furnace at 300℃ for 30 minutes. Group II: Ti-S was treated at 500℃ for 30 minutes. Group III: Ti-S was treated at 750℃ for 30 minutes. A scanning electron microscope, atomic force microscope, and X-ray diffraction were used to assess surface characteristics and chemical composition. The water contact angle and surface energy were measured to assess physical properties. Results The titanium dioxide (TiO2) thickness increased as the treatment temperature increased. Additional peaks belonging to rutile TiO2 were only found in group III. The contact angle in group III was significantly lower than any of the other groups. The surface energy significantly increased as the treatment temperature increased, especially in group III. In the 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, after 24 hours of incubation, the assessment of cell viability showed that the optical density of the control had a higher tendency than any other group, but there was no significant difference. However, the alkaline phosphatase activity increased as the temperature increased, especially in group III. Conclusions Consequently, the surface characteristics and biocompatibility increased as the temperature increased. This indicates that surface modification by thermal treatment could be another useful method for medical and dental implants. PMID:22803009

  1. Feasibility of cold rolling titanium strip cast by the plasma melt overflow process

    SciTech Connect

    Gaspar, T.A.; Sukonnik, I.M.; Bird, R.K.; Brewer, W.D.

    1995-12-31

    A new fabrication method tailored specifically for titanium alloys and intermetallics combined direct strip casting and cold rolling to produce foil products by completely eliminating hot working steps. Titanium strips 0.4-mm- to 0.7-mm-thick and 100-mm-wide were cast by the plasma melt overflow process. The cast strips were cold rolled to 0.15-mm-thick, fully dense foils. The effect of thermal and mechanical treatments on the microstructure of the cast strip was investigated. The cold rolled foils were characterized by measurement of average surface roughness, chemical composition, gas content and tensile properties.

  2. Dissimilar friction welding of titanium alloys to alloy 718

    SciTech Connect

    Kuo, M.; Albright, C.E.; Baeslack, W.A. III

    1994-12-31

    The design of advanced, high-performance gas-turbine engines will require the utilization of elevated-temperature titanium-based materials, including conventional alloys, titanium aluminides, and titanium metal-matrix composites. The most efficient utilization of these materials in the engine compressor section would be achieved by directly joining these materials to existing nickel-base superalloys, such as Alloy 718. To date, the dissimilar welding of titanium alloys to nickel-based alloys has not been common practice because intermetallic compounds form in the weld and cause embrittlement. Special welding techniques must be developed to inhibit this compound formation and to provide high strength welds. In this investigation, a friction welding process was developed for joining titanium alloys (Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V) to nickel-based superalloy Alloy 718. An interlayer system comprised of copper and niobium sheet layers was employed as a diffusion barrier and weld deformation enhancer. A postweld heat treatment (PWHT, 700{degrees}C for 20 min in vacuum) under axial pressure (Ksi) was used to improve the joint strength consistency. The following conclusions can be drawn from this investigation: (1) A friction welding technique has been developed for joining titanium alloys (Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V) to Alloy 718 using an interlayer system of niobium and copper. Joint strengths averaging approximately 50 Ksi were achieved. (2) Deformation was concentrated in the interlayers, especially the copper interlayer, during friction welding. Increased reduction in length (RIL) during friction welding resulted in a decrease in the interlayer thicknesses. (3) The EDS results showed that the niobium and copper interlayers prevent interdiffusion between the two parent metals, producing formation of detrimental phases.

  3. Grafting titanium nitride surfaces with sodium styrene sulfonate thin films.

    PubMed

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

    2014-09-01

    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/cm(2). PMID:25280842

  4. 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

  5. Corneal thickness in glaucoma.

    PubMed

    De Cevallos, E; Dohlman, C H; Reinhart, W J

    1976-02-01

    The central corneal stromal thickness of patients with open angle glaucoma, secondary glaucoma (the majority aphakic), or a history of unilateral acute angle closure glaucoma were measured and compared with the stromal thickness of a group of normal patients. In open angle glaucoma, there was a small but significant increase in the average stromal thickness. This thickness increase was, in all likelihood, due to an abnormal function of the endothelium in this disease since the level of the intraocular pressure did not seem to be a factor. There was no correlation between stromal thickness and duration of the glaucoma or type of anti-glaucomatous medication. Most cases of secondary glaucome, controlled medically or not, had markedly increased corneal thickness, again, most likely, due to endothelial damage rather than to level of intraocular pressure. After an angle closure attack, permanent damage to the cornea was found to be rare. PMID:1247273

  6. Strength of inserts in titanium alloy machining

    NASA Astrophysics Data System (ADS)

    Kozlov, V.; Huang, Z.; Zhang, J.

    2016-04-01

    In this paper, a stressed state of a non-worn cutting wedge in a machined titanium alloy (Ti6Al2Mo2Cr) is analyzed. The distribution of contact loads on the face of a cutting tool was obtained experimentally with the use of a ‘split cutting tool’. Calculation of internal stresses in the indexable insert made from cemented carbide (WC8Co) was carried out with the help of ANSYS 14.0 software. Investigations showed that a small thickness of the cutting insert leads to extremely high compressive stresses near the cutting edge, stresses that exceed the ultimate compressive strength of cemented carbide. The face and the base of the insert experience high tensile stresses, which approach the ultimate tensile strength of cemented carbide and increase a probability of cutting insert destruction. If the thickness of the cutting insert is bigger than 5 mm, compressive stresses near the cutting edge decrease, and tensile stresses on the face and base decrease to zero. The dependences of the greatest normal and tangential stresses on thickness of the cutting insert were found. Abbreviation and symbols: m/s - meter per second (cutting speed v); mm/r - millimeter per revolution (feed rate f); MPa - mega Pascal (dimension of specific contact loads and stresses); γ - rake angle of the cutting tool [°] α - clearance angle of the sharp cutting tool [°].

  7. Beta titanium alloys and their role in the titanium industry

    NASA Astrophysics Data System (ADS)

    Bania, Paul J.

    1994-07-01

    The class of titanium alloys generically referred to as the beta alloys is arguably the most versatile in the titanium family. Since these alloys offer the highest strength-to-weight ratios and deepest hardenability of all titanium alloys, one might expect them to compete favorably for a variety of aerospace applications. To the contrary, however, except for one very successful application (Ti-13V-11Cr-3Al on the SR-71), the beta alloys have remained a very small segment of the industry. As a perspective on this situation, this article reviews some past and present applications of titanium alloys. It also descibes some unique new alloys and applications that promise to reverse historical trends.

  8. Descaling and cleaning titanium and titanium alloy surfaces

    SciTech Connect

    Not Available

    1981-01-01

    The recommended practice covers a cleaning and descaling procedure useful to producers, users, and fabricators of titanium and titanium alloys for the removal of ordinary shop soils, oxides, and scales resulting from heat treatment operations and foreign substances present as surface contaminants. The procedures are not mandatory for removal of the indicated soils but rather serve as a guide when titanium and titanium alloys are being processed in the wrought, cast, or fabricated form. The soils should be removed prior to chemical milling, joining, plating, fabrication, and in any situation where foreign substances interfere with the corrosion resistance, stability, and quality of the finished product. The recommended practice discusses processing soil removal, blast cleaning, pickling, descaling, and inspection. (JMT)

  9. Lead Thickness Measurements

    SciTech Connect

    Rucinski, R.; /Fermilab

    1998-02-16

    The preshower lead thickness applied to the outside of D-Zero's superconducting solenoid vacuum shell was measured at the time of application. This engineering documents those thickness measurements. The lead was ordered in sheets 0.09375-inch and 0.0625-inch thick. The tolerance on thickness was specified to be +/- 0.003-inch. The sheets all were within that thickness tolerance. The nomenclature for each sheet was designated 1T, 1B, 2T, 2B where the numeral designates it's location in the wrap and 'T' or 'B' is short for 'top' or 'bottom' half of the solenoid. Micrometer measurements were taken at six locations around the perimeter of each sheet. The width,length, and weight of each piece was then measured. Using an assumed pure lead density of 0.40974 lb/in{sup 3}, an average sheet thickness was calculated and compared to the perimeter thickness measurements. In every case, the calculated average thickness was a few mils thinner than the perimeter measurements. The ratio was constant, 0.98. This discrepancy is likely due to the assumed pure lead density. It is not felt that the perimeter is thicker than the center regions. The data suggests that the physical thickness of the sheets is uniform to +/- 0.0015-inch.

  10. Fibrous capsule formation around titanium and copper.

    PubMed

    Suska, Felicia; Emanuelsson, Lena; Johansson, Anna; Tengvall, Pentti; Thomsen, Peter

    2008-06-15

    Previous studies suggest that implant material properties influence the quality and quantity of fibrous capsule around the implant. However, the precise relation between material surface chemistry, early inflammatory response, and fibrous subsequent repair outcome is still unknown. Titanium (Ti) and copper (Cu), surfaces with different inflammatory potential, were implanted subcutaneously in rats and retrieved fibrous capsules were analyzed after 28 and 56 days. Histological examinations show pronounced differences in capsule morphology. The fibrous capsule around Ti was thinner than that around Cu, with less number of the inflammatory cells in the layer close to the implant surface, and less and smaller blood vessels. The capsule around Cu was thick, with a large number of the inflammatory cells, particularly macrophages and giant cells, and increased number of blood vessels. Our study suggests that material surface properties, which initiate early, multiple cellular inflammatory events, are also associated with increased fibrosis and angiogenesis during repair phase. PMID:17896778

  11. Characterizations of titanium implant surfaces. III.

    PubMed

    Keller, J C; Stanford, C M; Wightman, J P; Draughn, R A; Zaharias, R

    1994-08-01

    There are several reports in the literature concerning the similarities and the differences between the oxide on cpTi and Ti-6A1-4V alloy; however, their biological sequelae are not entirely known. In this work, a series of surface characterization techniques were used in conjunction with short term in vitro biological assays to assess the effects of materials selection (cpTi and Ti alloy) on osteoblast-like cell responses. Surface analysis indicated that with the exception of oxide thickness, there were no significant differences in surface characteristics between the two implant materials. These results were reflected in the biological studies, where the levels of cell attachment and adaptation of the attached cells to the titanium surfaces were similar. These results are in general agreement with previous in vivo studies and continue to indicate that cpTi and Ti alloy are suitable, biologically compatible materials for fabrication of dental implants. PMID:7983092

  12. Advanced titanium processing

    SciTech Connect

    Hartman, Alan D.; Gerdemann, Stephen J.; Schrems, Karol K.; Holcomb, Gordon R.; Argetsinger, Edward R.; Hansen, Jeffrey S.; Paige, Jack I.; Turner, Paul C.

    2001-01-01

    The Albany Research Center of the U.S. Department of Energy has been investigating a means to form useful wrought products by direct and continuous casting of titanium bars using cold-wall induction melting rather than current batch practices such as vacuum arc remelting. Continuous ingots produced by cold-wall induction melting, utilizing a bottomless water-cooled copper crucible, without slag (CaF2) additions had minor defects in the surface such as ''hot tears''. Slag additions as low as 0.5 weight percent were used to improve the surface finish. Therefore, a slag melted experimental Ti-6Al-4V alloy ingot was compared to a commercial Ti-6Al-4V alloy ingot in the areas of physical, chemical, mechanical, and corrosion attributes to address the question, ''Are any detrimental effects caused by slag addition''?

  13. Hydrogen in titanium alloys

    SciTech Connect

    Wille, G W; Davis, J W

    1981-04-01

    The titanium alloys that offer properties worthy of consideration for fusion reactors are Ti-6Al-4V, Ti-6Al-2Sn-4Zr-2Mo-Si (Ti-6242S) and Ti-5Al-6Sn-2Zr-1Mo-Si (Ti-5621S). The Ti-6242S and Ti-5621S are being considered because of their high creep resistance at elevated temperatures of 500/sup 0/C. Also, irradiation tests on these alloys have shown irradiation creep properties comparable to 20% cold worked 316 stainless steel. These alloys would be susceptible to slow strain rate embrittlement if sufficient hydrogen concentrations are obtained. Concentrations greater than 250 to 500 wppm hydrogen and temperatures lower than 100 to 150/sup 0/C are approximate threshold conditions for detrimental effects on tensile properties. Indications are that at the elevated temperature - low hydrogen pressure conditions of the reactors, there would be negligible hydrogen embrittlement.

  14. Controlled implant/soft tissue interaction by nanoscale surface modifications of 3D porous titanium implants

    NASA Astrophysics Data System (ADS)

    Rieger, Elisabeth; Dupret-Bories, Agnès; Salou, Laetitia; Metz-Boutigue, Marie-Helene; Layrolle, Pierre; Debry, Christian; Lavalle, Philippe; Engin Vrana, Nihal

    2015-05-01

    Porous titanium implants are widely employed in the orthopaedics field to ensure good bone fixation. Recently, the use of porous titanium implants has also been investigated in artificial larynx development in a clinical setting. Such uses necessitate a better understanding of the interaction of soft tissues with porous titanium structures. Moreover, surface treatments of titanium have been generally evaluated in planar structures, while the porous titanium implants have complex 3 dimensional (3D) architectures. In this study, the determining factors for soft tissue integration of 3D porous titanium implants were investigated as a function of surface treatments via quantification of the interaction of serum proteins and cells with single titanium microbeads (300-500 μm in diameter). Samples were either acid etched or nanostructured by anodization. When the samples are used in 3D configuration (porous titanium discs of 2 mm thickness) in vivo (in subcutis of rats for 2 weeks), a better integration was observed for both anodized and acid etched samples compared to the non-treated implants. If the implants were also pre-treated with rat serum before implantation, the integration was further facilitated. In order to understand the underlying reasons for this effect, human fibroblast cell culture tests under several conditions (directly on beads, beads in suspension, beads encapsulated in gelatin hydrogels) were conducted to mimic the different interactions of cells with Ti implants in vivo. Physical characterization showed that surface treatments increased hydrophilicity, protein adsorption and roughness. Surface treatments also resulted in improved adsorption of serum albumin which in turn facilitated the adsorption of other proteins such as apolipoprotein as quantified by protein sequencing. The cellular response to the beads showed considerable difference with respect to the cell culture configuration. When the titanium microbeads were entrapped in cell

  15. Development of technologies for welding interconnects to fifty-micron thick silicon solar cells

    NASA Technical Reports Server (NTRS)

    Patterson, R. E.

    1982-01-01

    A program was conducted to develop technologies for welding interconnects to 50 microns thick, 2 by 2 cm solar cells. The cells were characterized with respect to electrical performance, cell thickness, silver contact thickness, contact waviness, bowing, and fracture strength. Weld schedules were independently developed for each of the three cell types and were coincidentally identical. Thermal shock tests (100 cycles from 100 C to -180 C) were performed on 16 cell coupons for each cell type without any weld joint failures or electrical degradation. Three 48 cell modules (one for each cell type) were assembled with 50 microns thick cells, frosted fused silica covers, silver clad Invar interconnectors, and Kapton substrates.

  16. Brazing titanium to stainless steel

    NASA Technical Reports Server (NTRS)

    Batista, R. I.

    1980-01-01

    Titanium and stainless-steel members are usually joined mechanically for lack of any other effective method. New approach using different brazing alloy and plating steel member with nickel resolves problem. Process must be carried out in inert atmosphere.

  17. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, Barbara S.; Lauf, Robert J.

    1995-01-01

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors.

  18. Thick film hydrogen sensor

    DOEpatents

    Hoffheins, B.S.; Lauf, R.J.

    1995-09-19

    A thick film hydrogen sensor element includes an essentially inert, electrically-insulating substrate having deposited thereon a thick film metallization forming at least two resistors. The metallization is a sintered composition of Pd and a sinterable binder such as glass frit. An essentially inert, electrically insulating, hydrogen impermeable passivation layer covers at least one of the resistors. 8 figs.

  19. Education and "Thick" Epistemology

    ERIC Educational Resources Information Center

    Kotzee, Ben

    2011-01-01

    In this essay Ben Kotzee addresses the implications of Bernard Williams's distinction between "thick" and "thin" concepts in ethics for epistemology and for education. Kotzee holds that, as in the case of ethics, one may distinguish between "thick" and "thin" concepts of epistemology and, further, that this distinction points to the importance of…

  20. Coating Films of Titanium Nitride Prepared by Ion and Vapor Deposition Method

    NASA Astrophysics Data System (ADS)

    Satou, Mamoru; Andoh, Yasunori; Ogata, Kiyoshi; Suzuki, Yasuo; Matsuda, Koji; Fujimoto, Fuminori

    1985-06-01

    Titanium nitride coating films were prepared on polished stainless steel and graphite plates by vacuum evaporation of titanium with simultaneous bombardment by nitrogen ions with an energy of 10 to 30 keV (IVD method). The compositional variations of each element with depth and the crystal structure were analysed by means of XPS, RBS and X-ray diffraction. It was confirmed that a significant intermixed layer exists at the interface. The thickness of this layer was about 440 Å for a film prepared on a stainless-steel plate at about 300°C by a 30 keV nitrogen ion beam, and decreased with decrease of the ion energy. Films were mainly composed of TiN crystallites with [100] axes preferentially oriented normal to the film surfaces. Some titanium was bound to oxygen and carbon atoms, but there were no metallic-state titanium atoms.

  1. Dense and porous titanium substrates with a biomimetic calcium phosphate coating

    NASA Astrophysics Data System (ADS)

    Ribeiro, A. A.; Balestra, R. M.; Rocha, M. N.; Peripolli, S. B.; Andrade, M. C.; Pereira, L. C.; Oliveira, M. V.

    2013-01-01

    The present work studied a biomimetic method using a simplified solution (SS) with calcium and phosphorus ions for coating titanium substrates, in order to improve their bioactivity. Commercially pure titanium dense sheet, microporous and macroporous titanium samples, both produced by powder metallurgy, were treated in NaOH solution followed by heat-treating and immersed in SS for 7, 14 or 21 days. The samples characterization was performed by quantitative metallographic analysis, confocal scanning optical microscopy, scanning electron microscopy, energy dispersive spectroscopy and low angle X-ray diffraction. The results showed coatings with calcium phosphate precipitation in all samples, with globular or plate-like morphology, typical of hydroxyapatite and octacalcium phosphate, respectively, indicating that the solution (SS) has potential for coating titanium substrates. In addition, the different surfaces of substrates had an effect on the formed calcium phosphate phase and thickness of coatings, depending on the substrate type and imersion time in the simplified solution.

  2. Continuous production of titanium powder

    SciTech Connect

    Gerdemann, Stephen J.; Oden, Laurence L.; White, Jack C.

    1997-01-01

    Although incremental improvements have been made to the Kroll process since its inception in 1948, the process in use today remains essentially the same batch process developed by Dr. Kroll and perfected by the U.S. Bureau of Mines. In this process, titanium tetrachloride (TiCl4) is reduced by magnesium to produce titanium metal. There are two major limitations to the Kroll process: (1) it is a batch process; and (2) the reduction of TiCl4 proceeds so rapidly that the sponge formed is an interlocking dendritic mass with inclusions of magnesium, magnesium salts and titanium subchloride that must undergo several purification steps before the metal is suitable for use. The Albany Research Center (ARC), formerly the U.S. Bureau of Mines, has investigated a new, continuous titanium metal production process in which a titanium powder is produced in a bath of molten salt. In this process, the rate of the reduction reaction was slowed and controlled by diluting the reactants with molten chloride salts. The diluted reactant streams were combined in a continuous stirred tank reactor, operated much like a crystallizer. New titanium metal forms on the already present small Ti particles. When the Ti particles become too large to remain suspended in solution, they fall to the bottom of the reactor and are removed. Initial experiments show promise but problems remain in obtaining the required purity and uniform particle size.

  3. Low cost titanium--myth or reality

    SciTech Connect

    Turner, Paul C.; Hartman, Alan D.; Hansen, Jeffrey S.; Gerdemann, Stephen J.

    2001-01-01

    In 1998, approximately 57,000 tons of titanium metal was consumed in the form of mill products (1). Only about 5% of the 4 million tons of titanium minerals consumed each year is used to produce titanium metal, with the remainder primarily used to produce titanium dioxide pigment. Titanium metal production is primarily based on the direct chlorination of rutile to produce titanium tetrachloride, which is then reduced to metal using the Kroll magnesium reduction process. The use of titanium is tied to its high strength-to-weight ratio and corrosion resistance. Aerospace is the largest application for titanium, and titanium cost has prevented its use in non-aerospace applications including the automotive and heavy vehicle industries.

  4. Titanium Isopropoxide Precursor Volume Consumption as a Function of Temperature for Titanium Dioxide Thin Films Grown by Atomic Layer Deposition

    NASA Astrophysics Data System (ADS)

    Constantin, Costel

    2012-02-01

    Atomic layer deposition (ALD) offers tremendous opportunities for controlling material synthesis on an atomic level and for creating nanolayers with unique new functionalities. ALD is a chemical gas phase thin film deposition method based on alternating surface reactions that employs two or more precursors. ALD is often used for growth of high k dielectric constant oxide films. Titanium dioxide material have a k value of 80, and a band gap of ˜ 3 eV, and due to strong oxidizing properties thin films coated on construction materials and glass have fog proof, and self cleaning properties. Our ALD reactor employs liquid Titanium Isopropoxide [TiOCH(CH3)24] as a metal precursor and distilled H2O as an oxygen source to grow thin films of titanium dioxide [TiO2] on silicon [Si], gallium nitride [GaN], and Aluminium foil [Al-foil] substrates. Titanium Isopropoxide exhibit a vapor pressure surge above 40^o C and we report the volume precursor consumption as a function of precursor temperature and thin film thickness for ALD grown TiO2 on Si, GaN, and Al-foil substrates. We will also present dielectric constants of the TiO2 thin films measured with a variable angle spectroscopic ellipsometer.

  5. Induction Bonding of Prepreg Tape and Titanium Foil

    NASA Technical Reports Server (NTRS)

    Messier, Bernadette C.; Hinkley, Jeffrey A.; Johnston, Norman J.

    1998-01-01

    Hybrid structural laminates made of titanium foil and carbon fiber reinforced polymer composite offer a potential for improved performance in aircraft structural applications. To obtain information needed for the automated fabrication of hybrid laminates, a series of bench scale tests were conducted of the magnetic induction bonding of titanium foil and thermoplastic prepreg tape. Foil and prepreg specimens were placed in the gap of a toroid magnet mounted in a bench press. Several magnet power supplies were used to study power at levels from 0.5 to 1.75 kW and frequencies from 50 to 120 kHz. Sol-gel surface-treated titanium foil, 0.0125 cm thick, and PIXA/IM7 prepreg tape were used in several lay-up configurations. Data were obtained on wedge peel bond strength, heating rate, and temperature ramp over a range of magnet power levels and frequencies at different "power-on" times for several magnet gap dimensions. These data will be utilized in assessing the potential for automated processing. Peel strengths of foil-tape bonds depended on the maximum temperature reached during heating and on the applied pressure. Maximum peel strengths were achieved at 1.25kW and 8OkHz. Induction heating of the foil appears to be capable of good bonding up to 10 plies of tape. Heat transfer calculations indicate that a 20-40 C temperature difference exists across the tape thickness during heat-up.

  6. Omega phase formation in titanium and titanium alloys

    SciTech Connect

    Gray, G.T. III; Morris, C.E.; Lawson, A.C.

    1992-05-01

    Although the response of titanium alloys to dynamic loading is receiving increased attention in the literature (particularly in the area of shear-band formation), a more limited experimental database exists concerning the detailed structure/property relationships of titanium alloys subjected to shock loading. In this study, preliminary results concerning the influence of alloy chemistry on the property of omega-phase formation and its structure in three titanium alloys are presented. The influence of shock-wave deformation on the phase stability and substructure evolution of high-purity (low-interstitial) titanium, A-70 (3700 ppm oxygen) titanium, and Ti-6Al-4V were probed utilizing real-time velocity interferometry (VISAR) and ``soft`` shock-recovery techniques. VISAR wave profiles of shock-loaded high-purity titanium revealed the omega-phase pressure-induced transition to occur at approximately 10.4 GPa. Wave profile measurements on A-70 Ti shocked to pressures up to 35 GPa and Ti-6Al-4V shocked to pressures up to 25 GPa exhibited no evidence of a three-wave structure indicative of a pressure-induced phase transition. Neutron and X-ray diffractometry and TEM analysis confirmed the presence of retained {omega}-phase in the electrolytic-Ti and the absence of {omega}-phase in the shock-recovered A-70 Ti and Ti-6Al-4V. Suppression of the {alpha}-{omega} phase transition in A-70 Ti, containing a high interstitial oxygen content, is seen to simultaneously correlate with suppression of deformation twinning. Neutron diffraction was used to measure the in-situ bulk lattice constants and volume fraction of the {alpha} and {omega} phases in the recovered high-purity titanium samples that were shock loaded. The influence of alloy content on the kinetics of formation/retention of {omega}-phase and substructure evolution is discussed and contrasted in light of previous literature studies.

  7. Removing Biofilms from Microstructured Titanium Ex Vivo: A Novel Approach Using Atmospheric Plasma Technology

    PubMed Central

    Rupf, Stefan; Idlibi, Ahmad Nour; Marrawi, Fuad Al; Hannig, Matthias; Schubert, Andreas; von Mueller, Lutz; Spitzer, Wolfgang; Holtmann, Henrik; Lehmann, Antje; Rueppell, Andre; Schindler, Axel

    2011-01-01

    The removal of biofilms from microstructured titanium used for dental implants is a still unresolved challenge. This experimental study investigated disinfection and removal of in situ formed biofilms from microstructured titanium using cold atmospheric plasma in combination with air/water spray. Titanium discs (roughness (Ra): 1.96 µm) were exposed to human oral cavities for 24 and 72 hours (n = 149 each) to produce biofilms. Biofilm thickness was determined using confocal laser scanning microscopy (n = 5 each). Plasma treatment of biofilms was carried out ex vivo using a microwave-driven pulsed plasma source working at temperatures from 39 to 43°C. Following plasma treatment, one group was air/water spray treated before re-treatment by second plasma pulses. Vital microorganisms on the titanium surfaces were identified by contact culture (Rodac agar plates). Biofilm presence and bacterial viability were quantified by fluorescence microscopy. Morphology of titanium surfaces and attached biofilms was visualized by scanning electron microscopy (SEM). Total protein amounts of biofilms were colorimetrically quantified. Untreated and air/water treated biofilms served as controls. Cold plasma treatment of native biofilms with a mean thickness of 19 µm (24 h) to 91 µm (72 h) covering the microstructure of the titanium surface caused inactivation of biofilm bacteria and significant reduction of protein amounts. Total removal of biofilms, however, required additional application of air/water spray, and a second series of plasma treatment. Importantly, the microstructure of the titanium discs was not altered by plasma treatment. The combination of atmospheric plasma and non-abrasive air/water spray is applicable for complete elimination of oral biofilms from microstructured titanium used for dental implants and may enable new routes for the therapy of periimplant disease. PMID:22016784

  8. Synthesis and characterization of titanium carbide, titanium boron carbonitride, titanium boride/titanium carbide and titanium carbide/chromium carbide multilayer coatings by reactive and ion beam assisted, electron beam-physical vapor deposition (EB-PVD)

    NASA Astrophysics Data System (ADS)

    Wolfe, Douglas Edward

    The purpose of the present work was to investigate the synthesis of titanium carbide, TiBCN, TiB2/TiC and TiC/Cr23C6 multilayer coatings by several methods of electron beam-physical vapor deposition (EB-PVD) and examine the affects of various processing parameters on the properties and microstructures of the coatings. TiC was successfully deposited by reactive ion beam assisted (RIBA), EB-PVD and the results were compared to various titanium carbide coatings deposited by a variety of techniques. The affects of substrate temperature and ion beam current density were correlated with composition, hardness, changes in the lattice parameter, degree of crystallographic texture, residual stress, surface morphology, and microstructure. The average Vicker's hardness number was found to increase with increasing ion beam current density and increase over the substrate temperature range of 250°C to 650°C. The average Vicker's hardness number decreased at a substrate temperature of 750°C as a result of texturing and microstructure. The present investigation shows that the average Vicker's hardness number is not only a function of the composition, but also the microstructure including the degree of crystallographic texture. TiB2/TiC multilayer coatings were deposited by argon ion beam assisted, EB-PVD with varying number of total layers to two different film thicknesses under slightly different deposition conditions. In both cases, the hardness of the coatings increased with increasing number of total layers. The adhesion of the coatings ranged from 30 N to 50 N, with the better adhesion values obtained with the thinner coatings. The crystallographic texture coefficients of both the TiC and TiB2 layers were found to change with increasing number of total layers. The multilayer design was found to significantly affect the microstructure and grain size of the deposited coatings. The fracture toughness was found to decrease with increasing number of total layers and was

  9. Titanium nanostructures for biomedical applications.

    PubMed

    Kulkarni, M; Mazare, A; Gongadze, E; Perutkova, Š; Kralj-Iglič, V; Milošev, I; Schmuki, P; A Iglič; Mozetič, M

    2015-02-13

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties. PMID:25611515

  10. Titanium nanostructures for biomedical applications

    NASA Astrophysics Data System (ADS)

    Kulkarni, M.; Mazare, A.; Gongadze, E.; Perutkova, Š.; Kralj-Iglič, V.; Milošev, I.; Schmuki, P.; Iglič, A.; Mozetič, M.

    2015-02-01

    Titanium and titanium alloys exhibit a unique combination of strength and biocompatibility, which enables their use in medical applications and accounts for their extensive use as implant materials in the last 50 years. Currently, a large amount of research is being carried out in order to determine the optimal surface topography for use in bioapplications, and thus the emphasis is on nanotechnology for biomedical applications. It was recently shown that titanium implants with rough surface topography and free energy increase osteoblast adhesion, maturation and subsequent bone formation. Furthermore, the adhesion of different cell lines to the surface of titanium implants is influenced by the surface characteristics of titanium; namely topography, charge distribution and chemistry. The present review article focuses on the specific nanotopography of titanium, i.e. titanium dioxide (TiO2) nanotubes, using a simple electrochemical anodisation method of the metallic substrate and other processes such as the hydrothermal or sol-gel template. One key advantage of using TiO2 nanotubes in cell interactions is based on the fact that TiO2 nanotube morphology is correlated with cell adhesion, spreading, growth and differentiation of mesenchymal stem cells, which were shown to be maximally induced on smaller diameter nanotubes (15 nm), but hindered on larger diameter (100 nm) tubes, leading to cell death and apoptosis. Research has supported the significance of nanotopography (TiO2 nanotube diameter) in cell adhesion and cell growth, and suggests that the mechanics of focal adhesion formation are similar among different cell types. As such, the present review will focus on perhaps the most spectacular and surprising one-dimensional structures and their unique biomedical applications for increased osseointegration, protein interaction and antibacterial properties.

  11. Histomorphometric and histologic evaluation of titanium-zirconium (aTiZr) implants with anodized surfaces.

    PubMed

    Sharma, Ajay; McQuillan, A James; Shibata, Yo; Sharma, Lavanya A; Waddell, John Neil; Duncan, Warwick John

    2016-05-01

    The choice of implant surface has a significant influence on osseointegration. Modification of TiZr surface by anodization is reported to have the potential to modulate the osteoblast cell behaviour favouring more rapid bone formation. The aim of this study is to investigate the effect of anodizing the surface of TiZr discs with respect to osseointegration after four weeks implantation in sheep femurs. Titanium (Ti) and TiZr discs were anodized in an electrolyte containing DL-α-glycerophosphate and calcium acetate at 300 V. The surface characteristics were analyzed by scanning electron microscopy, electron dispersive spectroscopy, atomic force microscopy and goniometry. Forty implant discs with thickness of 1.5 and 10 mm diameter (10 of each-titanium, titanium-zirconium, anodized titanium and anodized titanium-zirconium) were placed in the femoral condyles of 10 sheep. Histomorphometric and histologic analysis were performed 4 weeks after implantation. The anodized implants displayed hydrophilic, porous, nano-to-micrometer scale roughened surfaces. Energy dispersive spectroscopy analysis revealed calcium and phosphorous incorporation into the surface of both titanium and titanium-zirconium after anodization. Histologically there was new bone apposition on all implanted discs, slightly more pronounced on anodised discs. The percentage bone-to-implant contact measurements of anodized implants were higher than machined/unmodified implants but there was no significant difference between the two groups with anodized surfaces (P > 0.05, n = 10). The present histomorphometric and histological findings confirm that surface modification of titanium-zirconium by anodization is similar to anodised titanium enhances early osseointegration compared to machined implant surfaces. PMID:26970768

  12. Light-induced chemical vapour deposition painting with titanium dioxide

    NASA Astrophysics Data System (ADS)

    Halary-Wagner, E.; Bret, T.; Hoffmann, P.

    2003-03-01

    Light-induced chemical vapour deposits of titanium dioxide are obtained from titanium tetra-isopropoxide (TTIP) in an oxygen and nitrogen atmosphere with a long pulse (250 ns) 308 nm XeCl excimer laser using a mask projection set-up. The demonstrated advantages of this technique are: (i) selective area deposition, (ii) precise control of the deposited thickness and (iii) low temperature deposition, enabling to use a wide range of substrates. A revolving mask system enables, in a single reactor load, to deposit shapes of controlled heights, which overlap to build up a complex pattern. Interferential multi-coloured deposits are achieved, and the process limitations (available colours and resolution) are discussed.

  13. Powder metallurgy titanium 6A1-4V plate

    SciTech Connect

    Geisendorfer, R.F.

    1980-01-01

    A powder metallurgical approach has been combined with controlled mill processing to produce a highly uniform plate material suitable for structural applications. Prealloyed ELI Titanium 6A1-4V powder produced by the rotating electrode process was consolidated into billet by hot isostatic pressing. The resulting billet of uniform composition and random texture was then hot cross-rolled to 3 cm thick plate. Following rolling, the plate was given a beta annealing heat treatment to maximize damage tolerance. The plate was characterized with respect to metallurgical structure, composition, texture, and room temperature mechanical properties. The results of the study show that a powder metallurgy titanium mill product possessing uniform macro- and microstructure is technically feasible and exhibits tensile and fatigue properties equivalent to those of conventionally produced ingot-source wrought plate.

  14. Effect of casting methods on castability of pure titanium.

    PubMed

    Takahashi, J; Zhang, J Z; Okazaki, M

    1993-12-01

    Two types of patterns were tested for castability: 1) polyester mesh pattern (20mm x 22mm with 100 open squares) and 2) 20mm x 20mm wax plates 1.0 and 1.5 mm in thickness. These materials were invested using a pre-arranged commercial phosphate-bonded investment for titanium. Three different types of casting machines were selected: 1) a pressure-type casting machine with separate melting and casting chambers, 2) a pressure-type casting machine with one chamber and 3) a centrifugal-type casting machine at 3000 rpm. Pure titanium (> 99.5%) was cast into the molds at a mold temperature of 100 degrees C. The castability of mesh pattern was evaluated in terms of the number of cast segment, and the cast plate was evaluated using X-ray transparent images by a digital imaging technique. The centrifugal casting method showed the best castability among these three casting methods. PMID:8004920

  15. Origami of thick panels

    NASA Astrophysics Data System (ADS)

    Chen, Yan; Peng, Rui; You, Zhong

    2015-07-01

    Origami patterns, including the rigid origami patterns in which flat inflexible sheets are joined by creases, are primarily created for zero-thickness sheets. In order to apply them to fold structures such as roofs, solar panels, and space mirrors, for which thickness cannot be disregarded, various methods have been suggested. However, they generally involve adding materials to or offsetting panels away from the idealized sheet without altering the kinematic model used to simulate folding. We develop a comprehensive kinematic synthesis for rigid origami of thick panels that differs from the existing kinematic model but is capable of reproducing motions identical to that of zero-thickness origami. The approach, proven to be effective for typical origami, can be readily applied to fold real engineering structures.

  16. Measuring coal thickness

    NASA Technical Reports Server (NTRS)

    Barker, C.; Blaine, J.; Geller, G.; Robinson, R.; Summers, D.; Tyler, J.

    1980-01-01

    Laboratory tested concept, for measuring thickness of overhead coal using noncontacting sensor system coupled to controller and high pressure water jet, allows mining machines to remove virtually all coal from mine roofs without danger of cutting into overlying rock.

  17. Importance of Corneal Thickness

    MedlinePlus

    ... News About Us Donate In This Section The Importance of Corneal Thickness email Send this article to ... is important because it can mask an accurate reading of eye pressure, causing doctors to treat you ...

  18. United States crustal thickness

    NASA Technical Reports Server (NTRS)

    Allenby, R. J.; Schnetzler, C. C.

    1983-01-01

    The thickness of the crust, the thickness of the basal (intermediate or lower) crustal layer, and the average velocity at the top of the mantle have been mapped using all available deep-penetrating seismic-refraction profiles in the conterminous United States and surrounding border areas. These profiles are indexed to their literature data sources. The more significant long wavelength anomalies on the three maps are briefly discussed and analyzed. An attempt to use Bouguer gravity to validate mantle structure was inconclusive.

  19. Evaluation of outer flaws in titanium alloys using eddy current measuring system

    SciTech Connect

    Chady, T.; Psuj, G.; Kowalczyk, J.

    2011-06-23

    In this paper results of shallow outer flaw detection in thick titanium alloy specimens is presented. In order to increase efficiency of inspections of minor defects an eddy current measuring system with a lock-in amplifier was used. The measurements were carried out for flat and cylindrical specimens with artificial flaws.

  20. Evaluation of Outer Flaws in Titanium Alloys Using Eddy Current Measuring System

    NASA Astrophysics Data System (ADS)

    Chady, T.; Psuj, G.; Kowalczyk, J.

    2011-06-01

    In this paper results of shallow outer flaw detection in thick titanium alloy specimens is presented. In order to increase efficiency of inspections of minor defects an eddy current measuring system with a lock-in amplifier was used. The measurements were carried out for flat and cylindrical specimens with artificial flaws.

  1. Titanium honeycomb panel testing

    NASA Astrophysics Data System (ADS)

    Richards, W. L.; Thompson, Randolph C.

    The paper describes the procedures of thermal mechanical tests carried out at the NASA Dryden Flight Research Facility on two tianium honeycomb wing panels bonded using liquid interface diffusion (LID) technique, and presents the results of these tests. The 58.4 cm square panels consisted of two 0.152-cm-thick Ti 6-2-4-2 face sheets LID-bonded to a 1.9-cm-thick honeycomb core, with bearing plates fastened to the perimeter of the upper and the lower panel surfaces. The panels were instrumented with sensors for measuring surface temperature, strain, and deflections to 315 C and 482 C. Thermal stress levels representative of those encountered during aerodynamic heating were produced by heating the upper panel surface and restraining all four edges. After more than 100 thermal cycles from room temperature to 315 C and 50 cycles from room temperature to 482 C, no significant structural degradation was detected in the panels.

  2. Titanium honeycomb panel testing

    NASA Technical Reports Server (NTRS)

    Richards, W. L.; Thompson, Randolph C.

    1991-01-01

    The paper describes the procedures of thermal mechanical tests carried out at the NASA Dryden Flight Research Facility on two tianium honeycomb wing panels bonded using liquid interface diffusion (LID) technique, and presents the results of these tests. The 58.4 cm square panels consisted of two 0.152-cm-thick Ti 6-2-4-2 face sheets LID-bonded to a 1.9-cm-thick honeycomb core, with bearing plates fastened to the perimeter of the upper and the lower panel surfaces. The panels were instrumented with sensors for measuring surface temperature, strain, and deflections to 315 C and 482 C. Thermal stress levels representative of those encountered during aerodynamic heating were produced by heating the upper panel surface and restraining all four edges. After more than 100 thermal cycles from room temperature to 315 C and 50 cycles from room temperature to 482 C, no significant structural degradation was detected in the panels.

  3. Plasma quench production of titanium from titanium tetrachloride

    SciTech Connect

    Sears, J.W.

    1994-10-01

    This project, Plasma Quench Production of Titanium from Titanium Tetrachloride, centers on developing a technique for rapidly quenching the high temperature metal species and preventing back reactions with the halide. The quenching technique chosen uses the temperature drop produced in a converging/diverging supersonic nozzle. The rapid quench provided by this nozzle prevents the back reaction of the halide and metal. The nature of the process produces nanosized particles (10 to 100 nm). The powders are collected by cyclone separators, the hydrogen flared, and the acid scrubbed. Aluminum and titanium powders have been produced in the laboratory-scale device at 1 gram per hour. Efforts to date to scale up this process have not been successful.

  4. Titanium pigmentation. An electron probe microanalysis study

    SciTech Connect

    Dupre, A.; Touron, P.; Daste, J.; Lassere, J.; Bonafe, J.L.; Viraben, R.

    1985-05-01

    A patient had an unusual pigmentary disease induced by titanium dioxide. The use of a topical cream containing titanium dioxide caused a xanthomalike appearance on the patient's penis. Electron probe microanalysis was valuable in establishing the cause of this balanitis.

  5. Method for Surface Texturing Titanium Products

    NASA Technical Reports Server (NTRS)

    Banks, Bruce A. (Inventor)

    1998-01-01

    The present invention teaches a method of producing a textured surface upon an arbitrarily configured titanium or titanium alloy object for the purpose of improving bonding between the object and other materials such as polymer matrix composites and/or human bone for the direct in-growth of orthopaedic implants. The titanium or titanium alloy object is placed in an electrolytic cell having an ultrasonically agitated solution of sodium chloride therein whereby a pattern of uniform "pock mark" like pores or cavities are produced upon the object's surface. The process is very cost effective compared to other methods of producing rough surfaces on titanium and titanium alloy components. The surface textures produced by the present invention are etched directly into the parent metal at discrete sites separated by areas unaffected by the etching process. Bonding materials to such surface textures on titanium or titanium alloy can thus support a shear load even if adhesion of the bonding material is poor.

  6. Comparative Evaluation of Antifungal Effect of Titanium, Zirconium and Aluminium Nanoparticles Coated Titanium Plates Against C. albicans

    PubMed Central

    Mohandoss, Karthikeyan; Balasubramaniam, Muthu Kumar

    2016-01-01

    Introduction The topographical modifications may vary from millimeter wide grooves to nano size structures. Recently growing nano technology is rapidly advancing surface engineering in implant dentistry. This advancement has resulted in difference in surface properties including the morphology, chemistry, crystal structure and mechanical properties of the implant. Aim To evaluate the anticandidal effect of titanium, zirconium and aluminium nanoparticles against C. albicans at 24 hours, 72 hours and one week time interval. Materials and Methods According to ISO/TR 11175:1993, the samples were prepared with the dimension of 20mm diameter and 1mm thickness in grade IV titanium. A total of 40 samples were made and the samples were divided into four groups. The samples without coating were Group-A (control), samples coated with titanium nano particles were Group-B, samples coated with zirconium nano particles were Group-C and samples coated with aluminium nano particles were Group-D. The samples were cleaned by sonicating in acetone and subsequently in water three times for 15 min. Then they were treated with TiO2, ZrO2 and Al2O3 nanoparticles. The discs were sterilized under uv radiation and placed in SDA for C.albicans. The colonies were counted in 24, 72 hours and one week intervals. Results The values were statistically analyzed using one-way ANOVA and Tukey HSD Test. Significance p-value was < .001, which showed that significant difference in C.F.U among the groups in titanium coated samples at 24 hours, 72 hours and one week time intervals. Conclusion TiO2 nanoparticles coated titanium plates showed significant anticandidal effect compared to ZrO2 and Al2O3 nanoparticles at 24, 72 hours and one week time interval. PMID:26894177

  7. Process for reproducibly preparing titanium subhydride

    SciTech Connect

    Carlson, R.S.

    1982-01-05

    Titanium subhydride is produced in a reactor by heating a selected amount of finely divided titanium compound at a selected temperature for a selected period of time under dynamic vacuum conditions. Hydrogen is removed substantially uniformly from each powder grain and there is produced a subhydride of substantially uniform titanium-hydrogen composition. Selection of the amount, temperature and time produces a subhydride of selected titanium hydrogen composition.

  8. Process for reproducibly preparing titanium subhydride

    DOEpatents

    Carlson, Richard S.

    1982-01-01

    Titanium subhydride is produced in a reactor by heating a selected amount of finely divided titanium compound at a selected temperature for a selected period of time under dynamic vacuum conditions. Hydrogen is removed substantially uniformly from each powder grain and there is produced a subhydride of substantially uniform titanium-hydrogen composition. Selection of the amount, temperature and time produces a subhydride of selected titanium-hydrogen composition.

  9. Characterization and protein-adsorption behavior of deposited organic thin film onto titanium by plasma polymerization with hexamethyldisiloxane.

    PubMed

    Hayakawa, Tohru; Yoshinari, Masao; Nemoto, Kimiya

    2004-01-01

    Plasma polymerized hexamethyldisiloxane (HMDSO) thin film was deposited onto titanium using a radio-frequency apparatus for the surface modification of titanium. A titanium disk was first polished using colloidal silica at pH=9.8. Plasma-polymerized HMDSO films were firmly attached to the titanium by heating the titanium to a temperature of approximately 250 degrees C. The thickness of the deposited film was 0.07-0.35mum after 10-60min of plasma polymerization. The contact angle with respect to double distilled water significantly increased after HMDSO coating. X-ray photoelectron spectroscopy revealed that the deposited thin film consisted of Si, C, and O atoms. No Ti peaks were observed on the deposited surface. The deposited HMDSO film was stable during 2-weeks immersion in phosphate buffer saline solution. Fourier transform reflection-absorption spectroscopy showed the formation of Si-H, Si-C, C-H, and Cz.dbnd6;O bonds in addition to Si-O-Si bonds. Quartz crystal microbalance-dissipation measurement demonstrated that the deposition of HMDSO thin films on titanium has a benefit for fibronectin adsorption at the early stage. In conclusion, plasma polymerization is a promising technique for the surface modification of titanium. HMDSO-coated titanium has potential application as a dental implant material. PMID:14580915

  10. Performance of supercapacitor with electrodeposited ruthenium oxide film electrodes—effect of film thickness

    NASA Astrophysics Data System (ADS)

    Park, Bong-Ok; Lokhande, C. D.; Park, Hyung-Sang; Jung, Kwang-Deog; Joo, Oh-Shim

    Thin-film ruthenium oxide electrodes are prepared by cathodic electrodeposition on a titanium substrate. Different deposition periods are used to obtain different film thicknesses. The electrodes are used to form a supercapacitor with a 0.5 M H 2SO 4 electrolyte. The specific capacitance and charge-discharge periods are found to be dependent on the electrode thickness. A maximum specific capacitance of 788 F g -1 is achieved with an electrode thickness of 0.0014 g cm -2. These results are explained by considering the morphological changes that take place with increasing film thickness.

  11. Mechanical properties of titanium connectors.

    PubMed

    Neo, T K; Chai, J; Gilbert, J L; Wozniak, W T; Engelman, M J

    1996-01-01

    The tensile mechanical properties of welded titanium joints were studied, and intact titanium was used as controls. Welded joints were fabricated with either a stereographic laser-welding technique or a gas tungsten arc welding technique. The effect of heat treatment following a simulated porcelain application was also investigated. Heat-treated laser welds had significantly lower ultimate tensile strengths. Heat treatment had no effect on the modulus of elasticity or elongation, but generally significantly decreased the yield strength of the titanium specimens. The gas tungsten are welding specimens had significantly higher yield strengths and elastic moduli than the other two groups. The elongation of the control specimens was significantly greater than the elongation of the gas tungsten arc welding specimens, which was in turn significantly higher than that of the laser-welded specimens. PMID:8957877

  12. Photonuclear reactions on titanium isotopes

    SciTech Connect

    Belyshev, S. S.; Dzhilavyan, L. Z.; Ishkhanov, B. S.; Kapitonov, I. M.; Kuznetsov, A. A. Orlin, V. N.; Stopani, K. A.

    2015-03-15

    The photodisintegration of titanium isotopes in the giant-dipole-resonance energy region is studied by the photon-activation method. Bremsstrahlung photons whose spectrum has the endpoint energy of 55 MeV is used. The yields and integrated cross sections are determined for photoproton reactions on the titanium isotopes {sup 47,48,49,50}Ti. The respective experimental results are compared with their counterparts calculated on the basis of the TALYS code and a combined photonucleon-reaction model. The TALYS code disregards the isospin structure of the giant dipole resonance and is therefore unable to describe the yield of photoproton reactions on the heavy titanium isotopes {sup 49,50}Ti.

  13. Adaptive mesh refinement in titanium

    SciTech Connect

    Colella, Phillip; Wen, Tong

    2005-01-21

    In this paper, we evaluate Titanium's usability as a high-level parallel programming language through a case study, where we implement a subset of Chombo's functionality in Titanium. Chombo is a software package applying the Adaptive Mesh Refinement methodology to numerical Partial Differential Equations at the production level. In Chombo, the library approach is used to parallel programming (C++ and Fortran, with MPI), whereas Titanium is a Java dialect designed for high-performance scientific computing. The performance of our implementation is studied and compared with that of Chombo in solving Poisson's equation based on two grid configurations from a real application. Also provided are the counts of lines of code from both sides.

  14. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  15. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  16. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  17. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  18. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  19. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  20. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  1. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  2. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  3. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  4. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  5. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  6. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide (CAS Reg. No. 13463-67-7) is exempted from the requirement of...

  7. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  8. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 1 2013-04-01 2013-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  9. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  10. 40 CFR 180.1195 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Titanium dioxide. 180.1195 Section 180.1195 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) PESTICIDE PROGRAMS... Titanium dioxide. Titanium dioxide is exempted from the requirement of a tolerance for residues in or...

  11. 21 CFR 73.3126 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.3126 Section 73.3126 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Medical Devices § 73.3126 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide (CAS Reg. No. 13463-67-7), Color Index No. 77891,...

  12. 21 CFR 73.1575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Titanium dioxide. 73.1575 Section 73.1575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Drugs § 73.1575 Titanium dioxide. (a) Identity and specifications. (1) The color additive titanium dioxide shall conform in identity and specifications to the...

  13. 21 CFR 73.2575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 1 2010-04-01 2010-04-01 false Titanium dioxide. 73.2575 Section 73.2575 Food and... ADDITIVES EXEMPT FROM CERTIFICATION Cosmetics § 73.2575 Titanium dioxide. (a) Identity and specifications. The color additive titanium dioxide shall conform in identity and specifications to the...

  14. Spectral and physical properties of electrochemically formed colored layers on titanium covered with clearcoats.

    PubMed

    Munro, Andrew; Cunningham, Michael F; Jerkiewicz, Gregory

    2011-04-01

    We present the application and characterization of two commercial polymer clearcoats to electrochemically formed colored passive layers on titanium with the aim of providing physical protection required in many of titanium's applications, while allowing the unique appearance of the colored layers to show through. Thin layers of an acrylic automotive clearcoat (∼3.5 μm thick) and an epoxy marine clearcoat (∼6.5 μm thick) are applied to the colored titanium surfaces using spin coating, and are found to slightly modify their visual properties, while maintaining their bright, well-defined sparkling colors. Both clearcoats are found to significantly reduce the surface roughness, thereby reducing potential wear from friction and the adhesion of fine dirt particles. They are also found to notably decrease the wetting properties of colored titanium, furthering its protection against damage from ambient and aqueous media. The clearcoats show the ability to protect colored titanium from physical and chemical damage, with the automotive clearcoat exhibiting superior adhesion. Our electrochemical coloring technique combined with the application of clearcoats creates a new and unique system that does not rely solely on a polymer coating for its colorful appearance and protection against corrosion. PMID:21410140

  15. Analysis of metal surfaces coated with europium-doped titanium dioxide by laser induced breakdown spectroscopy.

    PubMed

    Głogocka, Daria; Noculak, Agnieszka; Pucińska, Joanna; Jopek, Wojciech; Podbielska, Halina; Langner, Marek; Przybyło, Magdalena

    2015-01-01

    The surface passivation with titanium sol-gel coatings is a frequently used technique to control the adsorption of selected biological macromolecules and to reduce the exposure of the bulk material to biological matter. Due to the increasing number of new coating-preparation methods and new gel compositions with various types of additives, the quality and homogeneity determination of the surface covering is a critical factor affecting performance of any implanted material. While coating thickness is easy to determine, the homogeneity of the surface distribution of coating materials requires more elaborate methodologies. In the paper, the laser induced breakdown spectroscopy (LIBS) based method, capable to quantitate the homogeneity and uniformity of the europium in titanium dioxide sol-gel coatings on stainless steel surfaces prepared with two different procedures: spin-coating and dip-coating, is presented. The emission intensity of titanium has been used to determine the coating thickness whereas the relative values of europium and titanium emission intensities provide data on the coating homogeneity. The obtained results show that the spin-coating technique provides better surface coverage with titanium dioxide. However, when the surface coating compositions were compared the dip-coating technique was more reliable. PMID:26687457

  16. Femtosecond laser microstructuring of titanium surfaces for middle ear ossicular replacement prosthesis

    NASA Astrophysics Data System (ADS)

    Ilgner, Justus; Biedron, Slavomir; Fadeeva, Elena; Chichkov, Boris; Westhofen, Martin

    2009-02-01

    Introduction: While a variety of materials has been evaluated for replacement of human middle ear ossicles following inflammation, titanium and its alloys have shown excellent sound transmission properties and biocompatibility. However, cartilage thickness at the tympanic membrane interface deteriorates over time, while fibrous tissue formation may dislodge the titanium prosthesis. This study was performed to evaluate the effect of microstructures on titanium surfaces in contact with adjacent biological tissue. Materials and Methods: Titanium samples of 5mm diameter and 0,25mm thickness were structured by means of a Ti:Sapphire femtosecond laser operating at 970nm. The structures applied were lines of parabolic shape (cross-sectional) of 5µm (parallel), 5µm (cross-hatch) and 10µm width (parallel). The inter-groove distance between two maxima was exactly twice the line width. Results: Lines smaller than 5µm were not feasible due to the natural irregularity of the basic material with pits and level changes of up to 2µm. The process showed little debris and constant microstructure shape over the whole structured area (2x2mm). The resulting debris was examined for toxic by-products on human fibrobcytes and chondrocytes. Discussion: The results show that microstructures can be applied on titanium surfaces for human implantation with reproducible and constant shapes. Further studies will focus on cell culture which has suggested a relative selectivity for chondrocyte compared to fibrocyte growth in earlier studies with selected microstructures.

  17. Production of hydroxyapatite layers on the plasma electrolytically oxidized surface of titanium alloys.

    PubMed

    Lugovskoy, Alex; Lugovskoy, Svetlana

    2014-10-01

    Hydroxyapatite (HA) is a bioactive material that is widely used for improving the osseointegration of titanium dental implants. Titanium can be coated with HA by various methods, such as chemical vapor deposition (CVD), thermal spray, or plasma spray. HA coatings can also be grown on titanium surfaces by hydrothermal, chemical, and electrochemical methods. Plasma electrolytic oxidation (PEO), or microarc oxidation (MAO), is an electrochemical method that enables the production of a thick porous oxide layer on the surface of a titanium implant. If the electrolyte in which PEO is performed contains calcium and phosphate ions, the oxide layer produced may contain hydroxyapatite. The HA content can then be increased by subsequent hydrothermal treatment. The HA thus produced on titanium surfaces has attractive properties, such as a high porosity, a controllable thickness, and a considerable density, which favor its use in dental and bone surgery. This review summarizes the state of the art and possible further development of PEO for the production of HA on Ti implants. PMID:25175246

  18. Liquid thickness gauge

    NASA Technical Reports Server (NTRS)

    Weinstein, Leonard M. (Inventor)

    1988-01-01

    A method and apparatus are developed to measure the thickness of a liquid on a surface independent of liquid conductivity. Two pairs of round, corrosion resistant wires are mounted in an insulating material such that the cross-sectional area of each wire is flush with and normal to the surface. The resistance between each pair of wires is measured using two ac resistance measuring circuits, in which the ratio of the outputs of the two resistance measuring circuits is indicative of the thickness of the liquid on the surface.

  19. Surface characterization of radio-frequency glow discharged and autoclaved titanium surfaces.

    PubMed

    Kawahara, D; Ong, J L; Raikar, G N; Lucas, L C; Lemons, J E; Nakamura, M

    1996-01-01

    To characterize titanium surfaces treated with radio-frequency glow discharge (RFGD) after media exposure, surface chemical analyses were performed using x-ray photoelectron spectroscopy. Auger electron spectroscopy, and Fourier transform infrared-reflection absorption spectroscopy (FTIR-RAS). The RFGD treatments resulted in a cleaner surface as compared to as-sputtered or as-autoclaved titanium specimens. The oxide thickness of RFGD-treated titanium specimens was not statistically different from the as-autoclaved and as-sputter cleaned titanium specimens. Exposure to a phosphate-buffered saline solution revealed a greater deposition of calcium and phosphorous on the RFGD-treated surfaces. Auger electron spectroscopy depth profiles showed that calcium and phosphorous ions diffused into the titanium oxide layer. The calcium and phosphorous deposits were identified as amorphous calcium phosphate compounds using FTIR-RAS. These results suggest that RFGD treatments of titanium enhance calcium and/or phosphate affinity because of an increase in elemental interactions at the surface, thereby resulting in the formation of amorphous calcium phosphate compounds. PMID:8803338

  20. Low temperature, fast deposition of metallic titanium nitride films using plasma activated reactive evaporation

    SciTech Connect

    Montes de Oca Valero, J.A.; Le Petitcorps, Y.; Manaud, J.P.; Chollon, G.; Carrillo Romo, F.J.; Lopez M, A.

    2005-05-01

    Titanium and titanium nitride thin films were deposited on silica glass and W substrates at a high coating growth rate by plasma-activated reactive evaporation (ARE). The crystal structure, preferred orientation and grain size of the coatings were determined by x-ray diffraction (XRD) technique using Cu-K{alpha} x rays. The analysis of the coating morphology was performed by field-emission scanning electron microscopy (FE-SEM). The composition of the films was analyzed by Auger electron spectroscopy (AES) and electron-probe microanalysis (EPMA). The titanium and titanium nitride condensates were collected on a carbon-coated collodion film then characterized by transmission electron microscopy (TEM) in order to study the structures of the deposits at very short deposition times. The resistivity of the films was measured by using the four-point-probe method. The titanium coatings were found to consist of very fine particles (40 nm in grain size) and to exhibit a strong (002) texture. The titanium nitride coatings were substoichiometric (TiN{sub x},x<1), with an oxygen content ranging from 7 to 15 at. % depending on the deposition conditions. The deposits were found to exhibit a (111) preferred orientation. This behavior became stronger with coating thickness. In spite of the presence of oxygen, all the TiN{sub x} coatings obtained at low temperature and a high growth rate in this work exhibited a rather high electrical conductivity.

  1. Structural, mechanical and optical properties of nitrogen-implanted titanium at different pulse frequency

    NASA Astrophysics Data System (ADS)

    Raaif, Mohamed; Mohamed, Sodky H.; Abd El-Rahman, Ahmed M.; Kolitsch, Andreas

    2013-04-01

    Plasma-immersion ion implantation (PIII) is a potent method to obtain hard and wear-resistant surface on Ti by nitrogen implantation. This presentation is one part of a sequence of experiments to optimize the microstructure and physical properties of TiN through adapting the plasma-processing parameters. In this work, nitrogen ions were implanted into samples of pure Ti at different nitrogen pulse frequency without using any external source of heating. The nitrogen-implanted surfaces were characterized by X-ray diffraction (XRD), Auger electron spectroscopy (AES), optical microscope, nano-indentation technique, ball-on-disk type tribometer, surface profilemeter, Tafel polarization technique for corrosion performance and ellipsometry. The outcomes show that, nitrogen PIII is an effectual method for nitriding titanium and nitrogen pulse frequency affected the microstructure and physical properties of the treated Ti. X-ray diffraction depicted the formation of α-Ti (N) and the cubic TiN after implanting titanium by nitrogen and the thickness of the nitrided layer increased as the nitrogen pulse frequency increased. The wear and corrosion resistance of the nitrogen-implanted titanium are improved and the friction coefficient decreased from nearly 0.8 for the un-implanted titanium to 0.3 for the implanted titanium, this ascribed to the formation of the titanium nitrided phases. Ellipsometric measurements were carried out on the PIII titanium samples at different nitrogen pulse frequency. The ellipsometric measurements show that, the thickness of the nitrided layer and surface roughness increased while the refractive index decreased with increasing nitrogen pulse frequency.

  2. Thick Film Interference.

    ERIC Educational Resources Information Center

    Trefil, James

    1983-01-01

    Discusses why interference effects cannot be seen with a thick film, starting with a review of the origin of interference patterns in thin films. Considers properties of materials in films, properties of the light source, and the nature of light. (JN)

  3. Synthesis and properties of nanoscale titanium boride

    NASA Astrophysics Data System (ADS)

    Efimova, K. A.; Galevskiy, G. V.; Rudneva, V. V.

    2015-09-01

    This work reports the scientific and technological grounds for plasma synthesis of titanium diboride, including thermodynamic and kinetic conditions of boride formation when titanium and titanium dioxide are interacting with products resulting from boron gasification in the nitrogen - hydrogen plasma flow, and two variations of its behavior using the powder mixtures: titanium - boron and titanium dioxide - boron. To study these technology variations, the mathematical models were derived, describing the relation between element contents in the synthesized products of titanium and free boron and basic parameters. The probable mechanism proposed for forming titanium diboride according to a "vapour - melt - crystal" pattern was examined, covering condensation of titanium vapour in the form of aerosol, boriding of nanoscale melt droplets by boron hydrides and crystallization of titanium - boron melt. The comprehensive physical - chemical certification of titanium diboride was carried out, including the study of its crystal structure, phase and chemical composition, dispersion, morphology and particle oxidation. Technological application prospects for use of titanium diboride nanoscale powder as constituent element in the wettable coating for carbon cathodes having excellent physical and mechanical performance and protective properties.

  4. Fatigue behavior of titanium alloys

    SciTech Connect

    Boyer, R.R.; Eylon, D.; Luetjering, G.

    1999-07-01

    This symposium was international in nature, with leaders in the fields of fatigue technology and the metallurgy of titanium from the US, Europe and Asia. It covered basic research, development, applications and modeling--life predictions and design of both fatigue crack initiation and propagation of titanium alloys. There were presentations on the full range of titanium alloy systems, from commercially pure and {alpha}-alloys, {alpha}/{beta}- and {beta}-alloys to the gamma titanium aluminides. The effects of processing/heat treatment/microstructure on the fatigue properties were discussed, and models proposed to correlate the microstructures to the observed fatigue performance. Test environments reported on included hard vacuum (and the effect of vacuum level), vacuums with partial pressures of miscellaneous gases, lab air and aqueous media. A session was devoted to the effects of environment and fatigue enhancement via surface treatments using techniques such as shot peening and roller burnishing. The effects of dwell on both S-N and crack growth rate behavior were covered. It was a very comprehensive symposium with presentations from academia, government laboratories and industry, with industrial participants ranging from the petroleum industry to medical and aerospace interests. This book has been separated into four sections, representing the technology areas covered in various sessions, namely Mechanisms of Fatigue crack Initiation and Propagation of Conventional Alloys, Fatigue in Intermetallics, Environmental and Surface Aspects of Fatigue, and Application, Life Prediction and Design. Separate abstracts were prepared for most papers in this volume.

  5. Lactobacillusassisted synthesis of titanium nanoparticles

    PubMed Central

    2007-01-01

    An eco-friendlylactobacillussp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40–60 nm are found.

  6. PLUTONIUM-URANIUM-TITANIUM ALLOYS

    DOEpatents

    Coffinberry, A.S.

    1959-07-28

    A plutonium-uranium alloy suitable for use as the fuel element in a fast breeder reactor is described. The alloy contains from 15 to 60 at.% titanium with the remainder uranium and plutonium in a specific ratio, thereby limiting the undesirable zeta phase and rendering the alloy relatively resistant to corrosion and giving it the essential characteristic of good mechanical workability.

  7. Implantation induced hardening of nanocrystalline titanium thin films.

    PubMed

    Krishnan, R; Amirthapandian, S; Mangamma, G; Ramaseshan, R; Dash, S; Tyagi, A K; Jayaram, V; Raj, Baldev

    2009-09-01

    Formation of nanocrystalline TiN at low temperatures was demonstrated by combining Pulsed Laser Deposition (PLD) and ion implantation techniques. The Ti films of nominal thickness approximatly 250 nm were deposited at a substrate temperature of 200 degrees C by ablating a high pure titanium target in UHV conditions using a nanosecond pulsed Nd:YAG laser operating at 1064 nm. These films were implanted with 100 keV N+ ions with fluence ranging from 1.0 x 10(16) ions/cm2 to 1.0 x 10(17) ions/cm2 The structural, compositional and morphological evolutions were tracked using Transmission Electron Microscopy (TEM), Secondary Ion Mass Spectrometry (SIMS) and Atomic Force Microscopy (AFM), respectively. TEM analysis revealed that the as-deposited titanium film is an fcc phase. With increasing ion fluence, its structure becomes amorphous phase before precipitation of nanocrystalline fcc TIN phase. Compositional depth profiles obtained from SIMS have shown the extent of nitrogen concentration gradient in the implantation zone. Both as-deposited and ion implanted films showed much higher hardness as compared to the bulk titanium. AFM studies revealed a gradual increase in surface roughness leading to surface patterning with increase in ion fluence. PMID:19928244

  8. Hydroxyapatite electrodeposition on anodized titanium nanotubes for orthopedic applications

    NASA Astrophysics Data System (ADS)

    Parcharoen, Yardnapar; Kajitvichyanukul, Puangrat; Sirivisoot, Sirinrath; Termsuksawad, Preecha

    2014-08-01

    Nanotubes modification for orthopedic implants has shown interesting biological performances (such as improving cell adhesion, cell differentiation, and enhancing osseointegration). The purpose of this study is to investigate effect of titanium dioxide (TiO2) nanotube feature on performance of hydroxyapatite-coated titanium (Ti) bone implants. TiO2 nanotubes were prepared by anodization using ammonium fluoride electrolyte (NH4F) with and without modifiers (PEG400 and Glycerol) at various potential forms, and times. After anodization, the nanotubes were subsequently annealed. TiO2 nanotubes were characterized by scanning electron microscope and X-ray diffractometer. The amorphous to anatase transformation due to annealing was observed. Smooth and highly organized TiO2 nanotubes were found when high viscous electrolyte, NH4F in glycerol, was used. Negative voltage (-4 V) during anodization was confirmed to increase nanotube thickness. Length of the TiO2 nanotubes was significantly increased by times. The TiO2 nanotube was electrodeposited with hydroxyapatite (HA) and its adhesion was estimated by adhesive tape test. The result showed that nanotubes with the tube length of 560 nm showed excellent adhesion. The coated HA were tested for biological test by live/dead cell straining. HA coated on TiO2 nanotubes showed higher cells density, higher live cells, and more spreading of MC3T3-E1 cells than that growing on titanium plate surface.

  9. Small Titanium Oxo Clusters: Primary Structures of Titanium(IV) in Water.

    PubMed

    Zhang, Guanyun; Hou, Jie; Tung, Chen-Ho; Wang, Yifeng

    2016-04-01

    For sol-gel synthesis of titanium oxide, the titanium(IV) precursors are dissolved in water to form clear solutions. However, the solution status of titanium(IV) remains unclear. Herein three new and rare types of titanium oxo clusters are isolated from aqueous solutions of TiOSO4 and TiCl4 without using organic ligands. Our results indicate that titanium(IV) is readily hydrolyzed into oxo oligomers even in highly acidic solutions. The present clusters provide precise structural information for future characterization of the solution species and structural evolution of titanium(IV) in water and, meanwhile, are new molecular materials for photocatalysis. PMID:26990885

  10. Tensile properties of titanium electrolytically charged with hydrogen

    NASA Technical Reports Server (NTRS)

    Smith, R. J.; Otterson, D. A.

    1971-01-01

    Yield strength, ultimate tensile strength, and elongation were studied for annealed titanium electrolytically charged with hydrogen. The hydrogen was present as a surface hydride layer. These tensile properties were generally lower for uncharged titanium than for titanium with a continuous surface hydride; they were greater for uncharged titanium than for titanium with an assumed discontinuous surface hydride. We suggest that the interface between titanium and titanium hydride is weak. And the hydride does not necessarily impair strength and ductility of annealed titanium. The possibility that oxygen and/or nitrogen can embrittle titanium hydride is discussed.

  11. Thick film ink chemistry

    NASA Astrophysics Data System (ADS)

    Gehman, R. W.

    1982-03-01

    Twenty-six thick film inks from two vendors were proved for hybrid microcircuit production use. A data base of chemical information was established for all the inks to aid in future diagnostic and failure analysis activities. Efforts included both organic chemical analysis of printing vehicles and binders and inorganic chemical analysis of glass frits and electrically active phases. Analytical methods included infrared spectroscopy, mass spectroscopy, gas chromatography, X-ray fluorescence, emission spectroscopy, atomic absorption spectroscopy, and wet chemical techniques.

  12. Anomalous thickness dependence of quality factor in TiN film resonators grown on functionalized Si substrates

    NASA Astrophysics Data System (ADS)

    Xu, Peng; Kohler, Tim; Lock, Evgeniya; Rosen, Yaniv; Ramanayaka, Aruna; Guchhait, Samaresh; Osborn, Kevin

    Various properties affect the quality factor of superconducting resonators at millikelvin temperatures including the presence of nanoscale interfacial dielectric films and residual quasiparticles. Superconducting titanium nitride is polycrystalline such that growth phases may also affect the resonator quality. Here, we functionalize Si substrates in different hydrophobic and hydrophilic plasma environments, sputter titanium nitride on top and pattern the latter films into resonators. For each functionalization we study the quality factor dependence on the superconducting film thickness, where the thicknesses are changed only between 25 and 50 nm. As expected, most functionalizations reveal very little quality factor dependence on superconducting film thickness. However, other functionalizations dramatically, and even anomalously, increase or decrease the quality with thickness. For example, oxygen plasma functionalization causes the quality factor to increase by a factor of more than ten at single photon power with increased thickness. We report on the progress towards finding the intrinsic reason for strong quality factor dependences on surface functionalization.

  13. Development of Low Density Titanium Alloys for Structural Applications

    NASA Technical Reports Server (NTRS)

    Froes, F. H.; Suryanarayana, C.; Powell, C.; Ward-Close, C. Malcolm; Wilkes, D. M. J.

    1996-01-01

    In this report the results of a program designed to reduce the density of titanium by adding magnesium are presented. Because these two elements are immiscible under conventional ingot metallurgy techniques, two specialized powder metallurgy methods namely, mechanical alloying (MA) and physical vapor deposition (PVD) were implemented. The mechanical alloying experiments were done both at the University of Idaho and at the Defense Research Agency in UK. Since titanium is reactive with interstitial elements, a secondary goal of this research was to correlate solubility extensions with interstitial contamination content, especially oxygen and nitrogen. MA was carried out in SPEX 8000 shaker mils and different milling containers were utilized to control the level of contamination. Results showed that solubilities of Mg in Ti were obtained up to 28 at.% (16.4 wt. %) Mg in Ti for Ti-39.6 at. % (25 wt. %) Mg alloys, which greatly exceed those obtained under equilibrium conditions. This reflects a density reduction of approximately 26 %. Contamination of oxygen and nitrogen seemed to increase the solubility of magnesium in titanium in some cases; however, we were not able to make a clear correlation between contamination levels with solubilities. Work at the DRA has emphasized optimization of present PVD equipment, specifically composition and temperature control. Preliminary PVD data has shown Ti-Mg deposits have successfully been made up to 2 mm thick and that solubility extensions were achieved. The potential for density reduction of titanium by alloying with magnesium has been demonstrated; however, this work has only scratched the surface of the development of such low density alloys. Much research is needed before such alloys could be implemented into industry. Further funding is required in order to optimize the MA/PVD processes including contamination control, determination of optimal alloy compositions, microstructure development, and mechanical property

  14. Titanium-Oxygen Reactivity Study

    NASA Technical Reports Server (NTRS)

    Chafey, J. E.; Scheck, W. G.; Witzell, W. E.

    1962-01-01

    A program has been conducted at Astronautics to investigate the likelihood of occurrence of the catastrophic oxidation of titanium alloy sheet under conditions which simulate certain cases of accidental failure of the metal while it is in contact with liquid or gaseous oxygen. Three methods of fracturing the metal were used; they consisted of mechanical puncture, tensile fracture of welded joints, and perforation by very high velocity particles. The results of the tests which have been conducted provide further evidence of the reactivity of titanium with liquid and gaseous oxygen. The evidence indicates that the rapid fracturing of titanium sheet while it is in contact with oxygen initiates the catastrophic oxidation reaction. Initiation occurred when the speed of the fracture was some few feet per second, as in both the drop-weight puncture tests and the static tensile fracture tests of welded joints, as well as when the speed was several thousand feet per second, as in the simulated micrometeoroid penetration tests. The slow propagation of a crack, however, did not initiate the reaction. It may logically be concluded that the localized frictional heat of rapid fracture and/or spontaneous oxidation (exothermic) of minute particles emanating from the fracture cause initiation of the reaction. Under conditions of slow fracture, however, the small heat generated may be adequately dissipated and the reaction is not initiated. A portion of the study conducted consisted of investigating various means by which the reaction might be retarded or prevented. Providing a "barrier" at the titanium-oxygen interface consisting of either aluminum metal or a coating of a petroleum base corrosion inhibitor appeared to be only partially effective in retarding the reaction. The accidental puncturing or similar rupturing of thin-walled pressurized oxygen tanks on missiles and space vehicle will usually constitute loss of function, and may sometimes cause their catastrophic destruction

  15. Surface spectroscopic characterization of titanium implant materials

    NASA Astrophysics Data System (ADS)

    Lausmaa, Jukka; Kasemo, Bengt; Mattsson, Håkan

    1990-04-01

    Titanium is one of the most commonly used biomaterials for dental and orthopedic applications. Its excellent tissue compatibility is mainly due to the properties of the stable oxide layer which is present on the surface. This paper reports a detailed spectroscopic characterization of the surface composition of non-alloyed Ti implant materials, prepared according to procedures commonly used in clinical practice (machining, ultrasonic cleaning and sterilization). The main methods of characterization are XPS and AES, and complementary information is obtained by SIMS, EDX and NMA (nuclear microanalysis). The surface of the implants is found to consist of a thin surface oxide which is covered by a carbon-dominated contamination layer. By comparison with reference spectra from single crystal TiO 2 (rutile) the composition of the surface oxide is shown to be mainly TiO 2, with minor amounts of suboxides and TiN x. The thickness of the surface oxides is 2-6 nm, depending on the method of sterilization. The surface contamination layer is found to vary considerably from sample to sample and consists of mainly hydrocarbons with trace amounts of Ca, N, S, P, Cl. Some differences in surface composition between directly prepared surfaces, and some possible contamination sources, are identified and discussed shortly.

  16. The advantages of coated titanium implants prepared by radiofrequency sputtering from hydroxyapatite.

    PubMed

    Cooley, D R; Van Dellen, A F; Burgess, J O; Windeler, A S

    1992-01-01

    The method used to apply hydroxyapatite to implant surfaces may affect the thickness and ultimately the physical properties of the coating. This study investigated and compared the healing rates of bone around commercially pure titanium implants and titanium implants sputter-coated from a hydroxyapatite target. Forty-five sputter-coated implants and an equal number of noncoated titanium implants were placed into 15 partially edentulated dog mandibles. The implants were removed at three time periods and were evaluated mechanically and histologically. A multiple analysis of variance indicated that the interface bond strength was statistically greater (p less than 0.01) for the sputter-coated implants. Histologic analysis of the bone-implant interface demonstrated that coated implants had nearly twice the percentage of direct bone contact compared with noncoated implants. The results indicate that implants sputter-coated from a hydroxyapatite target will accelerate the healing of bone at the implant interface. PMID:1312597

  17. Influence of laser cladding regimes on structural features and mechanical properties of coatings on titanium substrates

    NASA Astrophysics Data System (ADS)

    Malyutina, Yulia N.; Lazurenko, Daria V.; Bataev, Ivan A.; Movtchan, Igor A.

    2015-10-01

    In this paper an influence of the tantalum content on the structure and properties of surface layers of the titanium alloy doped using a laser treatment technology was investigated. It was found that an increase of a quantity of filler powder per one millimeter of a track length contributed to a rise of the content of undissolved particles in coatings. The maximum thickness of a cladded layer was reached at the mass of powder per the length unit equaled to 5.5 g/cm. Coatings were characterized by the formation of a dendrite structure with attributes of segregation. The width of a quenched fusion zone grew with an increase in the rate of powder feed to the treated area. Significant strengthening of the titanium surface layer alloyed with tantalum was not observed; however, the presence of undissolved tantalum particles can decrease the hardness of titanium surface layers.

  18. Biocompatibility of supercritical CO2-treated titanium implants in a rat model.

    PubMed

    Hill, C M; Kang, Q K; Wahl, C; Jimenez, A; Laberge, M; Drews, M; Matthews, M A; An, Y H

    2006-04-01

    Supercritical phase CO2 is a promising method for sterilizing implantable devices and tissue grafts. The goal of this study is to evaluate the biocompatibility of titanium implants sterilized by supercritical phase CO2 in a rat subcutaneous implantation model. At 5 weeks post implantation titanium implants sterilized by supercritical phase CO2 produce a soft tissue reaction that is comparable to other methods of sterilization (steam autoclave, ultraviolet light radiation, ethylene oxide gas, and radio-frequency glow-discharge), as indicated by the thickness and density of the foreign body capsule, although there were some differences on the capillary density. Overall the soft tissue response to the implants was similar among all methods of sterilization, indicating supercritical phase CO2 treatment did not compromise the biocompatibility of the titanium implant. PMID:16705612

  19. Influence of laser cladding regimes on structural features and mechanical properties of coatings on titanium substrates

    SciTech Connect

    Malyutina, Yulia N. Lazurenko, Daria V. Bataev, Ivan A.; Movtchan, Igor A.

    2015-10-27

    In this paper an influence of the tantalum content on the structure and properties of surface layers of the titanium alloy doped using a laser treatment technology was investigated. It was found that an increase of a quantity of filler powder per one millimeter of a track length contributed to a rise of the content of undissolved particles in coatings. The maximum thickness of a cladded layer was reached at the mass of powder per the length unit equaled to 5.5 g/cm. Coatings were characterized by the formation of a dendrite structure with attributes of segregation. The width of a quenched fusion zone grew with an increase in the rate of powder feed to the treated area. Significant strengthening of the titanium surface layer alloyed with tantalum was not observed; however, the presence of undissolved tantalum particles can decrease the hardness of titanium surface layers.

  20. Corrosion resistance of titanium ion implanted AZ91 magnesium alloy

    SciTech Connect

    Liu Chenglong; Xin Yunchang; Tian Xiubo; Zhao, J.; Chu, Paul K.

    2007-03-15

    Degradable metal alloys constitute a new class of materials for load-bearing biomedical implants. Owing to their good mechanical properties and biocompatibility, magnesium alloys are promising in degradable prosthetic implants. The objective of this study is to improve the corrosion behavior of surgical AZ91 magnesium alloy by titanium ion implantation. The surface characteristics of the ion implanted layer in the magnesium alloys are examined. The authors' results disclose that an intermixed layer is produced and the surface oxidized films are mainly composed of titanium oxide with a lesser amount of magnesium oxide. X-ray photoelectron spectroscopy reveals that the oxide has three layers. The outer layer which is 10 nm thick is mainly composed of MgO and TiO{sub 2} with some Mg(OH){sub 2}. The middle layer that is 50 nm thick comprises predominantly TiO{sub 2} and MgO with minor contributions from MgAl{sub 2}O{sub 4} and TiO. The third layer from the surface is rich in metallic Mg, Ti, Al, and Ti{sub 3}Al. The effects of Ti ion implantation on the corrosion resistance and electrochemical behavior of the magnesium alloys are investigated in simulated body fluids at 37{+-}1 deg. C using electrochemical impedance spectroscopy and open circuit potential techniques. Compared to the unimplanted AZ91 alloy, titanium ion implantation significantly shifts the open circuit potential (OCP) to a more positive potential and improves the corrosion resistance at OCP. This phenomenon can be ascribed to the more compact surface oxide film, enhanced reoxidation on the implanted surface, as well as the increased {beta}-Mg{sub 12}Al{sub 17} phase.

  1. Deep flaws in weldments of aluminum and titanium

    NASA Technical Reports Server (NTRS)

    Masters, J. N.; Engstrom, W. L.; Bixler, W. D.

    1974-01-01

    Surface flawed specimens of 2219-T87 and 6Al-4V STA titanium weldments were tested to determine static failure modes, failure strength, and fatigue flaw growth characteristics. Thicknesses selected for this study were purposely set at values where, for most test conditions, abrupt instability of the flaw at fracture would not be expected. Static tests for the aluminum weldments were performed at room, LN2 and LH2 temperatures. Titanium static tests for tests were performed at room and LH2 temperatures. Results of the static tests were used to plot curves relating initial flaw size to leakage- or failure-stresses (i.e. "failure" locus curves). Cyclic tests, for both materials, were then performed at room temperature, using initial flaws only slightly below the previously established failure locus for typical proof stress levels. Cyclic testing was performed on pairs of specimens, one with and one without a simulated proof test cycle. Comparisons were made then to determine the value and effect of proof testing as affected by the various variables of proof and operating stress, flaw shape, material thickness, and alloy.

  2. The Effect of Taper Angle and Spline Geometry on the Initial Stability of Tapered, Splined Modular Titanium Stems.

    PubMed

    Pierson, Jeffery L; Small, Scott R; Rodriguez, Jose A; Kang, Michael N; Glassman, Andrew H

    2015-07-01

    Design parameters affecting initial mechanical stability of tapered, splined modular titanium stems (TSMTSs) are not well understood. Furthermore, there is considerable variability in contemporary designs. We asked if spline geometry and stem taper angle could be optimized in TSMTS to improve mechanical stability to resist axial subsidence and increase torsional stability. Initial stability was quantified with stems of varied taper angle and spline geometry implanted in a foam model replicating 2cm diaphyseal engagement. Increased taper angle and a broad spline geometry exhibited significantly greater axial stability (+21%-269%) than other design combinations. Neither taper angle nor spline geometry significantly altered initial torsional stability. PMID:25754255

  3. Metallographic preparation of titanium diboride coatings

    SciTech Connect

    McAllaster, M.E.

    1980-03-01

    A method is described for preparing metallographic cross sections of thin, hard, chemically vapor deposited titanium diboride coatings on various softer substrates. Standard metallographic preparation techniques were found to result in fracturing and edge rounding of the coatings. It is shown that these problems can be avoided by unidirectional grinding on worn 600 grit silicon carbide abrasive paper. Typical photomicrographs of chemically vapor deposited titanium diboride coatings are shown along with photomicrographs of intermediate phases that form at the titanium diboride - substrate interfaces.

  4. Production of titanium from ilmenite: a review

    SciTech Connect

    Kohli, R.

    1981-12-01

    The general principles for beneficiation of titanium ores are reviewed and the specific processes used in individual units in various countries are discussed. This is followed by a critical evaluation of various current and potential reduction methods for the production of titanium metal from the processed concentrates. Finally, the report outlines a research program for the development of a commercially viable alternative method for the production of titanium metal.

  5. Ultrafine-grained titanium for medical implants

    DOEpatents

    Zhu, Yuntian T.; Lowe, Terry C.; Valiev, Ruslan Z.; Stolyarov, Vladimir V.; Latysh, Vladimir V.; Raab, Georgy J.

    2002-01-01

    We disclose ultrafine-grained titanium. A coarse-grained titanium billet is subjected to multiple extrusions through a preheated equal channel angular extrusion (ECAE) die, with billet rotation between subsequent extrusions. The resulting billet is cold processed by cold rolling and/or cold extrusion, with optional annealing. The resulting ultrafine-grained titanium has greatly improved mechanical properties and is used to make medical implants.

  6. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, S.J.; White, J.C.

    1998-08-04

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag. 1 fig.

  7. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1999-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  8. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    DOEpatents

    Gerdemann, Stephen J.; White, Jack C.

    1998-01-01

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  9. Recovery of titanium values from titanium grinding swarf by electric furnace smelting

    SciTech Connect

    Gerdemann, S.J.; White, J.C.

    1999-10-19

    A method for the recovery of valuable materials from titanium grinding swarf is provided comprising the steps of sieving the accumulated titanium grinding swarf to remove unwanted coarse trash and grinding wheel fragments, pelletizing, and smelting in an electric arc furnace to produce ferrotitanium and/or high titanium slag.

  10. Fetal nuchal translucency thickness.

    PubMed

    Witters, I; Fryns, J R

    2007-01-01

    In the early 1990s Nicolaides introduced screening for trisomy 21 by fetal nuchal translucency thickness measurement with ultrasound between 11-13(+6) weeks. Already in 1866 L. Down noted that common features of patients with trisomy 21 are a skin being too large for the body and a flat face with a small nose. While detection rates for trisomy 21, given an invasive testing rate of 5%, were only 30% for screening by maternal age and 65% for screening by maternal serum triple test, the detection rate for screening by nuchal translucency combined with maternal age was 75% and this could be increased to 90% in combination with maternal serum screening (serum B-human chorionic gonadotropin and pregnancy-associated plasma protein-A) at 11-13(+6) weeks. The additional soft markers in the first trimester are the fetal nasal bone, the Doppler velocity waveform in the ductus venosus and tricuspid regurgitation and these markers can be used to further increase the detection rate of trisomy 21. In addition increased nuchal translucency thickness can also identify other chromosomal defects (mainly trisomy 13 and 18 and monosomy X) and major congenital malformations (mainly cardiac defects) and genetic syndromes. PMID:17515296

  11. The effects of hydrogen embrittlement of titanium

    NASA Technical Reports Server (NTRS)

    Taylor, Delbert J.

    1989-01-01

    Titanium alloys, by virtue of their attractive strength to density ratio, fatigue, fracture toughness and corrosion resistance are now commonly used in various aerospace and marine applications. The cost, once very expensive, has been reduced, making titanium even more of a competitive material today. Titanium and titanium alloys have a great affinity to several elements. Hydrogen, even in small amounts, can cause embrittlement, which in turn causes a reduction in strength and ductility. The reduction of strength and ductility is the subject of this investigation.

  12. Method for producing titanium aluminide weld rod

    DOEpatents

    Hansen, Jeffrey S.; Turner, Paul C.; Argetsinger, Edward R.

    1995-01-01

    A process for producing titanium aluminide weld rod comprising: attaching one end of a metal tube to a vacuum line; placing a means between said vacuum line and a junction of the metal tube to prevent powder from entering the vacuum line; inducing a vacuum within the tube; placing a mixture of titanium and aluminum powder in the tube and employing means to impact the powder in the tube to a filled tube; heating the tube in the vacuum at a temperature sufficient to initiate a high-temperature synthesis (SHS) reaction between the titanium and aluminum; and lowering the temperature to ambient temperature to obtain a intermetallic titanium aluminide alloy weld rod.

  13. Improving blood-compatibility of titanium by coating collagen-heparin multilayers

    NASA Astrophysics Data System (ADS)

    Chen, J. L.; Li, Q. L.; Chen, J. Y.; Chen, C.; Huang, N.

    2009-05-01

    This work deals with improving the blood-compatibility of titanium by coating it with heparin (Hep) and collagen (Col) using a layer-by-layer (LBL) self-assembly technique. In the work described here, LBL-produced Hep-Col film growth is initialized by deposition of a layer of positively charged poly L-Lysine (PLL) on a titanium surface, which is negatively charged after treatment with NaOH, followed by formation of a multilayer thin film formed by alternating deposition of negatively charged heparin and positively charged collagen utilizing electrostatic interaction. The chemical composition, wettability, surface topography, mass and thickness of the film were investigated by Fourier transform infrared spectroscopy, water contact angle measurement, scanning electron microscopy, atomic force microscopy, electronic analytical semi-microbalances, and XP stylus profilometry. The in vitro platelet adhesion and activation were investigated by a static platelet adhesion test probing the lactate dehydrogenase (LDH) release of adherent platelets after lysis and by a P-selectin assay. The clotting time was examined by activated partial thromboplastin time (APTT) and prothrombin time (PT) assays. All obtained data showed that the LBL film can significantly decrease platelet adhesion and activation, and prolong clotting time of APTT and PT compared to untreated titanium. LBL-produced Hep-Col films on titanium display more excellent anticoagulation performance than on the surface of titanium.

  14. Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

    PubMed

    Ji, Min-Kyung; Lee, Min-Joo; Park, Sang-Won; Lee, Kwangmin; Yun, Kwi-Dug; Kim, Hyun-Seung; Oh, Gye-Jeong; Kim, Ji-Hyun; Lim, Hyun-Pil

    2016-02-01

    The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values < or = 0.2 microm (the threshold Ra), which had no effect on bacterial adhesion. No significant difference of S. mutans adhesion was found between the surfaces of control, TiN-Ti, and N-Ti (P > 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans. PMID:27433640

  15. Artifacts and thresholding in X-ray CT of a cortical bone and titanium composite

    SciTech Connect

    Sutherland, C.J.; Gayou, D.E.

    1996-05-01

    X-Ray CT has the potential to provide precise and accurate data from which the mechanical properties of bone can be calculated. Such data would be useful in understanding the response of bone tissue to implants. Various artifacts can, however, degrade accuracy of the data. The aim of this study was to measure the artifactual errors produced in CT of a simulated femoral bone-titanium composite and to propose a method to correct for them. A composite phantom that simulates cortical bone and a titanium implant was designed and constructed. The phantom was scanned and the image data were analyzed over a range of thresholds with image analysis software developed for this study. The outer (OD) and inner (ID) diameter and the CT number of the cortical bone, with and without titanium, were measured over a range of cortical thicknesses. While ID can be accurately measured by choosing the proper threshold (800 HU), OD, even at optimal threshold, will be underestimated by {approx}2%. If a proper threshold is selected, CT number can also be accurately determined. Errors of tip to 5%, however, are produced by titanium unless corrected by proper threshold selection. Intramedullary titanium is not a deterrent to obtaining accurate measurements of cortical bone dimensions and properties. Proper choice of thresholds for image analysis of CT scan data can yield accuracy and precision of 2%. 34 refs., 3 figs.

  16. Calcium phosphate formation on titanium by low-voltage electrolytic treatments.

    PubMed

    Tanaka, Y; Kobayashi, E; Hiromoto, S; Asami, K; Imai, H; Hanawa, T

    2007-05-01

    Electrochemical treatments are expected to be effective for the coating of calcium phosphate ceramics to a titanium substrate. In the present study, two types of chronoamperometry with a step potential and a cyclic wave potential at low voltage (up to 2.0 V) and low current density were performed in Hanks' solution to modify the surface characteristics of titanium. Titanium oxide film formed by self-passivation, that formed as reconstructed film during electrochemical treatments, and a calcium phosphate layer precipitated through treatments were characterised by X-ray photoelectron spectroscopy. The thickness and compositions of the surface films and layers were quantified from the XPS results. Calcium phosphate formation during immersion in Hanks' solution for 1.0 Ms was evaluated by scanning electron microscopy with energy-dispersive X-ray spectrometry. The results confirmed that the electrolytic treatments in this study were effective to accelerate calcium phosphate formation on titanium in Hanks' solution in spite of their lower voltage than conventional methods. The results also suggested that the hydroxyl group in the surface oxide film might contribute to the formation of calcium phosphate. This technique is a promising process for the treatment of thin titanium materials. PMID:17143734

  17. [Comparison of fibroblastic cell compatibility of type I collagen-immobilized titanium between electrodeposition and immersion].

    PubMed

    Kyuragi, Takeru

    2014-03-01

    Titanium is widely used for medical implants. While many techniques for surface modification have been studied for optimizing its biocompatibility with hard tissues, little work has been undertaken to explore ways of maximizing its biocompatibility with soft tissues. We investigated cell attachment to titanium surfaces modified with bovine Type I collagen immobilized by either electrodeposition or a conventional immersion technique. The apparent thickness and durability of the immobilized collagen layer were evaluated prior to incubation of the collagen-immobilized titanium surfaces with NIH/3T3 mouse embryonic fibroblasts. The initial cell attachment and expression of actin and vinculin were evaluated. We determined that the immobilized collagen layer was much thicker and more durable when placed using the electrodeposition technique than the immersion technique. Both protocols produced materials that promoted better cell attachment, growth and structural protein expression than titanium alone. However, electrodeposition was ultimately superior to immersion because it is quicker to perform and produces a more durable collagen coating. We conclude that electrodeposition is an effective technique for immobilizing type I collagen on titanium surfaces, thus improving their cytocompatibility with fibroblasts. PMID:24812763

  18. Automated CBED processing: sample thickness estimation based on analysis of zone-axis CBED pattern.

    PubMed

    Klinger, M; Němec, M; Polívka, L; Gärtnerová, V; Jäger, A

    2015-03-01

    An automated processing of convergent beam electron diffraction (CBED) patterns is presented. The proposed methods are used in an automated tool for estimating the thickness of transmission electron microscopy (TEM) samples by matching an experimental zone-axis CBED pattern with a series of patterns simulated for known thicknesses. The proposed tool detects CBED disks, localizes a pattern in detected disks and unifies the coordinate system of the experimental pattern with the simulated one. The experimental pattern is then compared disk-by-disk with a series of simulated patterns each corresponding to different known thicknesses. The thickness of the most similar simulated pattern is then taken as the thickness estimate. The tool was tested on [0 1 1] Si, [0 1 0] α-Ti and [0 1 1] α-Ti samples prepared using different techniques. Results of the presented approach were compared with thickness estimates based on analysis of CBED patterns in two beam conditions. The mean difference between these two methods was 4.1% for the FIB-prepared silicon samples, 5.2% for the electro-chemically polished titanium and 7.9% for Ar(+) ion-polished titanium. The proposed techniques can also be employed in other established CBED analyses. Apart from the thickness estimation, it can potentially be used to quantify lattice deformation, structure factors, symmetry, defects or extinction distance. PMID:25544679

  19. Ultrasonic Inspection Of Thick Sections

    NASA Technical Reports Server (NTRS)

    Friant, C. L.; Djordjevic, B. B.; O'Keefe, C. V.; Ferrell, W.; Klutz, T.

    1993-01-01

    Ultrasonics used to inspect large, relatively thick vessels for hidden defects. Report based on experiments in through-the-thickness transmission of ultrasonic waves in both steel and filament-wound composite cases of solid-fuel rocket motors.

  20. Tribological evaluation of diamond coating on pure titanium in comparison with plasma nitrided titanium and uncoated titanium

    SciTech Connect

    Yan, B.; Loh, N.L.; Fu, Y.; Sun, C.Q.; Hing, P.

    1999-12-01

    Titanium alloys are characterized by poor tribological properties, and the traditional use of titanium alloys has been restricted to nontribological applications. The deposition of a well adherent diamond coating is a promising way to solve this problem. In this study, the tribological properties of diamond-coated titanium were studied using a pin-on-disk tribometer, and the results were compared with those of pure titanium and plasma nitrided titanium. The tribological behavior of pure titanium was characterized by high coefficient of friction and rapid wear of materials. Plasma nitriding improved the wear resistance only under low normal load; however, this hardened layer was not efficient in improving the wear resistance and the friction properties under high normal load. Diamond coating on pure titanium improved the wear resistance of titanium significantly. Surface profilometry measurement indicated that little or no wear of the diamond coating occurred under the test conditions loads. The roughness of the diamond coating was critical because it controlled the amount of abrasive damage on the counterface. Reducing the surface roughness by polishing led to the reductions in both the friction and wear of the counterface.

  1. Welded Titanium Case for Space-Probe Rocket Motor

    NASA Technical Reports Server (NTRS)

    Brothers, A. J.; Boundy, R. A.; Martens, H. E.; Jaffe, L. D.

    1959-01-01

    Early in 1958, the Jet Propulsion Laboratory of the California Institute of Technology was requested to participate in a lunar-probe mission code-named Juno II which would place a 15-lb Instrumented payload (Pioneer IV) in the vicinity of the moon. The vehicle was to use the same high-speed upper-stage assembly as flown on the successful Jupiter-C configuration; however, the first-stage booster was to be a Jupiter rather than a Redstone. An analysis of the intended flight and payload configuration Indicated that the feasibility of accomplishing the mission was questionable and that additional performance would have to be obtained if the mission was to be feasible. Since the most efficient way of Increasing the performance of a staged vehicle is to increase the performance of the last stage, a study of possible ways of doing this was made.. Because of the time schedule placed on this effort It was decided to reduce the weight of the fourth-stage rocket-motor case by substituting the annealed 6Al--4V titanium alloy for the Type 410 stainless steel. Although this introduced an unfamiliar material, It reduced the changes in design and fabrication techniques. This particular titanium alloy was chosen on the basis of previous tests which proved the suitability of the alloy as a pressure-vessel material when used at an annealed yield strength of about 120, 000 psi. The titanium-case fourth stage of Juno U is shown with the payload and on the missile in Fig. 1; the stainless-steel motor cases used in the Jupiter-C vehicle are shown in Fig. 2. The fourth-stage motor case has a diameter of 6 in., a length of approximately 38 in. center dot and a nominal cylindrical wall thickness of 0.025 in. As shown in Fig. 1, the case serves as the structural support of the payload and is aligned to the upper stage assembly through an alignment ring. The nozzle is threaded into the end of the motor case, and is of the ceramic-coated steel design. Figure 3 shows a comparison of the

  2. Light induced chemical vapour deposition of titanium oxide thin films at room temperature

    NASA Astrophysics Data System (ADS)

    Halary, E.; Benvenuti, G.; Wagner, F.; Hoffmann, P.

    2000-02-01

    High resolution patterned deposition of titania is achieved by light induced chemical vapour deposition (LICVD), by imaging a mask onto a glass substrate. A long pulse XeCl Excimer laser (308 nm) provides, by perpendicular irradiation, the energy to convert titanium tetraisopropoxide (TTIP) vapour into titanium dioxide films, in an oxygen atmosphere, on unheated glass substrates. The amorphous titania deposits contain about 6% carbon contamination according to X-ray photoelectron spectroscopy (XPS) measurements. The deposition rate increases with increasing laser fluence until a maximum value is reached, then remains constant over a wide range, and finally decreases with further fluence increase due to titania ablation or thermal effects. The film thickness increases linearly with the number of pulses after a nucleation period. The strong influence of the laser pulse repetition rate on the growth rate and the thickness profile are reported.

  3. 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.

  4. Gold-nickel-titanium brazing alloy

    DOEpatents

    Mizuhara, Howard

    1995-01-03

    A brazing alloy in accordance with this invention has the following composition, by weight: 91 to 99 gold, 0.5 to 7% nickel; 0.10 to 2% titanium. Alternatively, with palladium present, the composition is as follows, by weight: 83 to 96% gold; 3 to 10% palladium; 0.5 to 5% nickel; 0.10 to 2% titanium.

  5. Gold-nickel-titanium brazing alloy

    DOEpatents

    Mizuhara, Howard

    1990-07-03

    A brazing alloy in accordance with this invention has the following composition, by weight: 91 to 99% gold, 0.5 to 7% nickel; 0.10 to 2% titanium. Alternatively, with palladium present, the composition is as follows, by weight: 83 to 96% gold; 3 to 10% palladium; 0.5 to 5% nickel; 0.10 to 2% titanium.

  6. Bonding titanium to Rene 41 alloy

    NASA Technical Reports Server (NTRS)

    Scott, R. W.

    1972-01-01

    Pair of intermediate materials joined by electron beam welding method welds titanium to Rene 41 alloy. Bond is necessary for combining into one structure high strength-to-density ratio titanium fan blades and temperature resistant nickel-base alloy turbine-buckets in VTOL aircraft lift-fan rotor.

  7. [Dental welding titanium and its clinical usage].

    PubMed

    Li, H; Xiao, M; Zhao, Y

    1998-09-01

    Due to its excellent biocompatibility, desirable chemical and mechanical properties, Titanium has been used for implant denture, RPD and FPD, where welding techniques were indispensable. This paper introduces 5 useful modern ways to weld Titanium and their clinical usage. They are: laser, plasma welding, TIG, infraned brazing and Hruska electrowelding. PMID:12553259

  8. Fungal leaching of titanium from rock.

    NASA Technical Reports Server (NTRS)

    Silverman, M. P.; Munoz, E. F.

    1971-01-01

    Penicillium simplicissimum is found to solubilize up to 80% of the titanium in granitic rocks but less than 2% of the titanium in basaltic rocks. These findings were made in investigating the interactions of microorganisms with rocks and minerals of the biosphere in studies aimed at developing experiments for the detection of extraterrestrial life.

  9. Titanium carbon nitride coating. Final report

    SciTech Connect

    Nance, S.D.

    1992-04-01

    The purpose of this investigation was to determine the advantages of titanium carbon nitride (TiCN) coated tools. Cutting tests were conducted comparing TiCN coating directly against titanium nitride (TiN) coated and uncoated T-15 CPM end mills.

  10. Titanium carbide bipolar plate for electrochemical devices

    DOEpatents

    LaConti, Anthony B.; Griffith, Arthur E.; Cropley, Cecelia C.; Kosek, John A.

    2000-07-04

    A corrosion resistant, electrically conductive, non-porous bipolar plate is made from titanium carbide for use in an eletrochemical device. The process involves blending titanium carbide powder with a suitable binder material, and molding the mixture, at an elevated temperature and pressure.

  11. Mineral resource of the month: titanium

    USGS Publications Warehouse

    Gambogi, Joseph

    2011-01-01

    Titanium is hip - at least when it comes to airplanes and jewelry. Known for its high strength-to weight ratio and its resistance to corrosion, titanium and its alloys can also be found in everything from knee replacements to eyeglass frames to baseball bats to fighter planes.

  12. Waterway Ice Thickness Measurements

    NASA Technical Reports Server (NTRS)

    1978-01-01

    The ship on the opposite page is a U. S. Steel Corporation tanker cruising through the ice-covered waters of the Great Lakes in the dead of winter. The ship's crew is able to navigate safely by plotting courses through open water or thin ice, a technique made possible by a multi-agency technology demonstration program in which NASA is a leading participant. Traditionally, the Great Lakes-St. Lawrence Seaway System is closed to shipping for more than three months of winter season because of ice blockage, particularly fluctuations in the thickness and location of ice cover due to storms, wind, currents and variable temperatures. Shippers have long sought a system of navigation that would allow year-round operation on the Lakes and produce enormous economic and fuel conservation benefits. Interrupted operations require that industrial firms stockpile materials to carry them through the impassable months, which is costly. Alternatively, they must haul cargos by more expensive overland transportation. Studies estimate the economic benefits of year-round Great Lakes shipping in the hundreds of millions of dollars annually and fuel consumption savings in the tens of millions of gallons. Under Project Icewarn, NASA, the U.S. Coast Guard and the National Oceanic Atmospheric Administration collaborated in development and demonstration of a system that permits safe year-round operations. It employs airborne radars, satellite communications relay and facsimile transmission to provide shippers and ships' masters up-to-date ice charts. Lewis Research Center contributed an accurate methods of measuring ice thickness by means of a special "short-pulse" type of radar. In a three-year demonstration program, Coast Guard aircraft equipped with Side-Looking Airborne Radar (SLAR) flew over the Great Lakes three or four times a week. The SLAR, which can penetrate clouds, provided large area readings of the type and distribution of ice cover. The information was supplemented by short

  13. Adherence of sputtered titanium carbides

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1979-01-01

    Sputtered coatings of the refractory metal carbides are of great interest for applications where hard wear-resistant materials are desired. The usefulness of sputtered refractory carbides is often limited, in practice, by spalling or interfacial separation. In this work improvements in the adherence of refractory carbides on iron, nickel and titanium based alloys were obtained by using oxidation, reactive sputtering or sputtered interlayers to alter the coating-substrate interfacial region. X-ray photoelectron spectroscopy and argon ion etching were used to characterize the interfacial regions, and an attempt was made to correlate adherence as measured in wear tests with the chemical nature of the interface.

  14. Weld-brazing of titanium

    NASA Technical Reports Server (NTRS)

    Bales, T. T.; Royster, D. M.; Arnold, W. E., Jr.

    1974-01-01

    A joining process, designated weld-brazing, which combines resistance spotwelding and brazing has been developed at the NASA Langley Research Center. Resistance spot-welding is employed to position and align the parts and to establish a suitable faying surface gap for brazing; it contributes to the integrity of the joint. Brazing enhances the properties of the joint and reduces the stress concentrations normally associated with spotwelds. Ti-6Al-4V titanium alloy joints have been fabricated using 3003 aluminum braze both in a vacuum furnace and in a retort containing an inert gas environment.

  15. Harms titanium mesh cage fracture

    PubMed Central

    Klezl, Zdenek; Bookland, Markus J.; Wolinsky, Jean-Paul; Rezek, Zdenek; Gokaslan, Ziya L.

    2007-01-01

    Interbody fusion has become a mainstay of surgical management for lumbar fractures, tumors, spondylosis, spondylolisthesis and deformities. Over the years, it has undergone a number of metamorphoses, as novel instrumentation and approaches have arisen to reduce complications and enhance outcomes. Interbody fusion procedures are common and successful, complications are rare and most often do not involve the interbody device itself. We present here a patient who underwent an anterior L4 corpectomy with Harms cage placement and who later developed a fracture of the lumbar titanium mesh cage (TMC). This report details the presentation and management of this rare complication, as well as discusses the biomechanics underlying this rare instrumentation failure. PMID:17497187

  16. The present status of dental titanium casting

    NASA Astrophysics Data System (ADS)

    Okabe, Toru; Ohkubo, Chikahiro; Watanabe, Ikuya; Okuno, Osamu; Takada, Yukyo

    1998-09-01

    Experimentation in all aspects of titanium casting at universities and industries throughout the world for the last 20 years has made titanium and titanium-alloy casting nearly feasible for fabricating sound cast dental prostheses, including crowns, inlays, and partial and complete dentures. Titanium casting in dentistry has now almost reached the stage where it can seriously be considered as a new method to compete with dental casting using conventional noble and base-metal alloys. More than anything else, the strength of titanium’s appeal lies in its excellent biocompatibility, coupled with its comparatively low price and abundant supply. Research efforts to overcome some problems associated with this method, including studies on the development of new titanium alloys suitable for dental use, will continue at many research sites internationally.

  17. Stress-corrosion cracking of titanium alloys.

    NASA Technical Reports Server (NTRS)

    Blackburn, M. J.; Feeney, J. A.; Beck, T. R.

    1973-01-01

    In the light of research material published up to May 1970, the current understanding of the experimental variables involved in the stress-corrosion cracking (SCC) behavior of titanium and its alloys is reviewed. Following a brief summary of the metallurgy and electrochemistry of titanium alloys, the mechanical, electrochemical, and metallurgical parameters influencing SCC behavior are explored with emphasis on crack growth kinetics. Macro- and microfeatures of fractures are examined, and it is shown that many transgranular SCC failures exhibit morphological and crystallographic features similar to mechanical cleavage failures. Current SCC models are reviewed with respect to their ability to explain the observed SCC behavior of titanium and its alloys. Possible methods for eliminating or minimizing stress corrosion hazards in titanium or titanium alloy components are described.

  18. Microstructural investigation of thermally treated titanium subhydrides

    SciTech Connect

    Wang, P.S.; Wittberg, T.N.; Wolf, J.D.

    1984-09-05

    The ignition of titanium subhydride/potassium perchlorate pyrotechnic blends is influenced by the diffusion of oxygen into the titanium subhydride fuel. The following work is a preliminary study of the microstructural changes that take place during the dehydriding of titanium subhydride. Samples of TiH/sub 1/ /sub 63/ were dehydrided at temperatures between 625 and 775/sup 0/C. In the partially dehydrided samples, evidence of three different phases - ..cap alpha.. Ti (hexagonal), ..beta.. Ti (cubic), and ..gamma.. TiH/sub 2/ (cubic) - was seen. Microstructural examination of a TiH/sub 1/ /sub 15/ sample that had a layered structure is also reported. A furnace constructed for hydriding titanium foils is also described. Titanium subhydride foils having the stoichiometries TiH/sub 1/ /sub 53/ and TiH/sub 0/ /sub 87/ were prepared using this furnace.

  19. TiO{sub 2} nanotube, nanowire, and rhomboid-shaped particle thin films fixed on a titanium metal plate

    SciTech Connect

    Inoue, Yuko; Noda, Iwao; Torikai, Toshio; Watari, Takanori; Hotokebuchi, Takao; Yada, Mitsunori

    2010-01-15

    Titanium dioxide thin films having various nanostructures could be formed by various treatments on sodium titanate nanotube thin films approximately 5 {mu}m thick fixed on titanium metal plates. Using an aqueous solution with a lower hydrochloric acid concentration (0.01 mol/L) and a higher reaction temperature (90 deg. C) than those previously employed, we obtained a hydrogen titanate nanotube thin film fixed onto a titanium metal plate by H{sup +} ion-exchange treatment of the sodium titanate nanotube thin film. Calcination of hydrogen titanate nanotube thin films yielded porous thin films consisting of anatase nanotubes, anatase nanowires, and anatase nanoparticles grown directly from the titanium metal plate. H{sup +} ion-exchange treatment of sodium titanate nanotube thin films at 140 deg. C resulted in porous thin films consisting of rhomboid-shaped anatase nanoparticles. - Graphical abstract: Titanium dioxide nanotube, nanowire, and rhombic particle thin films could be formed by various treatments on a sodium titanate nanotube thin film fixed on a titanium metal plate.

  20. Ignition of Fuel Vapors Beneath Titanium Aircraft Skins Exposed to Lightning

    NASA Technical Reports Server (NTRS)

    Kosvic, T. C.; Helgeson, N. L.; Gerstein, M.

    1971-01-01

    Hot-spot and puncture ignition of fuel vapors by simulated lightning discharges was studied experimentally. The influences of skin coating, skin structure, discharge polarity, skin thickness, discharge current level, and current duration were measured and interpreted. Ignition thresholds are reported for titanium alloy constructed as sheets, sheets coated with sealants, and sandwich skins. Results indicated that the ignition threshold charge transfer for coated sheets, honeycomb, and truss skins is respectively about 200%, 400%, 800% that of bare alloy sheet of .102 cm (.040 in.)-thickness. It was found that hot-spot ignition can occur well after termination of the arc, and that sandwich materials allow ignition only if punctured.

  1. Synthesis of titanium-vanadium oxide materials from aqueous solutions via co-deposition

    NASA Astrophysics Data System (ADS)

    Shyue, Jing-Jong

    Titania-supported vanadium oxide is an important heterogeneous catalyst in a variety of applications. Therefore, the synthesis of mixed titanium-vanadium oxide films may be of interest for potential catalysts. While most vanadium-based catalysts consist of a vanadium oxide phase deposited on the surface of an oxide support, mixed titanium-vanadium oxides were co-deposited from aqueous solutions in a single step. The chemical composition of the titanium-vanadium oxide thin films on organic self-assembled monolayers (SAMs) was manipulated by chelating agents, including lactic acid and oxalic acid. Based on the dependence of Ti:V ratio in the films on the oxalic acid concentration, it is concluded that oxalic acid chelates both titanium and vanadium, but preferentially vanadium. Therefore, from solutions with [oxalate]:[vanadium] < 1:1, titanium-enriched films were formed. However, with [oxalate]: [vanadium] > 1:1, excess oxalic acid chelates titanium as well. Consequently, the Ti:V ratio dropped back to that of films deposited in the absence of chelating agents. At high concentrations of oxalic acid, both titanium and vanadium was chelated excessively. Therefore, no films formed. Lactic acid can be oxidized by pentavalent vanadium, so that it cannot chelate cations. Therefore, when [lactate]: [vanadium] < 1:2, V4+ was formed. These V4+ ions increased the deposition rate of vanadium, and vanadium-rich films were formed. For [lactate]:[vanadium] > 1:2, the remaining lactic acid preferentially chelate vanadium and showed effects comparable to those seen with oxalic acid. The vanadium content in the mixed oxide films affected the thickness of films formed on the alkylammonium SAMs but had little or no effect on the films formed on amine SAMs. This result is consistent with the presence of a Stern layer, previously reported to form on amine-terminated surfaces. In addition to forming thin films, titanium-vanadium oxide solid-solution powders were also prepared via co

  2. Titanium in Engine Valve Systems

    NASA Astrophysics Data System (ADS)

    Allison, J. E.; Sherman, A. M.; Bapna, M. R.

    1987-03-01

    Titanium alloys offer a unique combination of high strength-to-weight ratio, good corrosion resistance and favorable high temperature mechanical properties. Still, their relatively high cost has discouraged consideration for widespread use in automotive components. Recent demands for increased fuel economy have led to the consideration of these alloys for use as valve train materials where higher costs might be offset by improvements in performance and fuel economy. Lighter weight valve train components permit the use of lower spring loads, thus reducing friction and increasing fuel economy. Camshaft friction measurements made on a typical small displacement engine indicate that a twoto-four percent increase in fuel economy can be achieved. Valve train components are, however, subject to a severe operating environment, including elevated temperatures, sliding wear and high mechanical loads. This paper discusses the details of alloy and heat treatment selection for optimizing valve performance. When properly manufactured, titanium valves have been shown to withstand very stringent durability testing, indicating the technical feasibility of this approach to fuel economy improvement.

  3. Characterisation of titanium-titanium boride composites processed by powder metallurgy techniques

    SciTech Connect

    Selva Kumar, M.; Chandrasekar, P.; Chandramohan, P.; Mohanraj, M.

    2012-11-15

    In this work, a detailed characterisation of titanium-titanium boride composites processed by three powder metallurgy techniques, namely, hot isostatic pressing, spark plasma sintering and vacuum sintering, was conducted. Two composites with different volume percents of titanium boride reinforcement were used for the investigation. One was titanium with 20% titanium boride, and the other was titanium with 40% titanium boride (by volume). Characterisation was performed using X-ray diffraction, electron probe micro analysis - energy dispersive spectroscopy and wavelength dispersive spectroscopy, image analysis and scanning electron microscopy. The characterisation results confirm the completion of the titanium boride reaction. The results reveal the presence of titanium boride reinforcement in different morphologies such as needle-shaped whiskers, short agglomerated whiskers and fine plates. The paper also discusses how mechanical properties such as microhardness, elastic modulus and Poisson's ratio are influenced by the processing techniques as well as the volume fraction of the titanium boride reinforcement. - Highlights: Black-Right-Pointing-Pointer Ti-TiB composites were processed by HIP, SPS and vacuum sintering. Black-Right-Pointing-Pointer The completion of Ti-TiB{sub 2} reaction was confirmed by XRD, SEM and EPMA studies. Black-Right-Pointing-Pointer Hardness and elastic properties of Ti-TiB composites were discussed. Black-Right-Pointing-Pointer Processing techniques were compared with respect to their microstructure.

  4. Adhesive-Bonded Tab Attaches Thermocouples to Titanium

    NASA Technical Reports Server (NTRS)

    Cook, C. F.

    1982-01-01

    Mechanical strength of titanium-alloy structures that support thermocouples is preserved by first spotwelding thermocouples to titanium tabs and then attaching tabs to titanium with a thermosetting adhesive. In contrast to spot welding, a technique previously used for thermocouples, fatigue strength of the titanium is unaffected by adhesive bonding. Technique is also gentler than soldering or attaching thermocouples with a tap screw.

  5. Comparative osteogenesis of maxilla and iliac crest human bone marrow stromal cells attached to oxidized titanium - a pilot study

    PubMed Central

    Akintoye, Sunday O; Giavis, Parascevi; Stefanik, Derek; Levin, Lawrence; Mante, Francis K

    2010-01-01

    Objectives Severe alveolar bone loss affects dental implant placement. Bone augmentation by grafting iliac crest bone rich in osteoprogenitor cells like bone marrow stromal cells (BMSCs) requires a second surgical procedure in non-orofacial bone. Skeletal site-specific osteogenesis indicates maxilla and mandible BMSCs are highly proliferative and exhibit osteogenic properties superior to iliac crest BMSCs. Alveolar bone can be easily obtained during routine dental surgery, but it is unclear if titanium-attached alveolar BMSCs will retain their superior osteogenic properties. This study evaluated and compared in vitro osteogenic properties of titanium-attached maxilla and iliac crest BMSCs in same individuals. Materials and Methods Primary culture of maxilla and iliac crest BMSCs from four normal healthy volunteers were expanded in culture. In 24-well plates, first passage BMSCs were seeded directly (1 × 104 cells/well) on oxidized titanium discs (1.27cm diameter and 2mm thickness) or tissue culture plate. Each cell type was assessed for affinity for titanium, post-attachment survival and osteogenic differentiation based on alkaline phosphatase and osteopontin expressions. Results There was no difference in the affinity of maxilla and iliac crest BMSCs to titanium. However, titanium-attached maxilla BMSCs were apparently more osteogenically responsive than iliac crest cells based on calcium accumulation and gene expression of alkaline phosphatase and osteopontin. But these differences were not statistically significant in this small patient sample. Conclusion Maxilla and iliac crest BMSCs have similar attachment affinity for titanium. This pilot study indicate that titanium-attached maxilla BMSCs were more osteogenically responsive and may be a viable and more readily available donor graft material in implant dentistry. PMID:18983324

  6. Femtosecond laser microstructuring and bioactive nanocoating of titanium surfaces in relation to chondrocyte growth

    NASA Astrophysics Data System (ADS)

    Ilgner, Justus; Biedron, Slavomir; Fadeeva, Elena; Chichkov, Boris; Klee, Doris; Loos, Anneke; Sowa-Söhle, Eveline; Westhofen, Martin

    2010-02-01

    Introduction: Titanium implants can be regarded as the current gold standard for restoration of sound transmission in the middle ear following destruction of the ossicular chain by chronic inflammation. Many efforts have been made to improve prosthesis design, while less attention had been given to the role of the interface. We present a study on chemical nanocoating on microstructured titanium contact surface with bioactive protein. Materials and Methods: Titanium samples of 5mm diameter and 0,25mm thickness were structured by means of a Ti:Sapphire femtosecond laser operating at 970nm with parallel lines of 5μm depth, 5μm width and 10μm inter-groove distance. In addition, various nanolayers were applied to titanium samples by aminosilanization, to which Star-Polyethylene glycole (Star-PEG) molecules plus biomarkers (e.g. RGD peptide sequence) were linked. Results: Chondrocytes could be cultured on microstructured surfaces without reduced rate of vital / dead cells compared to native surfaces. Chondrocytes also showed contact guidance by growing along ridges particularly on 5μm lines. On nanocoated titanium samples, first results showed a strong effect of Star-PEG suppressing unspecific protein absorption, while RGD peptide sequence did not promote chondrocyte cell growth. Discussion: According to these results, the idea of promoting cell growth on titanium prosthesis contact surfaces compared to non-contact surfaces (e.g. prosthesis shaft) by nanocoating is practicable. However, relative selectivity induced by microstructures for growth of chondrocytes compared to fibrocytes is subject to further evaluation.

  7. Modification of the titanium alloy surface in electroexplosive alloying with boron carbide and subsequent electron-beam treatment

    SciTech Connect

    Gromov, Victor E. Budovskikh, Evgeniy A. Bashchenko, Lyudmila P. Kobzareva, Tatyana Yu. Semin, Alexander P.; Ivanov, Yurii F.; Wang, Xinli

    2015-10-27

    The modification of the VT6 titanium alloy surface in electroexplosion alloying with plasma being formed in titanium foil with a weighed powder of boron carbide with subsequent irradiation by a pulsed electron beam has been carried out. An electroexplosive alloying zone of a thickness up to 50 μm with a gradient structure is found to form. The subsequent electron-beam treatment of the alloying zone results in smoothing of the alloying surface and is accompanied by the formation of the multilayer structure with alternating layers of various alloying degree at a depth of 30 μm.

  8. Electrochromism of DC magnetron-sputtered TiO2: Role of film thickness

    NASA Astrophysics Data System (ADS)

    Sorar, Idris; Pehlivan, Esat; Niklasson, Gunnar A.; Granqvist, Claes G.

    2014-11-01

    Titanium dioxide films were prepared by reactive DC magnetron sputtering and the role of the film thickness d on the electrochromism was analyzed for 100 < d < 400 nm. The best properties were obtained for the thickest films, which yielded a mid-luminous transmittance modulation of 58% and a corresponding coloration efficiency of 26.3 cm2/C. The films were amorphous according to X-ray diffraction measurements and showed traces of adsorbed water as revealed by infrared spectroscopy.

  9. Titanium Coating of the Boston Keratoprosthesis

    PubMed Central

    Salvador-Culla, Borja; Jeong, Kyung Jae; Kolovou, Paraskevi Evi; Chiang, Homer H.; Chodosh, James; Dohlman, Claes H.; Kohane, Daniel S.

    2016-01-01

    Purpose We tested the feasibility of using titanium to enhance adhesion of the Boston Keratoprosthesis (B-KPro), ultimately to decrease the risk of implant-associated complications. Methods Cylindrical rods were made of poly(methyl methacrylate) (PMMA), PMMA coated with titanium dioxide (TiO2) over a layer of polydopamine (PMMATiO2), smooth (Ti) and sandblasted (TiSB) titanium, and titanium treated with oxygen plasma (Tiox and TiSBox). Topography and surface chemistry were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS). Adhesion force between rods and porcine corneas was measured ex vivo. Titanium sleeves, smooth and sandblasted, were inserted around the stem of the B-KPro and implanted in rabbits. Tissue adhesion to the stem was assessed and compared to an unmodified B-Kpro after 1 month. Results X-ray photoelectron spectroscopy demonstrated successful deposition of TiO2 on polydopamine-coated PMMA. Oxygen plasma treatment did not change the XPS spectra of titanium rods (Ti and TiSB), although it increased their hydrophilicity. The materials did not show cell toxicity. After 14 days of incubation, PMMATiO2, smooth titanium treated with oxygen plasma (Tiox), and sandblasted titanium rods (TiSB, TiSBox) showed significantly higher adhesion forces than PMMA ex vivo. In vivo, the use of a TiSB sleeve around the stem of the B-KPro induced a significant increase in tissue adhesion compared to a Ti sleeve or bare PMMA. Conclusions Sandblasted titanium sleeves greatly enhanced adherence of the B-KPro to the rabbit cornea. This approach may improve adhesion with the donor cornea in humans as well. Translational Relevance This approach may improve adhesion with donor corneas in humans. PMID:27152247

  10. Osteoconductivity of hydrophilic microstructured titanium implants with phosphate ion chemistry.

    PubMed

    Park, Jin-Woo; Jang, Je-Hee; Lee, Chong Soo; Hanawa, Takao

    2009-07-01

    This study investigated the surface characteristics and bone response of titanium implants produced by hydrothermal treatment using H(3)PO(4), and compared them with those of implants produced by commercial surface treatment methods - machining, acid etching, grit blasting, grit blasting/acid etching or spark anodization. The surface characteristics were evaluated by scanning electron microscopy, thin-film X-ray diffractometry, X-ray photoelectron spectroscopy, contact angle measurement and stylus profilometry. The osteoconductivity of experimental implants was evaluated by removal torque testing and histomorphometric analysis after 6 weeks of implantation in rabbit tibiae. Hydrothermal treatment with H(3)PO(4) and subsequent heat treatment produced a crystalline phosphate ion-incorporated oxide (titanium oxide phosphate hydrate, Ti(2)O(PO(4))(2)(H(2)O)(2); TiP) surface approximately 5microm in thickness, which had needle-like surface microstructures and superior wettability compared with the control surfaces. Significant increases in removal torque forces and bone-to-implant contact values were observed for TiP implants compared with those of the control implants (p<0.001). After thorough cleaning of the implants removed during the removal torque testing, a considerable quantity of attached bone was observed on the surfaces of the TiP implants. PMID:19332400

  11. Chemical vapor deposition coatings for oxidation protection of titanium alloys

    NASA Technical Reports Server (NTRS)

    Cunnington, G. R.; Robinson, J. C.; Clark, R. K.

    1991-01-01

    Results of an experimental investigation of the oxidation protection afforded to Ti-14Al-21Nb and Ti-14Al-23Nb-2V titanium aluminides and Ti-17Mo-3Al-3Nb titanium alloy by aluminum-boron-silicon and boron-silicon coatings are presented. These coatings are applied by a combination of physical vapor deposition (PVD) and chemical vapor deposition (CVD) processes. The former is for the application of aluminum, and the latter is for codeposition of boron and silicon. Coating thickness is in the range of 2 to 7 microns, and coating weights are 0.6 to 2.0 mg/sq cm. Oxidation testing was performed in air at temperatures to 1255 K in both static and hypersonic flow environments. The degree of oxidation protection provided by the coatings is determined from weight change measurements made during the testing and post test compositional analyses. Temperature-dependent total normal emittance data are also presented for four coating/substrate combinations. Both types of coatings provided excellent oxidation protection for the exposure conditions of this investigation. Total normal emittances were greater than 0.80 in all cases.

  12. Very Long Term Oxidation of Titanium Aluminides Investigated

    NASA Technical Reports Server (NTRS)

    Locci, Ivan E.; Brady, Michael P.; Smialek, James L.; Retallick, William B.

    2000-01-01

    Titanium aluminides (TiAl) are of great interest for intermediate-temperature (600 to 850 C) aerospace and power-generation applications because they offer significant weight savings over today's nickel alloys. TiAl alloys are being investigated for low-pressure turbine blade applications, exhaust nozzle components, and compressor cases in advanced subsonic and supersonic engines. Significant progress has been made in understanding the fundamental aspects of the oxidation behavior of binary TiAl alloys. However, most of this work has concentrated on short term (<1000 hr), high-temperature (900 to 1000 C) exposures. Also, there is not much data available in the literature regarding the oxidation behavior of the quaternary and higher order engineering alloys. This is especially true for the very long term, low-temperature conditions likely to be experienced during aerospace applications. An investigation at the NASA Glenn Research Center at Lewis Field was undertaken to characterize the long-term oxidation behavior of various model and advanced titanium aluminides for periods up to 7000 hr at 704 C in air using a high-resolution field emission scanning electron microscope. Also, a unique surface treatment technique developed to improve the oxidation resistance of TiAl was evaluated. The alloys included in this investigation are listed in the table. The table also shows typical alloy compositions and the specific weight changes and scale thickness measured for each alloy after exposure to 700 C for 7000 hr in air.

  13. X-Ray photoelectron spectroscopy study of radiofrequency-sputtered titanium, carbide, molybdenum carbide, and titanium boride coatings and their friction properties

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1977-01-01

    Radiofrequency sputtered coatings of titanium carbide, molybdenum carbide and titanium boride were tested as wear resistant coatings on stainless steel in a pin on disk apparatus. X-ray photoelectron spectroscopy (XPS) was used to analyze the sputtered films with regard to both bulk and interface composition in order to obtain maximum film performance. Significant improvements in friction behavior were obtained when properly biased films were deposited on deliberately preoxidized substrates. XPS depth profile data showed thick graded interfaces for bias deposited films even when adherence was poor. The addition of 10 percent hydrogen to the sputtering gas produced coatings with thin poorly adherent interfaces. Results suggest that some of the common practices in the field of sputtering may be detrimental to achieving maximum adherence and optimum composition for these refractory compounds.

  14. Titanium-potassium heat pipe corrosion studies

    SciTech Connect

    Lundberg, L.B.

    1984-07-01

    An experimental study of the susceptibility of wickless titanium/potassium heat pipes to corrosive attack has been conducted in vacuo at 800/sup 0/K for 6511h and at 900/sup 0/K for 4797h without failure or degradation. Some movement of carbon, nitrogen and oxygen was observed in the titanium container tube, but no evidence of attack could be detected in metallographic cross sections of samples taken along the length of the heat pipes. The lack of observable attack of titanium by potassium under these conditions refutes previous reports of Ti-K incompatibility.

  15. Stress corrosion cracking of titanium alloys

    NASA Technical Reports Server (NTRS)

    Statler, G. R.; Spretnak, J. W.; Beck, F. H.; Fontana, M. G.

    1974-01-01

    The effect of hydrogen on the properties of metals, including titanium and its alloys, was investigated. The basic theories of stress corrosion of titanium alloys are reviewed along with the literature concerned with the effect of absorbed hydrogen on the mechanical properties of metals. Finally, the basic modes of metal fracture and their importance to this study is considered. The experimental work was designed to determine the effects of hydrogen concentration on the critical strain at which plastic instability along pure shear directions occurs. The materials used were titanium alloys Ti-8Al-lMo-lV and Ti-5Al-2.5Sn.

  16. Ultraviolet laser treatment of titanium surface

    NASA Astrophysics Data System (ADS)

    Balchev, Ivaylo; Minkovski, Nikolai; Dimitrov, Krasimir; Shipochka, Maria; Barbucha, Robert

    2016-02-01

    Interaction of a third harmonic of DPSS laser, wavelength 355 nm and pulse duration of 30 ns with titanium wafers was studied. It was investigated the structure of laser ablated titanium surface, depending on the laser beam scanning speed, and laser pulse frequency. The titanium surface modification was studied by scanning electron microscopy (SEM) and XPS (X- ray Photoelectron Spectroscopy). Nanosecond irradiation with ultraviolet light of Ti plate led to the formation of high porous granular structures consisting of agglomerated micro- and submicro- particles.

  17. Oxygen-Barrier Coating for Titanium

    NASA Technical Reports Server (NTRS)

    Clark, Ronald K.; Unnam, Jalaiah

    1987-01-01

    Oxygen-barrier coating for titanium developed to provide effective and low-cost means for protecting titanium alloys from oxygen in environment when alloys used in high-temperature mechanical or structural applications. Provides protective surface layer, which reduces extent of surface oxidation of alloy and forms barrier to diffusion of oxygen, limiting contamination of substrate alloy by oxygen. Consists of submicron layer of aluminum deposited on surface of titanium by electron-beam evaporation, with submicron layer of dioxide sputtered onto aluminum to form coat.

  18. Highly reliable spin-coated titanium dioxide dielectric

    NASA Astrophysics Data System (ADS)

    Mondal, Sandip; Kumar, Arvind; Rao, K. S. R. Koteswara; Venkataraman, V.

    2016-05-01

    Dielectric degradation as low as 0.3 % has been observed for a highly reliable Titanium dioxide (TiO2) film after constant voltage stressing (CVS) with - 4 V for 105 second at room temperature (300 K). The film was fabricated by sol -gel spin - coating method on a lightly doped p-Si (~1015 cm-3) substrate. The equivalent oxide thickness (EOT) is 7 nm with a dielectric constant 33 (at 1 MHz). Metal - Oxide - Semiconductor (MOS) capacitors have been fabricated with an optimum annealing temperature of 800°C for one hour in a preheated furnace. The dielectric degradation is annealing temperature dependent. A degradation of 1.4 %, 1.2 % and 1.1 % has been observed for 400°C, 600°C and 1000°C temperature annealed MOS respectively. The dielectric degradation increases below or above the optimum temperature of annealing.

  19. DEVELOPMENT OF TITANIUM NITRIDE COATING FOR SNS RING VACUUM CHAMBERS.

    SciTech Connect

    HE,P.; HSEUH,H.C.; MAPES,M.; TODD,R.; WEISS,D.

    2001-06-18

    The inner surface of the ring vacuum chambers of the US Spallation Neutron Source (SNS) will be coated with {approximately}100 nm of Titanium Nitride (TiN). This is to minimize the secondary electron yield (SEY) from the chamber wall, and thus avoid the so-called e-p instability caused by electron multipacting as observed in a few high-intensity proton storage rings. Both DC sputtering and DC-magnetron sputtering were conducted in a test chamber of relevant geometry to SNS ring vacuum chambers. Auger Electron Spectroscopy (AES) and Rutherford Back Scattering (RBS) were used to analyze the coatings for thickness, stoichiometry and impurity. Excellent results were obtained with magnetron sputtering. The development of the parameters for the coating process and the surface analysis results are presented.

  20. Nanomechanical behavior of (1 0 0) oriented titanium thin films

    NASA Astrophysics Data System (ADS)

    Vasu, Kuraganti; Ghanashyam Krishna, Mamidipudi; Padmanabhan, Kuppuswamy Anantha

    2014-03-01

    Titanium thin films were deposited on single crystal Si (3 1 1) and polycrystalline 316 LN nuclear grade stainless steel substrates by RF magnetron sputtering. X-ray diffraction revealed that, irrespective of substrate type, films exhibit preferential growth along the (1 0 0) plane. The microstructure of the films corresponds to the zone-I type in structure zone model on both substrates. The hardness and Young's modulus of the films were extracted from load-displacement curves. The maximum values of hardness and Young's modulus were 12 and 132 GPa respectively for 220 nm thin film on SS substrate. The electrical resistivity data revealed that the films are metallic in nature and the resistivity is lower in the case of the 220 nm thickness film, on both substrates. The observed changes in mechanical and electrical properties can be correlated with variations in the microstructure of Ti films.

  1. Characterisation of DLC films deposited using titanium isopropoxide (TIPOT) at different flow rates.

    PubMed

    Said, R; Ali, N; Ghumman, C A A; Teodoro, O M N D; Ahmed, W

    2009-07-01

    In recent years, there has been growing interest in the search for advanced biomaterials for biomedical applications, such as human implants and surgical cutting tools. It is known that both carbon and titanium exhibit good biocompatibility and have been used as implants in the human body. It is highly desirable to deposit biocompatible thin films onto a range of components in order to impart biocompatibility and to minimise wear in implants. Diamond like carbon (DLC) is a good candidate material for achieving biocompatibility and low wear rates. In this study, thin films of diamond-like-carbon DLC were deposited onto stainless steel (316) substrates using C2H2, argon and titanium isopropoxide (TIPOT) precursors. Argon was used to generate the plasma in the plasma enhanced vapour deposition (PECVD) system. A critical coating feature governing the performance of the component during service is film thickness. The as-grown films were in the thickness range 90-100 nm and were found to be dependent on TIPOT flow rate. Atomic force microscopy (AFM) was used to characterise the surface roughness of the samples. As the flow rate of TIPOT increased the average roughness was found to increase in conjunction with the film thickness. Raman spectroscopy was used to investigate the chemical structure of amorphous carbon matrix. Surface tension values were calculated using contact angle measurements. In general, the trend of the surface tension results exhibited an opposite trend to that of the contact angle. The elemental composition of the samples was characterised using a VG ToF SIMS (IX23LS) instrument and X-ray photoelectron spectroscopy (XPS). Surprisingly, SIMS and XPS results showed that the DLC samples did not show evidence of titanium since no peaks representing to titanium appeared on the SIMS/XPS spectra. PMID:19916446

  2. Adherence of sputtered titanium carbides

    NASA Technical Reports Server (NTRS)

    Brainard, W. A.; Wheeler, D. R.

    1979-01-01

    The study searches for interface treatment that would increase the adhesion of TiC coating to nickel- and titanium-base alloys. Rene 41 (19 wt percent Cr, 11 wt percent Mo, 3 wt percent Ti, balance Ni) and Ti-6Al-4V (6 wt percent Al, 4 wt percent V, balance Ti) are considered. Adhesion of the coatings is evaluated in pin-and disk friction tests. The coatings and interface regions are examined by X-ray photoelectron spectroscopy. Results suggest that sputtered refractory compound coatings adhere best when a mixed compound of coating and substrate metals is formed in the interfacial region. The most effective type of refractory compound interface appears to depend on both substrate and coating material. A combination of metallic interlayer deposition and mixed compound interface formation may be more effective for some substrate coating combinations than either alone.

  3. Corrosion of Titanium Matrix Composites

    SciTech Connect

    Covino, B.S., Jr.; Alman, D.E.

    2002-09-22

    The corrosion behavior of unalloyed Ti and titanium matrix composites containing up to 20 vol% of TiC or TiB{sub 2} was determined in deaerated 2 wt% HCl at 50, 70, and 90 degrees C. Corrosion rates were calculated from corrosion currents determined by extrapolation of the tafel slopes. All curves exhibited active-passive behavior but no transpassive region. Corrosion rates for Ti + TiC composites were similar to those for unalloyed Ti except at 90 degrees C where the composites were slightly higher. Corrosion rates for Ti + TiB{sub 2} composites were generally higher than those for unalloyed Ti and increased with higher concentrations of TiB{sub 2}. XRD and SEM-EDS analyses showed that the TiC reinforcement did not react with the Ti matrix during fabrication while the TiB{sub 2} reacted to form a TiB phase.

  4. Neutron scattering and models: Titanium

    SciTech Connect

    Smith, A.B.

    1997-07-01

    Differential neutron elastic-scattering cross sections of elemental titanium were measured from 4.5 {r_arrow} 10.0 MeV in incident energy increments of {approx} 0.5 MeV. At each energy the measurements were made at forty or more scattering angles distributed between {approx} 17 and 160{degree}. Concurrently, differential neutron inelastic-scattering cross sections were measured for observed excitations of 0.975 {+-} 0.034, 1.497 {+-} 0.033, 2.322 {+-} 0.058, 3.252 {+-} 0.043, 3.700 {+-} 0.093, 4.317 {+-} 0.075 and 4.795 {+-} 0.100 MeV. All of the observed inelastically-scattered neutron groups were composites of contributions from several isotopes and/or levels. The experimental results were used to develop energy-average optical, statistical and coupled-channels models.

  5. The role of the domain size and titanium dopant in nanocrystalline hematite thin films for water photolysis

    NASA Astrophysics Data System (ADS)

    Yan, Danhua; Tao, Jing; Kisslinger, Kim; Cen, Jiajie; Wu, Qiyuan; Orlov, Alexander; Liu, Mingzhao

    2015-11-01

    also found that the role of the titanium dopant in improving the PEC performance is not apparently related to the films' electrical conductivity which had been widely believed, but is more likely due to the passivation of surface defects by the titanium dopants. Electronic supplementary information (ESI) available: Dependence of PEC activity on sample thicknesses, thermodynamic calculations for reactions between FTO and elemental titanium/iron, and the model of Mott-Schottky analysis and measurement of depletion region capacitance. See DOI: 10.1039/C5NR05894E

  6. Phase thickness approach for determination of thin film refractive index dispersion from transmittance spectra

    NASA Astrophysics Data System (ADS)

    Nenkov, M. R.; Pencheva, T. G.

    2008-06-01

    A novel approach for determination of refractive index dispersion n(λ ) and thickness d of thin films of negligible absorption and weak dispersion is proposed. The calculation procedure is based on determination of the phase thickness of the film in the spectral region of measured transmittance data. All points of measured spectra are included in the calculations. Barium titanate and titanium oxide thin films are investigated and their n(λ ) and d are calculated. The approach is validated using Swanepoel's method and it is found to be applicable for relatively thinner films when measured transmittance spectra have one minimum and one maximum only.

  7. Measuring Thicknesses of Wastewater Films

    NASA Technical Reports Server (NTRS)

    Schubert, F. H.; Davenport, R. J.

    1987-01-01

    Sensor determines when thickness of film of electrically conductive wastewater on rotating evaporator drum exceeds preset value. Sensor simple electrical probe that makes contact with liquid surface. Made of materials resistant to chemicals in liquid. Mounted on shaft in rotating cylinder, liquid-thickness sensor extends toward cylinder wall so tip almost touches. Sensor body accommodates probe measuring temperature of evaporated water in cylinder.

  8. Effects of broiler breast meat thickness and background on color measurements.

    PubMed

    Bianchi, M; Fletcher, D L

    2002-11-01

    Experiments were conducted to determine the influence of broiler and turkey breast meat thickness and background on breast meat color measurements. Broiler breast fillets were sliced into two 1 cm thick slices and the turkey breast fillets into three 1 cm slices. Color values for lightness (L*), redness (a*), and yellowness (b*) were measured on the same top slice singly or while placed over the corresponding broiler and turkey slices. Color was measured in triplicate while the fillets were placed on the following backgrounds: plastic-coated white paper, white nylon, aluminum foil, black plastic, and a yellow commercial packaging tray (broiler only). Sample thickness significantly affected L*, a*, and b* values of turkey and chicken. Increased breast meat thickness resulted in lower L*, a*, and b5 values. Increased turkey meat thickness from 1 to 2 cm resulted in lower a* and b* values; however, only lower L* values were observed, with sample thickness increased from 1 to 3 cm. No differences in meat color were found when increasing turkey meat sample thickness from 2 to 3 cm. Background had a significant effect on single (1 cm) broiler and turkey meat color measurements but did not influence the color readings of the thicker multiple slice samples. These results indicate that the application of machine vision or in-line color measurement systems may have to take into account breast meat thickness, and in thinner samples, background color. PMID:12455607

  9. Copper/nickel eutectic brazing of titanium

    NASA Technical Reports Server (NTRS)

    Kutchera, R. E.

    1971-01-01

    Technique joins titanium or one of its alloys to materials, such as iron, nickel or cobalt base material, or to refractory metals. To ensure formation of a satisfactory bond, the temperature, time, environment and pressure must be controlled.

  10. Determination of nitrogen in titanium nitride

    NASA Technical Reports Server (NTRS)

    Philipp, W. H.; Tetzlaff, J. E.

    1970-01-01

    Quantitative determination of nitrogen in titanium nitride involves dissolution of TiN in 10M hydrofluoric acid containing an oxidant. Released nitrogen is determined as ammonia. Best oxidizers are ferric chloride, potassium iodate, and potassium dichromate.

  11. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... hydrochloric acid. (c) Uses and restrictions. The color additive titanium dioxide may be safely used for..., not more than 0.3 percent. Acid soluble substances, not more than 0.5 percent. TiO2, not less than...

  12. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... hydrochloric acid. (c) Uses and restrictions. The color additive titanium dioxide may be safely used for..., not more than 0.3 percent. Acid soluble substances, not more than 0.5 percent. TiO2, not less than...

  13. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... hydrochloric acid. (c) Uses and restrictions. The color additive titanium dioxide may be safely used for..., not more than 0.3 percent. Acid soluble substances, not more than 0.5 percent. TiO2, not less than...

  14. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... hydrochloric acid. (c) Uses and restrictions. The color additive titanium dioxide may be safely used for..., not more than 0.3 percent. Acid soluble substances, not more than 0.5 percent. TiO2, not less than...

  15. 21 CFR 73.575 - Titanium dioxide.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... hydrochloric acid. (c) Uses and restrictions. The color additive titanium dioxide may be safely used for..., not more than 0.3 percent. Acid soluble substances, not more than 0.5 percent. TiO2, not less than...

  16. Investigation of Conditions of Titanium Carbonization - IV

    NASA Technical Reports Server (NTRS)

    Meerson, G. A.; Lipkes, Y. M.

    1949-01-01

    In a previous paper, results are presented of accurate investigations of the processes of titanium carbonization and the succeeding titanium carbide decarbonization as related to the phenomenon of the graphitization of soot by heating at a constant temperature in atmospheres of pure hydrogen and carbon monoxide. These tests showed that the processes of titanium carbonization-decarbonization in an atmosphere of pure gases without nitrogen proceed in the same direction as the analogous processes under the conditions of the production furnace. In this case, however, the presence of admixtures of nitrogen changes the quantitative results of the decarbonization process. Thermodynamic computations confirming the results of previous tests conducted at atmospheric pressure and additional tests of titanium carbonization at lowered pressures are presented herein.

  17. Degreasing of titanium to minimize stress corrosion

    NASA Technical Reports Server (NTRS)

    Carpenter, S. R.

    1967-01-01

    Stress corrosion of titanium and its alloys at elevated temperatures is minimized by replacing trichloroethylene with methanol or methyl ethyl ketone as a degreasing agent. Wearing cotton gloves reduces stress corrosion from perspiration before the metal components are processed.

  18. Valve, normally open, titanium: Pyronetics Model 1425

    NASA Technical Reports Server (NTRS)

    Avalos, E.

    1972-01-01

    An operating test series was applied to two explosive actuated, normally open, titanium valves. There were no failures. Tests included: proof pressure and external leakage test, gross leak test, post actuation leakage test, and burst pressure test.

  19. Holographic NDT of thin titanium plate described

    NASA Astrophysics Data System (ADS)

    Yang, R.

    1986-01-01

    Holography is a technique for recording the amplitude and phase changes of an object on a photographic plate in the form of interference fringes. Because the holographic interference method can examine a component in the noncontact mode and is not bothered by complicated part shape or surface roughness, it has been widely used in nondestructive testing. In the rapidly developing aerospace industry, titanium and titanium alloy thin plates are used more and more but local delamination has been found in the production process of bonded titanium plates. Using ultrasonic methods, such defects are difficult to detect and large area delaminations with tightly closed edges can easily be missed. Other testing methods are also unsuccessful. A holographic method was developed for detecting defects in thin titanium plates and several high temperature alloy plates were tested. The testing equipment, methods and results are discussed.

  20. Permanent mold casting of titanium alloy Ti-6Al-4V

    SciTech Connect

    Sadayappan, M.; Sahoo, M.; Lavender, C.; paul.jablonski, P.D.

    2008-01-01

    A literature review indicated that data on the effect of various casting defects, such as inclusions and porosity, on the properties of titanium alloy castings were not readily available. This information is required to reduce the cost of fabricating titanium castings for potential automotive applications. To this end, a research project was initiated to develop data on the as-cast properties of titanium alloy Ti-6Al-4V (Ti64). Step plate castings with 3.2, 6.3, 13, and 25 mm thick steps were produced in a high-density graphite mold following melting in an induction furnace with water-cooled copper hearth. The mechanical properties were determined in the as-cast condition and were found to be close to the values reported in standards. Few casting defects such as inclusions and porosity were observed, and the loss of strength due to these defects is not significant. It is shown that titanium castings with good mechanical properties can be produced in high-density graphite molds.

  1. Osteoblast response on co-modified titanium surfaces via anodization and electrospinning

    NASA Astrophysics Data System (ADS)

    Bayram, Cem; Demirbilek, Murat; Yalçın, Eda; Bozkurt, Murat; Doğan, Metin; Denkbaş, Emir Baki

    2014-01-01

    Topography plays a key role in osseointegration and surface modifications at the subcellular level, increasing initial cell attachment in the early period. In the past decade, nanosized texture on metal like a nanotube layer and also more recently extracellular matrix like surface modifications - such as polymeric nanofibrils - have been proposed for a better osseointegration in the literature. Here, we investigate two types of nanoscaled modifications alone and together for the first time. We characterized different types of surface modifications morphologically and investigated how they affected osteoblast cells in vitro, in terms of cell adhesion, proliferation, alkaline phosphatase activity and calcium content. We anodized titanium samples with a thickness of 0.127 mm to obtain a nanotubular titania layer and the silk fibroin (SF), as a biocompatible polymeric material, was electrospun onto both anodized and unanodized samples to acquire 4 sample groups. We analyzed the resulting samples morphologically by scanning electron microscopy (SEM). Cell adhesion, proliferation, alkaline phosphatase (ALP) activity and calcium content were evaluated at 3, 7 and 14 days. We found that cell proliferation increased by 70% on the groups having two modifications respect to unmodified titanium and after 7 days, ALP activity and calcium content were 110% and 150%, respectively, higher on surfaces having both surface treatments than that of unmodified group. In conclusion, a nanotube layer and SF nanofibers on a titanium surface enhanced cell attachment and proliferation most. Comodification of titanium surfaces by anodization and SF electrospinning may be useful to enhance osseointegration but it requires in vivo confirmation.

  2. Bonding of low-fusing dental porcelain to commercially pure titanium.

    PubMed

    Könönen, M; Kivilahti, J

    1994-09-01

    The objective of the investigation was to study the basic problems related to the firing of dental porcelain to commercially pure titanium. The firing of a low-fusing porcelain to sandblasted or electrolytically polished titanium was carried out in an ordinary dental furnace. The interfacial regions between the ceramic coatings and titanium were analyzed using scanning acoustic microscopy (C-SAM) and scanning electron microscopy (SEM) techniques. Thermal stresses in the joints were evaluated by means of a finite element model based on multilayer elastic strain analysis. The chemical reactions and their formation sequence at 750 degrees C was predicted thermodynamically and observed experimentally both at 750 and 800 degrees C. The C-SAM results gave evidence that the integrity of the porcelain-titanium joints are better in the sandblasted samples than in the electropolished ones, where defects were larger. SEM analyses of the same samples confirmed the C-SAM findings. Because the reaction layers are more continuous in the electropolished samples, cracks propagated more readily in these samples during the cooling procedure. Both thermodynamic calculations and experimental chemical analyses strongly indicate that the cause for the cracking of the reaction zone is thin layer of Ti (oxo)silicide and/or a relatively thick solid solution layer of Ti and oxygen. PMID:7814430

  3. Low elastic modulus contributes to the osteointegration of titanium alloy plug.

    PubMed

    Zhang, Yongquan; Wang, Junlin; Wang, Pan; Fan, Xiangli; Li, Xiaokang; Fu, Jun; Li, Shujun; Fan, Hongbin; Guo, Zheng

    2013-05-01

    Resurfacing of cartilage defect with mini titanium plug is considered a promising alternative for the treatment of focal chondral defects. Elastic modulus of the metal implant plays a significant role in force transmission which influences the stability of plug. This study assessed the effects of two kinds of titanium alloy plug with different elastic modulus, that is, titanium 2448 (Ti2448) plug and titanium-6 aluminum-4 vanadium (TAV) plug on osteointegration. The full-thickness chondral defects were created in bilateral knees of dogs and then TAV and Ti2448 plugs were implanted, respectively. After 12 weeks, radiographic evaluation did not reveal any signs of disassembly, subsidence, or periprosthetic radiolucency in both groups. Microcomputed tomography analysis revealed that bone histomorphometric parameters in Ti2448 group were all significantly better than those of TAV group. Furthermore, the value of pullout force in Ti2448 group was also significantly higher. Histology showed that the screw threads of Ti2448 plug were well integrated into the newly formed bone. In contrast, the trabecular bone was sparsely distributed around TAV plug. In conclusion, Ti2448 plug with low elastic modulus showed more favorable characteristics in osteointegration. Ti2448 may be a promising biomaterial for fabricating mini plug applied for cartilage resurfacing. PMID:23255397

  4. Study of the laser marking process of cold sprayed titanium coatings on aluminium substrates

    NASA Astrophysics Data System (ADS)

    Astarita, A.; Genna, S.; Leone, C.; Memola Capece Minutolo, F.; Squillace, A.; Velotti, C.

    2016-09-01

    This paper deals with the study of the laser marking process of titanium cold sprayed coatings on aluminium substrates. Despite several studies regarding the laser marking process are available in literature very few attention have been paid to the marking of cold sprayed coatings and there are no previous papers in literature. Also the phenomena occurring during the marking of a porous coating are to date not fully understood and will be discussed in this paper. The experimental campaign was also repeated on grade 2 titanium rolled sheets with a thickness of 2 mm. The marking tests were carried out under different experimental conditions varying the main process parameters (i.e. laser pulse power and laser scan speed), after that the mark sections were observed by optical microscope and SEM. Both the maximum penetration depth and width of the marks were acquired and also internal damages induced by the process were studied. A correlation between the process parameters and the mark's geometry was found. The results show the effectiveness of the laser process to produce high quality marks on both the titanium layer and the titanium sheet. Moreover, a higher mark penetration on Ti coating was observed compared to the Ti sheet. However, the results show also the possibility to introduce severe and hidden damages in both materials if the process parameters are not properly set.

  5. Characterization and quantification of oxides generated by anodization on titanium for implantation purposes

    NASA Astrophysics Data System (ADS)

    Aloia Games, L.; Pastore, J.; Bouchet, A.; Ballarre, J.

    2011-12-01

    The use of titanium as implant material is widely known in the surgery field. The formation of natural or artificial compact and protective oxide is a convenient tool for metal protection and a good way to generate phosphate deposits to enhance biocompatibility and bone fixation with the existing tissue. The present work has the aim of superficially modify commercially pure titanium sheets used in orthopedics and odontology, with a potencistatic anodization process with an ammonium phosphate and ammonium fluoride solution as electrolyte. The objective is to generate titanium oxides doped with phosphorous on the surface, to promote bioactivity. The characterization and quantification of the generated deposits is presented as a starting point for the future application of these materials. The applied characterization methods are X ray diffraction, micro-Raman spectroscopy analysis for evaluating the chemical and phase composition on the modified surface and PDI image analysis techniques that allow the segmentation of SEM images and the measurement and quantification of the oxides generated by the anodization process. The samples with polished treated surface at 30V have the deposit of a phosphate rich thick layer covering almost all the surface and spherical-shaped titanium oxide crystals randomly placed (covering more than 20% of the surface area).

  6. Enhanced Cell Integration to Titanium Alloy by Surface Treatment with Microarc Oxidation: A Pilot Study

    PubMed Central

    Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon; Kim, Hyoun Ee

    2009-01-01

    Microarc oxidation (MAO) is a surface treatment that provides nanoporous pits, and thick oxide layers, and incorporates calcium and phosphorus into the coating layer of titanium alloy. We presumed such modification on the surface of titanium alloy by MAO would improve the ability of cementless stems to osseointegrate. We therefore compared the in vitro ability of cells to adhere to MAOed titanium alloy to that of two different types of surface modifications: machined and grit-blasted. We performed energy-dispersive x-ray spectroscopy and scanned electron microscopy investigations to assess the structure and morphology of the surfaces. Biologic and morphologic responses to osteoblast cell lines (SaOS-2) were then examined by measuring cell proliferation, cell differentiation (alkaline phosphatase activity), and αvβ3 integrin. The cell proliferation rate, alkaline phosphatase activity, and cell adhesion in the MAO group increased in comparison to those in the machined and grit-blasted groups. The osteoblast cell lines of the MAO group were also homogeneously spread on the surface, strongly adhered, and well differentiated when compared to the other groups. This method could be a reasonable option for treating the surfaces of titanium alloy for better osseointegration. PMID:19434468

  7. Enhanced osseointegration of titanium implants with nanostructured surfaces: an experimental study in rabbits.

    PubMed

    Salou, Laëtitia; Hoornaert, Alain; Louarn, Guy; Layrolle, Pierre

    2015-01-01

    Titanium and its alloys are commonly used for dental implants because of their good mechanical properties and biocompatibility. The surface properties of titanium implants are key factors for rapid and stable bone tissue integration. Micro-rough surfaces are commonly prepared by grit-blasting and acid-etching. However, proteins and cells interact with implant surfaces in the nanometer range. The aim of this study was to compare the osseointegration of machined (MA), standard alumina grit-blasted and acid-etched (MICRO) and nanostructured (NANO) implants in rabbit femurs. The MICRO surface exhibited typical random cavities with an average roughness of 1.5 μm, while the NANO surface consisted of a regular array of titanium oxide nanotubes 37±11 nm in diameter and 160 nm thick. The MA and NANO surfaces had a similar average roughness of 0.5 μm. The three groups of implants were inserted into the femoral condyles of New Zealand White rabbits. After 4 weeks, the pull-out test gave higher values for the NANO than for the other groups. Histology corroborated a direct apposition of bone tissue on to the NANO surface. Both the bone-to-implant contact and bone growth values were higher for the NANO than for the other implant surfaces. Overall, this study shows that the nanostructured surface improved the osseointegration of titanium implants and may be an alternative to conventional grit-blasted and acid-etched surface treatments. PMID:25449926

  8. 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.

  9. Structure and properties of titanium surface layers after electron beam alloying with powder mixtures containing carbon

    NASA Astrophysics Data System (ADS)

    Lenivtseva, O. G.; Bataev, I. A.; Golkovskii, M. G.; Bataev, A. A.; Samoilenko, V. V.; Plotnikova, N. V.

    2015-11-01

    The structure and tribological properties of commercially pure titanium (cp-Ti) samples after non-vacuum electron beam surface alloying with carbon were studied. Two types of powders were used to introduce carbon in surface layer of cp-Ti: titanium carbide (TiC) and mixture of pure titanium and graphite ("Ti + C"). Single layer and multilayer coatings were studied. Application of electron beam for alloying provided cladding rate of 4.5 m2/h. The thickness of the clad coatings was 1.6-2.0 mm. The main phases received after "Ti + C" powder cladding were α-titanium, TiC, and retained graphite. In the samples obtained by cladding of TiC, graphite was not observed. A factor determining the microhardness and tribological properties of the cladded layer was the volume fraction of TiC. Maximum coating microhardness of 8 GPa was obtained by cladding of single layer of TiC powder or two layers of the "Ti + C" mixture. Two types of tests were carried out to evaluate the wear resistance of the samples. In friction tests against loose abrasive particles, the wear rate of the best samples was 9.3 times lower than that of cp-Ti. In wear tests using fixed abrasive particles, the relative wear resistance of the best samples was 2.3 times higher than that of cp-Ti.

  10. Thermal and aerothermal performance of a titanium multiwall thermal protection system

    NASA Technical Reports Server (NTRS)

    Avery, D. E.; Shideler, J. L.; Stuckey, R. N.

    1981-01-01

    A metallic thermal protection system (TPS) concept the multiwall designed for temperature and pressure at Shuttle body point 3140 where the maximum surface temperature is approximately 811 K was tested to evaluate thermal performance and structural integrity. A two tile model of titanium multiwall and a model consisting of a low temperature reusable surface insulation (LRSI) tiles were exposed to 25 simulated thermal and pressure Shuttle entry missions. The two systems performed the same, and neither system deteriorated during the tests. It is indicated that redesign of the multiwall tiles reduces tile thickness and/or weight. A nine tile model of titanium multiwal was tested for radiant heating and aerothermodynamics. Minor design changes that improve structural integrity without having a significant impact on the thermal protection ability of the titanium multiwall TPS are identified. The capability of a titanium multiwall thermal protection system to protect an aluminum surface during a Shuttle type entry trajectory at locations on the vehicle where the maximum surface temperature is below 811 K is demonstrated.

  11. A comparison of stainless steel and nickel-titanium K-files in curved root canals.

    PubMed

    Chan, A W; Cheung, G S

    1996-11-01

    The purpose of this study was to determine the effects of hand instrumentation using traditional stainless steel K-files and nickel-titanium K-files on the final shape of curved root canals. A total of 24 moderately curved canals in the mesial roots in extracted human mandibular first molars were randomly divided into two groups. These were instrumented manually using either stainless steel or nickel-titanium, K-files with the stepdown technique. The cross-sectional shape of each canal at three different horizontal levels were captured, before and after instrumentation, into a computer for comparison using image analyser software. Three parameters at each level were evaluated: (i) amount of dentine removed; (ii) least remaining dentine thicknesses on mesial and furcal aspects; and (iii) the amount and direction of canal transportation. The results showed that the two file types removed similar amounts of dentine at all three levels examined. The nickel-titanium files left a thicker layer of dentine on both the mesial and furcal aspects than stainless steel files. However, the difference was not significant (pooled T-test, P > 0.05). Both types of files transported the centre of the canals but the nickel-titanium instrument seemed to be safer because of the reduced amount of transportation towards the danger areas. PMID:10332236

  12. Interfacial reactions between titanium and borate glass

    SciTech Connect

    Brow, R.K.; Saha, S.K.; Goldstein, J.I.

    1992-12-31

    Interfacial reactions between melts of several borate glasses and titanium have been investigated by analytical scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). A thin titanium boride interfacial layer is detected by XPS after short (30 minutes) thermal treatments. ASEM analyses after longer thermal treatments (8--120 hours) reveal boron-rich interfacial layers and boride precipitates in the Ti side of the interface.

  13. Surface characterizations of variously treated titanium materials.

    PubMed

    Lim, Y J; Oshida, Y; Andres, C J; Barco, M T

    2001-01-01

    The attachment of cells to titanium surfaces is an important phenomenon in the area of clinical implant dentistry. A major consideration in designing implants has been to produce surfaces that promote desirable responses in the cells and tissues. To achieve these requirements, the titanium implant surface can be modified in various ways. This research was designed to elucidate the relationship between surface roughness (Ra) and contact angle (theta) of various engineered titanium surfaces of commercially pure titanium, titanium-aluminum-vanadium alloy (Ti-6Al-4V), and titanium-nickel (TiNi) alloy. The contact angle was measured using distilled water, 1% sodium chloride solution, human neutrophils, and osteoblast-like cells. Surface oxide crystallography was identified by transmission electron diffraction. It was found that: (1) there were no significant differences in contact angles among the 4 media; (2) for commercially pure titanium, a combined treatment (hydrofluoric acid/nitric acid/water --> sodium hydroxide --> oxidation) showed the lowest theta (10.51 degrees in water), while the surface treated with sulfuric acid showed the highest value (72.99 degrees in water); (3) for all commercially pure titanium samples, when theta is greater than 45 degrees, the contact angle increases linearly with Ra (hydrophobic nature) and the surface is covered with rutile-type oxide only, while the contact angle decreases linearly with Ra when theta is less than 45 degrees (hydrophilic nature) and the surface is covered with a mixture of rutile and anatase oxides; and (4) a similar trend was found on Ti-6Al-4V and TiNi surfaces. PMID:11432653

  14. Shattering the myth of the resonantly photo-pumped neon-like titanium laser

    SciTech Connect

    Nilsen, J.; MacGowan, B.J.; Da Silva, L.B.; Moreno, J.C.; Koch, J.A.

    1993-08-01

    Several years ago neon-like titanium (Z = 22) was made to lase at 326 {angstrom} on the 3p {yields} 3s (J = 0 {yields} 1) transition. At the time it was suggested that the lasing may be due to resonantly photo-pumping the neon-like titanium 2p {yields} 4d lines using 3s {yields} 2p and 3d {yields} 2p lines in carbon-like and nitrogen-like titanium which results in lasing on the 3p {yields} 3s transition in neon-like titanium. The strongest argument for this explanation was that adjacent elements (scandium and vanadium) did not lase while titanium was unique in having the above mentioned resonance. In addition a prepulse was required to make the titanium lase, suggestive of the formation of a low density plasma, and the plasma was very overstripped, so the above mentioned pump lines should be quite strong for photo-pumping. We have reinvestigated this laser system and will present results which show lasing on the 3p {yields} 3s (J = 0 {yields} 1) transition in neon-like chromium (Z = 24), iron (Z = 26), and nickel (Z = 28) at 285, 255, and 231 {angstrom} respectively. This destroys the myth of titanium being unique and makes highly unlikely that the previously mentioned photo-pumping mechanism is playing a significant role in the titanium laser. The chromium, iron, and nickel experiments all require a prepulse in order to lase and our calculations suggest that the prepulse is an exciting new way to create a uniform low density plasma when illuminating a thick slab target. This allows the proper conditions for gain and laser propagation for low Z neon-like ions and may also be applicable to other systems such as low Z nickel-like ions. We also will present experiments done on other low-Z materials and offer an explanation as to how the hyperfine effect is destroying the gain of neon-like ions with odd Z.

  15. Initial cytotoxicity of novel titanium alloys.

    PubMed

    Koike, M; Lockwood, P E; Wataha, J C; Okabe, T

    2007-11-01

    We assessed the biological response to several novel titanium alloys that have promising physical properties for biomedical applications. Four commercial titanium alloys [Super-TIX(R) 800, Super-TIX(R) 51AF, TIMETAL(R) 21SRx, and Ti-6Al-4V (ASTM grade 5)] and three experimental titanium alloys [Ti-13Cr-3Cu, Ti-1.5Si and Ti-1.5Si-5Cu] were tested. Specimens (n = 6; 5.0 x 5.0 x 3.0 mm(3)) were cast in a centrifugal casting machine using a MgO-based investment and polished to 600 grit, removing 250 mum from each surface. Commercially pure titanium (CP Ti: ASTM grade 2) and Teflon (polytetrafluoroethylene) were used as positive controls. The specimens were cleaned and disinfected, and then each cleaned specimen was placed in direct contact with Balb/c 3T3 fibroblasts for 72 h. The cytotoxicity [succinic dehydrogenase (SDH) activity] of the extracts was assessed using the MTT method. Cytotoxicity of the metals tested was not statistically different compared to the CP Ti and Teflon controls (p > 0.05). These novel titanium alloys pose cytotoxic risks no greater than many other commonly used alloys, including commercially pure titanium. The promising short-term biocompatibility of these Ti alloys is probably due to their excellent corrosion resistance under static conditions, even in biological environments. PMID:17385227

  16. Hydrocarbon Deposition Attenuates Osteoblast Activity on Titanium

    PubMed Central

    Hayashi, R.; Ueno, T.; Migita, S.; Tsutsumi, Y.; Doi, H.; Ogawa, T.; Hanawa, T.; Wakabayashi, N.

    2014-01-01

    Although the reported percentage of bone-implant contact is far lower than 100%, the cause of such low levels of bone formation has rarely been investigated. This study tested the negative biological effect of hydrocarbon deposition onto titanium surfaces, which has been reported to be inevitable. Osteogenic MC3T3-E1 cells were cultured on titanium disks on which the carbon concentration was experimentally regulated to achieve carbon/titanium (C/Ti) ratios of 0.3, 0.7, and 1.0. Initial cellular activities such as cell attachment and cell spreading were concentration-dependently suppressed by the amount of carbon on the titanium surface. The osteoblastic functions of alkaline phosphatase activity and calcium mineralization were also reduced by more than 40% on the C/Ti (1.0) surface. These results indicate that osteoblast activity is influenced by the degree of hydrocarbon contamination on titanium implants and suggest that hydrocarbon decomposition before implant placement may increase the biocompatibility of titanium. PMID:24868012

  17. Ultrathin to Nano Thickness TiN Coatings: Processing, Structural, Mechanical Behavior

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Kumar, Rakesh; Soni; Sreemany, M.; Pathak, L. C.

    2015-12-01

    The fabrication of titanium nitride (TiN) thin films with varying thicknesses by reactive magnetron sputtering at different substrate temperatures as well as deposition times has been investigated. With the increase of deposition times from 1 to 120 min, the TiN film thickness is increased from 15 nm to 2.1 µm. The effect of thickness and substrate temperature on the mechanical, microstructural, and structural behavior of these fabricated thin TiN films is investigated. The average hardness is found to vary between 22 and 42 GPa and modulus between 300 and 527 GPa. The grain sizes increase with the thickness of the deposited films and it is observed to vary between 20 and 65 nm.

  18. Influence of colorant and film thickness on thermal aging characteristics of oxo-biodegradable plastic bags

    NASA Astrophysics Data System (ADS)

    Leuterio, Giselle Lou D.; Pajarito, Bryan B.; Domingo, Carla Marie C.; Lim, Anna Patricia G.

    2016-05-01

    Functional, lightweight, strong and cheap plastic bags incorporated with pro-oxidants undergo accelerated degradation under exposure to heat and oxygen. This work investigated the effect of colorant and film thickness on thermal aging characteristics of commercial oxo-biodegradable plastic bag films at 70 °C. Degradation is monitored through changes in infrared absorption, weight, and tensile properties of thermally aged films. The presence of carbonyl band in infrared spectrum after 672 h of thermal aging supports the degradation behavior of exposed films. Results show that incorporation of colorant and increasing thickness exhibit low maximum weight uptake. Titanium dioxide as white colorant in films lowers the susceptibility of films to oxygen uptake but enhances physical degradation. Higher amount of pro-oxidant loading also contributes to faster degradation. Opaque films are characterized by low tensile strength and high elastic modulus. Decreasing the thickness contributes to lower tensile strength of films. Thermally aged films with colorant and low thickness promote enhanced degradation.

  19. Titanium resources of the commonwealth of independent states

    SciTech Connect

    Levine, R.M.; Gambogi, J.; Bond, A.R.

    1995-01-01

    The raw material base of the titanium industries of the Commonwealth of Independent States (CIS) is assessed, with a focus on the geology and mineralogy of producing the prospective deposits and prevailing end-use patterns in CIS and the world as a whole. Upon the break-up of the USSR, Ukraine was the only supplier of titanium ore for the titanium industries of the FSU, which are located in Russia, Kazakhstan, and Ukraine. Efforts of Russia and Kazakhstan to explore and develop their own titanium ore deposits are described, as are the uses of different titanium raw materials (e.g., ilmenite, rutile) in titanium metal and pigment production. FSU producers, now significant participants in world titanium markets, and expected to continue exports of titanium metal because of depressed domestic demand and still relatively low (but growing) levels of titanium consumption to pigment production. 29 refs., 2 figs., 1 tab.

  20. Atomic layer deposited titanium dioxide coatings on KD-II silicon carbide fibers and their characterization

    NASA Astrophysics Data System (ADS)

    Cao, Shiyi; Wang, Jun; Wang, Hao

    2016-03-01

    To provide oxidation protection and/or to act as an interfacial coating, titanium oxide (TiO2) coatings were deposited on KD-II SiC fibers by employing atomic layer deposition (ALD) technique with tetrakis(dimethylamido)titanium (TDMAT) and water (H2O) as precursors. The average deposition rate was about 0.08 nm per cycle, and the prepared coatings were smooth, uniform and conformal, shielding the fibers entirely. The as-deposited coatings were amorphous regardless of the coating thickness, and changed to anatase and rutile crystal phase after annealing at 600 °C and 1000 °C, respectively. The oxidation measurement suggests that the TiO2 coating enhanced the oxidation resistance of SiC fibers obviously. SiC fibers coated with a 70-nm-thick TiO2 layer retained a relatively high tensile strength of 1.66 GPa even after exposition to air at 1400 °C for 1 h, and thick silica layer was not observed. In contrast, uncoated SiC fibers were oxidized dramatically through the same oxidation treatment, covered with a macro-cracked thick silica film, and the tensile strength was not measurable due to interfilament adhesion. The above results indicate that TiO2 films deposited by ALD are a promising oxidation resistance coating for SiC fibers.

  1. [Investigation of castability and layered structure on margin of titanium cast crown].

    PubMed

    Ping, M W

    1997-12-01

    Previous studies on dental applications of pure titanium were mainly focused on its mechanical properties rather than its clinical aspects. The purpose of this study was to evaluate the margin castability and mechanical properties of C. P. titanium for better understanding of its suitability for clinical application. To simulate the crown margins, flat wax patterns, which had two different margin thicknesses, i.e., 20 and 40 degrees sharp edges respectively, were used. These patterns were cast using two casting systems, centrifugal and pressure systems. There were statistically significant differences between the samples made from the two types of patterns in terms of cast deficiency at the margins observed with a light microscope and the increased length of the margins measured with a video micrometer, but not between the samples made with the two different systems. Both the thickness of layered structures measured by a metallurgical light microscope and the micro-hardness by a Dynamic Hardness Tester were lowest at the apex of the margins in all samples. These observations were more evident among 20 degree samples than 40 degree samples. The layered structures were different among the casting systems. In conclusion, pure titanium is suitable for clinical application as restorative material when used appropriately. PMID:9483892

  2. Titanium dioxide antireflection coating for silicon solar cells by spray deposition

    NASA Technical Reports Server (NTRS)

    Kern, W.; Tracy, E.

    1980-01-01

    A high-speed production process is described for depositing a single-layer, quarter-wavelength thick antireflection coating of titanium dioxide on metal-patterned single-crystal silicon solar cells for terrestrial applications. Controlled atomization spraying of an organotitanium solution was selected as the most cost-effective method of film deposition using commercial automated equipment. The optimal composition consists of titanium isopropoxide as the titanium source, n-butyl acetate as the diluent solvent, sec-butanol as the leveling agent, and 2-ethyl-1-hexanol to render the material uniformly depositable. Application of the process to the coating of circular, large-diameter solar cells with either screen-printed silver metallization or with vacuum-evaporated Ti/Pd/Ag metallization showed increases of over 40% in the electrical conversion efficiency. Optical characteristics, corrosion resistance, and several other important properties of the spray-deposited film are reported. Experimental evidence indicates a wide tolerance in the coating thickness upon the overall efficiency of the cell. Considerations pertaining to the optimization of AR coatings in general are discussed, and a comprehensive critical survey of the literature is presented.

  3. Reconstruction with a patient-specific titanium implant after a wide anterior chest wall resection

    PubMed Central

    Turna, Akif; Kavakli, Kuthan; Sapmaz, Ersin; Arslan, Hakan; Caylak, Hasan; Gokce, Hasan Suat; Demirkaya, Ahmet

    2014-01-01

    The reconstruction of full-thickness chest wall defects is a challenging problem for thoracic surgeons, particularly after a wide resection of the chest wall that includes the sternum. The location and the size of the defect play a major role when selecting the method of reconstruction, while acceptable cosmetic and functional results remain the primary goal. Improvements in preoperative imaging techniques and reconstruction materials have an important role when planning and performing a wide chest wall resection with a low morbidity rate. In this report, we describe the reconstruction of a wide anterior chest wall defect with a patient-specific custom-made titanium implant. An infected mammary tumour recurrence in a 62-year old female, located at the anterior chest wall including the sternum, was resected, followed by a large custom-made titanium implant. Latissimus dorsi flap and split-thickness graft were also used for covering the implant successfully. A titanium custom-made chest wall implant could be a viable alternative for patients who had large chest wall tumours. PMID:24227881

  4. Effect of Liquid Feed-Stock Composition on the Morphology of Titanium Dioxide Films Deposited by Thermal Plasma Spray.

    PubMed

    Adán, C; Marugán, J; van Grieken, R; Chien, K; Pershin, L; Coyle, T; Mostaghimi, J

    2015-09-01

    Titanium dioxide coatings were deposited on the surface of titanium foils by Thermal Plasma Spray (TPS) process. Three different TiO2 coatings were prepared using the commercial TiO2-P25 nanopowder and titanium isopropoxide precursor solution as feed-stocks. Structure and morphology of the TiO2-P25 powder and the plasma sprayed coatings were analyzed by X-ray diffraction (XRD), Raman spectroscopy, N2 adsorption-desorption isotherms, UV-visible spectroscopy and Scanning Electron Microscopy (SEM). XRD and Raman results indicate that the TiO2 coatings were composed of an anatase/rutile mixture that is conditioned by the suspension composition used to be sprayed. Coatings prepared from TiO2-P25 nanoparticles in water suspension (NW-P25) and titanium isopropoxide solution suspension (NSP-P25) are incorporated into the coatings without phase transformation and their anatase/rutile ratio percentage remains very similar to the starting TiO2-P25 powder. On the contrary, when titanium isopropoxide solution is used for spraying (SP), the amount of rutile increases in the final TiO2 coating. SEM analysis also reveals different microstructure morphology, coating thickness, density and porosity of the three TiO2 films that depend significantly on the type of feed-stock employed. Interestingly, we have observed the role of titanium isopropoxide in the formation of more porous and cohesive layers of TiO2. The NSP-P25 coating, prepared with a mix of titanium isopropoxide solution based on TiO2 nanoparticles, presents higher deposition efficiencies and higher coating thickness than the film prepared with nanoparticles suspended in water (NW-P25) or with titanium isopropoxide solutions (SP). This is due to the precursor solution is acting as the cement between TiO2 nanoparticles, improving the cohesive strength of the coating. In sum, NSP-P25 and NW-P25 coatings display a good photocatalytic potential, based on their light absorption properties and mechanical stability. Band gap of

  5. Shape from equal thickness contours

    SciTech Connect

    Cong, G.; Parvin, B.

    1998-05-10

    A unique imaging modality based on Equal Thickness Contours (ETC) has introduced a new opportunity for 3D shape reconstruction from multiple views. We present a computational framework for representing each view of an object in terms of its object thickness, and then integrating these representations into a 3D surface by algebraic reconstruction. The object thickness is inferred by grouping curve segments that correspond to points of second derivative maxima. At each step of the process, we use some form of regularization to ensure closeness to the original features, as well as neighborhood continuity. We apply our approach to images of a sub-micron crystal structure obtained through a holographic process.

  6. Laser detection of material thickness

    DOEpatents

    Early, James W.

    2002-01-01

    There is provided a method for measuring material thickness comprising: (a) contacting a surface of a material to be measured with a high intensity short duration laser pulse at a light wavelength which heats the area of contact with the material, thereby creating an acoustical pulse within the material: (b) timing the intervals between deflections in the contacted surface caused by the reverberation of acoustical pulses between the contacted surface and the opposite surface of the material: and (c) determining the thickness of the material by calculating the proportion of the thickness of the material to the measured time intervals between deflections of the contacted surface.

  7. Improved Surface of Titanium Structure

    NASA Technical Reports Server (NTRS)

    Ecklund, R. C.; Hayase, M.; Yasui, K. K.

    1986-01-01

    Potential tooling pickup not acceptable on sandwich panels that have face sheets 0.016 in. (0.41 mm) thick. In this application, problem eliminated by changing tooling slipsheet from type 321 CRES to type 430 stainless steel and coating both slipsheet and face sheet with boron nitride powder and binder thinned in acetone.

  8. Oxidation resistant coating for titanium alloys and titanium alloy matrix composites

    NASA Technical Reports Server (NTRS)

    Brindley, William J. (Inventor); Smialek, James L. (Inventor); Rouge, Carl J. (Inventor)

    1992-01-01

    An oxidation resistant coating for titanium alloys and titanium alloy matrix composites comprises an MCrAlX material. M is a metal selected from nickel, cobalt, and iron. X is an active element selected from Y, Yb, Zr, and Hf.

  9. Hydrogen and deuterium diffusion in vanadium-titanium alloys

    NASA Astrophysics Data System (ADS)

    Peterson, D. T.; Herro, H. M.

    1987-02-01

    Hydrogen and deuterium diffusion coefficients were measured in vanadium-titanium alloys, containing up to 30 at. pct Ti, by Boltzmann-Matano techniques. Hydrogen and deuterium diffusivity decreased rapidly with titanium concentration. The diffusion coefficients showed an Arrhenius temperature dependence in each alloy between 230 and 473 K with activation energies that increased with titanium concentration. The diffusion coefficient decreased linearly with hydrogen concentration in all alloys. The terminal solid solubilities increased markedly with titanium concentration with deuterium showing a larger terminal solid solubility than hydrogen below ten percent titanium. The diffusion results do not fit a localized deep trapping of hydrogen by the titanium atoms.

  10. Hydrogen and deuterium diffusion in vanadium-titanium alloys

    SciTech Connect

    Peterson, D.T.; Herro, H.M.

    1987-02-01

    Hydrogen and deuterium diffusion coefficients were measured in vanadium-titanium alloys, containing up to 30 at. pct Ti, by Boltzmann-Matano techniques. Hydrogen and deutrium diffusivity decreased rapidly with titanium concentration. The diffusion coefficients showed an Arrhenius temperature dependence in each alloy between 230 and 473 K with activation energies that increased with titanium concentration. The diffusion coefficient decreased linearly with hydrogen concentration in all alloys. The terminal solid solubilities increased markedly with titanium concentration with deuterium showing a larger terminal solid solubility than hydrogen below ten percent titanium. The diffusion results do not fit a localized deep trapping of hydrogen by the titanium atoms.

  11. Fibrinogen and cellular adherability on differently treated titanium as implants

    NASA Astrophysics Data System (ADS)

    Fojt, Lukáš; Klapetek, Petr; Strašák, Luděk; Vetterl, Vladimír

    2012-02-01

    Adsorption of human plasma fibrinogen, osteoblasts, and fibroblasts on differently treated titanium samples as implants were examined in this study. Titanium samples were mechanically polished, chemically etched (with and without surface material loss), and grinded. The main goal of this study is to find the best surface treatment of titanium for its possible use as implants. Atomic force microscopy was used to evaluate the adsorption of human plasma fibrinogen onto the titanium samples. Cell counting was used to determine the adherability of osteoblasts and fibroblasts on the titanium samples. Our preliminary results show that the etched titanium surface with surface material loss is the best surface treatment used in our experiments.

  12. Will nonaerospace applications for titanium ever grow?

    NASA Astrophysics Data System (ADS)

    Katrak, Firoze E.; Servi, I. S.; Agarwal, J. C.

    1991-07-01

    Confronted with the currently attractive aerospace markets, titanium producers could choose to minimize their promotional effort in the nonaerospace sector. In such a case, primary producers would continue to give some support to a few nonaerospace market segments but would minimize product and market development in most other areas. Such a modus operandi is quite likely, in which case the 1990s may turn out to be as disappointing for the industrial application of titanium as were the 1980s. Such a trend is not desirable for titanium producers for two reasons: the military aerospace market is likely to shrink in the future,8 and the titanium content of commercial jet engines will decline.9 Thus, titanium producers need to adopt a strategy to increase nonaerospace applications. Such a strategy must accomplish at least the following: • Commit to reducing titanium mill product costs. • Convince potential users that titanium (sponge and) mill products will be available at a sustained cost much below the current cost. No radically new technologies are necessaryzzto meet the target sponge costs (i.e., the current processes can meet cost targets with plant and practice changes). • Begin developing new alloys specifically tailored to nonaerospace applications and lower-cost mill products. If and when new alloys become available, the potential growth in nonaerospace uses would be greater than the 1-10-100 rule, which applies to existing commercially pure titanium. • Work toward reducing value-added component costs by achieving cost reductions in secondary fabrication for selected niche applications. • Offer application engineering and technical support services, including the establishment of training centers (e.g., for field welding). • Develop estimates of cost effectiveness in target applications that will convince the users. If a strategy incorporating these elements is not adopted by titanium producers because of the short-term strength of aerospace demand

  13. NON-MELT PROCESSING OF "LOW-COST", ARMSTRONG TITANIUM AND TITANIUM ALLOY POWDERS

    SciTech Connect

    Peter, William H; Blue, Craig A; Clive, Scorey; Ernst, Bill; McKernan, John; Kiggans, Jim; Rivard, John D; Yu, Dr. Charlie

    2007-01-01

    In the last decade, a considerable effort has been made to develop new methods for producing low cost titanium and titanium powders. The Armstrong process is a new method of producing titanium powder via reducing TiCl4 vapor in molten sodium. The process is scalable, and can be used to produce pre-alloyed powders. Non-melt processing and powder metallurgy approaches are economically viable with the commercially pure powders. In this investigation, several non-melt processing technologies, including vacuum hot pressing, extrusion, roll compaction, and forging techniques, will be evaluated using the Armstrong titanium powders. The metallurgical, chemical, and mechanical properties of the processed titanium samples will be discussed.

  14. Effect of alloying on the phase composition of titanium carbonitride-titanium nickelide alloys

    NASA Astrophysics Data System (ADS)

    Askarova, L. Kh.; Grigorov, I. G.; Ermakov, A. N.; Zainulin, Yu. G.; Nikitina, E. V.

    2015-08-01

    X-ray diffraction, electron microprobe analysis, electron microscopy, and chemical analysis are used to study the effect of alloying with zirconium, niobium, vanadium, and molybdenum on the phase composition of titanium carbonitride-titanium nickel cermets. It is shown that two-phase alloys containing alloyed titanium carbonitride and titanium nickelide can only be produced by alloying with zirconium. The addition of niobium, molybdenum, and vanadium leads to the formation of a third phase, namely, Nb z Ni, Mo(Ti,C), or V4Ni, in the alloy. A correlation between the phase composition of the alloys and the ratio of the energies of formation of titanium carbides and the carbides of alloying elements is found.

  15. Improved Coal-Thickness Measurement

    NASA Technical Reports Server (NTRS)

    Barr, T. A.

    1984-01-01

    Summed signals and dielectric-filled antenna improve measurement. Improved FM radar for measuring thickness of coal seam eliminates spectrum splitting and reduces magnitude of echo from front coal surface.

  16. Metal thickness measurements using radiography

    NASA Astrophysics Data System (ADS)

    Achrekar, P. M.

    1986-04-01

    The present invention relates broadly to a radiographic inspection technique, and in particular to a metal thickness measurement method using radiography. The localized areas wherein the effective metal thickness is less than the minimum that is required for radiation shielding and which can render a shielding enclosure functionless, is readily determined. The invention comprises a process for assuring metal thickness in small regions. The actual metal thickness of small regions can be verified by comparing the optical densities of sections of the metal i.e., stepwedge. A comparator microphotometer, which compares optical densities of spectrum lines from spectrophotometers, compares the optical density of spectrum lines on an exposed spectrum plate (metal under test) with a standard plate (stepwedge).

  17. Edge-on thick discs

    NASA Astrophysics Data System (ADS)

    Kasparova, A.; Katkov, I.; Chilingarian, I.; Silchenko, O.; Moiseev, A.; Borisov, S.

    2016-06-01

    Although thick stellar discs are detected in nearly all edge-on disc galaxies, their formation scenarios still remain a matter of debate. Due to observational difficulties, there is a lack of information about their stellar populations. Using the Russian 6-m telescope BTA we collected deep spectra of thick discs in three edge-on early-type disc galaxies located in different environments: NGC4111 in a dense group, NGC4710 in the Virgo cluster, and NGC5422 in a sparse group. We see intermediate age (4 ‑ 5 Gyr) metal rich ([Fe/H] ~ ‑0.2 ‑ 0.0 dex) stellar populations in NGC4111 and NGC4710. On the other hand, NGC5422 does not harbour young stars, its only disc is thick and old (10 Gyr) and its α-element abundance suggests a long formation epoch implying its formation at high redshift. Our results prove the diversity of thick disc formation scenarios.

  18. Peripapillary choroidal thickness in childhood.

    PubMed

    Read, Scott A; Alonso-Caneiro, David; Vincent, Stephen J; Collins, Michael J

    2015-06-01

    Changes in the thickness of the invivo peripapillary choroid have been documented in a range of ocular conditions in adults; however, choroidal thickness in the peripapillary region of children has not been examined in detail. This study therefore aimed to investigate the thickness of the peripapillary choroid and the overlying retinal nerve fibre layer (RNFL) in a population of normal children with a range of refractive errors. Ninety-three children (37 myopes and 56 non-myopes) aged between 11 and 16 years, had measurements of peripapillary choroidal and RNFL thickness derived from enhanced depth imaging optical coherence tomography images (EDI-OCT, Heidelberg Spectralis). The average thickness was determined in a series of five 0.25 mm width concentric annuli (each divided into 8 equal sized 45° sectors) centred on the optic nerve head boundary, accounting for individual ocular magnification factors and the disc-fovea angle. Significant variations in peripapillary choroidal thickness were found to occur with both annulus location (p < 0.001) and sector position (p < 0.001) in this population of children. The innermost annulus (closest to the edge of the optic disc) exhibited the thinnest choroid (mean 77 ± 16 μm) and the outermost annulus, the thickest choroid (191 ± 52 μm). The choroid was thinnest inferior to the optic nerve head (139 ± 38 μm) and was thickest in the superior temporal sector (157 ± 40 μm). Significant differences in the distribution of choroidal thickness were also associated with myopia, with myopic children having significantly thinner choroids in the inner and outer annuli of the nasal and temporal sectors respectively (p < 0.001). RNFL thickness also varied significantly with annulus location and sector (p < 0.001), and showed differences in thickness distribution associated with refractive error. This study establishes the normal variations in the thickness of the peripapillary choroid with radial distance and azimuthal angle

  19. Development of metal oxide impregnated stilbite thick film ethanol sensor

    NASA Astrophysics Data System (ADS)

    Mahabole, M. P.; Lakhane, M. A.; Choudhari, A. L.; Khairnar, R. S.

    2016-05-01

    This paper presents the study of the sensing efficiency of Titanium oxide/ Stilbite and Copper oxide /Stilbite composites towards detection of hazardous pollutants like ethanol. Stilbite based composites are prepared by physically mixing zeolite with metal oxides namely TiO2 and CuO with weight ratios of 25:75, 50:50 and 75:25. The resulting sensor materials are characterized by X-ray diffraction and Fourier Transform Infrared Spectroscopy techniques. Composite sensors are fabricated in the form of thick film by using screen printing technique. The effect of metal oxide concentration on various ethanol sensing parameters such as operating temperature, maximum uptake capacity and response/recovery time are investigated. The results indicate that metal oxide impregnated stilbite composites have great potential as low temperature ethanol sensor.

  20. Titanium-silicon carbide composite lattice structures

    NASA Astrophysics Data System (ADS)

    Moongkhamklang, Pimsiree

    Sandwich panel structures with stiff, strong face sheets and lightweight cellular cores are widely used for weight sensitive, bending dominated loading applications. The flexural stiffness and strength of a sandwich panel is determined by the stiffness, strength, thickness, and separation of the face sheets, and by the compressive and shear stiffness and strength of the cellular core. Panel performance can be therefore optimized using cores with high specific stiffness and strength. The specific stiffness and strength of all cellular materials depends upon the specific elastic modulus and strength of the material used to make the structure. The stiffest and strongest cores for ambient temperature applications utilize carbon fiber reinforced polymer (CFRP) honeycombs and lattice structures. Few options exist for lightweight sandwich panels intended for high temperature uses. High temperature alloys such as Ti-6A1-4V can be applied to SiC monofilaments to create very high specific modulus and strength fibers. These are interesting candidates for the cores of elevated temperature sandwich structures such as the skins of hypersonic vehicles. This dissertation explores the potential of sandwich panel concepts that utilize millimeter scale titanium matrix composite (TMC) lattice structures. A method has been developed for fabricating millimeter cell size cellular lattice structures with the square or diamond collinear truss topologies from 240 mum diameter Ti-6A1-4V coated SiC monofilaments (TMC monofilaments). Lattices with relative densities in the range 10% to 20% were manufactured and tested in compression and shear. Given the very high compressive strength of the TMC monofilaments, the compressive strengths of both the square and diamond lattices were dominated by elastic buckling of the constituent struts. However, under shear loading, some of the constituent struts of the lattices are subjected to tensile stresses and failure is then set by tensile failure of the

  1. Development and Evaluation of Titanium Spacesuit Bearings

    NASA Technical Reports Server (NTRS)

    Rhodes, Richard; Battisti, Brian; Ytuarte, Raymond, Jr.; Schultz, Bradley

    2016-01-01

    The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an

  2. Wrong melanoma thickness measurement: check it or leave it?

    PubMed

    Chokoeva, A A; Tchernev, G; Philipov, S; Cardoso, J C; Zanardelli, M; Lotti, T

    2014-01-01

    Cutaneous malignant melanoma (CMM) is one of the most aggressive forms of skin cancer, accounting for about 90% of deaths from cutaneous neoplasms, and its incidence has increased significantly in recent years. According to the 2012 European criteria for diagnosis and treatment of malignant melanoma, diagnosis should be based on the combination of clinical features, dermoscopic data and histological examination, preferably after excisional biopsy. Tumour thickness and other parameters for local staging according to the AJCC classification should be included in the pathology report. Although many factors influence the prognosis and course of the disease, it has been established in a number of studies that tumour thickness is the most important parameter. Therapy of malignant melanoma in its initial stages mostly consists of wide local excision with 1 to 2 cm margins, and sentinel lymph node biopsy that is usually performed in cases of tumours with a thickness greater than 1 mm. We present the case of a 58-year-old Bulgarian male with cutaneous superficial spreading malignant melanoma, in which, after complete excision, histological examination established an inaccurate tumour thickness (0.7 mm), with consequent inadequate staging and further management. After reassessment of the results in another institution (as well as their confirmation by two additional independent histopathology laboratories in our country – 1.92 mm), in the National Oncological Hospital where the patient was initially evaluated, sentinel lymph node biopsy was not performed, contrary to the generally accepted European and World standards. With the present case we raise some current issues regarding diagnosis and therapy of Bulgarian patients (not only in the case presented) with malignant melanoma in the 21st century, and discuss the urgent need for external quality control procedures and standardization of the histopathologic reporting, which is of paramount importance in the staging and

  3. Bone Response to Surface-Modified Titanium Implants: Studies on the Early Tissue Response to Implants with Different Surface Characteristics

    PubMed Central

    Larsson Wexell, C.; Thomsen, P.; Aronsson, B.-O.; Tengvall, P.; Rodahl, M.; Lausmaa, J.; Kasemo, B.; Ericson, L. E.

    2013-01-01

    In a series of experimental studies, the bone formation around systematically modified titanium implants is analyzed. In the present study, three different surface modifications were prepared and evaluated. Glow-discharge cleaning and oxidizing resulted in a highly stoichiometric TiO2 surface, while a glow-discharge treatment in nitrogen gas resulted in implants with essentially a surface of titanium nitride, covered with a very thin titanium oxide. Finally, hydrogen peroxide treatment of implants resulted in an almost stoichiometric TiO2, rich in hydroxyl groups on the surface. Machined commercially pure titanium implants served as controls. Scanning Auger Electron Spectroscopy, Scanning Electron Microscopy, and Atomic Force Microscopy revealed no significant differences in oxide thickness or surface roughness parameters, but differences in the surface chemical composition and apparent topography were observed. After surface preparation, the implants were inserted in cortical bone of rabbits and evaluated after 1, 3, and 6 weeks. Light microscopic evaluation of the tissue response showed that all implants were in contact with bone and had a large proportion of newly formed bone within the threads after 6 weeks. There were no morphological differences between the four groups. Our study shows that a high degree of bone contact and bone formation can be achieved with titanium implants of different surface composition and topography. PMID:24174936

  4. Oxygen diffusion from anodic surface oxide films on titanium subhydride studies by auger electron spectroscopy and electron energy loss spectroscopy

    NASA Astrophysics Data System (ADS)

    Wang, P. S.; Wittberg, T. N.; Wolf, J. D.; Keil, R. G.

    TiH sub x (0.5 less than x less than 1.7) samples were prepared from titanium foil in order to study the diffusion of oxygen in the titanium subhydride. An anodic oxide, 1000A thick, was grown on the titanium subhydride foils in an agueous saturated solution of ammonium tetraborate. These anodized samples were then heat treated at temperatures between 500 and 600(0)C and changes in the profile of oxygen concentration as a function of depth were monitored using auger electron spectroscopy. From this data then it was possible to calculate the diffusivity of oxygen in the titanium subhydride. It was also found that electron energy loss spectroscopy could be used to determine the titanium subhydride stoichiometry in the near-surface region. This was done by measuring the energy of the bulk plasmon loss peak, which for TiH sub x, varies linearly with hydrogen content. The amount of dehydriding which occurred following a given heat treatment could be determined from profiles of the plasmon loss energy as a function of depth. A sample of anodized TiH0 87 was studied in some detail. Significant dehydriding of this sample for heat treatment times of less than one hour only occured at temperatures above 550(0)C.

  5. Titanium template for scaphoid reconstruction.

    PubMed

    Haefeli, M; Schaefer, D J; Schumacher, R; Müller-Gerbl, M; Honigmann, P

    2015-06-01

    Reconstruction of a non-united scaphoid with a humpback deformity involves resection of the non-union followed by bone grafting and fixation of the fragments. Intraoperative control of the reconstruction is difficult owing to the complex three-dimensional shape of the scaphoid and the other carpal bones overlying the scaphoid on lateral radiographs. We developed a titanium template that fits exactly to the surfaces of the proximal and distal scaphoid poles to define their position relative to each other after resection of the non-union. The templates were designed on three-dimensional computed tomography reconstructions and manufactured using selective laser melting technology. Ten conserved human wrists were used to simulate the reconstruction. The achieved precision measured as the deviation of the surface of the reconstructed scaphoid from its virtual counterpart was good in five cases (maximal difference 1.5 mm), moderate in one case (maximal difference 3 mm) and inadequate in four cases (difference more than 3 mm). The main problems were attributed to the template design and can be avoided by improved pre-operative planning, as shown in a clinical case. PMID:25167978

  6. Ordered mesoporous silica films with pores oriented perpendicular to a titanium nitride substrate.

    PubMed

    Robertson, Calum; Beanland, Richard; Boden, Stuart A; Hector, Andrew L; Kashtiban, Reza J; Sloan, Jeremy; Smith, David C; Walcarius, Alain

    2015-02-14

    The production of thin mesoporous silica films with small (∼2-3 nm) pores oriented perpendicular to a titanium nitride growth surface is demonstrated using two methods. These are the growth from a Stöber silica solution with surfactant ordering at the surface of the electrode, and electrochemically assisted growth from an acidic sol achieved by polarisation of the electrode surface. The thickness, pore order and pore size that can be achieved with these two methods is contrasted. A number of methods to vary the pore size by using different surfactants and swelling agents are explored. The advantage of applying these growth methods on titanium nitride surfaces is that it provides access to a wider electrochemical window for nanowire growth and sensor applications with non-aqueous electrolytes whilst retaining good film growth and adhesion properties. PMID:25589465

  7. Titanium dioxide encapsulation of supported Ag nanoparticles on the porous silica bead for increased photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Liu, Hui; Deng, Lu; Sun, Chaochao; Li, Junqi; Zhu, Zhenfeng

    2015-01-01

    A new synthetic strategy has been developed to encapsulate Ag nanoparticles in heterogeneous catalysts to prevent their dropping and sintering. Ag nanoparticles with diameters about 5-10 nm were first supported on the porous silica bead. These were then covered with a fresh layer of titanium dioxide with the thickness about 5 nm. SEM and TEM images were used to confirm the success of each synthesis step, and the photocatalytic activity of the as-synthesized samples was evaluated by photocatalytic decolorization of Rhodamine B (Rh B) aqueous solution at ambient temperature under both UV and visible light irradiation. The resulting titanium dioxide encapsulated Ag nanoparticles exhibited an enhanced photocatalytic activity under both UV and visible light irradiation, this can be attributed to effective charge separation and light harvesting of the plasmonic silver nanoparticles decoration, even the reducing of the exciton recombination rate caused by the small grain size of anatase TiO2 nanocrystals.

  8. Association of Titanium Mesh and Bovine Pericardium Membrane in the Treatment of Severe Enophthalmos.

    PubMed

    Silva, Leonardo de Freitas; Magalhães, Tibério Gomes; Santana, Diego Matos; Pimentel, Gabriel Gomes; Faverani, Leonardo Perez; Mello, Manoel de Jesus Rodrigues

    2015-10-01

    The blowout fractures may be classified as pure or impure depending on the associated structures. There are 2 main theories attempting to describe the mechanism of injury, the hydraulic, and blocking mechanism. The complications of this type of fracture may involve diplopia, enophthalmos, and ocular movement restriction. Several materials are available for the reconstruction of orbital floor, including the titanium mesh, which present great properties, such as easy modeling and stabilization, small thickness, and shape maintenance. There, however, are disadvantages such as the possibility of adherence formation. The aim of this report is to describe the case of a patient with an 8-month blowout fracture sequel, presenting extensive enophthalmos and treated by affixing a titanium mesh associated with bovine pericardium membrane in the orbital floor. Therefore, based on a 2-year follow-up, it was possible to observe how effective the association between these 2 materials in solving the case was. PMID:26468837

  9. Optimizatin Of Pulsed Nd:YAG Laser Parameters For Titanium Seam-Welding

    SciTech Connect

    Akman, E.; Canel, T.; Demir, A.; Sinmazcelik, T.

    2007-04-23

    Titanium alloys are the most advantageous metals for the medical and aerospace industry because of their light weight and excellent corrosion resistance. Several techniques were investigated to achieve reliable welds with optimal distortion for the fabrication components used in industry. Laser welding is the most important joining technique because of its precision, rapid processing. For pulse mode Nd:YAG laser; pulse shape, energy, duration, repetition rate and peak power are the most important parameters effects the weld quality. And also the combinations of these parameters are very important for pulsed laser seam-welding. In this study, an experimental work has been done to determine the pulsed laser seam-welding parameters for 3mm thick titanium alloys using the Lumonics JK760TR Nd:YAG pulsed laser.

  10. Titanium thermodiffusional nitriding by CO{sub 2} laser: Process parameters controlling the nitride growth

    SciTech Connect

    L`Enfant, H.; Laurens, P.; Catherine, M.C.S.

    1996-12-31

    Solid state nitriding of titanium under cw CO{sub 2} laser was investigated. The nitriding kinetics were studied in the case of CO{sub 2} laser treatment in isothermal conditions, and were compared to those obtained by using a conventional heating system. Identical kinetics rate constants and activation energy were obtained; therefore CO{sub 2} irradiation of the titanium surface did not influence nitride growth. Studying nitriding treatment in non isothermal conditions showed that high heating rates induced modifications of the nitride morphology (compared to isothermal treatments). At last, the authors investigated the evolution of the CO{sub 2}-surface coupling during the nitriding treatment. It was found that it depended only on the surface temperature and the substrate surface roughness since the growth of a few micrometers thick nitride layer did not modify the coupling.

  11. In Situ Transformation of Chitosan Films into Microtubular Structures on the Surface of Nanoengineered Titanium Implants.

    PubMed

    Gulati, Karan; Johnson, Lucas; Karunagaran, Ramesh; Findlay, David; Losic, Dusan

    2016-04-11

    There is considerable interest in combining bioactive polymers such as chitosan with titanium bone implants to promote bone healing and address therapeutic needs. However, the fate of these biodegradable polymers especially on titanium implants is not fully explored. Here we report in situ formation of chitosan microtube (CMT) structures from chitosan films on the implant surface with titania nanotubes (TNTs) layer, based on phosphate buffer-induced transformation and precipitation process. We have comprehensively analyzed this phenomenon and the factors that influence CMT formation, including substrate topography, immersion solution and its pH, effect of coating thickness, and time of immersion. Significance of reported in situ formation of chitosan microtubes on the TNTs surface is possibly to tailor properties of implants with favorable micro and nano morphology using a self-ordering process after the implant's insertion. PMID:26999291

  12. Surface hardening of titanium alloys with melting depth controlled by heat sink

    DOEpatents

    Oden, Laurance L.; Turner, Paul C.

    1995-01-01

    A process for forming a hard surface coating on titanium alloys includes providing a piece of material containing titanium having at least a portion of one surface to be hardened. The piece having a portion of a surface to be hardened is contacted on the backside by a suitable heat sink such that the melting depth of said surface to be hardened may be controlled. A hardening material is then deposited as a slurry. Alternate methods of deposition include flame, arc, or plasma spraying, electrodeposition, vapor deposition, or any other deposition method known by those skilled in the art. The surface to be hardened is then selectively melted to the desired depth, dependent on the desired coating thickness, such that a molten pool is formed of the piece surface and the deposited hardening material. Upon cooling a hardened surface is formed.

  13. Fabrication of single-phase titanium carbide layers from MWCNTs using high DC pulse

    NASA Astrophysics Data System (ADS)

    Kim, Woo Sik; Moon, Sook Young; Lee, Jeong Hoon; Bang, Sin Young; Choi, Bong Geun; Ham, Heon; Sekino, Tohru; Shim, Kwang Bo

    2010-02-01

    Single-phase layered titanium carbide (TiC) was successfully synthesized by reacting carbon nanotubes (CNTs) and titanium dioxide (TiO2) under a high direct current (DC) pulse. Single-phase TiC layer fabrication is confirmed as the transformation of multi-layered graphene from MWCNTs. Therefore its thickness and width is almost identical to those of transformed graphene layers. This is the first report on the formation of single-phase layered nano-TiC. Scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS) and high-resolution transmission electron microscopy (HR-TEM) were used for the characteristic analysis of single-phase layered TiC structures.

  14. Economical Fabrication of Thick-Section Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Babcock, Jason; Ramachandran, Gautham; Williams, Brian; Benander, Robert

    2010-01-01

    A method was developed for producing thick-section [>2 in. (approx.5 cm)], continuous fiber-reinforced ceramic matrix composites (CMCs). Ultramet-modified fiber interface coating and melt infiltration processing, developed previously for thin-section components, were used for the fabrication of CMCs that were an order of magnitude greater in thickness [up to 2.5 in. (approx.6.4 cm)]. Melt processing first involves infiltration of a fiber preform with the desired interface coating, and then with carbon to partially densify the preform. A molten refractory metal is then infiltrated and reacts with the excess carbon to form the carbide matrix without damaging the fiber reinforcement. Infiltration occurs from the inside out as the molten metal fills virtually all the available void space. Densification to <5 vol% porosity is a one-step process requiring no intermediate machining steps. The melt infiltration method requires no external pressure. This prevents over-infiltration of the outer surface plies, which can lead to excessive residual porosity in the center of the part. However, processing of thick-section components required modification of the conventional process conditions, and the means by which the large amount of molten metal is introduced into the fiber preform. Modification of the low-temperature, ultraviolet-enhanced chemical vapor deposition process used to apply interface coatings to the fiber preform was also required to accommodate the high preform thickness. The thick-section CMC processing developed in this work proved to be invaluable for component development, fabrication, and testing in two complementary efforts. In a project for the Army, involving SiC/SiC blisk development, nominally 0.8 in. thick x 8 in. diameter (approx. 2 cm thick x 20 cm diameter) components were successfully infiltrated. Blisk hubs were machined using diamond-embedded cutting tools and successfully spin-tested. Good ply uniformity and extremely low residual porosity (<2

  15. Evaluation of boron-epoxy-reinforced titanium tubular truss for application to a space shuttle booster thrust structure

    NASA Technical Reports Server (NTRS)

    Corvelli, N.; Carri, R.

    1972-01-01

    Results of a study to demonstrate the applicability of boron-epoxy-composite-reinforced titanium tubular members to a space shuttle booster thrust structure are presented and discussed. The experimental results include local buckling of all-composite and composite-reinforced-metal cylinders with low values of diameter-thickness ratio, static tests on composite-to-metal bonded step joints, and a test to failure of a boron-epoxy-reinforced titanium demonstration truss. The demonstration truss failed at 118 percent of design ultimate load. Test results and analysis for all specimens and the truss are compared. Comparing an all-titanium design and a boron-epoxy-reinforced-titanium (75 percent B-E and 25 percent Ti) design for application to the space shuttle booster thrust structure indicates that the latter would weigh approximately 24 percent less. Experimental data on the local buckling strength of cylinders with a diameter-thickness ratio of approximately 50 are needed to insure that undue conservatism is not used in future designs.

  16. Analysis and Test of Deep Flaws in Thin Sheets of Aluminum and Titanium. Volume 2: Crack Opening Displacement and Stress-Strain Data

    NASA Technical Reports Server (NTRS)

    Finger, R. W.

    1978-01-01

    Static fracture tests were performed on surface flawed specimens of aluminum and titanium alloys. A simulated proof overload cycle was applied prior to all of the cyclic tests. Variables included in each test series were flaw shapes and thickness. Additionally, test temperature was a variable for the aluminum test series. The crack opening displacement and stress-strain data obtained are presented.

  17. Hydrothermal growth and characterization of titanium dioxide nanostructures for use in dye sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Sorge, Judith D.

    As the world's energy needs continue to grow, next generation photovoltaic cells are in high demand because they offer the possibility of an inexpensive alternative to current energy production techniques. Dye sensitized solar cells (DSSC's), utilize common materials and low cost commercialization techniques, which make them a compelling choice for research in this area. This research focuses on the titanium dioxide coating, which transfers electrons from the photoactive dye to the electrode. 3-4% efficient DSSC's using doctor bladed titanium dioxide coatings with a specific surface area of 55-60m2/g have been demonstrated in our laboratory. To enhance the efficiency of these cells, both the surface area and the electron conduction of the titania layer must be optimized. This has been done by utilizing high aspect ratio nanoparticles of titania instead of mesoporous layers formed with spherical particles. Anodization of titanium metal or anodic alumina membrane templating are common ways to produce nanorods, but involve complex processes leading toward expensive commercialization. This research instead focuses on the hydrothermal growth of nanofibrous titania on a titanium metal substrate, removing the need for dispersion and deposition procedures as well as using a low temperature processing method. Depending upon the formulation utilized, a variety of structures can be produced, from thick carpets of nanofiber strands to large platelets. The composition and morphology of the products have been characterized with respect to the growth conditions using electron microscopy, energy dispersive spectroscopy and x-ray diffraction. The compositional analysis is used to investigate the complicated reaction mechanisms in the system. Coatings of titania nanotubes were then tested in the DSSC's, as were those with the titanium metal substrate acting as the photo anode. Modeling the geometric parameters of the different pore structures of the coatings helps us to understand

  18. Aluminum nitride on titanium for CMOS compatible piezoelectric transducers

    PubMed Central

    Doll, Joseph C; Petzold, Bryan C; Ninan, Biju; Mullapudi, Ravi; Pruitt, Beth L

    2010-01-01

    Piezoelectric materials are widely used for microscale sensors and actuators but can pose material compatibility challenges. This paper reports a post-CMOS compatible fabrication process for piezoelectric sensors and actuators on silicon using only standard CMOS metals. The piezoelectric properties of aluminum nitride (AlN) deposited on titanium (Ti) by reactive sputtering are characterized and microcantilever actuators are demonstrated. The film texture of the polycrystalline Ti and AlN films is improved by removing the native oxide from the silicon substrate in situ and sequentially depositing the films under vacuum to provide a uniform growth surface. The piezoelectric properties for several AlN film thicknesses are measured using laser doppler vibrometry on unpatterned wafers and released cantilever beams. The film structure and properties are shown to vary with thickness, with values of d33f, d31 and d33 of up to 2.9, −1.9 and 6.5 pm V−1, respectively. These values are comparable with AlN deposited on a Pt metal electrode, but with the benefit of a fabrication process that uses only standard CMOS metals. PMID:20333316

  19. Aluminum nitride on titanium for CMOS compatible piezoelectric transducers

    NASA Astrophysics Data System (ADS)

    Doll, Joseph C.; Petzold, Bryan C.; Ninan, Biju; Mullapudi, Ravi; Pruitt, Beth L.

    2010-02-01

    Piezoelectric materials are widely used for microscale sensors and actuators but can pose material compatibility challenges. This paper reports a post-CMOS compatible fabrication process for piezoelectric sensors and actuators on silicon using only standard CMOS metals. The piezoelectric properties of aluminum nitride (AlN) deposited on titanium (Ti) by reactive sputtering are characterized and microcantilever actuators are demonstrated. The film texture of the polycrystalline Ti and AlN films is improved by removing the native oxide from the silicon substrate in situ and sequentially depositing the films under vacuum to provide a uniform growth surface. The piezoelectric properties for several AlN film thicknesses are measured using laser doppler vibrometry on unpatterned wafers and released cantilever beams. The film structure and properties are shown to vary with thickness, with values of d33f, d31 and d33 of up to 2.9, -1.9 and 6.5 pm V-1, respectively. These values are comparable with AlN deposited on a Pt metal electrode, but with the benefit of a fabrication process that uses only standard CMOS metals.

  20. Steel and titanium hollow sphere foams

    SciTech Connect

    Hurysz, K.M.; Clark, J.L.; Nagel, A.R.; Lee, K.J.; Cochran, J.K.; Sanders, T.H. Jr.; Hardwicke, C.U.

    1998-12-31

    Metal hollow sphere foams are fabricated by bonding millimeter sized metal alloy hollow spheres at points of contact. The spheres are formed as powder shells from slurries. For stainless steel spheres, the starting powder is a mixture of iron and chromium oxide. Thermal treatment in hydrogen reduces the oxides to Fe/Cr alloys with less than 2% porosity in sphere walls. The nominal composition is close to that of 405 stainless. Carburization in CO/CO{sub 2} atmosphere followed by heat treatment produces foams of either 410 or 420 type stainless steels depending on carbon content. Compressive stress-strain behavior was measured on point contact bonded stainless foams both before and after carburization. Hardness measurements on steel sphere walls were used to estimate the yield strength. Relative strengths of the foams were positioned between open and closed cell models. This was encouraging because bonding in the foams was less than optimum and the hollow sphere walls contained defects. As processing improves, strengths should increase. To produce titanium alloy spheres, the starting powder is titanium alloy hydride. Thermal treatment in an inert atmosphere decomposes the hydride and sinters the titanium powder in the sphere walls to greater than 96% relative density. Both titanium and Ti-6V-4V spheres and foams have been produced. Oxygen contents are a concern for titanium compositions and processing is being altered to reduce oxygen levels to increase ductility.

  1. A superior process for forming titanium hydrogen isotopic films

    NASA Technical Reports Server (NTRS)

    Steinberg, R.; Alger, D. L.; Cooper, D. W.

    1975-01-01

    Process forms stoichiometric, continuous, strongly bonded titanium hydrogen isotopic films. Films have thermal and electrical conductivities approximately the same as bulk pure titanium, ten times greater than those of usual thin films.

  2. Tape casting and partial melting of Bi-2212 thick films

    NASA Technical Reports Server (NTRS)

    Buhl, D.; Lang, TH.; Heeb, B.; Gauckler, L. J.

    1995-01-01

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 microns. The orientation of the (a,b)-plane of the grains was parallel to the substrate with a misalignment of less than 6 deg. At 77 K/0T a critical current density of 15, 000 A/sq cm was reached in films of the dimension 1 cm x 2 cm x 20 microns (1 micron V/cm criterion, resistively measured). At 4 K/0T the highest value was 350,000 A/sq cm (1 nV/cm criterion, magnetically measured).

  3. Tape casting and partial melting of Bi-2212 thick films

    SciTech Connect

    Buhl, D.; Lang, T.; Heeb, B.

    1994-12-31

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density of 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).

  4. Microstructural Development and Deposition Behavior of Titanium Powder Particles in Warm Spraying Process: From Single Splat to Coating

    NASA Astrophysics Data System (ADS)

    Kim, Keehyun; Kuroda, Seiji; Watanabe, Makoto

    2010-12-01

    Warm spraying has been developed by NIMS, in which powder particles are accelerated and simultaneously heated, and deposited onto a suitable substrate in thermally softened solid state. In this study, commercially available titanium powder was sprayed onto steel substrate by the spraying process. Microstructural developments and deposition behaviors from a deposited single particle to a thick coating layer were observed by high resolution electron microscopes. A single titanium particle sprayed onto the substrate was severely deformed and grain-refined mainly along the interfacial boundary of particle/substrate by the impact of the sprayed particle. A successive impact by another particle further deformed the previously deposited particle and induced additional grain refinement of the remaining part. In a thick coating layer, the severe deformation and grain refinement were also observed. The results have demonstrated the complex deposition behavior of sprayed particles in the warm spraying using thermally softened metallic powder particles.

  5. A comparison of the marginal adaptation of cathode-arc vapor-deposited titanium and cast base metal copings

    PubMed Central

    Wu, JC; Lai, LC; Sheets, CG; Earthman, J; Newcomb, R

    2011-01-01

    Statement of problem A new fabrication process has been developed where a titanium coping, which has a gold colored titanium nitride outer layer can be reliably fused to porcelain, but the marginal adaptation characteristics are still undetermined. Purpose The primary purpose of this study is to compare the rate of Clinically Acceptable Marginal Adaptation (CAMA-defined as a marginal gap mean ≤60 μm) of cathode-arc vapor-deposited titanium with the CAMA rate for the cast base metal copings. In addition, the study will evaluate the marginal gap scores themselves to assess their mean difference between the two study groups. Finally, the study will present two analyses of group differences in variability to support the contention that the titanium copings perform more consistently than their base metal counterparts. Material and methods Thirty-seven cathode-arc vapor-deposited titanium copings and 40 cast base metal copings were evaluated by computer-based image analysis using an optical microscope. The conventional lost wax technique was used to fabricate the 40 cast base metal copings that were 0.3 mm thick. The titanium copings were 0.3 mm thick and were formed by a collection of atomic titanium vapor onto a refractory die duplicate in a high vacuum chamber. Fifty vertical marginal gap measurements were collected from each of the 77 copings and the mean of these measurements was computed to form a gap score for each coping. Next, the gap score was compared to the 60 μm criterion to classify each coping as to whether it did or did not achieve Clinically Acceptable Marginal Adaption (CAMA). A comparison of the CAMA rates for each type of coping was used to address the primary purpose of this study. In addition, the gap scores themselves were used to test the (one-sided) hypothesis that the mean of the titanium gap scores is smaller than the mean of the base metal gap scores. Finally, the assertion that the titanium copings provide more consistency in their

  6. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, Paul R.

    1987-01-01

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and circumference by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  7. Tube wall thickness measurement apparatus

    DOEpatents

    Lagasse, P.R.

    1985-06-21

    An apparatus for measuring the thickness of a tube's wall for the tube's entire length and radius by determining the deviation of the tube wall thickness from the known thickness of a selected standard item. The apparatus comprises a base and a first support member having first and second ends. The first end is connected to the base and the second end is connected to a spherical element. A second support member is connected to the base and spaced apart from the first support member. A positioning element is connected to and movable relative to the second support member. An indicator is connected to the positioning element and is movable to a location proximate the spherical element. The indicator includes a contact ball for first contacting the selected standard item and holding it against the spherical element. The contact ball then contacts the tube when the tube is disposed about the spherical element. The indicator includes a dial having a rotatable needle for indicating the deviation of the tube wall thickness from the thickness of the selected standard item.

  8. System for measuring film thickness

    DOEpatents

    Batishko, Charles R.; Kirihara, Leslie J.; Peters, Timothy J.; Rasmussen, Donald E.

    1990-01-01

    A system for determining the thicknesses of thin films of materials exhibiting fluorescence in response to exposure to excitation energy from a suitable source of such energy. A section of film is illuminated with a fixed level of excitation energy from a source such as an argon ion laser emitting blue-green light. The amount of fluorescent light produced by the film over a limited area within the section so illuminated is then measured using a detector such as a photomultiplier tube. Since the amount of fluorescent light produced is a function of the thicknesses of thin films, the thickness of a specific film can be determined by comparing the intensity of fluorescent light produced by this film with the intensity of light produced by similar films of known thicknesses in response to the same amount of excitation energy. The preferred embodiment of the invention uses fiber optic probes in measuring the thicknesses of oil films on the operational components of machinery which are ordinarily obscured from view.

  9. Metallography of gamma titanium aluminides

    SciTech Connect

    Baeslack, W.A. III . Dept. of Welding Engineering); McQuay, P.A.; Lee, D.S. ); Fletcher, E.D. )

    1993-12-01

    The microstructures of forged and heat treated Ti-48A1-2Nb-2Mn (at.%) and Ti-48A1-2Nb-2Cr (at.%) gamma titanium aluminides have been revealed by the application of selected metallographic preparation techniques and characterized using light microscopy. Examination of the as-polished specimen surface under polarized light was highly effective in revealing the equiaxed gamma grain structure and twins within the gamma grains, but it did not delineate alpha-two phase present at gamma grain boundaries or within a lamellar gamma/alpha-two constituent. Bright-field and differential-interference contrast light microscopy analyses of specimens chemically etched with Kroll's reagent (100mL H[sub 2]O + 4mL HNO[sub 3] + 2mL HF) were marginally effective in characterizing the equiaxed gamma grain structure and likewise did not reveal the alpha-two phase. Furthermore, the application of Kroll's reagent resulted in localized dissolution in the form of fine grooves or microcracks oriented in preferred directions within the equiaxed gamma grains. Under light microscopy, gamma grains that experienced this attack resembled the lamellar gamma/alpha-two constituent. The alpha-two phase was most clearly revealed using an etching solution comprised of 30mL lactic acid + 30mL HNO[sub 3] + 3mL HF, while the gamma grain and twin boundaries were most effectively revealed using an etching solution comprised of 30mL HCL + 10mL HNO[sub 3] + 5mL H[sub 2]O[sub 2] + 3mL HF. An etching solution of 25 mL H[sub 2]O + 50mL glycerol + 25mL HNO[sub 3] + 2mL HF was very effective in simultaneously revealing both the gamma and alpha-two phase morphologies.

  10. Genotoxicity of titanium dioxide nanoparticles.

    PubMed

    Chen, Tao; Yan, Jian; Li, Yan

    2014-03-01

    Titanium dioxide nanoparticles (TiO(2)-NPs, <100 nm) are increasingly being used in pharmaceuticals and cosmetics due to the unique properties derived from their small sizes. However, their large surface-area to mass ratio and high redox potential may negatively impact human health and the environment. TiO(2)-NPs can cause inflammation, pulmonary damage, fibrosis, and lung tumors and they are possibly carcinogenic to humans. Because cancer is a disease involving mutation, there are a large number of studies on the genotoxicity of TiO(2)-NPs. In this article, we review the results that have been reported in the literature, with a focus on data generated from the standard genotoxicity assays. The data include genotoxicity results from the Ames test, in vitro and in vivo Comet assay, in vitro and in vivo micronucleus assay, sister chromatid exchange assay, mammalian cell hypoxanthine-guanine phosphoribosyl transferase gene assay, the wing somatic mutation and recombination assay, and the mouse phosphatidylinositol glycan, class A gene assay. Inconsistent results have been found in these assays, with both positive and negative responses being reported. The in vitro systems for assessing the genotoxicity of TiO(2)-NPs have generated a greater number of positive results than the in vivo systems, and tests for DNA and chromosome damage have produced more positive results than the assays measuring gene mutation. Nearly all tests for measuring the mutagenicity of TiO(2)-NPs were negative. The current data indicate that the genotoxicity of TiO(2)-NPs is mediated mainly through the generation of oxidative stress in cells. PMID:24673907

  11. Effect of sample thickness on 511 keV single Compton-scattered gamma rays

    NASA Astrophysics Data System (ADS)

    Díaz-H, K. V.; Cristancho, F.

    2016-07-01

    Gamma backscattering experiments were performed on metal foils varying some geometric parameters of the assembly. A collimated beam from a 22Na source impinges on aluminum sheets of dimensions 33.3×20.4×1.0 cm3 and iron sheets of (33.2×20.4×0.2) cm3. The backscattered photons are detected by a 3″×3″ CsI scintillator detector placed at 90° to the incident beam. The experimental results show that thickness of metalic samples can be determined with a very small uncertainty.

  12. [Study of pure titanium electrolytic polishing].

    PubMed

    Morita, N

    1990-03-01

    This study attempted to polish pure titanium test pieces electrolytically to mirror surface at the size of cast denture frames. Electrolytic polishing of pure titanium could be done on an area of 30 cm2 with a non-aqueous electrolyte. Small pure titanium plates could be polished electrolytically, but a uniformly smooth surface could not be obtained easily with large testpiece. The optimal electrolytic conditions were 30 V for 6 min at 25 degrees C using a solution consisting of 70 ml ethyl alcohol, 30 ml iso-propyl alcohol, 6 g aluminum chloride, and 25 g zinc chloride. The solution was safe and had less restriction of frequency of use. PMID:2135513

  13. Lactam inhibiting Streptococcus mutans growth on titanium.

    PubMed

    Xavier, J G; Geremias, T C; Montero, J F D; Vahey, B R; Benfatti, C A M; Souza, J C M; Magini, R S; Pimenta, A L

    2016-11-01

    The aim of this work was to analyze the activity of novel synthetic lactams on preventing biofilm formation on titanium surfaces. Titanium (Ti6Al4V) samples were exposed to Streptococcus mutans cultures in the presence or absence of a synthetic lactam. After 48h incubation, planktonic growth was determined by spectrophotometry. Biofilm was evaluated by crystal violet staining and colony forming units (CFU·ml(-)(1)), followed by scanning electron microscopy (SEM). Results showed that the average of adhered viable cells was approximately 1.5×10(2)CFU/ml in the presence of lactam and 4×10(2)CFU/ml in its absence. This novel compound was considerable active in reducing biofilm formation over titanium surfaces, indicating its potential for the development of antimicrobial drugs targeting the inhibition of the initial stages of bacterial biofilms on dental implants abutments. PMID:27524086

  14. Process for preparing titanium nitride powder

    DOEpatents

    Bamberger, C.E.

    1988-06-17

    A process for making titanium nitride powder by reaction of titanium phosphates with sodium cyanide. The process of this invention may comprise mixing one or more phosphates of Ti with a cyanide salt in the absence of oxygen and heating to a temperature sufficient to cause reaction to occur. In the preferred embodiment the ratio of cyanide salt to Ti should be at least 2 which results in the major Ti-containing product being TiN rather than sodium titanium phosphate byproducts. The process is an improvement over prior processes since the byproducts are water soluble salts of sodium which can easily be removed from the preferred TiN product by washing. 2 tabs.

  15. Stainless steel to titanium bimetallic transitions

    NASA Astrophysics Data System (ADS)

    Kaluzny, J. A.; Grimm, C.; Passarelli, D.

    2015-12-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented. Operated by Fermi Research Alliance, LLC under Contract No. De-AC02-07CH11359 with the United States Department of Energy.

  16. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, Richard K.; McCollister, Howard L.; Phifer, Carol C.; Day, Delbert E.

    1997-01-01

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La.sub.2 O.sub.3, B.sub.2 O.sub.3, TiO.sub.2 and Al.sub.2 O.sub.3 in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps).

  17. Titanium sealing glasses and seals formed therefrom

    DOEpatents

    Brow, R.K.; McCollister, H.L.; Phifer, C.C.; Day, D.E.

    1997-12-02

    Alkaline-earth lanthanoborate sealing-glass compositions containing CaO, La{sub 2}O{sub 3}, B{sub 2}O{sub 3}, TiO{sub 2} and Al{sub 2}O{sub 3} in various combinations of mole-% are provided. These sealing-glass compositions are useful for forming hermetic glass-to-metal seals with titanium and titanium alloys that have a high aqueous durability for component or device applications requiring exposure to moisture, water or body fluids. Particular applications of the titanium sealing-glass compositions include forming glass-to-metal seals for lithium batteries and implanted biomedical devices (e.g. batteries, pacemakers, defibrillators, pumps). 2 figs.

  18. Stainless Steel to Titanium Bimetallic Transitions

    SciTech Connect

    Kaluzny, J. A.; Grimm, C.; Passarelli, D.

    2015-01-01

    In order to use stainless steel piping in an LCLS-II (Linac Coherent Light Source Upgrade) cryomodule, stainless steel to titanium bimetallic transitions are needed to connect the stainless steel piping to the titanium cavity helium vessel. Explosion bonded stainless steel to titanium transition pieces and bimetallic transition material samples have been tested. A sample transition tube was subjected to tests and x-ray examinations between tests. Samples of the bonded joint material were impact and tensile tested at room temperature as well as liquid helium temperature. The joint has been used successfully in horizontal tests of LCLS-II cavity helium vessels and is planned to be used in LCLS-II cryomodules. Results of material sample and transition tube tests will be presented.

  19. Fermion localization on thick branes

    SciTech Connect

    Melfo, Alejandra; Pantoja, Nelson; Tempo, Jose David

    2006-02-15

    We consider chiral fermion confinement in scalar thick branes, which are known to localize gravity, coupled through a Yukawa term. The conditions for the confinement and their behavior in the thin-wall limit are found for various different BPS branes, including double walls and branes interpolating between different AdS{sub 5} spacetimes. We show that only one massless chiral mode is localized in all these walls, whenever the wall thickness is keep finite. We also show that, independently of wall's thickness, chiral fermionic modes cannot be localized in dS{sub 4} walls embedded in a M{sub 5} spacetime. Finally, massive fermions in double wall spacetimes are also investigated. We find that, besides the massless chiral mode localization, these double walls support quasilocalized massive modes of both chiralities.

  20. LTCC Thick Film Process Characterization

    DOE PAGESBeta

    Girardi, M. A.; Peterson, K. A.; Vianco, P. T.

    2016-05-01

    Low temperature cofired ceramic (LTCC) technology has proven itself in military/space electronics, wireless communication, microsystems, medical and automotive electronics, and sensors. The use of LTCC for high frequency applications is appealing due to its low losses, design flexibility and packaging and integration capability. Moreover, we summarize the LTCC thick film process including some unconventional process steps such as feature machining in the unfired state and thin film definition of outer layer conductors. The LTCC thick film process was characterized to optimize process yields by focusing on these factors: 1) Print location, 2) Print thickness, 3) Drying of tapes and panels,more » 4) Shrinkage upon firing, and 5) Via topography. Statistical methods were used to analyze critical process and product characteristics in the determination towards that optimization goal.« less

  1. Applications of film thickness equations

    NASA Technical Reports Server (NTRS)

    Hamrock, B. J.; Dowson, D.

    1983-01-01

    A number of applications of elastohydrodynamic film thickness expressions were considered. The motion of a steel ball over steel surfaces presenting varying degrees of conformity was examined. The equation for minimum film thickness in elliptical conjunctions under elastohydrodynamic conditions was applied to roller and ball bearings. An involute gear was also introduced, it was again found that the elliptical conjunction expression yielded a conservative estimate of the minimum film thickness. Continuously variable-speed drives like the Perbury gear, which present truly elliptical elastohydrodynamic conjunctions, are favored increasingly in mobile and static machinery. A representative elastohydrodynamic condition for this class of machinery is considered for power transmission equipment. The possibility of elastohydrodynamic films of water or oil forming between locomotive wheels and rails is examined. The important subject of traction on the railways is attracting considerable attention in various countries at the present time. The final example of a synovial joint introduced the equation developed for isoviscous-elastic regimes of lubrication.

  2. Titanium-nitrogen reaction investigated for application to gettering systems

    NASA Technical Reports Server (NTRS)

    Arntzen, J. D.; Coleman, L. F.; Kyle, M. L.; Pierce, R. D.

    1968-01-01

    Titanium is one of several gettering materials available for removing nitrogen from inert gases. The reaction rate of titanium-metal sponge and nitrogen in argon-nitrogen mixtures was studied at 900 degrees C. The rate was found to depend upon the partial pressure of nitrogen in the gas phase. Mathematical relationships simulate titanium systems.

  3. New Method For Joining Stainless Steel to Titanium

    NASA Technical Reports Server (NTRS)

    Emanuel, W. H.

    1982-01-01

    In new process, edge of stainless-steel sheet is perforated, and joined to titanium by resistance seam welding. Titanium flows into perforations, forming a strong interlocking joint. Process creates a quasi-metallurgical bond between the thin sheets of stainless steel and titanium.

  4. Recent developments in Japanese titanium research and development

    NASA Astrophysics Data System (ADS)

    Niinomi, M.

    1996-07-01

    Activity in the titanium industries in Japan has been steadily increasing as the demand for titanium and titanium alloys in consumer goods grows. The key issues in continuing the growth of these applications are lowering costs and developing new markets. In this article, advances in R&D reported mainly in the Japanese journals and at Japanese conferences are briefly described.

  5. Enhancing osseointegration using surface-modified titanium implants

    NASA Astrophysics Data System (ADS)

    Yang, Y.; Oh, N.; Liu, Y.; Chen, W.; Oh, S.; Appleford, M.; Kim, S.; Kim, K.; Park, S.; Bumgardner, J.; Haggard, W.; Ong, J.

    2006-07-01

    Osseointegrated dental implants are used to replace missing teeth. The success of implants is due to osseointegration or the direct contact of the implant surface and bone without a fibrous connective tissue interface. This review discusses the enhancement of osseointegration by means of anodized microporous titanium surfaces, functionally macroporous graded titanium coatings, nanoscale titanium surfaces, and different bioactive factors.

  6. Array of titanium dioxide nanostructures for solar energy utilization

    DOEpatents

    Qiu, Xiaofeng; Parans Paranthaman, Mariappan; Chi, Miaofang; Ivanov, Ilia N; Zhang, Zhenyu

    2014-12-30

    An array of titanium dioxide nanostructures for solar energy utilization includes a plurality of nanotubes, each nanotube including an outer layer coaxial with an inner layer, where the inner layer comprises p-type titanium dioxide and the outer layer comprises n-type titanium dioxide. An interface between the inner layer and the outer layer defines a p-n junction.

  7. Method for synthesis of titanium dioxide nanotubes using ionic liquids

    SciTech Connect

    Qu, Jun; Luo, Huimin; Dai, Sheng

    2013-11-19

    The invention is directed to a method for producing titanium dioxide nanotubes, the method comprising anodizing titanium metal in contact with an electrolytic medium containing an ionic liquid. The invention is also directed to the resulting titanium dioxide nanotubes, as well as devices incorporating the nanotubes, such as photovoltaic devices, hydrogen generation devices, and hydrogen detection devices.

  8. 40 CFR 721.10601 - Lanthanum lead titanium zirconium oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Lanthanum lead titanium zirconium... Specific Chemical Substances § 721.10601 Lanthanum lead titanium zirconium oxide. (a) Chemical substance... titanium zirconium oxide (PMN P-11-273; CAS No. 1227908-26-0) is subject to reporting under this...

  9. 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... titanium zirconium oxide (PMN P-11-270; CAS No. 61461-40-3) is subject to reporting under this section...

  10. Investigation of the vapour-plasma plume in the welding of titanium by high-power ytterbium fibre laser radiation

    NASA Astrophysics Data System (ADS)

    Bykovskiy, D. P.; Petrovskii, V. N.; Uspenskiy, S. A.

    2015-03-01

    The vapour-plasma plume produced in the welding of 6-mm thick VT-23 titanium alloy plates by ytterbium fibre laser radiation of up to 10 kW power is studied in the protective Ar gas medium. High-speed video filming of the vapour-plasma plume is used to visualise the processes occurring during laser welding. The coefficient of inverse bremsstrahlung by the welding plasma plume is calculated from the data of the spectrometric study.

  11. Structure and machinability of thin-walled parts made of titanium alloy powder using electron beam melting technology

    NASA Astrophysics Data System (ADS)

    Isaev, A.; Grechishnikov, V.; Kozochkin, M.; Volosova, M.; Petuhov, Yu; Peretyagin, P.

    2016-04-01

    The present study aims at study of structure and properties of raw and thermal treated titanium-based powder material used to produce the thin-walled components by electron beam melting technology. Producing the end product means also studying the finishing cutting process. Examining the quality of end product in terms of geometric tolerance and thin walls thickness stability consists of control the surface roughness is also included in this study.

  12. A unique approach to accurately measure thickness in thick multilayers.

    PubMed

    Shi, Bing; Hiller, Jon M; Liu, Yuzi; Liu, Chian; Qian, Jun; Gades, Lisa; Wieczorek, Michael J; Marander, Albert T; Maser, Jorg; Assoufid, Lahsen

    2012-05-01

    X-ray optics called multilayer Laue lenses (MLLs) provide a promising path to focusing hard X-rays with high focusing efficiency at a resolution between 5 nm and 20 nm. MLLs consist of thousands of depth-graded thin layers. The thickness of each layer obeys the linear zone plate law. X-ray beamline tests have been performed on magnetron sputter-deposited WSi(2)/Si MLLs at the Advanced Photon Source/Center for Nanoscale Materials 26-ID nanoprobe beamline. However, it is still very challenging to accurately grow each layer at the designed thickness during deposition; errors introduced during thickness measurements of thousands of layers lead to inaccurate MLL structures. Here, a new metrology approach that can accurately measure thickness by introducing regular marks on the cross section of thousands of layers using a focused ion beam is reported. This new measurement method is compared with a previous method. More accurate results are obtained using the new measurement approach. PMID:22514179

  13. The effect of silica-containing binders on the titanium/face coat reaction

    SciTech Connect

    Frueh, C.; Poirier, D.R.; Maguire, M.C.

    1996-11-01

    The interactions of CP-Ti and Ti-6Al-4V with investment molds containing alumina/silica and yttria/silica face coat systems were studied. Containerless melting in a vacuum was employed and small test samples were made by drop casting into the molds. The effects of the face coat material and mold preheat temperatures on the thickness of the alpha case on the castings were evaluated with microhardness and microprobe measurements. It was found that the thickness of the alpha case was the same, whether a yttria/silica or alumina/silica face coat was used, indicating that the silica binder reacted with the titanium. Hence, the use of expensive refractories, such as yttria, represents an unnecessary cost when combined with a silica binder. It was also found that the alloyed titanium castings had a thinner alpha case than those produced from CP-Ti, which suggests that the thickness of the alpha case depends on the crystal structure of the alloy during cooling from high temperatures. Furthermore, castings made in small yttria crucibles used as molds exhibited little or no alpha case.

  14. Ion nitriding of titanium alpha plus beta alloy for fusion reactor applications

    NASA Astrophysics Data System (ADS)

    Rolinski, E.; Sharp, G.; Cowgill, D. F.; Peterman, D. J.

    1998-02-01

    The titanium alpha plus beta alloy, Ti-6Al-4V, has been plasma nitrided at 1033 K in pure nitrogen to produce a 9 μm thick surface nitride zone, followed by a 5 μm thick Al-enriched zone and a 100 μm thick nitrogen diffusion zone. X-ray diffraction and Auger electron spectroscopy indicate that the nitride zone consists of two layers: a thin TiN layer at the surface followed by a Ti 2N layer. In preliminary tests, the deuterium retention of nitrided titanium specimens was determined after exposure to fluences of 4×10 25 m -2, 60 eV D + ions at 440 K and of 2×10 25 m -2, 800 eV D + ions at 623 K. The results are compared to the retention found for similar exposure of the untreated alloy and to model simulations. Implications for the use of these materials in a fusion environment are discussed.

  15. 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.

  16. Phased Array Ultrasonic Inspection of Titanium Forgings

    SciTech Connect

    Howard, P.; Klaassen, R.; Kurkcu, N.; Barshinger, J.; Chalek, C.; Nieters, E.; Sun, Zongqi; Fromont, F. de

    2007-03-21

    Aerospace forging inspections typically use multiple, subsurface-focused sound beams in combination with digital C-scan image acquisition and display. Traditionally, forging inspections have been implemented using multiple single element, fixed focused transducers. Recent advances in phased array technology have made it possible to perform an equivalent inspection using a single phased array transducer. General Electric has developed a system to perform titanium forging inspection based on medical phased array technology and advanced image processing techniques. The components of that system and system performance for titanium inspection will be discussed.

  17. Diffusion of lithium in titanium oxide

    NASA Astrophysics Data System (ADS)

    Shea, Patrick; Ye, Jianchao; Wood, Brandon; Bonev, Stanimir

    Titanium oxide has generated interest lately as a promising anode candidate for use in lithium-ion batteries. We report first principles calculations on the mobility of lithium atoms in both crystalline and amorphous phases of titanium oxide. Density functional theory calculations of structural properties and diffusion energy barriers are combined with rate theory and a lattice gas model to study diffusion of lithium over a range of concentrations. A summary of results, including significant differences in the mobility between amorphous and crystalline phases, will be presented and discussed.

  18. Beta titanium: a new orthodontic alloy.

    PubMed

    Burstone, C J; Goldberg, A J

    1980-02-01

    Historically, few alloys have been used in the fabrication of orthodontic appliances. This article reviews the gold-based, stainless steel, chrome-cobalt-nickel, and nitinol alloys, as well as beta titanium, a new material for orthodontics. Mechanical properties and manipulative characteristics are summarized to develop a basis for the selection of the proper alloy for a given clinical situation. The beta titanium wire has a unique balance of low stiffness, high springback, formability, and weldability which indicates its use in a wide range of clinical applications. A number of such applications are described. PMID:6928342

  19. Rapidly solidified titanium alloys by melt overflow

    SciTech Connect

    Gaspar, T.A.; Bruce, T.J. Jr.; Hackman, L.E.; Brasmer, S.E.; Dantzig, J.A.; Baeslack, W.A. III.

    1989-09-01

    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.

  20. Hydrogen partitioning and transport in titanium aluminides

    NASA Technical Reports Server (NTRS)

    Han, Kwang S.; Lee, Weon S.

    1993-01-01

    This report gives the final summary of the research work perfomed from March 1, 1990 to August 28, 1993. Brief descriptions of the research findings are given on the surface variation of Ti-14Al-21Nb as a function of temperature under ultrahigh vacuum conditions; titanium aluminides: surface composition effects as a function of temperature; Auger electron intensity variation in oxygen-charged silver; and segregation of sulfur on a titanium surface studied by Auger electron spectroscopy. Each description details one or more of the attached corresponding figures. Published journal documents are provided as appendices to give further detail.

  1. Nickel and titanium nanoboride composite coating

    NASA Astrophysics Data System (ADS)

    Efimova, K. A.; Galevsky, G. V.; Rudneva, V. V.; Kozyrev, N. A.; Orshanskaya, E. G.

    2015-09-01

    Electrodeposition conditions, structural-physical and mechanical properties (microhardness, cohesion with a base, wear resistance, corrosion currents) of electroplated composite coatings on the base of nickel with nano and micro-powders of titanium boride are investigated. It has been found out that electro-crystallization of nickel with boride nanoparticles is the cause of coating formation with structural fragments of small sizes, low porosity and improved physical and mechanical properties. Titanium nano-boride is a component of composite coating, as well as an effective modifier of nickel matrix. Nano-boride of the electrolyte improves efficiency of the latter due to increased permissible upper limit of the cathodic current density.

  2. Titanium reinforced boron-polyimide composite

    NASA Technical Reports Server (NTRS)

    Clark, G. A.; Clayton, K. I.

    1969-01-01

    Processing techniques for boron polyimide prepreg were developed whereby composites could be molded under vacuum bag pressure only. A post-cure cycle was developed which resulted in no loss in room temperature mechanical properties of the composite at any time during up to 16 hours at 650 F. A design utilizing laminated titanium foil was developed to achieve a smooth transition of load from the titanium attachment points into the boron-reinforced body of the structure. The box beam test article was subjected to combined bending and torsional loads while exposed to 650 F. Loads were applied incrementally until failure occurred at 83% design limit load.

  3. Reliability of Various Measurement Stations for Determining Plantar Fascia Thickness and Echogenicity

    PubMed Central

    Bisi-Balogun, Adebisi; Cassel, Michael; Mayer, Frank

    2016-01-01

    This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of ≥0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC. PMID:27089369

  4. Reliability of Various Measurement Stations for Determining Plantar Fascia Thickness and Echogenicity.

    PubMed

    Bisi-Balogun, Adebisi; Cassel, Michael; Mayer, Frank

    2016-01-01

    This study aimed to determine the relative and absolute reliability of ultrasound (US) measurements of the thickness and echogenicity of the plantar fascia (PF) at different measurement stations along its length using a standardized protocol. Twelve healthy subjects (24 feet) were enrolled. The PF was imaged in the longitudinal plane. Subjects were assessed twice to evaluate the intra-rater reliability. A quantitative evaluation of the thickness and echogenicity of the plantar fascia was performed using Image J, a digital image analysis and viewer software. A sonography evaluation of the thickness and echogenicity of the PF showed a high relative reliability with an Intra class correlation coefficient of ≥0.88 at all measurement stations. However, the measurement stations for both the PF thickness and echogenicity which showed the highest intraclass correlation coefficient (ICCs) did not have the highest absolute reliability. Compared to other measurement stations, measuring the PF thickness at 3 cm distal and the echogenicity at a region of interest 1 cm to 2 cm distal from its insertion at the medial calcaneal tubercle showed the highest absolute reliability with the least systematic bias and random error. Also, the reliability was higher using a mean of three measurements compared to one measurement. To reduce discrepancies in the interpretation of the thickness and echogenicity measurements of the PF, the absolute reliability of the different measurement stations should be considered in clinical practice and research rather than the relative reliability with the ICC. PMID:27089369

  5. Eddy current thickness measurement apparatus

    DOEpatents

    Rosen, Gary J.; Sinclair, Frank; Soskov, Alexander; Buff, James S.

    2015-06-16

    A sheet of a material is disposed in a melt of the material. The sheet is formed using a cooling plate in one instance. An exciting coil and sensing coil are positioned downstream of the cooling plate. The exciting coil and sensing coil use eddy currents to determine a thickness of the solid sheet on top of the melt.

  6. Chemistry of titanium dioxide nanoparticles

    NASA Astrophysics Data System (ADS)

    McCormick, John

    With increasing energy costs, government regulations, and an expanding population, alternative low-cost methods for the treatment of waste air and water have shown renewed interest. The utilization of solar energy to promote catalytic reactions, including photodegradation of pollutants, is an attractive and well-established field of research. Titanium dioxide nanoparticles are the most widely employed catalyst material in photocatalytic studies. Owing to its high surface area and electronic structure, the anatase phase of TiO 2 is an excellent photocatalyst. However, a detailed understanding of the physical, chemical, and electronic properties of TiO2 that influence the photocatalytic reaction rate does not exist. One goal of this work is the determination of how the degradation rate over TiO2 nanoparticle is influenced by the particle size. To meet this goal, detailed analysis of the particles was carried out using standard catalytic techniques combined with infrared spectroscopy to probe the decomposition of an organic probe molecule, formic acid. It was shown using infrared spectroscopy that the size of the particle does influence the rate of photodegradation. However for particles as small as five nanometers, the increased rate could be described by accounting for the increased surface area of the particles. Novel synthesis conditions for the synthesis of high purity particles is required to develop a better understanding of how the size can influence the particle's catalytic properties. Combustion synthesis serves as an attractive method for the synthesis of high purity TiO2 nanoparticles. The high temperatures present in a combustion flame promotes the decomposition of organometallic precursors and subsequent synthesis of metal oxide nanoparticles. Numerous synthesis conditions can influence the product powder. This research investigated some of these conditions for the synthesis of TiO2 nanoparticles. Additionally the thermal properties of TiO2 nanoparticles

  7. Titanium hypersensitivity. A hidden threat for dental implant patients?

    PubMed

    Bilhan, Hakan; Bural, Canan; Geckili, Onur

    2013-01-01

    Titanium and its alloys have been widely used for dental prosthetic devices because of their superior mechanical properties and biocompatibility. However, the incidence of titanium hypersensitivity or allergy is still unknown and the discussion about its existence is ongoing. Unexplained implant failures have also forced dental clinicians to investigate the possibility of titanium hypersensitivity or allergy. This review focuses on the potential of dental implant-related titanium hypersensitivity or allergic reactions. It includes an examination of the existing scientific literature and current knowledge. Evidence-based data and studies related to titanium hypersensitivity in dental implant patients are also discussed. PMID:24027897

  8. Thick resist for MEMS processing

    NASA Astrophysics Data System (ADS)

    Brown, Joe; Hamel, Clifford

    2001-11-01

    The need for technical innovation is always present in today's economy. Microfabrication methods have evolved in support of the demand for smaller and faster integrated circuits with price performance improvements always in the scope of the manufacturing design engineer. The dispersion of processing technology spans well beyond IC fabrication today with batch fabrication and wafer scale processing lending advantages to MEMES applications from biotechnology to consumer electronics from oil exploration to aerospace. Today the demand for innovative processing techniques that enable technology is apparent where only a few years ago appeared too costly or not reliable. In high volume applications where yield and cost improvements are measured in fractions of a percent it is imperative to have process technologies that produce consistent results. Only a few years ago thick resist coatings were limited to thickness less than 20 microns. Factors such as uniformity, edge bead and multiple coatings made high volume production impossible. New developments in photoresist formulation combined with advanced coating equipment techniques that closely controls process parameters have enable thick photoresist coatings of 70 microns with acceptable uniformity and edge bead in one pass. Packaging of microelectronic and micromechanical devices is often a significant cost factor and a reliability issue for high volume low cost production. Technologies such as flip- chip assembly provide a solution for cost and reliability improvements over wire bond techniques. The processing for such technology demands dimensional control and presents a significant cost savings if it were compatible with mainstream technologies. Thick photoresist layers, with good sidewall control would allow wafer-bumping technologies to penetrate the barriers to yield and production where costs for technology are the overriding issue. Single pass processing is paramount to the manufacturability of packaging

  9. Procedure for Automated Eddy Current Crack Detection in Thin Titanium Plates

    NASA Technical Reports Server (NTRS)

    Wincheski, Russell A.

    2012-01-01

    This procedure provides the detailed instructions for conducting Eddy Current (EC) inspections of thin (5-30 mils) titanium membranes with thickness and material properties typical of the development of Ultra-Lightweight diaphragm Tanks Technology (ULTT). The inspection focuses on the detection of part-through, surface breaking fatigue cracks with depths between approximately 0.002" and 0.007" and aspect ratios (a/c) of 0.2-1.0 using an automated eddy current scanning and image processing technique.

  10. Titanium and Ruthenium Phthalocyanines for NO2 Sensors: A Mini-Review

    PubMed Central

    Paoletti, Anna Maria; Pennesi, Giovanna; Rossi, Gentilina; Generosi, Amanda; Paci, Barbara; Albertini, Valerio Rossi

    2009-01-01

    This review presents studies devoted to the description and comprehension of phenomena connected with the sensing behaviour towards NO2 of films of two phthalocyanines, titanium bis-phthalocyanine and ruthenium phthalocyanine. Spectroscopic, conductometric, and morphological features recorded during exposure to the gas are explained and the mechanisms of gas-molecule interaction are also elucidated. The review also shows how X-ray reflectivity can be a useful tool for monitoring morphological parameters such as thickness and roughness that are demonstrated to be sensitive variables for monitoring the exposure of thin films of sensor materials to NO2 gas. PMID:22346697

  11. Titanium nanostructures made by local oxidation with the atomic force microscope

    NASA Astrophysics Data System (ADS)

    Vullers, R. J. M.; Ahlskog, M.; Van Haesendonck, C.

    1999-04-01

    Surfaces can be oxidized under ambient conditions with the tip of a scanning probe microscope when applying a voltage between surface and tip. The oxidation process is voltage- and humidity-dependent, and can be explained in terms of anodic oxidation. Sufficiently thin metal films (e.g., Ti or Al) can be completely oxidized down to the substrate, enabling the direct writing of nanostructures. We report on the fabrication and electrical measurements of Ti lines and Ti/TiO x/Ti junctions defined in titanium thin films having a thickness smaller than 10 nm.

  12. The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene)

    DOE PAGESBeta

    Mashtalir, O.; Lukatskaya, Maria R.; Kolesnikov, Alexander I.; Raymundo-Pinero, E.; Naguib, Michael; Barsoum, M. W.; Gogotsi, Yury G.

    2016-03-25

    Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. Furthermore, the hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g–1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.

  13. The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene).

    PubMed

    Mashtalir, O; Lukatskaya, M R; Kolesnikov, A I; Raymundo-Piñero, E; Naguib, M; Barsoum, M W; Gogotsi, Y

    2016-04-28

    Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g(-1) in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm. PMID:27088300

  14. Titanium Metal Powder Production by the Plasma Quench Process

    SciTech Connect

    R. A. Cordes; A. Donaldson

    2000-09-01

    The goals of this project included the scale-up of the titanium hydride production process to a production rate of 50 kg/hr at a purity level of 99+%. This goal was to be achieved by incrementally increasing the production capability of a series of reactor systems. This methodic approach was designed to allow Idaho Titanium Technologies to systematically address the engineering issues associated with plasma system performance, and powder collection system design and performance. With quality powder available, actual fabrication with the titanium hydride was to be pursued. Finally, with a successful titanium production system in place, the production of titanium aluminide was to be pursued by the simultaneously injection of titanium and aluminum precursors into the reactor system. Some significant accomplishments of the project are: A unique and revolutionary torch/reactor capable of withstanding temperatures up to 5000 C with high thermal efficiency has been operated. The dissociation of titanium tetrachloride into titanium powder and HC1 has been demonstrated, and a one-megawatt reactor potentially capable of producing 100 pounds per hour has been built, but not yet operated at the powder level. The removal of residual subchlorides and adsorbed HC1 and the sintering of powder to form solid bodies have been demonstrated. The production system has been operated at production rates up to 40 pounds per hour. Subsequent to the end of the project, Idaho Titanium Technologies demonstrated that titanium hydride powder can indeed be sintered into solid titanium metal at 1500 C without sintering aids.

  15. Titanium Oxide: A Bioactive Factor in Osteoblast Differentiation

    PubMed Central

    Santiago-Medina, P.; Sundaram, P. A.; Diffoot-Carlo, N.

    2015-01-01

    Titanium and titanium alloys are currently accepted as the gold standard in dental applications. Their excellent biocompatibility has been attributed to the inert titanium surface through the formation of a thin native oxide which has been correlated to the excellent corrosion resistance of this material in body fluids. Whether this titanium oxide layer is essential to the outstanding biocompatibility of titanium surfaces in orthopedic biomaterial applications is still a moot point. To study this critical aspect further, human fetal osteoblasts were cultured on thermally oxidized and microarc oxidized (MAO) surfaces and cell differentiation, a key indicator in bone tissue growth, was quantified by measuring the expression of alkaline phosphatase (ALP) using a commercial assay kit. Cell attachment was similar on all the oxidized surfaces although ALP expression was highest on the oxidized titanium alloy surfaces. Untreated titanium alloy surfaces showed a distinctly lower degree of ALP activity. This indicates that titanium oxide clearly upregulates ALP expression in human fetal osteoblasts and may be a key bioactive factor that causes the excellent biocompatibility of titanium alloys. This result may make it imperative to incorporate titanium oxide in all hard tissue applications involving titanium and other alloys. PMID:26664360

  16. Dynamic Fatigue of a Titanium Silicate Glass

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Nettles, Alan T.; Cagle, Holly A.; Smith, W. Scott (Technical Monitor)

    2002-01-01

    A dynamic fatigue study was performed on a Titanium Silicate Glass in order to assess its susceptibility to delayed failure. Fracture mechanics techniques were used to analyze the results for the purpose of making lifetime predictions for optical elements made from this material. The material has reasonably good resistance (N=23 to stress corrosion in ambient conditions).

  17. Coating for prevention of titanium combustion

    NASA Technical Reports Server (NTRS)

    Anderson, V. G.; Funkhouser, M.; Mcdaniel, P.

    1980-01-01

    A limited number of coating options for titanium gas turbine engine components were explored with the objective of minimizing potential combustion initiation and propagation without adversely affecting component mechanical properties. Objectives were met by two of the coatings, ion-plated platinum plus electroplated copper plus electroplated nickel and ion vapor deposited aluminum.

  18. Superplastic Titanium Tube Applies Pressure For Sintering

    NASA Technical Reports Server (NTRS)

    Mueller, Allen H.; Pleimann, Thomas R.

    1992-01-01

    In newly developed technique, titanium vessel filled with gas to exert pressure necessary for sintering. Used in brazing, sintering, and hot forming. Simplifies fabrication of parts having complicated shapes and has potential for variety of applications, including fabrication of heat pipes for high-performance vehicles.

  19. Titanium surface hydrophilicity enhances platelet activation.

    PubMed

    Alfarsi, Mohammed A; Hamlet, Stephen M; Ivanovski, Saso

    2014-01-01

    Titanium implant surface modification is a key strategy used to enhance osseointegration. Platelets are the first cells that interact with the implant surface whereupon they release a wide array of proteins that influence the subsequent healing process. This study therefore investigated the effect of titanium surface modification on the attachment and activation of human platelets. The surface characteristics of three titanium surfaces: smooth (SMO), micro-rough (SLA) and hydrophilic micro-rough (SLActive) and the subsequent attachment and activation of platelets following exposure to these surfaces were determined. The SLActive surface showed the presence of significant nanoscale topographical features. While attached platelets appeared to be morphologically similar, significantly fewer platelets attached to the SLActive surface compared to both the SMO and SLA surfaces. The SLActive surface however induced the release of the higher levels of chemokines β-thromboglobulin and platelet factor 4 from platelets. This study shows that titanium surface topography and chemistry have a significant effect on platelet activation and chemokine release. PMID:25311339

  20. Lactobacillus assisted synthesis of titanium nanoparticles

    NASA Astrophysics Data System (ADS)

    Prasad, K.; Jha, Anal K.; Kulkarni, A. R.

    2007-05-01

    An eco-friendly lactobacillus sp. (microbe) assisted synthesis of titanium nanoparticles is reported. The synthesis is performed at room temperature. X-ray and transmission electron microscopy analyses are performed to ascertain the formation of Ti nanoparticles. Individual nanoparticles as well as a number of aggregates almost spherical in shape having a size of 40 60 nm are found.

  1. Ab-inition melting curve of titanium

    NASA Astrophysics Data System (ADS)

    Stutzmann, Vincent; Bouchet, Johann; Bottin, Francois

    2014-03-01

    Thermodynamical properties of titanium are of great interest for aerospace and aviation industries and many studies are done in order to understand its behaviour under pressure (P) and temperature (T) : phase transitions at low T, melting curve at high T and P. In this work we compute the first ab-initio melting curve of titanium. This one is obtained with the Abinit package using DFT, in the GGA approximation, and in the framework of the projector augmented wave method (PAW). At first, we perform ground state calculations and study the five allotropic phases of titanium. Two PAW atomic data are generated with two different cutoff radius. The larger one gives results near previews ab-initio calculations, whereas the smaller one gives results near all electron calculation. Using the second PAW atomic data and performing ab-initio molecular dynamic simulations, we then compute the melting curve of titanium with three different methods. Results show relevance of our calculations, but also discrepencies with experimental data.

  2. Titanium nitride electrodes for thermoelectric generators

    DOEpatents

    Novak, Robert F.; Schmatz, Duane J.; Hunt, Thomas K.

    1987-12-22

    The invention is directed to a composite article suitable for use in thermoelectric generators. The article comprises a thin film of titanium nitride as an electrode deposited onto solid electrolyte. The invention is also directed to the method of making same.

  3. Stress corrosion crack inhibiting method for titanium

    NASA Technical Reports Server (NTRS)

    Beck, T. R.

    1970-01-01

    Addition of oxyanions to liquid solvents in excess of the number of chloride, bromide, or iodide ions present prevents cracking of titanium-aluminum alloys under exposure to aqueous and other solvent environments. The molar concentration of oxyanion is set from 10 to 100 times higher than concentration of halide ions.

  4. Oxygen diffusion from anodic surface oxide films on titanium subhydride studied by auger electron spectroscopy and electron energy loss spectroscopy

    SciTech Connect

    Wang, P.S.; Wittberg, T.N.; Wolf, J.D.; Keil, R.G.

    1984-01-01

    In the present study, TiH/sub x/ (0.5 < x < 1.7) samples were prepared from titanium foil in order to study the diffusion of oxygen in the titanium subhydride. An anodic oxide, 1000A thick, was grown on the titanium subhydride foils in an aqueous saturated solution of ammonium tetraborate. These anodized samples were then heat treated at temperatures between 500 and 600/sup 0/C and changes in the profile of oxygen concentration as a function of depth were monitored using AES. From this data then it was possible to calculate the diffusivity of oxygen in the titanium subhydride. It was also found that electron energy loss spectroscopy (EELS) could be used to determine the titanium subhydride stoichiometry in the near-surface region. This was done by measuring the energy of the bulk plasmon loss peak, which for TiH/sub x/, varies linearly with hydrogen content. The amount of dehydriding which had occurred following a given heat treatment could be determined from profiles of the plasmon loss energy as a function of depth. A sample of anodized TiH/sub 0/ /sub 87/ was studied in some detail. Significant dehydriding of this sample for heat treatment times of less than one hour, only occurred at temperatures above 550/sup 0/C. Likewise, oxide dissolution was only significant at temperatures greater than 550/sup 0/C. In general, for the heat treatment parameters which were chosen, the diffusivity of oxygen in TiH/sub 0/ /sub 87/ was about an order of magnitude lower than that for oxygen in titanium.

  5. The effect of heat- or ultra violet ozone-treatment of titanium on complement deposition from human blood plasma.

    PubMed

    Linderbäck, Paula; Harmankaya, Necati; Askendal, Agneta; Areva, Sami; Lausmaa, Jukka; Tengvall, Pentti

    2010-06-01

    Titanium (Ti) is a well known metallic biomaterial extensively used in dental, orthopaedic-, and occasionally also in blood contacting applications. It integrates well to bone and soft tissues, and is shown upon blood plasma contact to activate the intrinsic pathway of coagulation and bind complement factor 3b. The material properties depend largely on those of the nm-thick dense layer of TiO(2) that becomes rapidly formed upon contact with air and water. The spontaneously formed amorphous Ti-oxide has a pzc approximately 5-6 and its water solubility is at the order of 1-2 micromolar. It is often subjected to chemical- and heat treatments in order to increase the anatase- and rutile crystallinity, to modify the surface topography and to decrease the water solubility. In this work, we prepared sol-gel derived titanium and smooth PVD titanium surfaces, and analysed their oxide and protein deposition properties in human blood plasma before and after annealing at 100-500 degrees C or upon UVO-treatment for up to 96 hours. The blood plasma results show that complement deposition vanished irreversibly after heat treatment at 250-300 degrees C for 30 minutes or after UVO exposure for 24 hours or longer. XPS and infrared spectroscopy indicated change of surface water/hydroxyl binding upon the heat- and UVO treatments, and increased Ti oxidation. XRD analysis confirmed an increased crystallinity and both control (untreated) and annealed smooth titanium displayed low XRD-signals indicating some nanocrystallinity, with predominantly anatase phase. The current results show that the behaviour of titanium dioxide in blood contact can be controlled through relatively simple means, such as mild heating and illumination in UV-light, which both likely irreversibly change the stoichiometry and structure of the outmost layers of titanium dioxide and its OH/H(2)O binding characteristics. PMID:20363497

  6. Processing, microstructure, and mechanical behavior of titanium dioxide nanotubes

    NASA Astrophysics Data System (ADS)

    Crawford, Grant Alan

    Titanium dioxide nanotubes are of considerable interest for use in hydrogen generation, solar cells, chemical sensors, and bioactive coatings. In this study, nanotube coatings were fabricated on a Ti substrate via anodic oxidation. A novel hierarchical coating consisting of nanotubes (˜50 nm diameter) on the nano-scale and large pores/pits (˜1-20 mum) on the micro-scale was developed. This coating has potential for use as a bioactive coating on Ti bone implants. The mechanisms for nanotube formation and microscopic pitting were discussed. Microstructure characterization was conducted using scanning electron microscopy, focused ion beam, transmission electron microscopy, and image analysis. The effect of processing variables (i.e. time, temperature, pH) on nanotube characteristics (i.e. diameter, wall thickness, length) and hierarchical structure (i.e. pit/pore size and density) was studied. Anodization time was found to affect nanotube length and microscopic pit size and density. Lowering the electrolyte pH decreased the nanotube length and microscopic pit density. Increasing electrolyte temperature decreased nanotube length and increased pit/pore density. Anodization time, pH, and temperature, showed little effect on nanotube diameter or wall thickness. Microscopic pitting in the nanotube coating was found to occur above grain boundaries in the Ti substrate and above Ti grains with (0001) orientation. It was discovered that neighboring nanotubes are connected by ridges on the tube walls and an incoherent interface is formed between crystalline Ti and amorphous titanium dioxide. The influence of Ti substrate orientation on the growth kinetics and nanotube morphology was examined. Ti grains with surface orientations near (0001) experience retarded nanotube growth compared to (xxx0) orientations. This orientation dependence is likely related to differences in atomic density. Conventional nanoindentation and interfacial force microscopy (IFM), was employed to probe

  7. UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

    PubMed Central

    Saita, Makiko; Ikeda, Takayuki; Yamada, Masahiro; Kimoto, Katsuhiko; Lee, Masaichi Chang-Il; Ogawa, Takahiro

    2016-01-01

    Background Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability. Methods and results Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization. Conclusion UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite

  8. Machined Titanium Heat-Pipe Wick Structure

    NASA Technical Reports Server (NTRS)

    Rosenfeld, John H.; Minnerly, Kenneth G.; Gernert, Nelson J.

    2009-01-01

    Wick structures fabricated by machining of titanium porous material are essential components of lightweight titanium/ water heat pipes of a type now being developed for operation at temperatures up to 530 K in high-radiation environments. In the fabrication of some prior heat pipes, wicks have been made by extruding axial grooves into aluminum unfortunately, titanium cannot be extruded. In the fabrication of some other prior heat pipes, wicks have been made by in-situ sintering of metal powders shaped by the use of forming mandrels that are subsequently removed, but in the specific application that gave rise to the present fabrication method, the required dimensions and shapes of the heat-pipe structures would make it very difficult if not impossible to remove the mandrels due to the length and the small diameter. In the present method, a wick is made from one or more sections that are fabricated separately and assembled outside the tube that constitutes the outer heat pipe wall. The starting wick material is a slab of porous titanium material. This material is machined in its original flat configuration to form axial grooves. In addition, interlocking features are machined at the mating ends of short wick sections that are to be assembled to make a full-length continuous wick structure. Once the sections have been thus assembled, the resulting full-length flat wick structure is rolled into a cylindrical shape and inserted in the heatpipe tube (see figure). This wick-structure fabrication method is not limited to titanium/water heat pipes: It could be extended to other heat pipe materials and working fluids in which the wicks could be made from materials that could be pre-formed into porous slabs.

  9. 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. PMID:27582071

  10. Titanium corrosion in alkaline hydrogen peroxide environments

    NASA Astrophysics Data System (ADS)

    Been, Jantje

    1998-12-01

    The corrosion of Grade 2 titanium in alkaline hydrogen peroxide environments has been studied by weight loss corrosion tests, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR) measurements and potentiodynamic polarography. Calcium ions and wood pulp were investigated as corrosion inhibitors. In alkaline peroxide, the titanium corrosion rate increased with increasing pH, temperature, and hydrogen peroxide concentration. The corrosion controlling mechanism is thought to be the reaction of the oxide with the perhydroxyl ion. No evidence of thermodynamically stable calcium titanate was found in the surface film of test coupons exposed to calcium-inhibited alkaline peroxide solutions. Calcium inhibition is probably the result of low local alkali and peroxide concentrations at the metal surface produced by reaction of adsorbed calcium with hydrogen peroxide. It has been shown that the inhibiting effect of calcium is temporary, possibly through an effect of calcium on the chemical and/or physical stability of the surface oxide. Pulp is an effective and stable corrosion inhibitor. Raising the pulp concentration decreased the corrosion rate. The inhibiting effect of pulp may be related to the adsorption and interaction of the pulp fibers with H 2O2, thereby decreasing the peroxide concentration and rendering the solution less corrosive. The presence of both pulp and calcium led to higher corrosion rates than obtained by either one inhibitor alone. Replacement of hydrofluoric acid with alkaline peroxide for pickling of titanium was investigated. Titanium corrosion rates in alkaline peroxide exceeded those obtained in the conventional hydrofluoric acid bath. General corrosion was observed with extensive roughening of the surface giving a dull gray appearance. Preferred dissolution of certain crystallographic planes was investigated through the corrosion of a titanium single crystal. Whereas the overall effect on the corrosion rate was small

  11. International strategic minerals inventory summary report; titanium

    USGS Publications Warehouse

    Towner, R.R.; Gray, J.M.; Porter, L.M.

    1988-01-01

    Ilmenite and rutile are currently the most important titanium-bearing minerals, although anatase may be important in the future. Both ilmenite and rutile occur in hard-rock and placer deposits, but at present all rutile production and about half of the ilmenite production are from placer deposits. Anatase occurs in laterite deposits in Brazil, which at present are largely undeveloped. World ilmenite resources in identified deposits that are economically exploitable (R1E} are sufficient for about 150 years at current production rates, and about two-thirds of these resources are in China, the Soviet Union, and Norway. World rutile R1E resources would last about 80 years at current production rates, and some 54 percent of these resources are in Australia, the United States, and Italy. Combined R1E resources of anatase (which are all in Brazil) and rutile would last 300 years at current rutile production rates. Over 95 percent of the world's mine production of titanium-bearing minerals is used to manufacture titanium dioxide pigment for paint and other products. Most of the remaining 4 to 5 percent of production, which is largely rutile, is used for making titanium metal. Australia and Canada are the largest ilmenite producers, together supplying about half the world total; South Africa, Norway, and the Soviet Union together account for another third. Australia accounts for half the total world rutile production, with Sierra Leone and South Africa together accounting for another third. Australia and Norway are the largest exporters of titanium minerals. Unless major new deposits are discovered and developed in the traditional producing countries, the pattern of world production of both ilmenite and rutile could change substantially by 2020.

  12. Detection of tightly closed flaws by nondestructive testing (NDT) methods in steel and titanium

    NASA Technical Reports Server (NTRS)

    Rummel, W. D.; Rathke, R. A.; Todd, P. H., Jr.; Tedrow, T. L.; Mullen, S. J.

    1976-01-01

    X-radiographic, liquid penetrant, ultrasonic, eddy current and magnetic particle testing techniques were optimized and applied to the evaluation of 4340 steel (180 KSI-UTS) and 6Al-4V titanium (STA) alloy specimens. Sixty steel specimens containing a total of 176 fatigue cracks and 60 titanium specimens containing a total of 135 fatigue cracks were evaluated. The cracks ranged in length from .043 cm (0.017 inch) to 1.02 cm (.400 inch) and in depth from .005 cm (.002 inch) to .239 cm (.094 inch) for steel specimens. Lengths ranged from .048 cm (0.019 inch) to 1.03 cm (.407 inch) and depths from 0.010 cm (.004 inch) to .261 cm (0.103 inch) for titanium specimens. Specimen thicknesses were nominally .152 cm (0.060 inch) and 0.635 cm (0.250 inch) and surface finishes were nominally 125 rms. Specimens were evaluated in the "as machined" surface condition, after etch surface and after proof loading in a randomized inspection sequence.

  13. Effect of alloy chemistry and exposure conditions on the oxidation of titanium

    NASA Technical Reports Server (NTRS)

    Unnam, J.; Shenoy, R. N.; Clark, R. K.

    1984-01-01

    Multiwall is a new thermal protection system concept for advanced space transportation vehicles. The system consists of discrete panels made up of multiple layers of foil gage metal. Titanium is the proposed candidate metal for multiwall panels in the reentry temperature range up to 675 C. Oxidation and embrittlement are the principal concerns related to the use of Ti in heat shield applications. The results of a broad study on the oxidation kinetics of several titanium alloys subjected to different exposure conditions are described. The alloys include commercially pure titanium, Ti-6Al-4V, and Ti-6Al-2Sn-4Zr-2Mo. Oxidation studies were performed on these alloys exposed at 704 C in 5-760 torr air pressure and 0 to 50% relative humidity. The resulting weight gains were correlated with oxide thickness and substrate contamination. The contamination depth and weight gains due to solid solutioning were obtained from microhardness depth profiles and hardness versus weight percent oxygen calibration data.

  14. Surface modification of titanium by nano-TiO 2/HA bioceramic coating

    NASA Astrophysics Data System (ADS)

    He, G.; Hu, J.; Wei, S. C.; Li, J. H.; Liang, X. H.; Luo, E.

    2008-11-01

    A nano-TiO 2/hydroxyapatite composite bioceramic coating was developed and applied to the surfaces of pure titanium discs by the sol-gel method. A TiO 2 anatase bioceramic coating was utilized in the inner layer, which could adhere tightly to the titanium substrate. A porous hydroxyapatite (HA) bioceramic coating was utilized in the outer layer, which has higher solubility and better short-term bioactivity. Conventional HA coatings and commercially pure titanium were used as controls. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were employed to characterize the crystallization, surface morphology, and thickness of the coatings. The bioactivities of the coatings were evaluated by in vitro osteoblast cultures. Results showed that the nano-TiO 2/HA composite bioceramic coating exhibited good crystallization and homogeneous, nano-scale surface morphology. In addition, the nano-TiO 2/HA coating adhered tightly to the substrate, and the in vitro osteoblast cultures exhibited satisfactory bioactivity.

  15. Wear and corrosion resistance of anti-bacterial Ti-Cu-N coatings on titanium implants

    NASA Astrophysics Data System (ADS)

    Wu, Haibo; Zhang, Xiangyu; He, Xiaojing; Li, Meng; Huang, Xiaobo; Hang, Ruiqiang; Tang, Bin

    2014-10-01

    Anti-bacterial coatings with excellent wear and corrosion resistance play a vital role in ensuring the durability of implant materials in constant use. To this end, a novel anti-bacterial surface modification by combining magnetron sputtering with plasma nitriding was adopted in this paper to fabricate Cu-bearing Ti-based nitrides coatings (Ti-Cu-N) on titanium surface. The anti-bacterial properties of Ti-Cu-N coatings were evaluated. The microstructures and composition of the coatings were investigated by using FESEM, EDS, GDOES, XRD. The wear and corrosion resistance of the coatings were investigated. The results confirmed that an anti-bacterial Ti-Cu-N coating with a thickness of 6 μm and good adhesive strength to substrate was successfully achieved on titanium surface. As implied by XRD, the coatings were consisted of TiN, Ti2N, TiN0.3 phases. The surface micro-hardness and wear resistance of Ti-Cu-N coatings were significantly enhanced after plasma nitriding treatment. The analysis of potentiodynamic polarization curves and Nyquist plots obtained in 0.9 wt.% NaCl solution suggested that the Ti-Cu-N coatings also exhibited an excellent corrosion resistance. As mentioned above, it can be concluded that the duplex-treatment reported here was a versatile approach to develop anti-bacterial Ti-Cu-N coatings with excellent comprehensive properties on titanium implants.

  16. 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.

  17. Magnetic thin film deposition with pulsed magnetron sputtering: deposition rate and film thickness distribution

    NASA Astrophysics Data System (ADS)

    Ozimek, M.; Wilczyński, W.; Szubzda, B.

    2016-02-01

    The goal of conducted study was an experimental determining the relations between technological parameters of magnetron sputtering process on deposition rate (R) and thickness uniformity of magnetic thin films. Planar Ni79Fei6Mo5 target with a diameter of 100 mm was sputtered in argon (Ar) atmosphere. Deposition rate was measured in a function of gas pressure, target power and target-substrate distance. The highest value of R≈280 nmmin-1. The obtained results in deposition rate of magnetic film were compared to deposition rate of cooper (Cu), aluminum (Al), titanium (Ti) and titanium oxide (TiOx) and the deposition rate of Ni-Fe alloy were higher that Al and Ti. The film thickness distribution was measured for radial distance from the target centre ranging up to 60 mm and target-substrate distance ranging form 70 to 115 mm. Among others it was stated that for the larger value of target-substrate distance the larger uniform of film thickness are obtained.

  18. Accurate thickness measurement of graphene

    NASA Astrophysics Data System (ADS)

    Shearer, Cameron J.; Slattery, Ashley D.; Stapleton, Andrew J.; Shapter, Joseph G.; Gibson, Christopher T.

    2016-03-01

    Graphene has emerged as a material with a vast variety of applications. The electronic, optical and mechanical properties of graphene are strongly influenced by the number of layers present in a sample. As a result, the dimensional characterization of graphene films is crucial, especially with the continued development of new synthesis methods and applications. A number of techniques exist to determine the thickness of graphene films including optical contrast, Raman scattering and scanning probe microscopy techniques. Atomic force microscopy (AFM), in particular, is used extensively since it provides three-dimensional images that enable the measurement of the lateral dimensions of graphene films as well as the thickness, and by extension the number of layers present. However, in the literature AFM has proven to be inaccurate with a wide range of measured values for single layer graphene thickness reported (between 0.4 and 1.7 nm). This discrepancy has been attributed to tip-surface interactions, image feedback settings and surface chemistry. In this work, we use standard and carbon nanotube modified AFM probes and a relatively new AFM imaging mode known as PeakForce tapping mode to establish a protocol that will allow users to accurately determine the thickness of graphene films. In particular, the error in measuring the first layer is reduced from 0.1-1.3 nm to 0.1-0.3 nm. Furthermore, in the process we establish that the graphene-substrate adsorbate layer and imaging force, in particular the pressure the tip exerts on the surface, are crucial components in the accurate measurement of graphene using AFM. These findings can be applied to other 2D materials.

  19. Preparation of thick molybdenum targets

    NASA Technical Reports Server (NTRS)

    Singh, J. J.

    1974-01-01

    Thick natural molybdenum deposits on nickel plated copper substrates were prepared by thermal decomposition of molybdenum hexacarbonyl vapors on a heated surface in an inert gas atmosphere. The molybdenum metal atoms are firmly bonded to the substrate atoms, thus providing an excellent thermal contact across the junction. Molybdenum targets thus prepared should be useful for internal bombardment in a cyclotron where thermal energy inputs can exceed 10 kW.

  20. Soliton models for thick branes

    NASA Astrophysics Data System (ADS)

    Peyravi, Marzieh; Riazi, Nematollah; Lobo, Francisco S. N.

    2016-05-01

    In this work, we present new soliton solutions for thick branes in 4+1 dimensions. In particular, we consider brane models based on the sine-Gordon (SG), φ 4 and φ 6 scalar fields, which have broken Z2 symmetry in some cases and are responsible for supporting and stabilizing the thick branes. The origin of the symmetry breaking in these models resides in the fact that the modified scalar field potential may have non-degenerate vacua. These vacua determine the cosmological constant on both sides of the brane. We also study the geodesic equations along the fifth dimension, in order to explore the particle motion in the neighborhood of the brane. Furthermore, we examine the stability of the thick branes, by determining the sign of the w^2 term in the expansion of the potential for the resulting Schrödinger-like equation, where w is the five-dimensional coordinate. It turns out that the φ ^4 brane is stable, while there are unstable modes for certain ranges of the model parameters in the SG and φ ^6 branes.

  1. Central Corneal Thickness in Children

    PubMed Central

    2011-01-01

    Objective To report the central corneal thickness (CCT) in healthy white, African-American, and Hispanic children from birth to 17 years of age. Design Prospective observational multicenter study. Central corneal thickness was measured with a hand-held contact pachymeter. Results Two thousand seventy-nine children were included in the study, with ages ranging from day of birth to 17 years. Included were 807 white, 494 Hispanic, and 474 African-American individuals, in addition to Asian, unknown and mixed race individuals. African-American children had thinner corneas on average than that of both white (p< .001) and Hispanic children (p< .001) by approximately 20 micrometers. Thicker median CCT was observed with each successive year of age from age 1 to 11 years, with year-to-year differences steadily decreasing and reaching a plateau after age 11 at 573 micrometers in white and Hispanic children and 551 micrometers in African-American children. For every 100 micrometers of thicker CCT measured, the intraocular pressure was 1.5 mmHg higher on average (p< 0.001). For every diopter of increased myopic refractive error (p< 0.001) CCT was 1 micrometer thinner on average. Conclusions Median CCT increases with age from 1 to 11 years with the greatest increase present in the youngest age groups. African-American children on average have thinner central corneas than white and Hispanic children, while white and Hispanic children demonstrate similar central corneal thickness. PMID:21911662

  2. Thickness of western mare basalts

    NASA Technical Reports Server (NTRS)

    Dehon, R. A.

    1979-01-01

    An isopach map of the basalt thickness in the western mare basins is constructed from measurements of the exposed external rim height of partially buried craters. The data, although numerically sparse, is sufficiently distributed to yield gross thickness variations. The average basalt thickness in Oceanus Procellarum and adjacent regions is 400 m with local lenses in excess of 1500 m in the circular maria. The total volume of basalt in the western maria is estimated to be in the range of 1.5 x 10 to the 6th power cu km. The chief distinction between the eastern and western maria appears to be one of basalt volumes erupted to the surface. Maximum volumes of basalt are deposited west of the central highlands and flood subjacent terrain to a greater extent than on the east. The surface structures of the western maria reflect the probability of a greater degree of isostatic response to a larger surface loading by the greater accumulation of mare basalt.

  3. Measuring Metal Thickness With an Electric Probe

    NASA Technical Reports Server (NTRS)

    Shumka, A.

    1986-01-01

    Thickness of metal parts measured from one side with aid of Kelvin probe. Method developed for measuring thickness of end plate on sealed metal bellows from outside. Suitable for thicknesses of few thousandth's of inch (few hundred micrometers). Method also used to determine thickness of metal coatings applied by sputtering, electroplating, and flame spraying.

  4. Measuring Rind Thickness on Polyurethane Foam

    NASA Technical Reports Server (NTRS)

    Johnson, C.; Miller, J.; Brown, H.

    1985-01-01

    Nondestructive test determines rind thickness of polyurethane foam. Surface harness of foam measured by Shore durometer method: hardness on Shore D scale correlates well with rind thickness. Shore D hardness of 20, for example, indicates rind thickness of 0.04 inch (1 millimeter). New hardness test makes it easy to determine rind thickness of sample nondestructively and to adjust fabrication variables accordingly.

  5. Surface hardening of titanium alloys by gas phase nitridation under kinetic control

    NASA Astrophysics Data System (ADS)

    Liu, Lizhi

    This work describes a nitriding process for titanium and its alloys, which will improve the wear and corrosion resistance by forming a single phase Ti (N) solid solution that has the same lattice properties as the substrate, but not forming any nitrides on the surface. By kinetically controlling the chemical potential of nitrogen as diffusional interstitials, a large solubility can be achieved, which results in a super-hard surface. The nitrogen pressure, heat treatment temperature, and heat treatment time were investigated to form a desired diffusion profile without the formation of surface nitride compounds. This process can improve the wear resistance without the cost of reduced corrosion and fatigue resistance. A thermodynamic calculation has shown that the partial pressure of nitrogen acquired to avoiding the formation of nitrides is extremely low. A kinetic calculation, however, has indicated that a much higher nitrogen partial pressure can be afforded to nitride titanium alloys without forming nitrides. This kinetic calculation considers the impingement rate at the gas-solid interface, the sticking coefficient, and the interstitial diffusion coefficient. The conception of nitridation under kinetic control is verified in a laboratory-scale system, the design and construction of which is part of this work. Nitridation under well-defined and reproducible conditions was achieved by using a long fused silica tube as the reactor and sealing it with a hydrogen/oxygen torch. To clean the gas atmosphere in the tube prior to nitridation, titanium foil was integrated into the system as a getter material. After the titanium getter has cleaned the atmosphere from undesired impurities, the titanium or titanium alloy specimen was nitrided by exposing it to a well-controlled but very low nitrogen partial pressure, generated by a metal nitride/metal powder pack. With the Cr2N/Cr powder pack, for example, nitrogen pressure from 10-4 Pa to 10-1 Pa can be achieved by adjusting

  6. Mechanical evaluation of porous titanium (Ti6Al4V) structures with electron beam melting (EBM).

    PubMed

    Parthasarathy, Jayanthi; Starly, Binil; Raman, Shivakumar; Christensen, Andy

    2010-04-01

    Patient specific porous implants for the reconstruction of craniofacial defects have gained importance due to their better performance over their generic counterparts. The recent introduction of electron beam melting (EBM) for the processing of titanium has led to a one step fabrication of porous custom titanium implants with controlled porosity to meet the requirements of the anatomy and functions at the region of implantation. This paper discusses an image based micro-structural analysis and the mechanical characterization of porous Ti6Al4V structures fabricated using the EBM rapid manufacturing process. SEM studies have indicated the complete melting of the powder material with no evidence of poor inter-layer bonding. Micro-CT scan analysis of the samples indicate well formed titanium struts and fully interconnected pores with porosities varying from 49.75%-70.32%. Compression tests of the samples showed effective stiffness values ranging from 0.57(+/-0.05)-2.92(+/-0.17)GPa and compressive strength values of 7.28(+/-0.93)-163.02(+/-11.98)MPa. For nearly the same porosity values of 49.75% and 50.75%, with a variation in only the strut thickness in the sample sets, the compressive stiffness and strength decreased significantly from 2.92 GPa to 0.57 GPa (80.5% reduction) and 163.02 MPa to 7.28 MPa (93.54 % reduction) respectively. The grain density of the fabricated Ti6Al4V structures was found to be 4.423 g/cm(3) equivalent to that of dense Ti6Al4V parts fabricated using conventional methods. In conclusion, from a mechanical strength viewpoint, we have found that the porous structures produced by the electron beam melting process present a promising rapid manufacturing process for the direct fabrication of customized titanium implants for enabling personalized medicine. PMID:20142109

  7. Rapid prototyped porous nickel-titanium scaffolds as bone substitutes.

    PubMed

    Hoffmann, Waldemar; Bormann, Therese; Rossi, Antonella; Müller, Bert; Schumacher, Ralf; Martin, Ivan; de Wild, Michael; Wendt, David

    2014-01-01

    While calcium phosphate-based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel-titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel-titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel-titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel-titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel-titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel-titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold's pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel-titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium. PMID:25383165

  8. Rapid prototyped porous nickel–titanium scaffolds as bone substitutes

    PubMed Central

    Hoffmann, Waldemar; Bormann, Therese; Rossi, Antonella; Müller, Bert; Schumacher, Ralf; Martin, Ivan; Wendt, David

    2014-01-01

    While calcium phosphate–based ceramics are currently the most widely used materials in bone repair, they generally lack tensile strength for initial load bearing. Bulk titanium is the gold standard of metallic implant materials, but does not match the mechanical properties of the surrounding bone, potentially leading to problems of fixation and bone resorption. As an alternative, nickel–titanium alloys possess a unique combination of mechanical properties including a relatively low elastic modulus, pseudoelasticity, and high damping capacity, matching the properties of bone better than any other metallic material. With the ultimate goal of fabricating porous implants for spinal, orthopedic and dental applications, nickel–titanium substrates were fabricated by means of selective laser melting. The response of human mesenchymal stromal cells to the nickel–titanium substrates was compared to mesenchymal stromal cells cultured on clinically used titanium. Selective laser melted titanium as well as surface-treated nickel–titanium and titanium served as controls. Mesenchymal stromal cells had similar proliferation rates when cultured on selective laser melted nickel–titanium, clinically used titanium, or controls. Osteogenic differentiation was similar for mesenchymal stromal cells cultured on the selected materials, as indicated by similar gene expression levels of bone sialoprotein and osteocalcin. Mesenchymal stromal cells seeded and cultured on porous three-dimensional selective laser melted nickel–titanium scaffolds homogeneously colonized the scaffold, and following osteogenic induction, filled the scaffold’s pore volume with extracellular matrix. The combination of bone-related mechanical properties of selective laser melted nickel–titanium with its cytocompatibility and support of osteogenic differentiation of mesenchymal stromal cells highlights its potential as a superior bone substitute as compared to clinically used titanium. PMID:25383165

  9. Enhancing coating of brushite/hydroxyapatite layer on titanium alloy implant surface with additives

    NASA Astrophysics Data System (ADS)

    Abdel-Aal, E. A.; El-Sayed, D.; Shoeib, M.; Kandil, A. T.

    2013-11-01

    Brushite (CaHPO4·2H2O) was electrodeposited on titanium alloy substrate with and without H2O2. It was converted to hydroxyapatite [Ca10(PO4)6(OH)2] by NaOH treatment. Different H2O2 and NH4OH doses ranging from 0 ppm to 2400 ppm and from 0 ppm to 7000 ppm, respectively were used. The results showed that with increasing H2O2 dose up to 600 ppm, the weight gain and the coating thickness are increased. Further increase of H2O2 dose led to decrease of the weight gain and the coating thickness. Addition of ammonia led to decrease of the weight gain and the coating thickness. Thickness and weight gain of coated brushite layer are decreased with sodium hydroxide treatment and converted totally to hydroxyapatite. Coating thickness at Ca/P ratio of 1.67 and coating time of 1 h at current density of 1.5 mA/cm2 was about 14 and 18.5 μm without and with 600 ppm H2O2, respectively. It decreased to about 8 μm with addition of 7000 ppm ammonia solution.

  10. Characterization of thin hydroxyapatite layers formed on anodic titanium oxide films containing Ca and P by hydrothermal treatment.

    PubMed

    Ishizawa, H; Ogino, M

    1995-09-01

    An anodic titanium oxide film containing Ca and P (AOFCP) was formed on commercially pure titanium which was anodized in an electrolytic solution of dissolved beta-glycerophosphate (beta-GP) and calcium acetate (CA). Hydroxyapatite (HA) crystals were precipitated by hydrothermally heating the AOFCP at 300 degrees C. After hydrothermal treatment, the film was characterized by scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDX), and tensile tests. The morphology, composition, and amount of HA crystals precipitated were significantly affected by the composition of the electrolytes. Near-stoichiometric HA crystals with high crystallinity were precipitated completely covering the AOFCP surface at specific electrolyte concentrations. The HA layers were thin at 1-2 microns in thickness. The adhesive strength of the film increased with decreasing electrolyte concentration and the maximum value was about 40 MPa. In vitro tests for 300 days suggested that the stability of the film was high. The high adhesive strength may result from the AOFCP existing as an intermediate layer between the HA layer and a titanium substrate. The intervention of the AOFCP may have prevented abrupt changes in Ca and P content at an HA coating-titanium interface as seen in a plasma-sprayed one. The porous TiO2 matrix of the AOFCP may be suitable for nucleation sites of HA crystals, as well as SiO2 matrix of silicate bioactive glasses or glass ceramics. PMID:8567705

  11. Titanium Alloy Strong Back for IXO Mirror Segments

    NASA Technical Reports Server (NTRS)

    Byron, Glenn P.; Kai-Wang, Chan

    2011-01-01

    A titanium-alloy mirror-holding fixture called a strong back allows the temporary and permanent bonding of a 50 degree D263 glass x-ray mirror (IXO here stands for International X-ray Observatory). The strong back is used to hold and position a mirror segment so that mounting tabs may be bonded to the mirror with ultra-low distortion of the optical surface. Ti-15%Mo alloy was the material of choice for the strong back and tabs because the coefficient of thermal expansion closely matches that of the D263 glass and the material is relatively easy to machine. This invention has the ability to transfer bonded mounting points from a temporary location on the strong back to a permanent location on the strong back with minimal distortion. Secondly, it converts a single mirror segment into a rigid body with an acceptable amount of distortion of the mirror, and then maneuvers that rigid body into optical alignment such that the mirror segment can be bonded into a housing simulator or mirror module. Key problems are that the mirrors are 0.4-mm thick and have a very low coefficient of thermal expansion (CTE). Because the mirrors are so thin, they are very flexible and are easily distorted. When permanently bonding the mirror, the goal is to achieve a less than 1-micron distortion. Temperature deviations in the lab, which have been measured to be around 1 C, have caused significant distortions in the mirror segment.

  12. Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells

    PubMed Central

    Cherrington, Ruth; Wood, Benjamin Michael; Salaoru, Iulia; Goodship, Vannessa

    2016-01-01

    Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 µm thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm2 and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 °C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 ˚C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells. PMID:27166761

  13. Properties of pulsed laser deposited fluorinated hydroxyapatite films on titanium

    SciTech Connect

    Rau, J.V.; Smirnov, V.V.; Laureti, S.; Generosi, A.; Varvaro, G.; Fosca, M.; Ferro, D.; Cesaro, S. Nunziante; Albertini, V. Rossi; Barinov, S.M.

    2010-09-15

    Fluorinated hydroxyapatite coated titanium was investigated for application as implant coating for bone substitute materials in orthopaedics and dentistry. Pulsed laser deposition technique was used for films preparation. Fluorinated hydroxyapatite target composition, Ca{sub 10}(PO{sub 4}){sub 6}F{sub 1.37}(OH){sub 0.63}, was maintained at 2 J/cm{sup 2} of laser fluence and 500-600 {sup o}C of the substrate temperature. Prepared films had a compact microstructure, composed of spherical micrometric-size aggregates. The average surface roughness resulted to be of 3 nm for the film grown at 500 {sup o}C and of 10 nm for that grown at 600 {sup o}C, showing that the temperature increase did not favour the growth of a more fine granulated surface. The films were polycrystalline with no preferential growth orientation. The films grown at 500-600 {sup o}C were about 8 {mu}m thick and possessed a hardness of 12-13 GPa. Lower or higher substrate temperature provides the possibility to obtain coatings with different fine texture and roughness, thus tayloring them for various applications.

  14. Numerical study of porosity in titanium dental castings.

    PubMed

    Wu, M; Sahm, P R; Augthun, M; Spiekermann, H; Schädlich-Stubenrauch, J

    1999-09-01

    A commercial software package, MAGMASOFT (MAGMA Giessereitechnologie GmbH, Aachen, Germany), was used to study shrinkage and gas porosity in titanium dental castings. A geometrical model for two simplified tooth crowns connected by a connector bar was created. Both mold filling and solidification of this casting model were numerically simulated. Shrinkage porosity was quantitatively predicted by means of a built-in feeding criterion. The risk of gas pore formation was investigated using the numerical filling and solidification results. The results of the numerical simulations were compared with experiments, which were carried out on a centrifugal casting machine with an investment block mold. The block mold was made of SiO2 based slurry with a 1 mm thick Zr2 face coat to reduce metal-mold reactions. Both melting and casting were carried out under protective argon (40 kPa). The finished castings were sectioned and the shrinkage porosity determined. The experimentally determined shrinkage porosity coincided with the predicted numerical simulation results. No apparent gas porosity was found in these model castings. Several running and gating systems for the above model casting were numerically simulated. An optimized running and gating system design was then experimentally cast, which resulted in porosity-free castings. PMID:15348102

  15. Deposition Kinetics of Bioinspired Phenolic Coatings on Titanium Surfaces.

    PubMed

    Geißler, Sebastian; Barrantes, Alejandro; Tengvall, Pentti; Messersmith, Phillip B; Tiainen, Hanna

    2016-08-16

    Polyphenols can form functional coatings on a variety of different materials through auto-oxidative surface polymerization in a manner similar to polydopamine coatings. However, the mechanisms behind the coating deposition are poorly understood. We report the coating deposition kinetics of the polyphenol tannic acid (TA) and the simple phenolic compound pyrogallol (PG) on titanium surfaces. The coating deposition was followed in real time over a period of 24 h using a quartz crystal microbalance with dissipation monitoring (QCM-D). TA coatings revealed a multiphasic layer formation: the deposition of an initial rigid layer was followed by the buildup of an increasingly dissipative layer, before mass adsorption stopped after approximately 5 h of coating time. The PG deposition was biphasic, starting with the adsorption of a nonrigid viscoelastic layer which was followed by layer stiffening upon further mass adsorption. Coating evaluation by ellipsometry and AFM confirmed the deposition kinetics determined by QCM-D and revealed maximum coating thicknesses of approximately 50 and 75 nm for TA and PG, respectively. Chemical characterization of the coatings and polymerized polyphenol particles indicated the involvement of both physical and chemical interactions in the auto-oxidation reactions. PMID:27452793

  16. Charge density wave transition in single-layer titanium diselenide

    DOE PAGESBeta

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering.more » The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.« less

  17. Charge density wave transition in single-layer titanium diselenide

    PubMed Central

    Chen, P; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y; Chou, M Y; Mo, S. -K.; Hussain, Z; Fedorov, A. -V.; Chiang, T. -C.

    2015-01-01

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene—a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The observed Bardeen-Cooper-Schrieffer (BCS) behaviour of the gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk. PMID:26568512

  18. Charge density wave transition in single-layer titanium diselenide

    SciTech Connect

    Chen, P.; Chan, Y. -H.; Fang, X. -Y.; Zhang, Y.; Chou, M. Y.; Mo, S. -K.; Hussain, Z.; Fedorov, A. -V.; Chiang, T. -C.

    2015-11-16

    A single molecular layer of titanium diselenide (TiSe2) is a promising material for advanced electronics beyond graphene--a strong focus of current research. Such molecular layers are at the quantum limit of device miniaturization and can show enhanced electronic effects not realizable in thick films. We show that single-layer TiSe2 exhibits a charge density wave (CDW) transition at critical temperature TC=232±5 K, which is higher than the bulk TC=200±5 K. Angle-resolved photoemission spectroscopy measurements reveal a small absolute bandgap at room temperature, which grows wider with decreasing temperature T below TC in conjunction with the emergence of (2 × 2) ordering. The results are rationalized in terms of first-principles calculations, symmetry breaking and phonon entropy effects. The behavior of the Bardeen-Cooper-Schrieffer (BCS) gap implies a mean-field CDW order in the single layer and an anisotropic CDW order in the bulk.

  19. Digital Printing of Titanium Dioxide for Dye Sensitized Solar Cells.

    PubMed

    Cherrington, Ruth; Wood, Benjamin Michael; Salaoru, Iulia; Goodship, Vannessa

    2016-01-01

    Silicon solar cell manufacturing is an expensive and high energy consuming process. In contrast, dye sensitized solar cell production is less environmentally damaging with lower processing temperatures presenting a viable and low cost alternative to conventional production. This paper further enhances these environmental credentials by evaluating the digital printing and therefore additive production route for these cells. This is achieved here by investigating the formation and performance of a metal oxide photoelectrode using nanoparticle sized titanium dioxide. An ink-jettable material was formulated, characterized and printed with a piezoelectric inkjet head to produce a 2.6 µm thick layer. The resultant printed layer was fabricated into a functioning cell with an active area of 0.25 cm(2) and a power conversion efficiency of 3.5%. The binder-free formulation resulted in a reduced processing temperature of 250 °C, compatible with flexible polyamide substrates which are stable up to temperatures of 350 ˚C. The authors are continuing to develop this process route by investigating inkjet printing of other layers within dye sensitized solar cells. PMID:27166761

  20. In vivo evaluation of immediately loaded stainless steel and titanium orthodontic screws in a growing bone.

    PubMed

    Gritsch, Kerstin; Laroche, Norbert; Bonnet, Jeanne-Marie; Exbrayat, Patrick; Morgon, Laurent; Rabilloud, Muriel; Grosgogeat, Brigitte

    2013-01-01

    The present work intends to evaluate the use of immediate loaded orthodontic screws in a growing model, and to study the specific bone response. Thirty-two screws (half of stainless steel and half of titanium) were inserted in the alveolar bone of 8 growing pigs. The devices were immediately loaded with a 100 g orthodontic force. Two loading periods were assessed: 4 and 12 weeks. Both systems of screws were clinically assessed. Histological observations and histomorphometric analysis evaluated the percent of "bone-to-implant contact" and static and dynamic bone parameters in the vicinity of the devices (test zone) and in a bone area located 1.5 cm posterior to the devices (control zone). Both systems exhibit similar responses for the survival rate; 87.5% and 81.3% for stainless steel and titanium respectively (p = 0.64; 4-week period), and 62.5% and 50.0% for stainless steel and titanium respectively (p = 0.09; 12-week period). No significant differences between the devices were found regarding the percent of "bone-to-implant contact" (p = 0.1) or the static and dynamic bone parameters. However, the 5% threshold of "bone-to-implant contact" was obtained after 4 weeks with the stainless steel devices, leading to increased survival rate values. Bone in the vicinity of the miniscrew implants showed evidence of a significant increase in bone trabecular thickness when compared to bone in the control zone (p = 0.05). In our study, it is likely that increased trabecular thickness is a way for low density bone to respond to the stress induced by loading. PMID:24124540

  1. The effect of hydrazine intercalation on the structure and capacitance of 2D titanium carbide (MXene)

    NASA Astrophysics Data System (ADS)

    Mashtalir, O.; Lukatskaya, M. R.; Kolesnikov, A. I.; Raymundo-Piñero, E.; Naguib, M.; Barsoum, M. W.; Gogotsi, Y.

    2016-04-01

    Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g-1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm.Herein we show that hydrazine intercalation into 2D titanium carbide (Ti3C2-based MXene) results in changes in its surface chemistry by decreasing the amounts of fluorine, OH surface groups and intercalated water. It also creates a pillaring effect between Ti3C2Tx layers pre-opening the structure and improving the accessability to active sites. The hydrazine treated material has demonstrated a greatly improved capacitance of 250 F g-1 in acidic electrolytes with an excellent cycling ability for electrodes as thick as 75 μm. Electronic supplementary information (ESI) available: Characterization methods, additional XRD patterns (Fig. S1) and INS spectra (Fig. S2-S4). See DOI: 10.1039/c6nr01462c

  2. Tribocorrosion behaviour of anodic treated titanium surfaces intended for dental implants

    NASA Astrophysics Data System (ADS)

    Alves, A. C.; Oliveira, F.; Wenger, F.; Ponthiaux, P.; Celis, J.-P.; Rocha, L. A.

    2013-10-01

    Tribocorrosion plays an important role in the lifetime of metallic implants. Once implanted, biomaterials are subjected to micro-movements in aggressive biological fluids. Titanium is widely used as an implant material because it spontaneously forms a compact and protective nanometric thick oxide layer, mainly TiO2, in ambient air. That layer provides good corrosion resistance, and very low toxicity, but its low wear resistance is a concern. In this work, an anodizing treatment was performed on commercial pure titanium to form a homogeneous thick oxide surface layer in order to provide bioactivity and improve the biological, chemical and mechanical properties. Anodizing was performed in an electrolyte containing β-glycerophosphate and calcium acetate. The influence of the calcium acetate content on the tribocorrosion behaviour of the anodized material was studied. The concentration of calcium acetate in the electrolyte was found to largely affect the crystallographic structure of the resulting oxide layer. Better tribocorrosion behaviour was noticed on increasing the calcium acetate concentration.

  3. Titanium nanostructural surface processing for improved biocompatibility

    SciTech Connect

    Cheng, H.-C.; Lee, S.-Y.; Chen, C.-C.; Shyng, Y.-C.; Ou, K.-L.

    2006-10-23

    X-ray photoelectron spectroscopy, grazing incident x-ray diffraction, transmission electron microscopy, and scanning electron microscopy were conducted to evaluate the effect of titanium hydride on the formation of nanoporous TiO{sub 2} on Ti during anodization. Nano-titanium-hydride was formed cathodically before anodizing and served as a sacrificial nanoprecipitate during anodization. Surface oxidation occurred and a multinanoporous structure formed after cathodic pretreatments followed by anodization treatment. The sacrificial nanoprecipitate is directly dissolved and the Ti transformed to nanoporous TiO{sub 2} by anodization. The formation of sacrificial nanoprecipitates by cathodic pretreatment and of the multinanostructure by anodization is believed to improve biocompatibility, thereby promoting osseointegration.

  4. Environmental Studies on Titanium Aluminide Alloys

    NASA Technical Reports Server (NTRS)

    Brindley, William J.; Bartolotta, Paul A.; Smialek, James L.; Brady, Michael P.

    2005-01-01

    Titanium aluminides are attractive alternatives to superalloys in moderate temperature applications (600 to 850 C) by virtue of their high strength-to-density ratio (high specific strength). These alloys are also more ductile than competing intermetallic systems. However, most Ti-based alloys tend to degrade through interstitial embrittlement and rapid oxidation during exposure to elevated temperatures. Therefore, their environmental behavior must be thoroughly investigated before they can be developed further. The goals of titanium aluminide environmental studies at the NASA Lewis Research Center are twofold: characterize the degradation mechanisms for advanced structural alloys and determine what means are available to minimize degradation. The studies to date have covered the alpha 2 (Ti3Al), orthorhombic (Ti2AlNb), and gamma (TiAl) classes of alloys.

  5. First-principles study of titanium oxides

    SciTech Connect

    Leung, C.; Weinert, M.; Allen, P.B.; Wentzcovitch, R.M.

    1996-09-01

    Titanium forms a wide range of stoichiometric oxides. The low-temperature monoclinic phase of titanium monoxide Ti{sub 5}O{sub 5} has an ordered array of vacancies in an otherwise simple NaCl structure. Using the variable cell shape method and the local-density approximation, all 12 parameters of the crystal structure are relaxed. Comparisons with other possible structures and other transition-metal monoxides suggest that there is a competition between kinetic- and Madelung-energy contributions and that this low symmetry structure is stabilized in part by the overlap of occupied Ti-ion orbitals via the vacant oxygen site. Resistivities of the low-temperature Ti{sub 5}O{sub 5} phase fitted using the Bloch-Gr{umlt u}neisen formula imply that the monoxide is a borderline quasiparticle gas. {copyright} {ital 1996 The American Physical Society.}

  6. Resistive switching effect in titanium oxides.

    PubMed

    Tang, Zhensen; Chi, Yaqing; Fang, Liang; Liu, Rulin; Yi, Xun

    2014-02-01

    Resistive switching (RS) phenomena have been vigorously investigated in a large variety of materials and highlighted for its preeminent potential for the future nonvolatile semiconductor memory applications or reconfigurable logic circuits. Among the various resistive switching materials, the binary metal oxides demonstrate more advantageous for micro- or nano-electronics applications due to their simpler fabrication process and compatibility with conventional CMOS technology, though the mechanisms are controversial due to the diversity of RS effects. This review mainly focuses on the current understanding of the microscopic nature of RS in titanium oxides, in which the working mechanisms can be categorized into thermochemical metallization mechanism, valence change mechanism, and electrostatic/electronic mechanism. The approaches developed to investigate the RS and the specific switching processes related to different mechanisms are addressed. Since titanium oxides are oxygen-vacancy doped semiconductors, the role of defects is analyzed in detail and possible effective strategies to improve the performance of RS are addressed. PMID:24749437

  7. PEM Anchorage on Titanium Using Catechol Grafting

    PubMed Central

    Marie, Hélène; Barrere, Amélie; Schoentstein, Frédérique; Chavanne, Marie-Hélène; Grosgogeat, Brigitte; Mora, Laurence

    2012-01-01

    Background This study deals with the anchorage of polyelectrolyte films onto titanium surfaces via a cathecol-based linker for biomedical applications. Methodology The following study uses a molecule functionalized with a catechol and a carboxylic acid: 3-(3,4-dihydroxyphenyl)propanoic acid. This molecule is anchored to the TiO2 substrate via the catechol while the carboxylic acid reacts with polymers bearing amine groups. By providing a film anchorage of chemisorption type, it makes possible to deposit polyelectrolytes on the surface of titanium. Principal Findings Infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), contact angle and atomic force microscopy (AFM) measurements show that the different steps of grafting have been successfully performed. Conclusions This method based on catechol anchorage of polyelectrolytes open a window towards large possibilities of clinical applications. PMID:23226262

  8. Possible segregation caused by centrifugal titanium casting.

    PubMed

    Watanabe, K; Okawa, S; Kanatani, M; Nakano, S; Miyakawa, O; Kobayashi, M

    1996-12-01

    The possibility of the segregation under solidification process using a centrifugal casting machine was investigated using an electron probe microanalyzer with elemental distribution map, line analysis and quantitative analysis. When a very small quantity of platinum was added to local molten titanium during the casting process, macroscopic segregation was observed under conditions of density difference of 0.1 g/cm3 at the most, confirming that the centrifugal force of the casting machine is extremely strong. When a Ti-6Al-4V alloy was cast, however, no macroscopic segregation was observed. The centrifugal force of the casting machine examined in the present study hardly results in the body-force segregation in this titanium alloy. PMID:9550020

  9. Sustainable cooling method for machining titanium alloy

    NASA Astrophysics Data System (ADS)

    Boswell, B.; Islam, M. N.

    2016-02-01

    Hard to machine materials such as Titanium Alloy TI-6AI-4V Grade 5 are notoriously known to generate high temperatures and adverse reactions between the workpiece and the tool tip materials. These conditions all contribute to an increase in the wear mechanisms, reducing tool life. Titanium Alloy, for example always requires coolant to be used during machining. However, traditional flood cooling needs to be replaced due to environmental issues, and an alternative cooling method found that has minimum impact on the environment. For true sustainable cooling of the tool it is necessary to account for all energy used in the cooling process, including the energy involved in producing the coolant. Previous research has established that efficient cooling of the tool interface improves the tool life and cutting action. The objective of this research is to determine the most appropriate sustainable cooling method that can also reduce the rate of wear at the tool interface.

  10. Amorphouslike diffraction pattern in solid metallic titanium.

    PubMed

    Wang, Y; Fang, Y Z; Kikegawa, T; Lathe, C; Saksl, K; Franz, H; Schneider, J R; Gerward, L; Wu, F M; Liu, J F; Jiang, J Z

    2005-10-01

    Amorphouslike diffraction patterns of solid elemental titanium have been detected under high pressure and high temperature using in situ energy-dispersive x-ray diffraction and a multianvil press. The onset pressure and the temperature of formation of amorphous titanium is found to be close to the alpha-beta-omega triple point in the P-T phase diagram. Amorphous Ti has been found to be thermally stable up to 1250 degrees C for at least 3 min at some pressures. By analyzing the conditions for producing amorphous elemental Zr and Ti, we observed a multi-phase-point amorphization phenomenon for preparing single-element bulk amorphous metals. The results reported may open a new way to preparing single-element bulk amorphous metals with a high thermal stability. PMID:16241734

  11. High temperature, bonded titanium diboride sputter target

    SciTech Connect

    Hale, G.J.; Gates, W.G.

    1981-10-01

    A high-temperature bonding technique has been employed in the development of an improved sputter deposition target for hard, crack-prone materials such as titanium diboride (TiB/sub 2/). Titanium diboride was bonded to a thin metal backing plate, both materials having a similar linear coefficient of thermal expansion (LCTE) using a high-temperature braze alloy. The thin metal backing plate helps stabilize the movement of the target material during the sputter deposition operation. The bonded sputter target has a useable life of 50 to 75 times that of a unbonded target. This bonding technique may be used on a variety of hard, brittle, crack-prone, sputterable materials (including metal oxides, carbides borides, and nitrides). US Patent 4,209,375 has been issued as a result of this endeavor.

  12. Welding of gamma titanium aluminide alloys

    NASA Technical Reports Server (NTRS)

    Smashey, Russell W. (Inventor); Kelly, Thomas J. (Inventor); Snyder, John H. (Inventor); Sheranko, Ronald L. (Inventor)

    1998-01-01

    An article made of a gamma titanium aluminide alloy is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, cooling the entire article to a welding temperature of from about 1000.degree. F. to about 1400.degree. F., welding a preselected region in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected region so as to locally melt the alloy in the preselected region, providing a filler metal having the same composition as the gamma titanium aluminide alloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

  13. Adsorption of octylamine on titanium dioxide

    NASA Astrophysics Data System (ADS)

    Siwińska, Daria; Kołodziejczak-Radzimska, Agnieszka; Krysztafkiewicz, Andrzej; Jesionowski, Teofil

    2009-05-01

    Processes of adsorption and desorption of a model active substance (octylamine) on the surface of unmodified titanium dioxide (E 171) have been performed. The effects of concentration of octylamine and time of the process on the character of adsorption have been studied and the efficiency of the adsorption/desorption has been determined. The samples obtained have been studied by X-ray diffraction. The nitrogen adsorption/desorption isotherms, particle size distribution and absorption capacities of water, dibutyl phthalate and paraffin oil have been determined. The efficiency of octylamine adsorption on the surface of the titanium dioxide has been found positively correlated with the concentration of octylamine in the initial solution. The desorption of octylamine has decreased with increasing concentration of this compound adsorbed. For octylamine in low concentrations the physical adsorption has been found to dominate, which is desirable when using TiO 2 in the production of pharmaceuticals.

  14. Titanium implants in irradiated dog mandibles

    SciTech Connect

    Schweiger, J.W. )

    1989-08-01

    The use of osseointegrated titanium implants has been a great benefit to selected cancer patients who otherwise would not be able to wear conventional and/or maxillofacial prostheses. Cognizant of the risk of osteoradionecrosis, we used an animal model to seek experimental evidence for successful osseointegration in bone irradiated to tumoricidal levels. Five healthy male beagle dogs received 60 gray to a previously edentulated and healed area of the right hemimandible. The left hemimandible was kept as a nonirradiated control. After 9 months, titanium implants were placed and allowed an additional 5 1/2 months to osseointegrate. At that time, block specimens were obtained, radiographed, photographed, and analyzed histologically. Although statistical significance cannot be attached to the results, osseointegration was achieved in half of the irradiated specimens.

  15. Advances in gamma titanium aluminides and their manufacturing techniques

    NASA Astrophysics Data System (ADS)

    Kothari, Kunal; Radhakrishnan, Ramachandran; Wereley, Norman M.

    2012-11-01

    Gamma titanium aluminides display attractive properties for high temperature applications. For over a decade in the 1990s, the attractive properties of titanium aluminides were outweighed by difficulties encountered in processing and machining at room temperature. But advances in manufacturing technologies, deeper understanding of titanium aluminides microstructure, deformation mechanisms, and advances in micro-alloying, has led to the production of gamma titanium aluminide sheets. An in-depth review of key advances in gamma titanium aluminides is presented, including microstructure, deformation mechanisms, and alloy development. Traditional manufacturing techniques such as ingot metallurgy and investment casting are reviewed and advances via powder metallurgy based manufacturing techniques are discussed. Finally, manufacturing challenges facing gamma titanium aluminides, as well as avenues to overcome them, are discussed.

  16. Corrosion resistance of cast irons and titanium alloys as reference engineered metal barriers for use in basalt geologic storage: a literature assessment

    SciTech Connect

    Charlot, L.A.; Westerman, R.E.

    1981-07-01

    A survey and assessment of the literature on the corrosion resistance of cast irons and low-alloy titanium are presented. Selected engineering properties of cast iron and titanium are briefly described; however, the corrosion resistance of cast iron and titanium in aqueous solutions or in soils and their use in a basalt repository are emphasized. In evaluating the potential use of cast iron and titanium as structural barrier materials for long-lived nuclear waste packages, it is assumed that titanium has the general corrosion resistance to be used in relatively thin cross sections whereas the cost and availability of cast iron allows its use even in very thick cross sections. Based on this assumption, the survey showed that: The uniform corrosion of low-alloy titanium in a basalt environment is expected to be extremely low. A linear extrapolation of general corrosion rates with an added corrosion allowance suggests that a 3.2- to 6.4-mm-thick wall may have a life of 1000 yr. Pitting and crevice corrosion are not likely corrosion modes in basalt ground waters. It is also unlikely that stress corrosion cracking (SCC) will occur in the commercially pure (CP) titanium alloy or in palladiumor molybdenum-alloyed titanium materials. Low-alloy cast irons may be used as barrier metals if the environment surrounding the metal keeps the alloy in the passive range. The solubility of the corrosion product and the semipermeable nature of the oxide film allow significant uniform corrosion over long time periods. A linear extrapolation of high-temperature corrosion rates on carbon steels and corrosion rates of cast irons in soils gives an estimated metal penetration of 51 to 64 mm after 1000 yr. A corrosion allowance of 3 to 5 times that suggests that an acceptable cast iron wall may be from 178 to 305 mm thick. Although they cannot be fully assessed, pitting and crevice corrosion should not affect cast iron due to the ground-water chemistry of basalt.

  17. Preparation of titanium oxide ceramic membranes

    DOEpatents

    Anderson, Marc A.; Xu, Qunyin

    1992-01-01

    A procedure is disclosed for the reliable production of either particulate or polymeric titanium ceramic membranes by a highly constrained sol-gel procedure. The critical constraints in the procedure include the choice of alkyl alcohol solvent, the amount of water and its rate of addition, the pH of the solution during hydrolysis, and the limit of sintering temperature applied to the resulting gels.

  18. Thermal coatings for titanium-aluminum alloys

    NASA Technical Reports Server (NTRS)

    Cunnington, George R.; Clark, Ronald K.; Robinson, John C.

    1993-01-01

    Titanium aluminides and titanium alloys are candidate materials for use in hot structure and heat-shield components of hypersonic vehicles because of their good strength-to-weight characteristics at elevated temperature. However, in order to utilize their maximum temperature capability, they must be coated to resist oxidation and to have a high total remittance. Also, surface catalysis for recombination of dissociated species in the aerodynamic boundary layer must be minimized. Very thin chemical vapor deposition (CVD) coatings are attractive candidates for this application because of durability and very light weight. To demonstrate this concept, coatings of boron-silicon and aluminum-boron-silicon compositions were applied to the titanium-aluminides alpha2 (Ti-14Al-21Nb), super-alpha2 (Ti-14Al-23-Nb-2V), and gamma (Ti-33Al-6Nb-1Ta) and to the titanium alloy beta-21S (Ti-15Mo-3Al-3Nb-0.2Si). Coated specimens of each alloy were subjected to a set of simulated hypersonic vehicle environmental tests to determine their properties of oxidation resistance, surface catalysis, radiative emittance, and thermal shock resistance. Surface catalysis results should be viewed as relative performance only of the several coating-alloy combinations tested under the specific environmental conditions of the LaRC Hypersonic Materials Environmental Test System (HYMETS) arc-plasma-heated hypersonic wind tunnel. Tests were also conducted to evaluate the hydrogen transport properties of the coatings and any effects of the coating processing itself on fatigue life of the base alloys. Results are presented for three types of coatings, which are as follows: (1) a single layer boron silicon coating, (2) a single layer aluminum-boron-silicon coating, and (3) a multilayer coating consisting of an aluminum-boron-silicon sublayer with a boron-silicon outer layer.

  19. Powder processing of hybrid titanium neural electrodes

    NASA Astrophysics Data System (ADS)

    Lopez, Jose Luis, Jr.

    A preliminary investigation into the powder production of a novel hybrid titanium neural electrode for EEG is presented. The rheological behavior of titanium powder suspensions using sodium alginate as a dispersant are examined for optimal slip casting conditions. Electrodes were slip cast and sintered at 950°C for 1 hr, 1000°C for 1, 3, and 6 hrs, and 1050°C for 1 hr. Residual porosities from sintering are characterized using Archimedes' technique and image analysis. The pore network is gel impregnated by submerging the electrodes in electrically conductive gel and placing them in a chamber under vacuum. Gel evaporation of the impregnated electrodes is examined. Electrodes are characterized in the dry and gelled states using impedance spectrometry and compared to a standard silver- silver chloride electrode. Power spectral densities for the sensors in the dry and gelled state are also compared. Residual porosities for the sintered specimens were between 50.59% and 44.81%. Gel evaporation tests show most of the impregnated gel evaporating within 20 min of exposure to atmospheric conditions with prolonged evaporation times for electrodes with higher impregnated gel mass. Impedance measurements of the produced electrodes indicate the low impedance of the hybrid electrodes are due to the increased contact area of the porous electrode. Power spectral densities of the titanium electrode behave similar to a standard silver-silver chloride electrode. Tests suggest the powder processed hybrid titanium electrode's performance is better than current dry contact electrodes and comparable to standard gelled silver-silver chloride electrodes.

  20. Preparation of titanium oxide ceramic membranes

    DOEpatents

    Anderson, M.A.; Xu, Q.

    1992-03-17

    A procedure is disclosed for the reliable production of either particulate or polymeric titanium ceramic membranes by a highly constrained sol-gel procedure. The critical constraints in the procedure include the choice of alkyl alcohol solvent, the amount of water and its rate of addition, the pH of the solution during hydrolysis, and the limit of sintering temperature applied to the resulting gels.