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Sample records for coating hppc system

  1. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S. (Inventor)

    1984-01-01

    A high temperature oxidation resistant, thermal barrier coating system is disclosed for a nickel cobalt, or iron base alloy substrate. An inner metal bond coating contacts the substrate, and a thermal barrier coating covers the bond coating. NiCrAlR, FeCrAlR, and CoCrAlR alloys are satisfactory as bond coating compositions where R=Y or Yb. These alloys contain, by weight, 24.9-36.7% chromium, 5.4-18.5% aluminum, and 0.05 to 1.55% yttrium or 0.05 to 0.53% ytterbium. The coatings containing ytterbium are preferred over those containing yttrium. An outer thermal barrier coating of partial stabilized zirconium oxide (zirconia) which is between 6% and 8%, by weight, of yttrium oxide (yttria) covers the bond coating. Partial stabilization provides a material with superior durability. Partially stabilized zirconia consists of mixtures of cubic, tetragonal, and monoclinic phases.

  2. Thermal barrier coating system

    NASA Technical Reports Server (NTRS)

    Stecura, S.; Leibert, C. H. (Inventor)

    1977-01-01

    A coating system which contains a bond coating and a thermal barrier coating is applied to metal surfaces such as turbine blades and provides both low thermal conductivity and improved adherence when exposed to high temperature gases or liquids. The bond coating contains NiCrAlY and the thermal barrier coating contains a reflective oxide. The reflective oxides ZrO2-Y2O3 and ZrO2-MgO have demonstrated significant utility in high temperature turbine applications.

  3. Multilayer thermal barrier coating systems

    DOEpatents

    Vance, Steven J.; Goedjen, John G.; Sabol, Stephen M.; Sloan, Kelly M.

    2000-01-01

    The present invention generally describes multilayer thermal barrier coating systems and methods of making the multilayer thermal barrier coating systems. The thermal barrier coating systems comprise a first ceramic layer, a second ceramic layer, a thermally grown oxide layer, a metallic bond coating layer and a substrate. The thermal barrier coating systems have improved high temperature thermal and chemical stability for use in gas turbine applications.

  4. Combustion chemical vapor desposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-10-01

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings.

  5. Combustion chemical vapor deposited coatings for thermal barrier coating systems

    SciTech Connect

    Hampikian, J.M.; Carter, W.B.

    1995-12-31

    The new deposition process, combustion chemical vapor deposition, shows a great deal of promise in the area of thermal barrier coating systems. This technique produces dense, adherent coatings, and does not require a reaction chamber. Coatings can therefore be applied in the open atmosphere. The process is potentially suitable for producing high quality CVD coatings for use as interlayers between the bond coat and thermal barrier coating, and/or as overlayers, on top of thermal barrier coatings. In this report, the evaluation of alumina and ceria coatings on a nickel-chromium alloy is described.

  6. Ruthenium-containing bond coats for thermal barrier coating systems

    NASA Astrophysics Data System (ADS)

    Tryon, B.; Cao, F.; Murphy, K. S.; Levi, C. G.; Pollock, T. M.

    2006-01-01

    Bond coats for zirconia-based thermal barrier coating systems applied to nickel-based superalloys are typically composed of the B2 NiAl phase. Since RuAl has the same B2 crystal structure but a melting point 400°C higher than NiAl, ruthenium-modified aluminide bond coats could provide improved system temperature capability. Creep experiments on ternary Al-Ni-Ru alloys demonstrate greatly improved creep properties with increasing ruthenium content. Processing paths for ruthenium-modified NiAl-based bond coatings have been established within the bounds of commercially available coating systems. The oxidation resistance of ruthenium-modified bond coats during thermal cycling has been examined, and potential thermal barrier coating system implications are discussed.

  7. Active coatings technologies for tailorable military coating systems

    NASA Astrophysics Data System (ADS)

    Zunino, J. L., III

    2007-04-01

    The main objective of the U.S. Army's Active Coatings Technologies Program is to develop technologies that can be used in combination to tailor coatings for utilization on Army Materiel. The Active Coatings Technologies Program, ACT, is divided into several thrusts, including the Smart Coatings Materiel Program, Munitions Coatings Technologies, Active Sensor packages, Systems Health Monitoring, Novel Technology Development, as well as other advanced technologies. The goal of the ACT Program is to conduct research leading to the development of multiple coatings systems for use on various military platforms, incorporating unique properties such as self repair, selective removal, corrosion resistance, sensing, ability to modify coatings' physical properties, colorizing, and alerting logistics staff when tanks or weaponry require more extensive repair. A partnership between the U.S. Army Corrosion Office at Picatinny Arsenal, NJ along with researchers at the New Jersey Institute of Technology, NJ, Clemson University, SC, University of New Hampshire, NH, and University of Massachusetts (Lowell), MA, are developing the next generation of Smart Coatings Materiel via novel technologies such as nanotechnology, Micro-electromechanical Systems (MEMS), meta-materials, flexible electronics, electrochromics, electroluminescence, etc. This paper will provide the reader with an overview of the Active Coatings Technologies Program, including an update of the on-going Smart Coatings Materiel Program, its progress thus far, description of the prototype Smart Coatings Systems and research tasks as well as future nanotechnology concepts, and applications for the Department of Defense.

  8. Industrial laser-based coatings removal systems

    NASA Astrophysics Data System (ADS)

    Freiwald, David A.; Peebles, Henry C.; Case, Roger P.

    1998-09-01

    Industrial-cleaning-rate laser systems have been built and tested for removing various types of coatings, such as rad- contaminated coatings, non-rad but hazmat-contaminated coatings (e.g., Pb-based paint), and non-hazardous coatings from various types of substrates such as concrete, metals, and composite materials.

  9. Chrome - Free Aluminum Coating System

    NASA Technical Reports Server (NTRS)

    Bailey, John H.; Gugel, Jeffrey D.

    2010-01-01

    This slide presentation concerns the program to qualify a chrome free coating for aluminum. The program was required due to findings by OSHA and EPA, that hexavalent chromium, used to mitigate corrosion in aerospace aluminum alloys, poses hazards for personnel. This qualification consisted of over 4,000 tests. The tests revealed that a move away from Cr+6, required a system rather than individual components and that the maximum corrosion protection required pretreatment, primer and topcoat.

  10. Armor systems including coated core materials

    SciTech Connect

    Chu, Henry S.; Lillo, Thomas M.; McHugh, Kevin M.

    2012-07-31

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  11. Armor systems including coated core materials

    SciTech Connect

    Chu, Henry S; Lillo, Thomas M; McHugh, Kevin M

    2013-10-08

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  12. Metallic seal for thermal barrier coating systems

    NASA Technical Reports Server (NTRS)

    Miller, Robert A. (Inventor)

    1990-01-01

    The invention is particularly concerned with sealing thermal barrier coating systems of the type in use and being contemplated for use in diesel and other internal combustion engines. The invention also would find application in moderately high temperature regions of gas turbine engines and any other application employing a thermal barrier coating at moderate temperatures. Ni-35Cr-6Al-1Y, Ni-35Cr-6Al-1Yb, or other metallic alloy denoted as MCrAlx is applied over a zirconia-based thermal barrier overlayer. The close-out layer is glass-bead preened to densify its surface. This seals and protects the thermal barrier coating system.

  13. 7 CFR 3201.98 - Wastewater systems coatings.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 15 2013-01-01 2013-01-01 false Wastewater systems coatings. 3201.98 Section 3201.98... Designated Items § 3201.98 Wastewater systems coatings. (a) Definition. Coatings that protect wastewater... procurement preference for qualifying biobased wastewater systems coatings. By that date, Federal...

  14. 7 CFR 3201.98 - Wastewater systems coatings.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 15 2014-01-01 2014-01-01 false Wastewater systems coatings. 3201.98 Section 3201.98... Designated Items § 3201.98 Wastewater systems coatings. (a) Definition. Coatings that protect wastewater... procurement preference for qualifying biobased wastewater systems coatings. By that date, Federal...

  15. The Discovery Channel Telescope optical coating system

    NASA Astrophysics Data System (ADS)

    Marshall, Heather K.; Ash, Gary S.; Parsley, William F.

    2010-07-01

    The Discovery Channel Telescope (DCT) is a project of Lowell Observatory, undertaken with support from Discovery Communications, Inc., to design and construct a 4-meter class telescope and support facility on a site approximately 40 miles southeast of Flagstaff, AZ. Lowell Observatory contracted with Dynavac of Hingham, MA to design and build an optical coating system for the DCT optics. The DCT Optical Coating System includes a mechanical roughing pump, two high-vacuum cryogenic pumps, a Meissner trap, evaporative filament aluminum deposition system, LabView software and PLC-based control system, and all ancillary support equipment. The system was installed at the site and acceptance testing was completed in October 2009. The Optical Coating System achieved near perfect reflectivity performance, thickness uniformity of 1000 angstroms +/-10%, and adhesion conforming to MIL-F-48616, Section 4.6.8.1. This paper discusses the design and analysis of the coating system, the process of transportation and assembly as well as testing results.

  16. Optics and multilayer coatings for EUVL systems

    SciTech Connect

    Soufli, R; Bajt, S; Hudyma, R M; Taylor, J S

    2008-03-21

    EUV lithography (EUVL) employs illumination wavelengths around 13.5 nm, and in many aspects it is considered an extension of optical lithography, which is used for the high-volume manufacturing (HVM) of today's microprocessors. The EUV wavelength of illumination dictates the use of reflective optical elements (mirrors) as opposed to the refractive lenses used in conventional lithographic systems. Thus, EUVL tools are based on all-reflective concepts: they use multilayer (ML) coated optics for their illumination and projection systems, and they have a ML-coated reflective mask.

  17. Thermal barrier coating for alloy systems

    DOEpatents

    Seals, Roland D.; White, Rickey L.; Dinwiddie, Ralph B.

    2000-01-01

    An alloy substrate is protected by a thermal barrier coating formed from a layer of metallic bond coat and a top coat formed from generally hollow ceramic particles dispersed in a matrix bonded to the bond coat.

  18. Engineered coating systems protect meters, station piping

    SciTech Connect

    Not Available

    1986-03-01

    This paper describes how the Gas Division of the Colorado Springs, Colorado Department of Public Utilities has cut the frequency of painting exposed pipe, valves and associated equipment at the five gate metering stations, as well as distribution stations within the city and manifold stations where natural gas is distributed to nearby Ft. Carson and the U.S. Air Force Academy. Because of tourism in these areas, the city is very conscious of the appearance it presents. The Gas Division selected New Color Horizons coatings made by the Rust-Oleum Corp. They have cut down on maintenance costs and their facilities still have an excellent appearance. Greater coating durability was obtained through a system consisting of shop-applied enamel finish and a color-matched fast-drying aerosol spray coating to resist corrosion and the elements.

  19. ETV Program Report: Coatings for Wastewater Collection Systems - Standard Cement Materials, Epoxy Coating 4553

    EPA Science Inventory

    The Standard Cement Materials, Inc. Standard Epoxy Coating 4553™ (SEC 4553) epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Ma...

  20. Pentek metal coating removal system: Baseline report

    SciTech Connect

    1997-07-31

    The Pentek coating removal technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek coating removal system consisted of the ROTO-PEEN Scaler, CORNER-CUTTER{reg_sign}, and VAC-PAC{reg_sign}. They are designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M Roto Peen tungsten carbide cutters while the CORNER-CUTTER{reg_sign} uses solid needles for descaling activities. These hand tools are used with the VAC-PAC{reg_sign} vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure minimal, but noise exposure was significant. Further testing for each exposure is recommended because of the environment where the testing demonstration took place. It is feasible that the dust and noise levels will be higher in an enclosed operating environment of different construction. In addition, other areas of concern found were arm-hand vibration, whole-body, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout.

  1. Article Including Environmental Barrier Coating System

    NASA Technical Reports Server (NTRS)

    Lee, Kang N. (Inventor)

    2015-01-01

    An enhanced environmental barrier coating for a silicon containing substrate. The enhanced barrier coating may include a bond coat doped with at least one of an alkali metal oxide and an alkali earth metal oxide. The enhanced barrier coating may include a composite mullite bond coat including BSAS and another distinct second phase oxide applied over said surface.

  2. Near-infrared radiation curable multilayer coating systems and methods for applying same

    DOEpatents

    Bowman, Mark P; Verdun, Shelley D; Post, Gordon L

    2015-04-28

    Multilayer coating systems, methods of applying and related substrates are disclosed. The coating system may comprise a first coating comprising a near-IR absorber, and a second coating deposited on a least a portion of the first coating. Methods of applying a multilayer coating composition to a substrate may comprise applying a first coating comprising a near-IR absorber, applying a second coating over at least a portion of the first coating and curing the coating with near infrared radiation.

  3. Overlay metallic-cermet alloy coating systems

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.; Levine, S. R.; Glasgow, T. K. (Inventor)

    1984-01-01

    A substrate, such as a turbine blade, vane, or the like, which is subjected to high temperature use is coated with a base coating of an oxide dispersed, metallic alloy (cermet). A top coating of an oxidation, hot corrosion, erosion resistant alloy of nickel, cobalt, or iron is then deposited on the base coating. A heat treatment is used to improve the bonding. The base coating serves as an inhibitor to interdiffusion between the protective top coating and the substrate. Otherwise, the protective top coating would rapidly interact detrimentally with the substrate and degrade by spalling of the protective oxides formed on the outer surface at elevated temperatures.

  4. Advanced coating lining systems for challenging chemical environments

    SciTech Connect

    Brupbacher, J.M.; Stiles, J.E.

    1997-08-01

    Advanced coatings and coating lining systems are being increasingly used by industry to protect process equipment in challenging chemical environments. This includes not only severe corrosive liquors encountered in many Chemical Process Industry streams, but also the high purity process liquors and rinse systems of the pharmaceutical and microelectronics industries. This paper discusses the design options for optimizing the performance of fluoropolymer-based coating systems for industry-specific applications such as these. Design factors discussed will include surface pre-treatment options, chemical and mechanical bonding systems, field-proven and advanced polymer barrier coatings, homogeneous and graded polymer barrier stacks, and imbedded permeation barriers. The processing techniques for applying engineered coatings will be discussed since processing also plays an important role in the design options available to individual coating applicators and ultimate performance of the coating system applied. Several case studies will be presented and discussed.

  5. Magnetron co-sputtering system for coating ICF targets

    SciTech Connect

    Hsieh, E.J.; Meyer, S.F.; Halsey, W.G.; Jameson, G.T.; Wittmayer, F.J.

    1981-09-09

    Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres.

  6. Advanced thermal barrier coating system development. Technical progress report, June 1, 1996--July 31, 1996

    SciTech Connect

    1996-08-07

    An improved thermal barrier coating system with good reliability and thermal performance is described. The report discusses the coating process, manufacturing, repair, deposition, and microstructure of the coatings.

  7. Thermophysical and Thermomechanical Properties of Thermal Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    2000-01-01

    Thermal barrier coatings have been developed for advanced gas turbine and diesel engine applications to improve engine reliability and fuel efficiency. However, the issue of coating durability under high temperature cyclic conditions is still of major concern. The coating failure is closely related to thermal stresses and oxidation in the coating systems. Coating shrinkage cracking resulting from ceramic sintering and creep at high temperatures can further accelerate the coating failure process. The purpose of this paper is to address critical issues such as ceramic sintering and creep, thermal fatigue and their relevance to coating life prediction. Novel test approaches have been established to obtain critical thermophysical and thermomechanical properties of the coating systems under near-realistic temperature and stress gradients encountered in advanced engine systems. Emphasis is placed on the dynamic changes of the coating thermal conductivity and elastic modulus, fatigue and creep interactions, and resulting failure mechanisms during the simulated engine tests. Detailed experimental and modeling results describing processes occurring in the thermal barrier coating systems provide a framework for developing strategies to manage ceramic coating architecture, microstructure and properties.

  8. Formulation and production of intumescent coating systems

    NASA Technical Reports Server (NTRS)

    Hoffman, J.; Schwartz, H. R.

    1973-01-01

    Methods for manufacturing and producing fire protective intumescent coatings are described. The coatings consist of three reactive parts mixed together at the time of use. The chemical composition of the reactive parts is discussed. The characteristics of the coatings which are obtained by three types of processing are analyzed. Qualification tests of the materials to determine acceptability are reported.

  9. Thermal and Environmental Barrier Coatings for Advanced Propulsion Engine Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Miller, Robert A.

    2004-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. For future high performance engines, the development of advanced ceramic barrier coating systems will allow these coatings to be used to simultaneously increase engine operating temperature and reduce cooling requirements, thereby leading to significant improvements in engine power density and efficiency. In order to meet future engine performance and reliability requirements, the coating systems must be designed with increased high temperature stability, lower thermal conductivity, and improved thermal stress and erosion resistance. In this paper, ceramic coating design and testing considerations will be described for high temperature and high-heat-flux engine applications in hot corrosion and oxidation, erosion, and combustion water vapor environments. Further coating performance and life improvements will be expected by utilizing advanced coating architecture design, composition optimization, and improved processing techniques, in conjunction with modeling and design tools.

  10. The effect of microstructure at interface between coating and substrate on damping capacity of coating systems

    NASA Astrophysics Data System (ADS)

    Wang, Xueqin; Pei, Yanling; Ma, Yue

    2013-10-01

    Samples with various interface microstructures between the coating and the substrate were designed and fabricated in this paper. Dynamic mechanical thermal analyzer (DMTA) was utilized to investigate the dynamic mechanical properties of the samples and scanning electron microscopy (SEM) was used to observe the interface microstructure between the substrate and coating. The effect of the interface microstructure on damping was studied, and results indicated that the larger the coating/substrate interface thickness was and the more interface defects were, the higher interface system damping was. When the micro-hardness ratio of substrate to coating was increased, the damping of coating system was enhanced. The effect of the APS and EB-PVD coating on damping capacity was investigated. There was a dramatic increase in the damping value of the APS coating when the strain was higher than 20 ppm, while the damping amplitude effect of the EB-PVD coating was not so obvious, which could mainly be caused by the different energy dissipation mechanisms of the two coatings.

  11. Degradation and Failure Characteristics of NPP Containment Protective Coating Systems

    SciTech Connect

    Sindelar, R.L.

    2001-02-22

    A research program to investigate the performance and potential for debris formation of Service Level I coating systems used in nuclear power plant containment is being performed at the Savannah River Technology Center. The research activities are aligned to address phenomena important to cause coating disbondment as identified by the Industry Coatings Expert Panel. The period of interest for performance covers the time from application of the coating through 40 years of service, followed by a medium-to-large break loss-of-coolant accident scenario, which is a design basis accident (DBA) scenario. The interactive program elements are described in this report and the application of these elements to evaluate the performance of the specific coating system of Phenoline 305 epoxy-phenolic topcoat over Carbozinc 11 primer on a steel substrate. This system is one of the predominant coating systems present on steel substrates in NPP containment.

  12. Coated armor system and process for making the same

    DOEpatents

    Chu, Henry S.; Lillo, Thomas M.; McHugh, Kevin M.

    2010-11-23

    An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

  13. Failure Mechanism for Thermal Fatigue of Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Giolli, C.; Scrivani, A.; Rizzi, G.; Borgioli, F.; Bolelli, G.; Lusvarghi, L.

    2009-06-01

    Thick thermal barrier coatings (TBCs), consisting of a CoNiCrAlY bond coat and yttria-partially stabilized zirconia top coat with different porosity values, were produced by air plasma spray (APS). The thermal fatigue resistance limit of the TBCs was tested by furnace cycling tests (FCT) according to the specifications of an original equipment manufacturer (OEM). The morphology, residual stresses, and micromechanical properties (microhardness, indentation fracture toughness) of the TBC systems before and after FCT were analyzed. The thermal fatigue resistance increases with the amount of porosity in the top coat. The compressive in-plane stresses increase in the TBC systems after thermal cycling; nevertheless the increasing rate has a trend contrary to the porosity level of top coat. The data suggest that the spallation happens at the TGO/top coat interface. The failure mechanism of thick TBCs was found to be similar to that of conventional thin TBC systems made by APS.

  14. Magnetron co-sputtering system for coating ICF targets

    SciTech Connect

    Hsieh, E.J.; Meyer, S.F.; Halsey, W.G.; Jameson, G.T.; Wittmayer, F.J.

    1981-12-09

    Fabrication of Inertial Confinement Fusion (ICF) targets requires deposition of various types of coatings on microspheres. The mechanical strength, and surface finish of the coatings are of concern in ICF experiments. The tensile strength of coatings can be controlled through grain refinement, selective doping and alloy formation. We have constructed a magnetron co-sputtering system to produce variable density profile coatings with high tensile strength on microspheres. The preliminary data on the properties of a Au-Cu binary alloy system by SEM and STEM analysis is presented.

  15. Field repair of coated columbium Thermal Protection System (TPS)

    NASA Technical Reports Server (NTRS)

    Culp, J. D.

    1972-01-01

    The requirements for field repair of coated columbian panels were studied, and the probable cause of damage were identified. The following types of repair methods were developed, and are ready for use on an operational system: replacement of fused slurrey silicide coating by a short processing cycle using a focused radiant spot heater; repair of the coating by a glassy matrix ceramic composition which is painted or sprayed over the defective area; and repair of the protective coating by plasma spraying molybdenum disilicide over the damaged area employing portable equipment.

  16. Coated columbium thermal protection systems: An assessment of technological readiness

    NASA Technical Reports Server (NTRS)

    Levine, S. R.; Grisaffe, S. J.

    1973-01-01

    Evaluation and development to date show that of the coated columbium alloys FS-85 coated with R512E shows significant promise for a reusable thermal protection system (TPS) as judged by environmental resistance and the retention of mechanical properties and structural integrity of panels upon repeated reentry simulation. Production of the alloy, the coating, and full-sized TPS panels is well within current manufacturing technology. Small defects which arise from impact damage or from local coating breakdown do not appear to have serious immediate consequences in the use environment anticipated for the space shuttle orbiter TPS.

  17. Evaluation of Oxidation Damage in Thermal Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.

    1996-01-01

    A method based on the technique of dilatometry has been established to quantitatively evaluate the interfacial damage due to the oxidation in a thermal barrier coating system. Strain isolation and adhesion coefficients have been proposed to characterize the thermal barrier coating (TBC) performance based on its thermal expansion behavior. It has been found that, for a thermal barrier coating system consisting of ZrO2-8%Y2O3/FeCrAlY/4140 steel substrate, the oxidation of the bond coat and substrate significantly reduced the ceramic coating adherence, as inferred from the dilatometry measurements. The in-situ thermal expansion measurements under 30 deg C to 700 deg C thermal cycling in air showed that the adhesion coefficient, A(sub i) decreased by 25% during the first 35 oxidation cycles. Metallography showed that delamination occurred at both the ceramic/bond coat and bond coat/substrate interfaces. In addition, the strain isolation effect has been improved by increasing the FeCrAlY bond coat thickness. The strain isolation coefficient, Si, increased from about 0.04 to 0.25, as the bond coat thickness changed from 0.1 mm to 1.0 mm. It may be possible to design optimum values of strain isolation and interface adhesion coefficients to achieve the best TBC performance.

  18. Modeling of thermal stresses in elastic multilayer coating systems

    NASA Astrophysics Data System (ADS)

    Gao, Chunxue; Zhao, Zhiwei; Li, Xuehua

    2015-02-01

    The performance and reliability of multilayer coating systems are strongly influenced by thermal stresses. The present study develops an alternative analytical model to predict the thermal stresses in elastic multilayer coating systems. An exact closed-form solution is obtained which is independent of the number of coating layers. In addition, with the definition of the coordinate system, the closed-form solution is concisely formulated. Specific results are calculated for thermal stresses in HfO2/SiO2 multilayer optical coatings, and a finite element analysis is performed to confirm the analytical results. The two results agree fairly well with each other. Also, when the thicknesses of the coating layers are much less than the substrate thickness, the approximate solution is obtained based on the exact closed-form solution, and its accuracy is examined.

  19. Evaluation of several corrosion protective coating systems on aluminum

    NASA Technical Reports Server (NTRS)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  20. 14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. VIEW OF VACUUM COATING CHAMBER. THE SYSTEM USED TITANIUM VAPORS TO DEPOSIT TITANIUM COATING ONTO URANIUM PARTS UNDER A VACUUM. (1/11/83) - Rocky Flats Plant, Non-Nuclear Production Facility, South of Cottonwood Avenue, west of Seventh Avenue & east of Building 460, Golden, Jefferson County, CO

  1. Degradation and Failure Characteristics of NPP Containment Protective Coating Systems

    SciTech Connect

    Sindelar, R.L.

    2000-12-01

    A research program to investigate the performance and potential for failure of Service Level I coating systems used in nuclear power plant containment is in progress. The research activities are aligned to address phenomena important to cause failure as identified by the industry coatings expert panel.

  2. Corrosion Behavior of an Abradable Seal Coating System

    NASA Astrophysics Data System (ADS)

    Zhang, Feng; Xu, Cunguan; Lan, Hao; Huang, Chuanbing; Zhou, Yang; Du, Lingzhong; Zhang, Weigang

    2014-08-01

    A novel NiTi/BN composite abradable coating and two traditional Ni/C and Ni/BN coatings were manufactured with NiAl as the bond layer using thermal spray technology and their corrosion behaviors were investigated. In salt spray corrosion testing of the Ni/BN coating, defective sites of the metal matrix were corroded preferentially. Simulated occlusion experiments and electrochemical tests indicated that migration of ions resulted in pH decrease and Cl- enrichment in defects, and a more aggressive electrolyte led to a decrease of the corrosion potential of the metal inside defects but an increase of the corrosion current density, representing an autocatalytic corrosion process. Moreover, galvanic corrosion between the top and bond coatings of the abradable system was studied via the electrochemical technique. The results showed that, for the NiTi/BN, Ni/BN, and Ni/graphite coatings with a NiAl bond coating, current flow was generated between the anode and cathode. The NiTi/BN coating acted as the cathode due to its passivation, while the Ni/BN and Ni/graphite coatings acted as the anode because of their lower corrosion potential compared with the NiAl coating. The anode suffered serious corrosion damage due to galvanic corrosion, while the cathode corroded only slightly.

  3. Coatings.

    ERIC Educational Resources Information Center

    Anderson, Dennis G.

    1989-01-01

    This review covers analytical techniques applicable to the examination of coatings, raw materials, and substrates upon which coatings are placed. Techniques include chemical and electrochemical methods, chromatography, spectroscopy, thermal analysis, microscopy, and miscellaneous techniques. (MVL)

  4. Pegasus International, Inc. coating removal systems

    SciTech Connect

    1998-02-01

    The Pegasus Coating Removal System (PCRS) was demonstrated at Florida International University (FIU) where it was being evaluated for efficiency and cost. In conjunction with the FIU testing demonstration, a human factors assessment was conducted to assess the hazards and associated safety and health issues of concern for workers utilizing this technology. The PCRS is a chemical paste that is applied to the surface using a brush, roller, or airless sprayer. After the type of PCRS, thickness, and dwell time have been determined, a laminated backed material is placed on top of the chemical paste to slow down the drying process and to provide a mechanism to strip-off the chemical. After the dwell time is reached, the chemical substrate can be removed. Scrapers may be used to break-loose the layers as necessary or to break-loose the layers that are not removed when the laminated paper is picked up. Residue may also be cleaned off of the surface with a damp sponge with an agitating motion, absorbent sponges, or a vacuum, as needed. The paint and removal agent is then placed in drums for disposal at a later time. During the assessment sampling was conducted for organic vapors and general observational techniques were conducted for ergonomics. Recommendations for improved worker safety and health during application and removal of the PCRS include: (1) work practices that reflect avoidance of exposure or reducing the risk of exposure; (2) assuring all PPE and equipment are compatible with the chemicals being used; (3) work practices that reduce the worker`s need to walk on the slippery surface caused by the chemical or the use of special anti-slip soles; (4) careful control of overspray (if a spray application is used); and (5) the use of ergonomically designed long-handled tools to apply and remove the chemical (to alleviate some of the ergonomic concerns).

  5. Thermal certification tests of Orbiter Thermal Protection System tiles coated with KSC coating slurries

    NASA Technical Reports Server (NTRS)

    Milhoan, James D.; Pham, Vuong T.; Sherborne, William D.

    1993-01-01

    Thermal tests of Orbiter thermal protection system (TPS) tiles, which were coated with borosilicate glass slurries fabricated at Kennedy Space Center (KSC), were performed in the Radiant Heat Test Facility and the Atmospheric Reentry Materials & Structures Evaluation Facility at Johnson Space Center to verify tile coating integrity after exposure to multiple entry simulation cycles in both radiant and convective heating environments. Eight high temperature reusable surface insulation (HRSI) tiles and six low temperature reusable surface insulation (LRSI) tiles were subjected to 25 cycles of radiant heat at peaked surface temperatures of 2300 F and 1200 F, respectively. For the LRSI tiles, an additional cycle at peaked surface temperature of 2100 F was performed. There was no coating crack on any of the HRSI specimens. However, there were eight small coating cracks (less than 2 inches long) on two of the six LRSI tiles on the 26th cycle. There was practically no change on the surface reflectivity, physical dimensions, or weight of any of the test specimens. There was no observable thermal-chemical degradation of the coating either. For the convective heat test, eight HRSI tiles were tested for five cycles at a surface temperature of 2300 F. There was no thermal-induced coating crack on any of the test specimens, almost no change on the surface reflectivity, and no observable thermal-chemical degradation with an exception of minor slumping of the coating under painted TPS identification numbers. The tests demonstrated that KSC's TPS slurries and coating processes meet the Orbiter's thermal specification requirements.

  6. Dual- and triple-band AR coatings for IR systems

    NASA Astrophysics Data System (ADS)

    Cohen, Daniel; Stolov, Yevgeni; Azran, Amnon; Gilo, Mordechai

    2013-06-01

    Dual-band infrared camera systems allow viewing and comparison of the 3-5µ and 8-12µ spectrum regions, improve visibility at sunrise/sunset and help distinguish between targets and decoys. They also enhance the ability to defeat many IR countermeasures such as smoke, camouflage and flares. As dual band 3rd generation FLIR systems progress, we introduce coatings for these systems. This paper describes advanced dual band coatings for the 3-5µ and 8-12µ spectrum regions, with reference to single band coatings. Theoretical and measured designs are shown for ZnSe, ZnS, Ge and IG-6 substrates. Triple band AR coatings with additional transmittance at 1.06µ are also demonstrated.

  7. Degradation and failure characteristics of NPP containment protective coating systems

    SciTech Connect

    Sindelar, R.L.

    2000-03-30

    A research program to investigate the performance and potential for failure of Service Level 1 coating systems used in nuclear power plant containment is in progress. The research activities are aligned to address phenomena important to cause failure as identified by the industry coatings expert panel. The period of interest for performance covers the time from application of the coating through 40 years of service, followed by a medium-to-large break loss-of-coolant accident scenario, which is a design basis accident (DBA) scenario. The interactive program elements are discussed in this report and the application of these elements to the System 5 coating system (polyamide epoxy primer, carbon steel substrate) is used to evaluate performance.

  8. Reproducibility of electrochemical noise data from coated metal systems

    SciTech Connect

    Bierwagen, G.P.; Mills, D.J.; Tallman, D.E.; Skerry, B.S.

    1996-12-31

    The use of electrochemical noise (ECN) as a method to characterize the corrosion-protection properties of organic coatings on metal substrates was pioneered by Skerry and Eden, and since then has been used by others as a probe for coating metal corrosion studies. However, no statistical examination of the reproducibility of the data from such measurements has been published. In the data the authors present, they have done a systematic analysis of important experimental variables in such systems. They have examined the method for accuracy and reproducibility with respect to sample preparation, sample immersion, and metal substrate preparation. They have taken several marine coatings systems typical of US Navy use, prepared duplicate samples of coating metal systems, and examined them under the same immersion exposure. The variables they considered for reproducibility are paint application (in three-coat systems), metal panel preparation (grit-blasted steel), and immersion conditions. The authors present ECN data with respect to immersion time on the values of noise voltage standard deviation {sigma}{sub V}, noise current standard deviation {sigma}{sub I}, and the noise resistance R{sub n} as given by {sigma}{sub V}/{sigma}{sub I}. The variation among supposedly identical sample pairs in identical immersion monitored under identical conditions is presented. The statistics of the time records of the data are considered, and the variations with respect to specific coatings classes are also considered within the limits of the data. Based on these data, comments concerning ECN on coated metal systems as a predictive test method are presented along with special considerations that must be made to properly use the method for coating ranking and lifetime prediction.

  9. Physicochemical characterization and failure analysis of military coating systems

    NASA Astrophysics Data System (ADS)

    Keene, Lionel Thomas

    Modern military coating systems, as fielded by all branches of the U.S. military, generally consist of a diverse array of organic and inorganic components that can complicate their physicochemical analysis. These coating systems consist of VOC-solvent/waterborne automotive grade polyurethane matrix containing a variety of inorganic pigments and flattening agents. The research presented here was designed to overcome the practical difficulties regarding the study of such systems through the combined application of several cross-disciplinary techniques, including vibrational spectroscopy, electron microscopy, microtomy, ultra-fast laser ablation and optical interferometry. The goal of this research has been to determine the degree and spatial progression of weathering-induced alteration of military coating systems as a whole, as well as to determine the failure modes involved, and characterizing the impact of these failures on the physical barrier performance of the coatings. Transmission-mode Fourier Transform Infrared (FTIR) spectroscopy has been applied to cross-sections of both baseline and artificially weathered samples to elucidate weathering-induced spatial gradients to the baseline chemistry of the coatings. A large discrepancy in physical durability (as indicated by the spatial progression of these gradients) has been found between older and newer generation coatings. Data will be shown implicating silica fillers (previously considered inert) as the probable cause for this behavioral divergence. A case study is presented wherein the application of the aforementioned FTIR technique fails to predict the durability of the coating system as a whole. The exploitation of the ultra-fast optical phenomenon of femtosecond (10-15S) laser ablation is studied as a potential tool to facilitate spectroscopic depth profiling of composite materials. Finally, the interferometric technique of Phase Shifting was evaluated as a potential high-sensitivity technique applied to the

  10. System for NDE of thermal spray coating bonds

    SciTech Connect

    Green, D.R.; Wandling, C.R.; Gatto, F.B.; Rogers, F.S.

    1984-09-01

    A nondestructive testing system that is especially well suited to NDE of bonds between coatings and substrates has been developed. It injects heat into the test specimen surface from a hot gas pulse and detects and other coating problems by means of an emissivity independent infrared scanning method. This method is very practical and has been proven in numerous demonstrations. It is the only method known by the authors to be applicable to such a wide variety of coatings. Qualitative correlation between bond strength and scan results from the system was demonstrated on one small group of test specimens. Due to its emissivity independence, the method yields results that are, in many cases, far superior to other infrared-thermal NDE methods. It can be applied to coatings having tough surfaces, and no physical contact with the test specimen is required.

  11. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we coated coupons of selected alloy steels with diffusion coatings of Cr and Al, as well as with titanium and tantalum nitrides. The coated samples were analyzed for their surface composition. In several instances, the samples were also cut to determine the depth profile of the coating. Several of the early runs did not yield uniform or deep enough coatings and hence a significant portion of the effort in this period was devoted fixing the problems with our fluidized bed reactor. Before the end of the quarter we had prepared a number of samples, many of them in duplicates, and sent one set to Wabash River Energy Laboratory for them to install in their gasifier. The gasifier was undergoing a scheduled maintenance and thus presented an opportunity to place some of our coupons in the stream of an operating gasifier. The samples submitted included coated and uncoated pairs of different alloys.

  12. Numerical Study of a Four-Roll Coating System

    NASA Astrophysics Data System (ADS)

    Tsuda, Takeaki

    The characteristics of a four-roll coating system were numerically investigated and compared with experimental data to validate the theoretical models used in this study. In the theoretical models, a film splitting model using a power-law-type equation, a roll-gap model based on elastohydrodynamics, and a flow model from a rotating-cylinder system were applied. The parametric computations for each operational condition revealed the steady and dynamic behaviors of a coating film and liquid films on the coating rolls. The results of the frequency response to the speed disturbances of the coating rolls indicated that the sensitivity of the lowest coating roll to the disturbance was half that of the others; this implies that the requirement for the accuracy of a driving system of the coating roll is not as severe as compared with others. The experimental data and the numerical results at steady state agreed well. Therefore, the theoretical models used in this research were found to be appropriate.

  13. Evaluation of thermal barrier coating systems on novel substrates

    NASA Astrophysics Data System (ADS)

    Pint, B. A.; Wright, I. G.; Brindley, W. J.

    2000-06-01

    Testing was conducted on both plasma-sprayed (PS) and electron beam-physical vapor deposited (EB-PVD) Y2O3-stabilized ZrO2 (YSZ) thermal barrier coatings (TBCs) applied directly to oxidation-resistant substrates such as β-NiAl, oxide-dispersed FeCrAl, and NiCr. On an alloy that forms a very adherent alumina scale, β-NiAl+Zr, the coating lifetime of YSZ in furnace cyclic tests was 6 or more times longer than on state-of-the-art, YSZ coatings on single-crystal Ni-base superalloys with MCrAlY or Pt aluminide bond coats. Coatings on FeCrAl alloys appear to be a viable option for applications such as the external skin of the X-33, single stage to orbit, reusable launch vehicle. Model chromia-forming bond coat compositions also show promise for power generation applications at temperatures where hot corrosion may be a major problem. In general, while this work examined unique materials systems, many of the same fundamental failure mechanisms observed in conventional TBCs were observed.

  14. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. A review of the literature indicated that the Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. We selected diffusion coatings of Cr and Al, and surface coatings of Si and Ti for the preliminary testing. These coatings will be applied using the fluidized bed chemical vapor deposition technique developed at SRI which is rapid and relatively inexpensive. We have procured coupons of typical alloys used in a gasifier. These coupons will be coated with Cr, Al, Si, and Ti. The samples will be tested in a bench-scale reactor using simulated coal gas compositions. In addition, we will be sending coated samples for insertion in the gas stream of the coal gasifier.

  15. Ceramic coating system or water oxidation environments

    DOEpatents

    Hong, Glenn T.

    1996-01-01

    A process for water oxidation of combustible materials in which during at least a part of the oxidation corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises titanium dioxide coated onto a titanium metal substrate. Such ceramic composites have been found to be highly resistant to environments encountered in the process of supercritical water oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases, and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 700.degree. C. The ceramic composites are also resistant to degradation mechanisms caused by thermal stresses.

  16. Ceramic coating system for water oxidation environments

    SciTech Connect

    Hong, G.T.

    1996-08-13

    A process is described for water oxidation of combustible materials in which at least a part of the oxidation corrosive material is present and makes contact with at least a portion of the apparatus over a contact area on the apparatus. At least a portion of the contact surface area comprises titanium dioxide coated onto a titanium metal substrate. Such ceramic composites have been found to be highly resistant to environments encountered in the process of supercritical water oxidation. Such environments typically contain greater than 50 mole percent water, together with oxygen, carbon dioxide, and a wide range of acids, bases, and salts. Pressures are typically about 27.5 to about 1000 bar while temperatures range as high as 700 C. The ceramic composites are also resistant to degradation mechanisms caused by thermal stresses. 2 figs.

  17. Advanced thermal barrier coating system development. Technical progress report

    SciTech Connect

    1996-10-04

    The objectives of the program are to provide an improved TBC system with increased temperature capability and improved reliability relative to current state of the art TBC systems. The development of such a coating system is essential to the ATS engine meeting its objectives. The base program consists of three phases: Phase 1: Program Planning--Complete; Phase 2: Development; Phase 3: Selected Specimen--Bench Test. Work is currently being performed in Phase 2 of the program. In Phase 2, process improvements will be married with new bond coat and ceramic materials systems to provide improvements over currently available TBC systems. Coating reliability will be further improved with the development of an improved lifing model and NDE techniques. This will be accomplished by conducting the following program tasks: II.1 Process Modeling; II.2 Bond Coat Development; II.3 Analytical Lifing Model; II.4 Process Development; II.5 NDE, Maintenance and Repair; II.6 New TBC Concepts. A brief summary of progress made in each of these 6 areas is given.

  18. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-03-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we conducted two exposure tests with coated and uncoated coupons. The first one was aborted after a short period, because of a leak in the pressure regulator of a CO/CO{sub 2}/H{sub 2} gas mixture gas cylinder that was used to prepare the simulated coal gas stream. Nevertheless, this run was very instructive as it showed that during the brief exposure when the concentration of H{sub 2}S increased to 8.6%, even specialty alloys such as HR160 and I800 were badly corroded, yet the sample of a SS405-steel that was coated with Ti/Ta showed no signs of corrosion. After replacing the pressure regulator, a second run was conducted with a fresh set of coated and uncoated samples. The Ti/Ta-coated on to SS405 steel from the earlier runs was also exposed in this test. The run proceeded smoothly, and at the end of test the uncoated steels were badly damaged, some evidence of corrosion was found on coupons of HR160 and I800 alloys and the Cr-coated steels, but again, the Ti/Ta-coated sample appeared unaffected.

  19. Advanced Thermal Barrier Coating System Development. Technical progress report

    SciTech Connect

    1999-10-15

    The objectives of the program are to provide an improved TBC system with increased temperature capability and improved reliability relative to current state of the art TBC systems. The development of such a coating system is essential to the ATS engine meeting its objectives. The base program consists of three phases: Phase I: Program Planning - Complete; Phase II: Development; and Phase III: Selected Specimen - Bench Test. Work is being performed in Phase II and III of the program.

  20. Advanced Thermal Barrier Coating System Development. Technical progress report

    SciTech Connect

    1998-09-21

    The objectives of the program are to provide an improved TBC system with increased temperature capability and improved reliability relative to current state of the art TBC systems. The development of such a coating system is essential to the ATS engine meeting its objectives. The base program consists of three phases: Phase I: Program Planning - Complete; Phase II: Development; and Phase III: Selected Specimen - Bench Test. Work is being performed in Phase II and III of the program.

  1. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1989-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  2. Thin film coatings for space electrical power system applications

    NASA Technical Reports Server (NTRS)

    Gulino, Daniel A.

    1988-01-01

    This paper examines some of the ways in which thin film coatings can play a role in aerospace applications. Space systems discussed include photovoltaic and solar dynamic electric power generation systems, including applications in environmental protection, thermal energy storage, and radiator emittance enhancement. Potential applications of diamondlike films to both atmospheric and space based systems are examined. Also, potential uses of thin films of the recently discovered high-temperature superconductive materials are discussed.

  3. Peculiarities of modeling of nanoindentation of coating-substrate system

    NASA Astrophysics Data System (ADS)

    Eremina, Galina M.; Smolin, Alexey Yu.; Psakhie, Sergey G.

    2015-10-01

    In this paper we discuss some features that are important in modeling nanoindentation of strength coating deposited on metallic substrate. The modeling is performed by movable cellular automaton method, which is a representative of the discrete element methods in computational solid mechanics. Taking into account such factors as capability of the substrate material to harden, friction between the surface and the indenter as well as the presence of an intermediate layer between the coating and the substrate, it is shown that they can deeply affect the mechanical behavior of the system.

  4. Advanced thermal barrier coating system development. Technical progress report, January 1, 1996--March 31, 1996

    SciTech Connect

    1996-04-08

    Objectives of this program are to provide a thermal barrier coating system with increased temperature capability and improved reliability relative to current state of the art systems. This report describes the bond coat deposition process, manufacturing, and repair.

  5. Diffusion Coatings for Corrosion Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve its resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period we focused on getting a bench-scale test system to expose alloy coupons to simulated gasifier environment. The test facility was designed to allow about 20 specimen coupons to be exposed simultaneously for an extend period to a simulated coal gas stream at temperatures up to 1000 C. The simulated gas stream contained about 26%H{sub 2}, 39%CO, 17%CO{sub 2}, 1.4% H{sub 2}S and balance steam. We successfully ran a 100+h test with coated and uncoated stainless steel coupons. The tested alloys include SS304, SS316, SS405, SS409, SS410, and IN800. The main finding is that Ti/Ta coating provides excellent protection to SS405 under conditions where uncoated austenitic and ferritic stainless steel alloy coupons are badly corroded. Cr coatings also appear to afford some protection against corrosion.

  6. Pentek metal coating removal system: Baseline report; Greenbook (chapter)

    SciTech Connect

    1997-07-31

    The Pentek coating removal technology was tested and is being evaluated at Florida International University (FIU) as a baseline technology. In conjunction with FIU`s evaluation of efficiency and cost, this report covers evaluation conducted for safety and health issues. It is a commercially available technology and has been used for various projects at locations throughout the country. The Pentek coating removal system consisted of the ROTO-PEEN Scaler, CORNER-CUTTER{reg_sign}, and VAC-PAC{reg_sign}. They are designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M Roto Peen tungsten carbide cutters while the CORNER-CUTTER{reg_sign} uses solid needles for descaling activities. These hand tools are used with the VAC-PAC{reg_sign} vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure minimal, but noise exposure was significant. Further testing for each exposure is recommended because of the environment where the testing demonstration took place. It is feasible that the dust and noise levels will be higher in an enclosed operating environment of different construction. In addition, other areas of concern found were arm-hand vibration, whole-body, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout.

  7. High removal rate laser-based coating removal system

    DOEpatents

    Matthews, Dennis L.; Celliers, Peter M.; Hackel, Lloyd; Da Silva, Luiz B.; Dane, C. Brent; Mrowka, Stanley

    1999-11-16

    A compact laser system that removes surface coatings (such as paint, dirt, etc.) at a removal rate as high as 1000 ft.sup.2 /hr or more without damaging the surface. A high repetition rate laser with multiple amplification passes propagating through at least one optical amplifier is used, along with a delivery system consisting of a telescoping and articulating tube which also contains an evacuation system for simultaneously sweeping up the debris produced in the process. The amplified beam can be converted to an output beam by passively switching the polarization of at least one amplified beam. The system also has a personal safety system which protects against accidental exposures.

  8. Emittance and absorptance of NASA ceramic thermal barrier coating system. [for turbine cooling

    NASA Technical Reports Server (NTRS)

    Liebert, C. H.

    1978-01-01

    Spectral emittance measurements were made on a two-layer ceramic thermal barrier coating system consisting of a metal substrate, a NiCrAly bond coating and a yttria-stabilized zirconia ceramic coating. Spectral emittance data were obtained for the coating system at temperatures of 300 to 1590 K, ceramic thickness of zero to 0.076 centimeter, and wavelengths of 0.4 to 14.6 micrometers. The data were transformed into total hemispherical emittance values and correlated with respect to ceramic coating thickness and temperature using multiple regression curve fitting techniques. The results show that the ceramic thermal barrier coating system is highly reflective and significantly reduces radiation heat loads on cooled gas turbine engine components. Calculation of the radiant heat transfer within the nonisothermal, translucent ceramic coating material shows that the gas-side ceramic coating surface temperature can be used in heat transfer analysis of radiation heat loads on the coating system.

  9. ETV Program Report: Coatings for Wastewater Collection Systems - Protective Liner Systems, Inc., Epoxy Mastic, PLS-614

    EPA Science Inventory

    The Protective Liner Systems International, Inc. Epoxy Mastic PLS-614 coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Material and T...

  10. Robotic burnishing system for solid film lubricant coated parts

    SciTech Connect

    Fureigh, M.L.

    1986-05-01

    A robotic burnishing system in the Painting Department reduced the operation average standard hour content by 64% and maintains a good part-to-part quality level for a group of parts coated with solid film lubricant. Required to be safe and simple to operate, the system uses a small PUMA 260 robot to process coated axisymmetrical pieceparts. Special tooling and seven pairs of robotic fingers were designed and built to handle 24 different small pieceparts. Individual robotic programs were created for each part and stored on 5-1/4 in. floppy disks with backup copies in Numerical Control. The operators and the manufacturing department readily accepted the robotic system. Additional part geometries will be developed for robotic processing. 12 figs.

  11. Thermal Management Coating As Thermal Protection System for Space Transportation System

    NASA Technical Reports Server (NTRS)

    Kaul, Raj; Stuckey, C. Irvin

    2003-01-01

    This paper presents viewgraphs on the development of a non-ablative thermal management coating used as the thermal protection system material for space shuttle rocket boosters and other launch vehicles. The topics include: 1) Coating Study; 2) Aerothermal Testing; 3) Preconditioning Environments; 4) Test Observations; 5) Lightning Strike Test Panel; 6) Test Panel After Impact Testing; 7) Thermal Testing; and 8) Mechanical Testing.

  12. Reclamation system design of nanostructured coatings of touch-panel.

    PubMed

    Pa, P S

    2010-02-01

    A newly design reclamation system using an ultrasonic micro electroetching (UMECE) as a machining process for Indium-tin-oxide(ITO) nanostructured coatings dissolved from a surface of polyethyleneterephthalate (PET) of touch-panel is presented. The design features of the reclamation mechanism and a designed wedge-form tool are of major interest. The low yield of ITO nanostructured coatings is an important factor in optoelectronic semiconductor production. In the current experiment, a small diameter of the anode accompanying with a small distance between the two anodes, reduced the amount of time for effective ultrasonic micro electroetching of ITO since the effect of removal is facilitated by supplying sufficient electrochemical power. The performance of ultrasonics was found to be more effective than pulsed current, requiring no increase in electric power. Additionally, electric power, when combined with a fast feed rate, provides highly effective dissolution. Higher frequency or the greater power of ultrasonics corresponds to a higher dissolution rate for ITO nanostructured coatings. A small anode of the wedge-form tool or a small size of the cathode takes less time for the same amount of ITO removal. Importantly, ultrasonic micro electroetching with the designed wedge-form tool requires only a short period of time to dissolve the ITO's nanostructured coatings easily and cleanly. PMID:20352803

  13. Influence of Bond Coat Roughness on Life Time of APS Thermal Barrier Coating Systems under Thermo-Mechanical Load

    NASA Astrophysics Data System (ADS)

    Schmidt, Andreas; Aleksanoglu, Herman; Mao, Tongsheng; Scholz, Alfred; Berger, Christina

    The influence of the bond coat roughness on the life time of air plasma-sprayed (APS) thermal barrier coating systems (TBCs) was investigated under thermo-mechanical (TMF) load. The TBC system was applied on hollow cylindrical specimens made of the single crystal super alloy CMSX-4 in the orientation <001> with a MCrAlY-bond coat. Two different values of the bond coat roughness were investigated. In order to study the influence of the thicknesses of the thermally grown oxide layer (TGO), the specimens were isothermally oxidized at 1000 °C for a long term prior to the TMF experiments. The thermo-mechanical experiments show a higher number of cycles-to-failure for TBCs corresponding to an increase of the bond coat roughness. Furthermore, it could be demonstrated that a certain TGO thickness is needed to produce a total delamination of the top coat in the TMF experiments. This minimum thickness varies with the surface roughness of the bond coat and the TMF cycle's phase shift and strain range. Crack initiation and crack propagation were investigated by microscopical analyses, for example, SEM and EDX. Therefore most of the experiments were completed before a total delamination of the top coat occurred. On the basis of these investigations, crack initiation and crack propagation under thermo-mechanical load were described systematically.

  14. Degradation and Failure Characteristics of NPP Containment Protective Coating Systems

    SciTech Connect

    Sindelar, R.L.

    2001-04-10

    Nuclear power plants (NPPs) must ensure that the emergency core cooling system (ECCS) or safety-related containment spray system (CSS) remains capable of performing its design safety function throughout the life of the plant. This requires ensuring that long-term core cooling can be maintained following a postulated loss-of-coolant accident (LOCA). Adequate safety operation can be impaired if the protective coatings which have been applied to the concrete and steel structures within the primary containment fail, producing transportable debris which could then accumulate on BWR ECCS suction strainers or PWR ECCS sump debris screens located within the containment. This document will present the data collected during the investigation of coating specimens from plants.

  15. Pentek metal coating removal system: Baseline report; Summary

    SciTech Connect

    1997-07-31

    The Pentek metal coating removal system consists of the ROTO-PEEN Scaler, CORNER-CUTTER(R), and VAC-PAC(R). The system is designed to remove coatings from steel, concrete, brick, and wood. The Scaler uses 3M ROTO-PEEN tungsten carbide cutters, while the CORNER-CUTTER(R) uses solid needles for descaling activities. These are used with the VAC-PAC(R) vacuum system to capture dust and debris as removal of the coating takes place. The safety and health evaluation during the testing demonstration focused on two main areas of exposure: dust and noise. Dust exposure was minimal, but noise exposure was significant. Further testing for each exposure is recommended, since the outdoor environment where the testing demonstration took place may skew the results. It is feasible that dust and noise levels will be higher in an enclosed operating environment. Other areas of concern found were arm-hand vibration, whole-body vibration, ergonomics, heat stress, tripping hazards, electrical hazards, machine guarding, and lockout/tagout.

  16. Coatings and Surface Treatments for Reusable Entry Systems

    NASA Technical Reports Server (NTRS)

    Johnson, Sylvia M.

    2016-01-01

    This talk outlines work in coatings for TPS done at NASA Ames. coatings and surface treatments on reusable TPS are critical for controlling the behavior of the materials. coatings discussed include RCG, TUFI and HETC. TUFROc is also discussed.

  17. Thermal/environmental barrier coating system for silicon-based materials

    NASA Technical Reports Server (NTRS)

    Spitsberg, Irene T. (Inventor); Wang, Hongyu (Inventor)

    1999-01-01

    A coating system for a substrate containing a silicon-based material, such as silicon carbide-containing ceramic matrix materials containing silicon carbide and used to form articles exposed to high temperatures, including the hostile thermal environment of a gas turbine engine. The coating system includes a layer of barium strontium aluminosilicate (BSAS) as a bond coat for a thermal-insulating top coat. As a bond coat, the BSAS layer serves to adhere the top coat to a SiC-containing substrate. The BSAS bond coat exhibits sufficient environmental resistance such that, if the top coat should spall, the BSAS bond coat continues to provide a level of environmental protection to the underlying SiC-containing substrate.

  18. Advanced thermal barrier coating system development. Technical progress report, September 1, 1997--November 30, 1997

    SciTech Connect

    1997-12-12

    The objectives of this project were to provide an improved thermal barrier coating system with increased temperature capability and reliability. This report describes bond coat development, manufacturing, nondestructive evaluation, maintenance, and repair, and bench testing.

  19. Advanced thermal barrier coating system development. Technical progress report, August 1, 1996--September 30, 1996

    SciTech Connect

    1996-10-04

    Objectives of this program are to provide an advanced thermal barrier coating system with improved reliability and temperature capability. This report describes the coating/deposition process, repair, and manufacturing.

  20. Oxidation and degradation of thermal barrier coating systems

    NASA Astrophysics Data System (ADS)

    Haynes, James Allen

    Thermal barrier coatings (TBCs), which consist of an oxidation-resistant metallic bond coating overlaid with a thermally-insulating Ysb2Osb3-stabilized ZrOsb2 (YSZ) top coating, are used to protect superalloy hardware in gas turbine engines. Spallation of the YSZ is accelerated by growth of an interfacial Alsb2Osb3 scale at high temperatures. The mechanisms of oxidation-related degradation are not well understood for air plasma-sprayed (APS) TBCs, whereas Alsb2Osb3 thermomechanical failure is the dominant degradation mode in electron beam-physical vapor deposition (EB-PVD) TBCs. This work investigated the isothermal oxidation and thermocyclic degradation of various TBC systems; with particular emphasis on the growth kinetics, microstructures, flaw content, fracture behavior and micro-mechanical properties of the Alsb2Osb3 interfacial scales. The isothermal oxidation kinetics of plasma-sprayed NiCrAlY were not influenced by the presence of an APS YSZ top coating (at 1150sp°C). However, the isothermal oxidation rate constants of NiCoCrAlY bond coatings were accelerated by a factor of 2 (at 950, 1050 and 1150sp°C) when overlaid with a commercial EB-PVD TBC. Thermocyclic failure of APS TBCs occurred by progressive YSZ fracture and crack link-up. Severe fracture and buckling of the interfacial Alsb2Osb3 during thermal cycling did not induce rapid failure of APS TBCs. Evaluation of the interfacial Alsb2Osb3 scale microstructures (on APS TBCs) after thermal cycling revealed the following: thermocyclic damage occurred by both oxide-metal delamination and by internal fracture; Alsb2Osb3 scale crack healing by sintering occurred at 1150sp°C; surfaces with a sharp radius of curvature induced less Alsb2Osb3 damage than gradually convex surfaces; scale grain boundary void growth was accelerated by thermal cycling; and higher void contents were observed in scales which formed on convex surfaces. There were no significant changes in the hardness or Young's modulus of the Alsb2

  1. Reflectance Profile of BaTiO3 on Multilayer Antireflection Coating Systems

    NASA Astrophysics Data System (ADS)

    Karaomerlioglu, Filiz

    2011-05-01

    Antireflection (AR) coating systems are very important technology for optoelectronic devices. The optical characteristics of the system can be regulated by external electric or thermal field, and designed broadband ultra low reflection coating systems. It is investigated optical properties of multilayer AR coatings based on different ferroelectric materials to reduce reflectance in other studies. In this study, reflectance profile of BaTiO3 on multilayer AR coating systems has been developed in the visible region. It has been used ZnSe and ZrO2 as multilayer AR coatings, and BaTiO3 as the substrate. Fortran program has been simulated on Fresnell equations base.

  2. High removal rate laser-based coating removal system

    SciTech Connect

    Matthews, D.L.; Celliers, P.M.; Hackel, L.; Da Silva, L.B.; Dane, C.B.; Mrowka, S.

    1999-11-16

    A compact laser system is disclosed that removes surface coatings (such as paint, dirt, etc.) at a removal rate as high as 1,000 ft{sup 2}/hr or more without damaging the surface. A high repetition rate laser with multiple amplification passes propagating through at least one optical amplifier is used, along with a delivery system consisting of a telescoping and articulating tube which also contains an evacuation system for simultaneously sweeping up the debris produced in the process. The amplified beam can be converted to an output beam by passively switching the polarization of at least one amplified beam. The system also has a personal safety system which protects against accidental exposures.

  3. Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

    DOEpatents

    Moore, Karen A.; Zatorski, Raymond A.

    2005-07-12

    Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

  4. Isothermal and cyclic oxidation of an air plasma-sprayed thermal barrier coating system

    SciTech Connect

    Haynes, J.A.; Ferber, M.K.; Porter, W.D.; Rigney, E.D.

    1996-08-01

    Thermogravimetric methods for evaluating bond coat oxidation in plasma-sprayed thermal barrier coating (TBC) systems were assessed by high-temperature testing of TBC systems with air plasma-sprayed (APS) Ni-22Cr-10Al-1Y bond coatings and yttria-stabilized zirconia top coatings. High-mass thermogravimetric analysis (at 1150{sup degrees}C) was used to measure bond coat oxidation kinetics. Furnace cycling was used to evaluate APS TBC durability. This paper describes the experimental methods and relative oxidation kinetics of the various specimen types. Characterization of the APS TBCs and their reaction products is discussed.

  5. Hydrogen plasma tests of some insulating coating systems for the nuclear rocket thrust chamber

    NASA Technical Reports Server (NTRS)

    Current, A. N.; Grisaffe, S. J.; Wycoff, K. C.

    1972-01-01

    Several plasma-sprayed and slurry-coated insulating coating systems were evaluated for structural stability in a low-pressure hot hydrogen environment at a maximum heat flux of 19.6 million watts/sq meter. The heat was provided by an electric-arc plasma generator. The coating systems consisted of a number of thin layers of metal oxides and/or metals. The materials included molybdenum, nichrome, tungsten, alumina, zirconia, and chromia. The study indicates potential usefulness in this environment for some coatings, and points up the need for improved coating application techniques.

  6. Process optimization of a novel immediate release film coating system using QbD principles.

    PubMed

    Teckoe, Jason; Mascaro, Tracey; Farrell, Thomas P; Rajabi-Siahboomi, Ali R

    2013-06-01

    This work describes a quality-by-design (QbD) approach to determine the optimal coating process conditions and robust process operating space for an immediate release aqueous film coating system (Opadry® 200). Critical quality attributes (CQAs) or associated performance indicators of the coated tablets were measured while coating process parameters such as percent solids of the coating dispersion, coating spray rate, inlet air temperature, airflow rate and pan speed were varied, using a design of experiment protocol. The optimized process parameters were then confirmed by independent coating trials. Disintegration time of coated tablets was not affected by the coating process conditions used in this study, while tablet appearance, as determined by measurement of tablet color, coating defects and gloss was determined to be a CQA. Tablet gloss increased when low spray rate and low percent solids were used, as well as with increased coating pan speed. The study used QbD principles and experimental design models to provide a basis to identify ranges of coating process conditions which afford acceptable product quality. High productivity, color uniformity, and very low defect levels were obtained with Opadry 200 even when using a broad range of coating process conditions. PMID:23483430

  7. Thermal Fatigue Behavior of Thick and Porous Thermal Barrier Coatings Systems

    NASA Astrophysics Data System (ADS)

    Scrivani, A.; Rizzi, G.; Bardi, U.; Giolli, C.; Miranda, M. Muniz; Ciattini, S.; Fossati, A.; Borgioli, F.

    2007-12-01

    High-temperature thermal fatigue causes the failure of thermal barrier coating (TBC) systems. This paper addresses the development of thick TBCs, focusing on the microstructure and the porosity of the yttria partially stabilized zirconia (YPSZ) coating, regarding its resistance to thermal fatigue. Thick TBCs, with different porosity levels, were produced by means of a CoNiCrAlY bond coat and YPSZ top coat, both had been sprayed by air plasma spray. The thermal fatigue resistance of new TBC systems and the evolution of the coatings before and after thermal cycling was then evaluated. The limit of thermal fatigue resistance increases depending on the amount of porosity in the top coat. Raman analysis shows that the compressive in-plane stress increases in the TBC systems after thermal cycling, nevertheless the increasing rate has a trend which is contrary to the porosity level of top coat.

  8. Fused Silica Surface Coating for a Flexible Silica Mat Insulation System

    NASA Technical Reports Server (NTRS)

    Rhodes, W. H.

    1973-01-01

    Fused silica insulation coatings have been developed for application to a flexible mat insulation system. Based on crystalline phase nucleation and growth kinetics, a 99+% SiO2 glass was selected as the base composition. A coating was developed that incorporated the high emissivity phase NiCr2O4 as a two phase coating with goals of high emittance and minimum change in thermal expansion. A second major coating classification has a plasma sprayed emittance coating over a sealed pure amorphous SiO2 layer. A third area of development centered on extremely thin amorphous SiO2 coatings deposited by chemical vapor deposition. The coating characterization studies presented are mechanical testing of thin specimens extracted from the coatings, cyclic arc exposures, and emittance measurements before and after arc exposures.

  9. Influence of viscoelastic property on laser-generated surface acoustic waves in coating-substrate systems

    SciTech Connect

    Sun Hongxiang; Zhang Shuyi; Xu Baiqiang

    2011-04-01

    Taking account of the viscoelasticity of materials, the pulsed laser generation of surface acoustic waves in coating-substrate systems has been investigated quantitatively by using the finite element method. The displacement spectra of the surface acoustic waves have been calculated in frequency domain for different coating-substrate systems, in which the viscoelastic properties of the coatings and substrates are considered separately. Meanwhile, the temporal displacement waveforms have been obtained by applying inverse fast Fourier transforms. The numerical results of the normal surface displacements are presented for different configurations: a single plate, a slow coating on a fast substrate, and a fast coating on a slow substrate. The influences of the viscoelastic properties of the coating and the substrate on the attenuation of the surface acoustic waves have been studied. In addition, the influence of the coating thickness on the attenuation of the surface acoustic waves has been also investigated in detail.

  10. Improvement of charging characteristics of coating powders in electrostatic powder coating system

    NASA Astrophysics Data System (ADS)

    Takeuchi, Manabu

    2008-12-01

    The charging characteristics of coating powders were improved for both corona-charging and tribocharging type spray guns. The blow-off measurements showed that the charge-to-mass ratio of coating powders deposited on the substrate was larger than that of undeposited powders for both types of spray gun. The charge-to-mass ratio of the coating powders was increased by adding a pair of auxiliary electrode to the corona-charging spray gun. Free ions from the corona-charging spray gun were decreased by applying a magnetic field in the spraying space. The polymer tube of a tribocharging spray gun that contained a negative charge control agent was able to charge all the coating powders sufficiently positive

  11. An investigation of thin-film coating/substrate systems by nanoindentation

    SciTech Connect

    Li, J.; Thostenson, E.T.; Chou, T.W.; Riester, L.

    1998-04-01

    The indentation load-displacement behavior of three material systems tested with a Berkovich indenter has been examined. The materials studied were the substrate materials--silicon and polycarbonate, and the coating/substrate systems--diamond-like carbon (DLC) coating on silicon, and DLC coating on polycarbonate. They represent three material systems, namely, bulk, soft-coating/hard-substrate, and hard-coating on soft-substrate. Delaminations in the soft-coating/hard-substrate (DLC/Si) system and cracking in the hard-coating/soft-substrate system (DLC/Polycarbonate) were observed. Parallel to the experimental work, an elastic analytical effort has been made to examine the influence of the film thickness and the properties of the coating/substrate systems. Comparisons between the experimental data and analytical solutions of the load-displacement curves during unloading show good agreement. The analytical solution also suggests that the Young`s modulus and hardness of the thin film can not be measured accurately using Sneddon`s solution for bulk materials when the thickness of the film is comparable to the loading contact radius of the indenter. The elastic stress field analysis provides a basis for understanding the experimentally observed delaminations and cracking of the coating/substrate systems.

  12. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Angel Sanjurjo

    2004-05-01

    Heat-exchangers, filters, turbines, and other components in integrated coal gasification combined cycle system must withstand demanding conditions of high temperatures and pressure differentials. Under the highly sulfiding conditions of the high temperature coal gas, the performance of components degrade significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy may improve is resistance to such sulfidation attack and decrease capital and operating costs. A review of the literature indicates that the corrosion reaction is the competition between oxidation and sulfidation reactions. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers.

  13. Characterization of thermosetting systems for coil coating applications

    SciTech Connect

    Muzeau, E.; Seytre, G.; Hellouin, R.; Bonnebat, C.

    1996-01-01

    The molecular mobility temperatures ({alpha} relaxation) of polyester/melamine coatings applied on metallic substrate at different flash curing temperatures or PMT are investigated by means of calorimetric (DSC), thermomechanical (DMA) or dielectric (DETA) methods, using polyester precursors with varied molecular structures. A good correlation is observed between the Tg or T{alpha} temperatures obtained from different measurements, which are mainly related to the corresponding characteristics of the polyester precursor. However, these temperatures are not significantly influenced by the PMT values. Other characteristics of the molecular mobility such as the amplitude of the dielectric or mechanical {alpha} relaxation or elongation at break, are noticeably dependent upon both the molecular characteristics of the polyester precursor and the PMT value. A spatial arrangement of the network consistent with these results is proposed which helps to understand the mechanical behaviour of polyester/melamine systems. {copyright} {ital 1996 American Institute of Physics.}

  14. DIFFUSION COATINGS FOR CORROSION RESISTANT COMPONENTS IN COAL GASIFICATION SYSTEMS

    SciTech Connect

    Gopala N. Krishnan

    2004-05-01

    Advanced electric power generation systems use a coal gasifier to convert coal to a gas rich in fuels such as H{sub 2} and CO. The gas stream contains impurities such as H{sub 2}S and HCl, which attack metal components of the coal gas train, causing plant downtime and increasing the cost of power generation. Corrosion-resistant coatings would improve plant availability and decrease maintenance costs, thus allowing the environmentally superior integrated gasification combined cycle plants to be more competitive with standard power-generation technologies. A startup meeting was held at the National Energy Technology Center, Pittsburgh, PA site on July 28, 2003. SRI staff described the technical approach of the project.

  15. Conceptual design of an aircraft automated coating removal system

    SciTech Connect

    Baker, J.E.; Draper, J.V.; Pin, F.G.; Primm, A.H.; Shekhar, S.

    1996-05-01

    Paint stripping of the U.S. Air Force`s large transport aircrafts is currently a labor-intensive, manual process. Significant reductions in costs, personnel and turnaround time can be accomplished by the judicious use of automation in some process tasks. This paper presents the conceptual design of a coating removal systems for the tail surfaces of the C-5 plane. Emphasis is placed on the technology selection to optimize human-automation synergy with respect to overall costs, throughput, quality, safety, and reliability. Trade- offs between field-proven vs. research-requiring technologies, and between expected gain vs. cost and complexity, have led to a conceptual design which is semi-autonomous (relying on the human for task specification and disturbance handling) yet incorporates sensor- based automation (for sweep path generation and tracking, surface following, stripping quality control and tape/breach handling).

  16. DEVELOPMENT OF A NO-VOC/NO-HAP WOOD FURNITURE COATINGS SYSTEM

    EPA Science Inventory

    The report gives results of the development and demonstration of a no-VOC (volatile organic compound)/no-HAP (hazardous air pollutant) wood furniture coating system. The performance characteristics of the new coating system are excellent in terms of adhesion, drying time, gloss, ...

  17. Low frictional property of copper oxide thin films optimised using a combinatorial sputter coating system

    NASA Astrophysics Data System (ADS)

    Goto, Masahiro; Kasahara, Akira; Tosa, Masahiro

    2006-01-01

    A combinatorial sputter coating system has been developed that can optimize the crystal preferred orientation of coating films. With this system, it is possible to synthesize various kinds of coatings whilst precisely controlling conditions such as the sputter gas, the gas pressure, the gas partial pressure, the r.f. power, the substrate temperature, the distance between the substrate and target, etc. In this way, we successfully synthesized copper oxide coatings with different crystal preferred orientations, and low frictional property was obtained by optimizing the crystal preferred orientation.

  18. Morphological analysis of galvanized coating applied under vibrowave process system conditions

    NASA Astrophysics Data System (ADS)

    Lebedev, V. A.; Ivanov, V. V.; Fedorov, V. P.

    2016-04-01

    The article presents the morphological research results of galvanized coating applied to the metal surface in the course of mechanical and chemical synthesis realized under vibrowave process system conditions. The paper reveals the specifics of the coating morphology, its activating role in free-moving indentors formed under the impact of low-frequency vibrations and its positive influence on the operational performance of the part surface layer. The advantages of this galvanized coating application method are presented in comparison with conventional methods.

  19. Residual Stresses in Thermal Barrier Coatings for a Cu-8Cr-4Nb Substrate System

    NASA Technical Reports Server (NTRS)

    Ghosn, Louis J.; Raj, Sai V.

    2002-01-01

    Analytical calculations were conducted to determine the thermal stresses developed in a coated copper-based alloy, Cu-8%(at.%)Cr-4%Nb (designated as GRCop-84), after plasma spraying and during heat-up in a simulated rocket engine environment. Finite element analyses were conducted for two coating systems consisting of a metallic top coat, a pure copper bond coat and the GRCop-84. The through thickness temperature variations were determined as a function of coating thickness for two metallic coatings, a Ni-17%(wt%)Cr-6%Al-0.5%Y alloy and a Ni-50%(at.%)Al alloy. The residual stresses after low-pressure plasma spraying of the NiCrAlY and NiAl coatings on GRCop-84 substrate were also evaluated. These analyses took into consideration a 50.8 mm copper bond coat and the effects of an interface coating roughness. The through the thickness thermal stresses developed in coated liners were also calculated after 15 minutes of exposure in a rocket environment with and without an interfacial roughness.

  20. Performance of fuel failure detection system for coated particle fuels

    SciTech Connect

    Treada, H.; Ohkawa, H.; Ohlsu, H.; Wakayama, N.; Yoshida, H.

    1985-04-01

    An experimental system was developed for a study of fuel failure detection (FFD) method for coated particle fuels (CPF's) of a high-temperature gas-cooled reactor. Various performance of the FFD-system were examined using a CPF-irradiation rig in the Japan Material Testing Reactor. By experiments, it was made sure that the counting rates of fission products (FP's), released from the CPF's, change with the reactor-power and the fuel-temperature remarkably even during the normal reactor operation. Also, an ability of the selective detection of only short-life FP-nuclides was studied in relation to the travelling time of the sampling gas. The results showed that the contributions of the short-life FP-nuclides such as Kr-89 and Kr-90 are more than 80 percent to the total FP-counting rate at the shortest travelling time of 120 sec. It is concluded that the selective detection of only the short-life FP-nuclides can be realized by controlling the travelling time properly.

  1. Design of novel plasma sprayed hydroxyapatite-bond coat bioceramic systems

    NASA Astrophysics Data System (ADS)

    Heimann, R. B.

    1999-12-01

    Bond coats based on bioinert ceramic materials such as titania and zirconia were developed to increase the adhesion strength of the coating system hydroxyapatite-bond coat to Ti-6Al-4V alloy surfaces used for hip endoprostheses and dental root implants. The bond coats improved the adhesion strength, measured by a modified ASTM D 3167-76 peel test, by up to 100% and also the resorption resistance as determined by in vitro leaching in simulated protein-free body fluid for up to 28 days.

  2. Thermal and Environmental Barrier Coating Development for Advanced Propulsion Engine Systems

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Miller, Robert A.; Fox, Dennis S.

    2008-01-01

    Ceramic thermal and environmental barrier coatings (TEBCs) are used in gas turbine engines to protect engine hot-section components in the harsh combustion environments, and extend component lifetimes. Advanced TEBCs that have significantly lower thermal conductivity, better thermal stability and higher toughness than current coatings will be beneficial for future low emission and high performance propulsion engine systems. In this paper, ceramic coating design and testing considerations will be described for turbine engine high temperature and high-heat-flux applications. Thermal barrier coatings for metallic turbine airfoils and thermal/environmental barrier coatings for SiC/SiC ceramic matrix composite (CMC) components for future supersonic aircraft propulsion engines will be emphasized. Further coating capability and durability improvements for the engine hot-section component applications can be expected by utilizing advanced modeling and design tools.

  3. Evaluation of the Lifetime and Thermal Conductivity of Dysprosia-Stabilized Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Curry, Nicholas; Markocsan, Nicolaie; Östergren, Lars; Li, Xin-Hai; Dorfman, Mitch

    2013-08-01

    The aim of this study was the further development of dysprosia-stabilized zirconia coatings for gas turbine applications. The target for these coatings was a longer lifetime and higher insulating performance compared to today's industrial standard thermal barrier coating. Two morphologies of ceramic top coat were studied: one using a dual-layer system and the second using a polymer to generate porosity. Evaluations were carried out using a laser flash technique to measure thermal properties. Lifetime testing was conducted using thermo-cyclic fatigue testing. Microstructure was assessed with SEM and Image analysis was used to characterize porosity content. The results show that coatings with an engineered microstructure give performance twice that of the present reference coating.

  4. Approaches to investigate delamination and interfacial toughness in coated systems: an overview

    NASA Astrophysics Data System (ADS)

    Chen, Jinju; Bull, S. J.

    2011-01-01

    The fundamental property which often dictates the performance of a coating is its adhesion to the substrate and thus there are many techniques to measure adhesion. The choice of methods is dependent on many factors such as the mechanical properties of the coating and substrate, the interface properties, the microstructure of the coating/substrate system, residual stress, coating thickness and the intended application. Most tests aim to introduce a stable interfacial crack and make it propagate under controlled conditions and model this process to determine adhesion. The corresponding models are either stress analysis-based or energy-based. With the advent of miniature systems and very thin functional coatings, there is a need for characterization of adhesion at small length scales and some specific tests have been developed which are not appropriate for thicker coatings. Among these, indentation and scratch methods have the widest range of applicability but it is necessary to analyse the failure mechanisms before choosing an appropriate model to extract adhesion parameters. This paper reviews the main quantitative adhesion tests for coatings and highlights the tests which can be used to assess submicrometre coatings and thin films. The paper also highlights the modelling and analysis methods necessary to extract reliable adhesion properties illustrating this with examples for submicrometre coatings on silicon and architectural glass.

  5. Characteristics of MCrAlY coatings sprayed by high velocity oxygen-fuel spraying system

    SciTech Connect

    Itoh, Y.; Saitoh, M.; Tamura, M.

    2000-01-01

    High velocity oxygen-fuel (HVOF) spraying system in open air has been established for producing the coatings that are extremely clean and dense. It is thought that the HVOF sprayed MCrAlY (M is Fe, Ni and/or Co) coatings can be applied to provide resistance against oxidation and corrosion to the hot parts of gas turbines. Also, it is well known that the thicker coating can be sprayed in comparison with any other thermal spraying systems due to improved residual stresses. However, thermal and mechanical properties of HVOF coatings have not been clarified. Especially, the characteristics of residual stress, that are the most important property from the view point of production technique, have not been made clear. In this paper, the mechanical properties of HVOF sprayed MCrAlY coatings were measured in both the case of as-sprayed and heat-treated coatings in comparison with a vacuum plasma sprayed MCrAlY coatings. It was confirmed that the mechanical properties of HVOF sprayed MCrAlY coatings could be improved by a diffusion heat treatment to equate the vacuum plasma sprayed MCrAlY coatings. Also, the residual stress characteristics were analyzed using a deflection measurement technique and a X-ray technique. The residual stress of HVOF coating was reduced by the shot-peening effect comparable to that of a plasma spray system in open air. This phenomena could be explained by the reason that the HVOF sprayed MCrAlY coating was built up by poorly melted particles.

  6. Microfibrillated cellulose coatings as new release systems for active packaging.

    PubMed

    Lavoine, Nathalie; Desloges, Isabelle; Bras, Julien

    2014-03-15

    In this work, a new use of microfibrillated cellulose (MFC) is highlighted for high-added-value applications. For the first time, a nanoporous network formed by MFC coated on paper is used for a controlled release of molecules. The release study was carried out in water with caffeine as a model molecule. The release process was studied by means of (i) continuous, and (ii) intermittent diffusion experiments (with renewal of the medium every 10 min). The effect of the MFC was first observed for the samples impregnated in the caffeine solution. These samples, coated with MFC (coat weight of about 7 g/m(2)), released the caffeine over a longer period (29 washings compared with 16), even if the continuous diffusions were similar for both samples (without and with MFC coating). The slowest release of caffeine was observed for samples coated with the mixture (MFC+caffeine). Moreover, the caffeine was only fully released 9h after the release from the other samples was completed. This study compared two techniques for the introduction of model molecules in MFC-coated papers. The latter offers a more controlled and gradual release. This new approach creates many opportunities especially in the food-packaging field. A similar study could be carried out with an active species. PMID:24528763

  7. Coating system to permit direct brazing of ceramics

    DOEpatents

    Cadden, Charles H.; Hosking, F. Michael

    2003-01-01

    This invention relates to a method for preparing the surface of a ceramic component that enables direct brazing using a non-active braze alloy. The present invention also relates to a method for directly brazing a ceramic component to a ceramic or metal member using this method of surface preparation, and to articles produced by using this brazing method. The ceramic can be high purity alumina. The method comprises applying a first coating of a silicon-bearing oxide material (e.g. silicon dioxide or mullite (3Al.sub.2 O.sub.3.2SiO.sub.2) to the ceramic. Next, a thin coating of active metal (e.g. Ti or V) is applied. Finally, a thicker coating of a non-active metal (e.g. Au or Cu) is applied. The coatings can be applied by physical vapor deposition (PVD). Alternatively, the active and non-active metals can be co-deposited (e.g. by sputtering a target made of mullite). After all of the coatings have been applied, the ceramic can be fired at a high temperature in a non-oxidizing environment to promote diffusion, and to enhance bonding of the coatings to the substrate. After firing, the metallized ceramic component can be brazed to other components using a conventional non-active braze alloy. Alternatively, the firing and brazing steps can be combined into a single step. This process can replace the need to perform a "moly-manganese" metallization step.

  8. Innovative fiber coating systems based on organic modified ceramics

    NASA Astrophysics Data System (ADS)

    Schuster, Kay; Kobelke, Jens; Rose, Klaus; Helbig, Manfred; Zoheidi, Mohammad; Heinze, Alexander

    2010-02-01

    We describe the application of inorganic organic hybrid materials (ORMOCERs) as optical fiber coatings for use in Fiber Bragg Grating sensors and high power transmission fibers. The materials are UV curable, enable a single layer thickness of about 50 μm and show high a high peak temperature stability >300 °C. Regarding the fiber protection the coatings have been investigated using tensile strength measurements before and after temperature load. Best coatings maintain the high tensile strength of 68 N (125 μm fiber) with a Weibull parameter of 182 after a temperature cycling up to 300 °C. For the first time a low refractive index ORMOCER will be presented showing a numerical aperture of 0.47 at a wavelength of 1000 nm on a pure silica fiber. This corresponds to a refractive index of 1.37. The fiber possesses a fiber loss of 18 dB/km at a wavelength of 1000 nm. The fibers have been coated using a gravity as well as pressure technology. The latter possesses extremely minimized die equipment and is therefore well applicable for small coating amounts. The so called dead volume within the coating die is about 1 ml. The overall dead volume is only influenced by the supply pipe and can be reduced down to 5 ml.

  9. Modeling Multilayer Antireflection Coating Systems Based on LiNbO3

    NASA Astrophysics Data System (ADS)

    Karaomerlioglu, Filiz

    Antireflection coatings have had the greatest impact on optics. The antireflection (AR) coating is the critically important technology in obtaining high performance of optoelectronic devices. In the present paper, characteristics of the ferroelectric based multilayered antireflection coating systems are investigated. Multilayer antireflection coatings consisting of insulator thin films have been modeled in the region between the 400 nm and 800 nm visible bands of electromagnetic spectrum to reduce reflectance from ferroelectric based substrate. In this type of antireflection coating we can regulate the optical properties of a system by external electric (or thermal field) and design a broadband low reflection coating system for optoelectronic devices. In order to design and simulate the normal incidence wideband visible multilayer AR coatings, we have developed a Fortran software program based upon Fresnell equations. Different types of layers which are two-different materials like ZnSe and ZrO2 for even-folded multilayer (two-, four-, six-, eight-, ten-, and twelve-layer) antireflection coatings are used. Ferroelectric material, LiNbO3 is used as the substrate. The optical thicknesses of each layer are equal to a quarter-wave thick at a certain wavelength.

  10. Corrosion and oxidation properties of NiCr coatings sprayed in presence of gas shroud system

    NASA Astrophysics Data System (ADS)

    Morks, M. F.; Berndt, C. C.

    2010-04-01

    The oxidation of a NiCr bond coat during air plasma spraying was controlled by designing a gas shroud system attached to the plasma torch nozzle. Two nozzles, termed as "normal" and "high-speed" nozzles examined the effect of nozzle internal design on the microstructure and phase structure of coatings. X-ray diffraction and SEM morphologies showed that the shroud system reduced the oxidation of NiCr particles during the spray process. Compared with conventional air plasma spraying, the argon gas shroud reduced the coating hardness because the volume fraction of partially melted particles increased. The high-speed nozzle reduced the oxidation and hardness of NiCr coatings due to the increase of partially melted particles in the coatings.

  11. Numerical investigations of failure in EB-PVD thermal barrier coating systems

    NASA Astrophysics Data System (ADS)

    Glynn, Michael L.

    Thermal barrier coating (TBC) systems are used in high temperature applications in turbine engines. TBCs are applied on superalloy substrates and are multilayered coatings comprised of a metallic bond coat, a thermally grown oxide (TGO) and a ceramic top coat. They provide thermal protection for the superalloy substrate and are considered to hold the greatest potential for increased operating temperatures. Failure of the TBC system most commonly occurs as a result of large scale buckling and spallation. The buckling is a consequence of many small-scale delaminations that arise in the top coat above local imperfections in the TGO, and durability of the TBC system is governed by a sequence of crack nucleation, propagation and coalescence. The numerical investigations that are employed in this dissertation are used to determine the stress development near the imperfections and are based on microstructural observations and measured material properties of TBC test buttons supplied by GE Aircraft Engines. The test buttons were subject to thermal cycling at GE and cycled to different percentages of TBC life. Numerical simulations of two different types of TBC tests are used to show that the top coat out-of-plane stress increases with a decrease of the substrate radius of curvature and a decrease in the heating rate. An inherent scaling parameter in the TBC system is identified and used to demonstrate that the stress developed in the top coat is governed by the evolution of an imperfection in the TGO. The effect of a martensitic phase transformation in the bond coat, related to a change in bond coat chemistry, is shown to significantly increase the top coat out-of-plane tensile stress. Finally, a subsurface crack is simulated in the top coat and used to determine the influence of the bond coat on failure of the TBC system. While the bond coat inelastic properties are the most important factors in determining the extent of the crack opening displacement, the bond coat

  12. An Improved Approach to Fracture Toughness Assessment of Brittle Coating on Ductile Substrate Systems under Indentation

    NASA Astrophysics Data System (ADS)

    Demidova, Natalia V.

    Fracture toughness is an important material property that determines the structural integrity of a component with pre-existing or service-generated flaws. In the present research, an indentation-based method and the associated fracture mechanics model are proposed for fracture toughness assessment of brittle coating/ductile substrate systems. The proposed models consider well-developed radial/median cracks generated under sharp indentation, despite that the crack formation process may have gone through crack initiation and propagation phases. For generality, the geometry of a well-developed crack is assumed to be semi-elliptical in shape. The driving force of the crack is considered to stem from the residual plastic zone expansion under the indenter, as well as the far-field Boussinesq (elastic) stress. Three well-defined configurations are studied. For the first configuration, a crack with a depth of less than 7% of the coating thickness is considered. In this case, the problem is treated as the one for the monolithic material with the coating material properties. For the second configuration, a crack that runs deeper than 7% of the coating thickness but is still within the coating layer is analyzed. In this case, the composite hardness is introduced into the analysis to account for the influence of the substrate material properties; and furthermore, an interface correction factor is proposed to take into account the presence of the coating/substrate interface and its influence on the stress intensity factor of the well-developed elliptical cracks. For the third configuration, a crack penetrating into the substrate is considered. In this case, based on the condition of deformation compatibility across the coating/substrate interface, the bulk modulus for the coating/substrate system is introduced into the analysis. A series of indentation tests are conducted on a WC/10Co/4Cr coating/1080 low carbon steel substrate specimen, which is a brittle coating on a ductile

  13. Electrokinetic Properties of Lubricin Antiadhesive Coatings in Microfluidic Systems.

    PubMed

    Greene, George W; Duffy, Emer; Shallan, Aliaa; Wuethrich, Alain; Paull, Brett

    2016-02-23

    Lubricin is a glycoprotein found in articular joints which has long been recognized as being an important biological boundary lubricant molecule and, more recently, an impressive antiadhesive that readily self-assembles into a well ordered, polymer brush layer on virtually any substrate. The lubricin molecule possesses an overabundance of anionic charge, a property that is atypical among antiadhesive molecules, that enables its use as a coating for applications involving electrokinetic processes such as electrophoresis and electroosmosis. Coating the surfaces of silica and polymeric microfluidic devices with self-assembled lubricin coatings affords a unique combination of excellent fouling resistance and high charge density that enables notoriously "sticky" biomolecules such as proteins to be used and controlled electrokinetically in the device without complications arising from nonspecific adsorption. Using capillary electrophoresis, we characterized the stability, uniformity, and electrokinetic properties of lubricin coatings applied to silica and PTFE capillaries over a range of run buffer pHs and when exposed to concentrated solutions of protein. In addition, we demonstrate the effectiveness of lubricin as a coating to minimize nonspecific protein adsorption in an electrokinetically controlled polydimethylsiloxane/silica microfluidic device. PMID:26814794

  14. An investigation of enhanced capability thermal barrier coating systems for diesel engine components

    NASA Technical Reports Server (NTRS)

    Holtzman, R. L.; Layne, J. L.; Schechter, B.

    1984-01-01

    Material systems and processes for the development of effective and durable thermal barriers for heavy duty diesel engines were investigated. Seven coating systems were evaluated for thermal conductivity, erosion resistance, corrosion/oxidation resistance, and thermal shock resistance. An advanced coating system based on plasma sprayed particle yttria stabilized zirconia (PS/HYSZ) was judged superior in these tests. The measured thermal conductivity of the selected coating was 0.893 W/m C at 371 C. The PS/HYSZ coating system was applied to the piston crown, fire deck and valves of a single cylinder low heat rejection diesel engine. The coated engine components were tested for 24 hr at power levels from 0.83 MPa to 1.17 MPa brake mean effective pressure. The component coatings survived the engine tests with a minimum of distress. The measured fire deck temperatures decreased 86 C (155 F) on the intake side and 42 C (75 F) on the exhaust side with the coating applied.

  15. Development of Thermal Barrier Coating System with Superior Thermal Cyclic Properties with an Intermediate Layer Containing MoSi2

    NASA Astrophysics Data System (ADS)

    Sonoya, Keiji; Tobe, Shogo

    The authors have developed a method of improving the thermal cyclic resistance of the thermal barrier coating system that is deposited on gas turbine components. A conventional thermal barrier coating consists of a duplex system: a top coating and a bond coating. The developed system has a protective intermediate layer of MoSi2 which prevents oxidation of the bond coating. The conventional duplex plasma -sprayed coating was delaminated after 20 thermal cycles. On the other hand, the developed triple-layered coating system was not delaminated after 60 cycles. The reason for the enhanced resistance to thermal cycles of the developed triple-layered coating system is that the MoSi2 layer between the top coating and the bond coating has a self-repairing property. MoSi2 oxidizes to form SiO2, which seals the cracks and pores formed between the top coating and the bond coating. Thus, the formation of a thermally grown oxide(TGO), which causes the delamination of the coating, is prevented and the thermal cyclic resistance is improved.

  16. Design of broadband multilayer dichroic coating for a high-efficiency solar energy harvesting system.

    PubMed

    Jiachen, Wang; Lee, Sang Bae; Lee, Kwanil

    2015-05-20

    We report on the design and performance of a broadband dichroic coating for a solar energy conversion system. As a spectral beam splitter, the coating facilitates a hybrid system that combines a photovoltaic cell with a thermal collector. When positioned at a 45° angle with respect to incident light, the coating provides high reflectance in the 40-1100 nm and high transmission in the 1200-2000 nm ranges for a photovoltaic cell and a thermal collector, respectively. Numerical simulations show that our design leads to a sharp transition between the reflection and transmission bands, low ripples in both bands, and slight polarization dependence. PMID:26192518

  17. ETV Program Report: Coatings for Wastewater Collection Systems - Epoxy Tec International, Inc., CPP RC3

    EPA Science Inventory

    The Epoxytec, Inc. CPP™ epoxy coating used for wastewater collection system rehabilitation was evaluated by EPA’s Environmental Technology Verification Program under laboratory conditions at the Center for Innovative Grouting Material and Technology (CIGMAT) Laboratory at the Uni...

  18. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2007-03-31

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the hightemperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several 409 low alloy steel samples after coating them in our fluidized bed reactor and also after exposing them to our corrosion test. We report the following findings: 1. A protective coating was deposited inside a porous 409 steel sample to protect it from sulfidation attack. The coating was based on a combination of Si diffusion layer, Nb interlayer and nitrides of titanium and silicon. 2. Analysis of solid coupons exposed to simulated coal gas at 900 C for 300 h showed that multilayer metal/ceramic coatings provide a better protection than ceramic coatings. 3. Deposition of several ceramic/metal multilayer coatings showed that coatings with niobium and tantalum interlayers have good adhesion. However, coatings with a tungsten interlayer suffered localized delaminating and coatings with Zr interlayers showed poor adhesion. 4. Analysis of solid coupons, coated with the above-mentioned multilayer films, after exposure to simulated coal gas at 900 C for 300 h showed that niobium is the best candidate for interlayer material.

  19. Biomimetic nanowire coatings for next generation adhesive drug delivery systems.

    PubMed

    Fischer, Kathleen E; Alemán, Benjamin J; Tao, Sarah L; Hugh Daniels, R; Li, Esther M; Bünger, Mark D; Nagaraj, Ganesh; Singh, Parminder; Zettl, Alex; Desai, Tejal A

    2009-02-01

    Without bioadhesive delivery devices, complex compounds are typically degraded or cleared from mucosal tissues by the mucous layer.While some chemically modified, microstructured surfaces have been studied in aqueous environments,adhesion due to geometry alone has not been investigated. Silicon nanowire-coated beads show significantly better adhesion than those with targeting agents under shear, and can increase the lift-off force 100-fold. We have shown that nanowire coatings, paired with epithelial physiology, significantly increase adhesion in mucosal conditions. PMID:19199759

  20. Thermodynamics and kinetics of reactions in protective coating systems

    NASA Technical Reports Server (NTRS)

    Gupta, B.; Sarkhel, A.; Shankar, S.; Seigle, L.

    1975-01-01

    A study of the aluminization of Ni from packs containing various percentages of unalloyed Al confirmed that the surface aluminum content of specimens aluminized tends to decrease with time and consequently a simple parabolic law for the weight-gain vs. time relationship is not obeyed. The diffusivity-composition relationship in NiAl was examined, and a set of curves is presented. A numerical method for the calculation of coating dissolution rates was developed and applied to NiAl-Ni3Al type of coatings.

  1. Approach to the development of CAD/CAM system for multilayer optical coatings

    NASA Astrophysics Data System (ADS)

    Mohan Rao, G. R.; Nagendra, C. L.; Thutupalli, G. K. M.

    1990-08-01

    CADCAM system is very vital in the development and production of high efficiency optical coatings, in which in-situ analysis and optiniizatfrxi is the nucleus. A new algoritlin for in-situ analysis and optimization of coatings has been proposed, which has provision for precise determination of optical parameters, namely refractive index n, and gearetrical thickness d, of any layer :tt the multilayered configuration and, to account for adverse effect of the deviaticxs in the optical pareters through global re-optimization of the coatings. It has been implemented on 8086/8087 microprocessor systn in which 8086 is a 16 bit microprocessor and 8087, a coprocessor for high speed floating point operatixs. The validity of the algorithn has been established through a wide range of hypothetical case studies and experimental deve1opint of a few coatings such as wideband antireflecticx coatings (ARCs).

  2. Finite Element Modeling of the Different Failure Mechanisms of a Plasma Sprayed Thermal Barrier Coatings System

    NASA Astrophysics Data System (ADS)

    Ranjbar-Far, M.; Absi, J.; Mariaux, G.

    2012-12-01

    A new finite element model is used to investigate catastrophic failures of a thermal barrier coatings system due to crack propagation along the interfaces between the ceramic top-coat, thermally grown oxide, and bond-coat layers, as well as between the lamellas structure of the ceramic layer. The thermo-mechanical model is designed to take into account a non-homogenous temperature distribution and the effects of the residual stresses generated during the coating process. Crack propagation is simulated using the contact tool "Debond" present in the ABAQUS finite element code. Simulations are performed with a geometry corresponding to similar or dissimilar amplitudes of asperity, and for different thicknesses of the oxide layer. The numerical results have shown that crack evolution depends crucially on the ratio of the loading rate caused by growth and swelling of the oxide layer and also on the interface roughness obtained during the spraying of coatings.

  3. Polyurethane/polysiloxane ceramer coatings: Corrosion resistant unicoat system for aircraft application

    NASA Astrophysics Data System (ADS)

    Ni, Hai

    New organic/inorganic ceramer coating system was developed using polyurethane as an organic phase and polysiloxane as the inorganic phase. The objective of the study was to develop a unicoat corrosion resistant coating which strongly adheres to aluminum substrates. The pre-ceramic silicon-oxo clusters react with the metal substrate, protecting it from oxidation, whereas the organic composition functions as a binder providing mechanical properties, optical properties, and chemical, wear and fluid resistance. The new ceramer coatings were evaluated as a replacement for chromate based coatings. The alkoxysilane-functionalized coupling agent was prepared from hexamethylene diisocyanate (HDI) isocyanurate and 3-aminopropyltriethoxysilane. The functionalized isocyanurate was characterized by 1H, 13C and 29Si NMR and electrospray ionization-mass spectrometry. An organic/inorganic hybrid coating system was formulated using the alkoxysilane-functionalized isocyanurate and HDI isocyanurate. The coating properties indicated that alkoxysilane-functionalized isocyanurate enhanced adhesion up to 500%. Based on the hybrid polyurea/alkoxysilane system, the polyurea/polysiloxane ceramer coating system was formulated with tetraethyl orthosilicate (TEOS) oligomers. Evaluation of ceramer coatings showed that coating properties were affected by both the concentration of TEOS oligomers and alkoxysilane functionalized isocyanurate. In addition, the para-toluene sulfonic acid was used to catalyze the moisture curing process for the ceramer coating system. The addition of acid catalyst further increased the adhesion. A series of high solids cycloaliphatic polyesters were synthesized to improve the UV-resistance for the organic/inorganic unicoat system. The polyurethane/polysiloxane ceramer coatings were formulated with the addition of the cycloaliphatic polyesters into the polyurea/polysiloxane system. The investigation of the polyurethane ceramer coatings indicated that the film

  4. Cyclic Failure Mechanisms of Thermal and Environmental Barrier Coating Systems Under Thermal Gradient Test Conditions

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Lee, Kang N.; Miller, Robert A.

    2002-01-01

    Plasma-sprayed ZrO2-8wt%Y2O3 and mullite+BSAS/Si multilayer thermal and environmental barrier coating (TBC-EBC) systems on SiC/SiC ceramic matrix composite (CMC) substrates were thermally cyclic tested under high thermal gradients using a laser high-heat-flux rig in conjunction with furnace exposure in water-vapor environments. Coating sintering and interface damage were assessed by monitoring the real-time thermal conductivity changes during the laser heat-flux tests and by examining the microstructural changes after exposure. Sintering kinetics of the coating systems were also independently characterized using a dilatometer. It was found that the coating failure involved both the time-temperature dependent sintering and the cycle frequency dependent cyclic fatigue processes. The water vapor environments not only facilitated the initial coating conductivity increases due to enhanced sintering and interface reaction, but also promoted later conductivity reductions due to the accelerated coating cracking and delamination. The failure mechanisms of the coating systems are also discussed based on the cyclic test results and are correlated to the sintering and thermal stress behavior under the thermal gradient test conditions.

  5. A simple method for the assessment of the contact modulus for coated systems

    NASA Astrophysics Data System (ADS)

    Bull, S. J.

    2015-06-01

    This paper describes a simple method to determine the elastic modulus of a coating on a substrate using nanoindentation based on the load support of a truncated cone of material beneath the indenter. The cone angle is shown to be 32.48° in all cases. The effect of the coating on the measured contact modulus increases more rapidly as the contact scale is reduced. The model describes the behaviour of a range of coating substrate systems very well, but deviations are observed in cases where pile-up or tip end-shape variations affect the experimental data. It is possible to use a fit of a simplified form of the model to experimental data for coatings on stiff substrates to determine the elastic properties of the coating independent of the substrate. The model can be generalized for multilayer coatings; this is essential when compliant coating layers are sandwiched between stiffer layers. The model shows that the mechanical properties of thin stiff coatings on compliant substrates cannot be successfully determined from indentation data. The ISO14577 extrapolation method should therefore not be used in such circumstances.

  6. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Astrophysics Data System (ADS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  7. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    NASA Technical Reports Server (NTRS)

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-01

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 10(exp 13) to 10(exp 15) n per square centimeters. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 10(exp 15) to 10(exp 16) n per square centimeters with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  8. Post Irradiation Evaluation of Thermal Control Coatings and Solid Lubricants to Support Fission Surface Power Systems

    SciTech Connect

    Bowman, Cheryl L.; Jaworske, Donald A.; Stanford, Malcolm K.; Persinger, Justin A.; Khorsandi, Behrooz; Blue, Thomas E.

    2007-01-30

    The development of a nuclear power system for space missions, such as the Jupiter Icy Moons Orbiter or a lunar outpost, requires substantially more compact reactor design than conventional terrestrial systems. In order to minimize shielding requirements and hence system weight, the radiation tolerance of component materials within the power conversion and heat rejection systems must be defined. Two classes of coatings, thermal control paints and solid lubricants, were identified as material systems for which limited radiation hardness information was available. Screening studies were designed to explore candidate coatings under a predominately fast neutron spectrum. The Ohio State Research Reactor Facility staff performed irradiation in a well characterized, mixed energy spectrum and performed post irradiation analysis of representative coatings for thermal control and solid lubricant applications. Thermal control paints were evaluated for 1 MeV equivalent fluences from 1013 to 1015 n/cm2. No optical degradation was noted although some adhesive degradation was found at higher fluence levels. Solid lubricant coatings were evaluated for 1 MeV equivalent fluences from 1015 to 1016 n/cm2 with coating adhesion and flexibility used for post irradiation evaluation screening. The exposures studied did not lead to obvious property degradation indicating the coatings would have survived the radiation environment for the previously proposed Jupiter mission. The results are also applicable to space power development programs such as fission surface power for future lunar and Mars missions.

  9. Effects of coating spray speed and convective heat transfer on transient thermal stress in thermal barrier coating system during the cooling process of fabrication

    NASA Astrophysics Data System (ADS)

    Song, Yan; Lv, Zhichao; Liu, Yilun; Zhuan, Xin; Wang, T. J.

    2015-01-01

    The coating spray speed and the convective heat transfer have significant effects on transient thermal stress in TBCs (Thermal Barrier Coating system) during the cooling process of fabrication. In this work, a simplified analytical model is developed firstly, to predict the transient thermal stress in YSZ (ZrO2-8%Y2O3) coating and shear stress at the coating-substrate interface during the cooling process of fabrication. Then, based on this simplified model, the effects of coating spray speed which determines the initial temperature field of YSZ coating, and the convective heat transfer coefficient between YSZ coating and the environment on transient thermal stress in TBCs during the cooling process have been studied. The results indicate that the YSZ coating spray speed has a significant effect on the transient thermal stress in YSZ coating and the shear stress near the edge of YSZ-substrate interface; effect of convective heat transfer on the thermal stress is more significant when convective heat transfer coefficient is bigger enough, and for a given convective heat transfer the effect becomes smaller as the cooling down process going on.

  10. A concept for the EQ coating system for nickel-based superalloys

    NASA Astrophysics Data System (ADS)

    Kawagishi, K.; Sato, A.; Harada, H.

    2008-07-01

    Nickel-based single-crystal superalloys with high concentrations of refractory elements are prone to generate a diffusion layer called a secondary reaction zone (SRZ) beneath their bond coating during long exposure to high temperatures. The SRZ causes a reduction of the load-bearing cross section and it is detrimental to the creep properties of thin-walled turbine airfoils. In this study, a new bond coat system, “EQ coating,” which is thermodynamically stable and suppresses SRZ has been proposed. Diffusion couples of coating materials and substrate alloys were made and heat treated at 1,100°C for 300 h and 1,000 h. Cyclic oxidation examinations were carried out at 1,100°C in air and the oxidation properties of EQ coating materials were discussed. High-velocity frame-sprayed EQ coatings designed for second-generation nickel-based superalloys were deposited on fourth-and fifth-generation nickel-based superalloys, and the stability of the microstructure at the interface and creep property of the coating system were investigated.

  11. Thermal High- and Low-Cycle Fatigue Behavior of Thick Thermal Barrier Coating Systems

    NASA Technical Reports Server (NTRS)

    Miller, Robert A.

    1998-01-01

    Ceramic thermal barrier coatings have received increasing attention for advanced gas turbine and diesel engine applications because of their ability to provide thermal insulation to engine components. However, the durability of these coatings under the severe thermal cycling conditions encountered in a diesel engine (ref. 1) still remains a major issue. In this research at the NASA Lewis Research Center, a high-power laser was used to investigate the thermal fatigue behavior of a yttria-stabilized zirconia coating system under simulated diesel engine conditions. The mechanisms of fatigue crack initiation and propagation, and of coating failure under complex thermal low-cycle fatigue (LCF, representing stop/start cycles) and thermal high-cycle fatigue (HCF, representing operation at 1300 rpm) are described. Continuous wave and pulse laser modes were used to simulate pure LCF and combined LCF/HCF, respectively (ref. 2). The LCF mechanism was found to be closely related to the coating sintering and creep at high temperatures. These creep strains in the ceramic coating led to a tensile stress state during cooling, thus providing the major driving force for crack growth under LCF conditions. The combined LCF/HCF tests induced more severe coating surface cracking, microspallation, and accelerated crack growth than did the pure LCF test. HCF thermal loads also facilitated lateral crack branching and ceramic/bond coat interface delaminations. HCF is associated with the cyclic stresses originating from the high-frequency temperature fluctuation at the ceramic coating surface. The HCF thermal loads act on the crack by a wedging mechanism (ref. 1), resulting in continuous crack growth at temperature. The HCF stress intensity factor amplitude increases with the interaction depth and temperature swing, and decreases with the crack depth. HCF damage also increases with the thermal expansion coefficient and the Young's modulus of the ceramic coating (refs. 1 and 3).

  12. Testing of Environmentally Preferable Aluminum Pretreatments and Coating Systems for Use on Space Shuttle Solid Rocket Boosters (SRB)

    NASA Technical Reports Server (NTRS)

    Clayton, C.; Raley, R.; Zook, L.

    2001-01-01

    The solid rocket booster (SRB) has historically used a chromate conversion coating prior to protective finish application. After conversion coating, an organic paint system consisting of a chromated epoxy primer and polyurethane topcoat is applied. An overall systems approach was selected to reduce waste generation from the coatings application and removal processes. While the most obvious waste reduction opportunity involved elimination of the chromate conversion coating, several other coating system configurations were explored in an attempt to reduce the total waste. This paper will briefly discuss the use of a systems view to reduce waste generation from the coating process and present the results of the qualification testing of nonchromated aluminum pretreatments and alternate coating systems configurations.

  13. Measured catalycities of various candidate space shuttle thermal protection system coatings at low temperatures

    NASA Technical Reports Server (NTRS)

    Scott, C. D.

    1973-01-01

    Atom recombination catalytic rates for surface coatings of various candidate thermal protection system materials for the space shuttle vehicle were obtained from measurements in arc jet, air flow. The coatings, chrome oxides, siliconized carbon/carbon, hafnium/tantalum carbide on carbon/carbon, and niobium silicide, were bonded to the sensitive surface of transient slug calorimeters that measured the heat transfer rates to the coatings. The catalytic rates were inferred from these heat transfer rates Surface temperatures of the calorimeters varied from approximately 300 to 410 K.

  14. Weathering performance of industrial atmospheric coating systems in the Arabian Gulf

    SciTech Connect

    Carew, J.; Al-Hashem, A.; Riad, W.T.; Othman, M.; Islam, M.

    1994-12-31

    The performance and durability of a number of industrial coating systems have been studied for two and a half years at five weathering sites in the industrial belt of Shuaiba Area, Kuwait, in the Arabian Gulf. The outdoor weathering performance of eleven coating systems was related to the prevailing industrial atmospheric conditions, and comparison made to their behavior under laboratory accelerated conditions. The coating systems studied included acrylic enamel, micaceous iron oxide epoxy, alkyd enamel, alkyd gloss, chlorinated rubber, polyurethane, and water-based acrylic. Experience in Kuwait has shown that with the longer hours of strong sunshine and ambient temperatures, as well as the chemical content of the atmosphere (e.g. O{sub 3}, SO{sub 2}, NO{sub X}, NH{sub 3}, Cl), dust retention and sandstorm, degrading of coatings has tended to be faster than in Western countries which most of these generic coating system were developed. Two accelerated test methods were used to evaluate the protective properties of the above mentioned coatings when applied to steel panels.

  15. Advanced Oxide Material Systems For 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal/environmental barrier coatings (T/EBCs) are being developed for low emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor containing combustion environments. The 1650 C T/EBC system is required to have better thermal stability, lower thermal conductivity, and improved sintering and thermal stress resistance than current coating systems. In this paper, the thermal conductivity, water vapor stability and cyclic durability of selected candidate zirconia-/hafnia-, pyrochlore- and magnetoplumbite-based T/EBC materials are evaluated. The test results have been used to downselect the T/EBC coating materials, and help demonstrate advanced 1650OC coatings feasibility with long-term cyclic durability.

  16. Hyperspectral characterization of the adjustable nano-coating systems

    NASA Astrophysics Data System (ADS)

    Murzina, Marina V. A.; Farrell, J. Paul; Aktsipetrov, Oleg A.; Murzina, Tatyana V.

    2005-05-01

    Nano-coatings with adjustable optical features is one of the revolutionary technologies of today. In this work, we investigate how hyperspectral imaging can detect adjustable nano-surfaces used, for example, for active camouflage. The distinct attributes of the nano-coating spectra are discussed. Fast algorithms of utilizing hyperspectral information for recognizing these attributes are suggested. The research applies to both recognizing the camouflaged objects and to building unrecognizable camouflage technology. In the context of tracking active camouflage, the identification of characteristic spectral attributes is especially important. Active spectra can constantly change, therefore confusing traditional hyperspectral classification. In contrast, the identified general spectral attributes stay the same allowing for robust identification and reliable tracking of the camouflaged objects.

  17. Broad Band Antireflection Coating on Zinc Sulphide Window for Shortwave infrared cum Night Vision System

    NASA Astrophysics Data System (ADS)

    Upadhyaya, A. S.; Bandyopadhyay, P. K.

    2012-11-01

    In state of art technology, integrated devices are widely used or their potential advantages. Common system reduces weight as well as total space covered by its various parts. In the state of art surveillance system integrated SWIR and night vision system used for more accurate identification of object. In this system a common optical window is used, which passes the radiation of both the regions, further both the spectral regions are separated in two channels. ZnS is a good choice for a common window, as it transmit both the region of interest, night vision (650 - 850 nm) as well as SWIR (0.9 - 1.7 μm). In this work a broad band anti reflection coating is developed on ZnS window to enhance the transmission. This seven layer coating is designed using flip flop design method. After getting the final design, some minor refinement is done, using simplex method. SiO2 and TiO2 coating material combination is used for this work. The coating is fabricated by physical vapour deposition process and the materials were evaporated by electron beam gun. Average transmission of both side coated substrate from 660 to 1700 nm is 95%. This coating also acts as contrast enhancement filter for night vision devices, as it reflect the region of 590 - 660 nm. Several trials have been conducted to check the coating repeatability, and it is observed that transmission variation in different trials is not very much and it is under the tolerance limit. The coating also passes environmental test for stability.

  18. Ring retroreflector system consisting of cube-corner reflectors with special coating

    SciTech Connect

    Burmistrov, V B; Sadovnikov, M A; Sokolov, A L; Shargorodskiy, V D

    2013-09-30

    The ring retroreflector system (RS) consisting of cubecorner reflectors (CCRs) with a special coating of reflecting surfaces, intended for uniaxially Earth-oriented navigation satellites, is considered. The error of distance measurement caused by both the laser pulse delay in the CCR and its spatial position (CCR configuration) is studied. It is shown that the ring RS, formed by the CCR with a double-spot radiation pattern, allows the distance measurement error to be essentially reduced. (nanogradient dielectric coatings and metamaterials)

  19. Modeling of vapor transport of electron beam evaporation based coating system

    NASA Astrophysics Data System (ADS)

    Maiti, Namita; Tak, Atul; Khabade, Yashodhan; Suryawanshi, V. B.; Das, A. K.

    2012-06-01

    The modeling of vapor transport of an electron beam evaporation based coating system has been carried out in this work. Computational fluid dynamics (CFD) modeling has been tailored to analyze the evaporation and deposition of titanium material. Based on the physical model, the model relates the output power of the electron gun and the temperature profile on the evaporant surface. The simulated vapor distribution helps in predicting the coating thickness. The experimental results presented here agree with the simulation results.

  20. Evaluation of the efficiency of radioactive decontamination for alkyd and epoxy-urethane coating systems

    NASA Astrophysics Data System (ADS)

    Jevremović, Milutin; Milošević, Bratislav; Lazarević, Nataša

    2010-01-01

    This article presents experimental results obtained by the investigation of the efficiency of radioactive decontamination of a metal surface with alkyd and epoxy-urethane coating systems, which are used for the painting of military equipment. During the evaluation of the efficiency of decontamination, the impact of contaminants on the coating was not examined but the amount of contaminants residual after decontamination was, and was determined by activity measurements of the surface. The samples for testing were painted aluminum plates contaminated by liquid solutions of radioactive isotopes 60Co, 133Ba, 152Eu and 241Am (A=12297.91 Bq/ml). Decontamination of contaminated samples was performed with 0.5% detergent solution on the basis of synthetic surfactants. The activity measurements of samples were conducted using gamma spectroscopy system with a high-resolution high-purity germanium (HPGe) detector of relative efficiency of 50% at 60Co (1.33 MeV). The degree of removal of the radioactivity on the samples was observed as an indicator of the efficiency of decontamination. A comparison of the results is presented in relation to the retention time of the contamination on the surface coating, which is an important factor for the efficiency of decontamination. The samples with an alkyd coating system showed better efficiency of decontamination than the samples with the epoxy-urethane coating system, although the coatings based on epoxy and urethane resin were superior in relation to the alkyd in terms of protection, decorative characteristics and chemical resistance. The difference in the efficiency of decontamination for the examined coatings increases almost linearly in relation to the retention time of the contaminants in the coating.

  1. Final Scientific/Technical Report "Arc Tube Coating System for Color Consistency"

    SciTech Connect

    Buelow, Roger; Jenson, Chris; Kazenski, Keith

    2013-03-21

    DOE has enabled the use of coating materials using low cost application methods on light sources to positively affect the output of those sources. The coatings and light source combinations have shown increased lumen output of LED fixtures (1.5%-2.0%), LED arrays (1.4%) and LED powered remote phosphor systems Philips L-Prize lamp (0.9%). We have also demonstrated lifetime enhancements (3000 hrs vs 8000 hrs) and shifting to higher CRI (51 to 65) in metal halide high intensity discharge lamps with metal oxide coatings. The coatings on LEDs and LED products are significant as the market is moving increasingly more towards LED technology. Enhancements in LED performance are demonstrated in this work through the use of available materials and low cost application processes. EFOI used low refractive index fluoropolymers and low cost dipping processes for application of the material to surfaces related to light transmission of LEDs and LED products. Materials included Teflon AF, an amorphous fluorinated polymer and fluorinated acrylic monomers. The DOE SSL Roadmap sets goals for LED performance moving into the future. EFOI's coating technology is a means to shift the performance curve for LEDs. This is not limited to one type of LED, but is relevant across LED technologies. The metal halide work included the use of sol-gel solutions resulting in silicon dioxide and titanium dioxide coatings on the quartz substrates of the metal halide arc tubes. The coatings were applied using low cost dipping processes.

  2. Monitoring Local Strain in a Thermal Barrier Coating System Under Thermal Mechanical Gas Turbine Operating Conditions

    NASA Astrophysics Data System (ADS)

    Manero, Albert; Sofronsky, Stephen; Knipe, Kevin; Meid, Carla; Wischek, Janine; Okasinski, John; Almer, Jonathan; Karlsson, Anette M.; Raghavan, Seetha; Bartsch, Marion

    2015-07-01

    Advances in aircraft and land-based turbine engines have been increasing the extreme loading conditions on traditional engine components and have incited the need for improved performance with the use of protective coatings. These protective coatings shield the load-bearing super alloy blades from the high-temperature combustion gases by creating a thermal gradient over their thickness. This addition extends the life and performance of blades. A more complete understanding of the behavior, failure mechanics, and life expectancy for turbine blades and their coatings is needed to enhance and validate simulation models. As new thermal-barrier-coated materials and deposition methods are developed, strides to effectively test, evaluate, and prepare the technology for industry deployment are of paramount interest. Coupling the experience and expertise of researchers at the University of Central Florida, The German Aerospace Center, and Cleveland State University with the world-class synchrotron x-ray beam at the Advanced Photon Source in Argonne National Laboratory, the synergistic collaboration has yielded previously unseen measurements to look inside the coating layer system for in situ strain measurements during representative service loading. These findings quantify the in situ strain response on multilayer thermal barrier coatings and shed light on the elastic and nonelastic properties of the layers and the role of mechanical load and internal cooling variations on the response. The article discusses the experimental configuration and development of equipment to perform in situ strain measurements on multilayer thin coatings and provides an overview of the achievements thus far.

  3. Development of TiN Coating System for Long Beam Ducts of Accelerators

    NASA Astrophysics Data System (ADS)

    Shibata, Kyo; Hisamatsu, Hiromi; Kanazawa, Ken-Ichi; Suetsugu, Yusuke; Shirai, Mitsuru

    A Titanium Nitride (TiN) coating system for long beam ducts of accelerators was developed to reduce the secondary electron yield (SEY) from the inner surface and to mitigate the electron cloud effect. Coating was carried out by DC magnetron sputtering of pure titanium in argon (2.0 Pa) and nitrogen (0.5 Pa) atmospheres. A copper beam duct with a maximum length of 3.6 m was set vertically, and a titanium rod as a cathode was suspended from the top along the central axis of the duct. A movable solenoid coil with a length of 0.8 m externally supplied a magnetic field of 16 mT to accommodate the long duct. By moving the solenoid coil at specified time intervals, the TiN film was uniformly coated on the inner surface. The thickness of the coating was 200 nm, and the temperature of the ducts during the coating was 130°C. Several coated ducts were installed into the KEKB positron ring during the summer shutdown in 2007. In the subsequent beam operation, the reduction of electrons in the coated duct was confirmed.

  4. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2006-06-30

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several coated and exposed samples of 409 steel by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX). We report here on findings of this analysis: (1) A SS409 coupon that was coated with multilayered combined nitrides of Ti, Al, and Si showed adherent coatings on the surface; (2) A similarly coated coupon, after exposure to simulated coal gas at 900 C for 300 h, revealed that the coating has cracked during the exposure; (3) An SS409 coupon that was coated with nitrides of Ti and Si with a barrier layer of tungsten in between to improve the adhesion of the coating and to prevent outward diffusion of iron to the surface. (4) A porous coupon was coated with nitrides of Ti and Al and examination of the coupon revealed deposition of Ti at the interior surfaces. A similarly prepared coupon was exposed to simulated coal gas at 370 C for 300 h, and it showed no corrosion.

  5. Burner Rig Evaluation of Thermal Barrier Coating Systems for Nickel-Base Alloys

    NASA Technical Reports Server (NTRS)

    Gedwill, M. A.

    1981-01-01

    Eight plasma sprayed bond coatings were evaluated for their potential use with ZrO2-Y2O3 thermal barrier coatings (TECs) which are being developed for coal derived fuel fired gas turbines. Longer TBC lives in cyclic burner rig oxidation to 1050 C were achieved with the more oxidation resistant bond coatings. These were Ni-14.1Cr-13.4A1-0.10Ar, Ni-14.1C4-14.4Al-0.16Y, and Ni-15.8Cr-12.8Al-0.36Y on Rene 41. The TBC systems performed best when 0.015-cm thick bond coatings were employed that were sprayed at 20 kW using argon 3.5v/o hydrogen. Cycling had a more life limiting influence on the TBC than accumulated time at 1050 C.

  6. Crack Driving Forces in a Multilayered Coating System for Ceramic Matrix Composite Substrates

    NASA Technical Reports Server (NTRS)

    Ghosn, Louis J.; Zhu, Dongming; Miller, Robert A.

    2005-01-01

    The effects of the top coating thickness, modulus and shrinkage strains on the crack driving forces for a baseline multilayer Yttria-Stabilized-Zirconia/Mullite/Si thermal and environment barrier coating (TEBC) system for SiC/SiC ceramic matrix composite substrates are determined for gas turbine applications. The crack driving forces increase with increasing modulus, and a low modulus thermal barrier coating material (below 10 GPa) will have no cracking issues under the thermal gradient condition analyzed. Since top coating sintering increases the crack driving forces with time, highly sintering resistant coatings are desirable to maintain a low tensile modulus and maintain a low crack driving force with time. Finite element results demonstrated that an advanced TEBC system, such as ZrO2/HfO2, which possesses improved sintering resistance and high temperature stability, exhibited excellent durability. A multi-vertical cracked structure with fine columnar spacing is an ideal strain tolerant coating capable of reducing the crack driving forces to an acceptable level even with a high modulus of 50 GPa.

  7. EGFR-Targeted Adenovirus Dendrimer Coating for Improved Systemic Delivery of the Theranostic NIS Gene

    PubMed Central

    Grünwald, Geoffrey K; Vetter, Alexandra; Klutz, Kathrin; Willhauck, Michael J; Schwenk, Nathalie; Senekowitsch-Schmidtke, Reingard; Schwaiger, Markus; Zach, Christian; Wagner, Ernst; Göke, Burkhard; Holm, Per S; Ogris, Manfred; Spitzweg, Christine

    2013-01-01

    We recently demonstrated tumor-selective iodide uptake and therapeutic efficacy of combined radiovirotherapy after systemic delivery of the theranostic sodium iodide symporter (NIS) gene using a dendrimer-coated adenovirus. To further improve shielding and targeting we physically coated replication-selective adenoviruses carrying the hNIS gene with a conjugate consisting of cationic poly(amidoamine) (PAMAM) dendrimer linked to the peptidic, epidermal growth factor receptor (EGFR)-specific ligand GE11. In vitro experiments demonstrated coxsackie-adenovirus receptor-independent but EGFR-specific transduction efficiency. Systemic injection of the uncoated adenovirus in a liver cancer xenograft mouse model led to high levels of NIS expression in the liver due to hepatic sequestration, which were significantly reduced after coating as demonstrated by 123I-scintigraphy. Reduction of adenovirus liver pooling resulted in decreased hepatotoxicity and increased transduction efficiency in peripheral xenograft tumors. 124I-PET-imaging confirmed EGFR-specificity by significantly lower tumoral radioiodine accumulation after pretreatment with the EGFR-specific antibody cetuximab. A significantly enhanced oncolytic effect was observed following systemic application of dendrimer-coated adenovirus that was further increased by additional treatment with a therapeutic dose of 131I. These results demonstrate restricted virus tropism and tumor-selective retargeting after systemic application of coated, EGFR-targeted adenoviruses therefore representing a promising strategy for improved systemic adenoviral NIS gene therapy. PMID:24193032

  8. Current status and approaches to developing press-coated chronodelivery drug systems.

    PubMed

    Lin, Shan-Yang; Kawashima, Yoshiaki

    2012-02-10

    The past several decades have seen the development of many controlled-release preparations featuring constant release rates to maintain drug concentrations in the human body, regardless of the patient's physiological condition. However, long-term constant drug concentrations in the blood and tissue can cause problems such as resistance, tolerability, and drug side effects. People vary considerably in their physiological and biochemical conditions during any 24 h period, due to the circadian rhythm, and thus, the constant delivery of a drug into the body seems both unnecessary and undesirable. If the drug release profile mimics a living system's pulsatile hormone secretion, then it may improve drug efficacy, and reduce the toxicity of a specific drug administration schedule. Medication and treatments provided according to the body's circadian rhythms will result in better outcomes. This may be provided by a chronopharmaceutical dosage regimen with pulsatile release that matches the circadian rhythm resulting from a disease state, so optimizing the therapeutic effect while minimizing side effects. The press coating technique is a simple and unique technology used to provide tablets with a programmable lag phase, followed by a fast, or rate-controlled, drug release after administration. The technique offers many advantages, and no special coating solvent or coating equipment is required for manufacturing this type of tablet. The present review article introduces chronopharmaceutical press-coated products from a patient physiological needs perspective. The contents of this article include biological rhythms and pulsatile hormone secretion in humans, the reasons for using pulsatile drug delivery for disease treatment, recent chronopharmaceutical preparations appearing on the market, updated compilation of all research articles and press-coated delivery techniques, factors affecting the performance and drug release characteristics of press-coated delivery systems, and

  9. Refractory Materials for Flame Deflector Protection System Corrosion Control: Coatings Systems Literature Survey

    NASA Technical Reports Server (NTRS)

    Calle, Luz M.; Hintze, Paul E.; Parlier, Christopher R.; Sampson, Jeffrey W.; Coffman, Brekke E.; Coffman, Brekke E.; Curran, Jerome P.; Kolody, Mark R.; Whitten, Mary; Perisich, Steven; Trejo, David

    2009-01-01

    When space vehicles are launched, extreme heat, exhaust, and chemicals are produced and these form a very aggressive exposure environment at the launch complex. The facilities in the launch complex are exposed to this aggressive environment. The vehicle exhaust directly impacts the flame deflectors, making these systems very susceptible to high wear and potential failure. A project was formulated to develop or identify new materials or systems such that the wear and/or damage to the flame deflector system, as a result of the severe environmental exposure conditions during launches, can be mitigated. This report provides a survey of potential protective coatings for the refractory concrete lining on the steel base structure on the flame deflectors at Kennedy Space Center (KSC).

  10. Thermodynamics and kinetics of reactions in protective coating systems

    NASA Technical Reports Server (NTRS)

    Gupta, B.; Sarkhel, A.; Sivakumar, R.; Seigle, L.

    1974-01-01

    Investigations of fluoride activated packs with Al:Ni ratios greater than 50 a/o prove that the specimen surface is not in equilibrium with the pack at high Al:Ni ratios but that an activity gradient exists between pack and specimen. Therefore, gaseous diffusion and possibly surface reactions play a role in determining the overall rate of Al deposition in such packs. Noticeable differences in coating behavior have been obtained in packs activated with chloride and iodide, and it appears that poorest results are obtained with iodides, better with chlorides, and best with fluorides. A numerical method has been perfected for calculating rates of solid-state diffusion controlled coating formation, allowing for the variation of diffusivity with composition in the NiAl phase. Layer growth rates can now be accurately predicted from a knowledge of the surface and substrate compositions. Furthermore, the correct diffusion profiles are obtained by this method. These differ substantially from the profile obtained when the diffusivity is assumed constant.

  11. Indigenous hydroxyapatite coated and bioactive glass coated titanium dental implant system – Fabrication and application in humans

    PubMed Central

    Mistry, Surajit; Kundu, Debabrata; Datta, Someswar; Basu, Debabrata; Soundrapandian, Chidambaram

    2011-01-01

    Background: The use of different bioactive materials as coating on dental implant to restore tooth function is a growing trend in modern Dentistry. In the present study, hydroxyapatite and the bioactive glass-coated implants were evaluated for their behavior in osseous tissue following implantation in 14 patients. Materials and Methods: Bioactive glass and hydroxyapatite formulated and prepared for coating on Ti-6Al-4V alloy. Hydroxyapatite coating was applied on the implant surface by air plasma spray technique and bioactive glass coating was applied by vitreous enameling technique. Their outcome was assessed after 6 months in vivo study in human. Results: Hydroxyapatite and bioactive glass coating materials were nontoxic and biocompatible. Uneventful healing was observed with both types of implants. Conclusion: The results showed bioactive glass is a good alternative coating material for dental implant. PMID:22028507

  12. The Development of Environmental Barrier Coating Systems for SiC-SiC Ceramic Matrix Composites: Environment Effects on the Creep and Fatigue Resistance

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Ghosn, Louis J.

    2014-01-01

    Topics covered include: Environmental barrier coating system development: needs, challenges and limitations; Advanced environmental barrier coating systems (EBCs) for CMC airfoils and combustors; NASA EBC systems and material system evolutions, Current turbine and combustor EBC coating emphases, Advanced development, processing, testing and modeling, EBC and EBC bond coats: recent advances; Design tool and life prediction of coated CMC components; Advanced CMC-EBC rig demonstrations; Summary and future directions.

  13. Broadband durable antireflection coating for an E-O system window having multiple-wavelength applications

    NASA Astrophysics Data System (ADS)

    Hasan, Wasim; Bui, Hoa T.

    1992-12-01

    Conventional ZnS, clear ZnS, ZnSe, and ZnS/ZnSe sandwich materials along with 8 to 12 micrometers anti-reflection (AR) coatings have been used as windows for forward looking infrared (FLIR) thermal imaging electro-optical sensors (such as those incorporated on PAVE TACK, F-18, and LANTIRN pods). Conventional ZnS also has been used as dome material for IR Maverick missiles and other missile applications. All of these systems have separate windows/systems for target designation, rangefinding, and low light level television (LLLTV) applications. New generation system require that a single window provide multispectral capabilities to perform various functions. A graded index AR coating developed at Hughes Danbury Optical Systems (HDOS) provides the multispectral capabilities and is highly durable for subsonic aircraft and missile applications. The spectral performance, durability, rain- erosion, and some sand and dust data of such a coating are presented in this paper. The data is also presented for this coating in conjunction with grids for EMI attenuation. The transmission of the coating as a function angle of incidence is also presented.

  14. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-09-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period, we conducted several exposure tests with coated and uncoated coupons including a ''500-h'' test. The first experiment was a 316-h test and was designed to look at the performance of Ti/Ta nitride coatings, which seemed to fare the best in earlier tests. The next experiment was a 112-h test with a range of pure metals and commercially available materials. Its purpose was to help identify those metals that best withstood gasifier environment, and hence should be good ingredients for coatings. Finally, we ran a ''500-h'' test, which was also our milestone, with coupons coated with Ti/Ta nitride or Cr/Al coatings.

  15. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2006-12-31

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we analyzed several coated and exposed samples of 409 steel by scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX), and report on the findings of four samples: (1) Analysis of two porous coupons after exposure to the porous metal particulate filter of the coal gasification power plant at 370 C for 2140 hours revealed that corrosion takes place in the bulk of the sample while the most external zone surface survived the test. (2) Coating and characterization of several porous 409 steel coupons after being coated with nitrides of Ti, Al and/or Si showed that adjusting experimental conditions results in thicker coatings in the bulk of the sample. (3) Analysis of coupons exposed to simulated coal gas at 370 C for 300 hours showed that a better corrosion resistance is achieved by improving the coatings in the bulk of the samples.

  16. Mechanical Characterization of CrN/CrAlN Multilayer Coatings Deposited by Magnetron Sputtering System

    NASA Astrophysics Data System (ADS)

    Kaouther, Khlifi; Hafedh, Dhiflaoui; Lassaad, Zoghlami; Ahmed, Ben Cheikh Larbi

    2015-10-01

    Chromium-based coatings are deposited on a 100Cr6 (AISI 52100) substrate by a physical vapor deposition magnetron sputtering system. The coatings have different structures, such as a CrN monolayer and CrAlN multilayer. The structural and morphological compositions of the coatings were evaluated using glow discharge optical emission spectroscopy, atomic force microscopy, and cross-sectional scanning electron microscopy. Nano-indentation tests were performed to investigate the mechanical properties. Domes and craters are shown to be uniformly distributed over the entire surfaces of the two coatings. Additionally, the CrN/CrAlN multilayer coating exhibits a rough surface, attractive mechanical properties, a high compressive stress, and a high plastic and elastic deformation resistance. The improvement of the mechanical properties of the CrN/CrAlN coating is mainly attributed to a reduction in the crystallite size. We found that this reduction was related to three factors: (1) the compositional change resulting from the substitution of aluminum for chromium, which can produce a decrease in the interatomic distance; (2) the structure of CrN/CrAlN, which was characterized by grain size refinement; and (3) the high number of interfaces, which explains the widely accepted concept of dislocation blocking by the layer interfaces.

  17. Design and Environmental Factors Contributing to the Failure of Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Weeks, Matthew David

    Gas turbine engines are a staple of 21st century air and sea propulsion systems and are also a critical component in large-scale electricity generation. The hot-section components of these engines are protected by a complex ceramic and metal multi-layer coating called a thermal barrier coating (TBC) system. The failure of TBC systems occurs as a result of both thermo-chemical and thermo-mechanical degradation. This research involves exploring both of these mechanisms for two distinctly different issues. The United States Navy is currently making a push to implement the use of alternative fuels by 2012, but the use of these fuels (syngas, high hydrogen content, and alternatives to JP-8) presents significant materials durability challenges. Initial data suggests that high water vapor levels, high sulfur concentrations, and ash deposits from fuel impurities lead to unique, and severe, degradation modes. This research is aimed at addressing the effects of differing combustion environment characteristics on the corrosion and oxidation of TBC systems. On the industrial front, there is a constant driver to better understand and predict coating failure, particularly in air-plasma sprayed (APS) TBC systems. The morphology of the metal-ceramic interface is known to play a key role in the generation of compressive and tensile stresses that eventually cause coating failure in typical engine environments. Experimental evidence and field experience have shown that a tortuous interface is generally beneficial to coating lifetime. Nevertheless, for the past 40 years engineers have struggled to find a functional correlation between BC topology and coating system lifetime. This document also addresses the progress that has been made toward the establishment of this functional correlation.

  18. Low-speed pressure measurements using a luminescent coating system

    NASA Astrophysics Data System (ADS)

    Brown, Owen Clayton

    In this work, the history of the development of the Pressure Sensitive Paint (PSP) technique in both the United States and Russia is first discussed in detail. A review of the various PSP tests conducted to date is given. A thorough discussion of the physics and chemistry of luminescent coatings is provided. The processes of converting intensity signals in digital data values are described; image processing procedures used to remove noise sources and convert intensity data into pressure measurements are reviewed. A general uncertainty analysis of the technique is then conducted. A baseline series of low-speed tests at M < 0.2 were conducted using unswept and swept NACA 0012 airfoils. The results of these tests are reviewed. Significant sources of noise were found: experimental processes were modified to reduce these noise components. These process improvements led to results that are unmatched in the literature: RMS Cp errors ranged from 0.21 at M = 0.03 (10 m/s) to 0.03 at M = 0.15 (50 m/s). Analyses were also conducted to identify optimized calibration techniques using pressure taps. A detailed uncertainty analysis is presented using both analytical and Monte Carlo simulation methods. This analysis confirms the observed measurement errors are reasonable, and that if using the in-situ technique, very good accuracies are indeed realizable at low speeds. Utilizing improved testing techniques, several other experiments at M < 0.2 were conducted to demonstrate the utility and capability of luminescent coatings in the Low-Speed regime, including a NACA 63-215 Mod B main element with a half-span Fowler flap, the deck of a Navy amphibious helicopter landing ship model, and a NASCAR racing model at various drafting orientations.

  19. A View of Compatible Heat-Resistant Alloy and Coating Systems at High-Temperatures

    SciTech Connect

    Narita, Toshio

    2009-09-14

    Conventional and advanced coatings were reviewed, and it was pointed out that the coated Ni-base superalloys decreased their creep rupture life significantly at higher temperatures, and the advanced high strength superalloy became more remarkably. Concept of diffusion barrier coating system (DBC system) and their formation process was introduced, and the results obtained for several heat-resistant alloys, stainless steel (SUS310S), Ni-Mo base alloy (Hastelloy-X), and 4{sup th} generation single crystal superalloy (TMS-138) were given. It was noted that creep-rupture life of the SUS310S and Hastelloy-X with the DBC system became longer than those of the bare alloys with or without conventional {beta}-NiAl coatings. This is due to slow creep-deformation of the Re-base alloy layer as the diffusion barrier. A novel concept based on combination of superalloys and coatings was proposed, by taking both the materials science and corrosion science into consideration.

  20. A View of Compatible Heat-Resistant Alloy and Coating Systems at High-Temperatures

    NASA Astrophysics Data System (ADS)

    Narita, Toshio

    2009-09-01

    Conventional and advanced coatings were reviewed, and it was pointed out that the coated Ni-base superalloys decreased their creep rupture life significantly at higher temperatures, and the advanced high strength superalloy became more remarkably. Concept of diffusion barrier coating system (DBC system) and their formation process was introduced, and the results obtained for several heat-resistant alloys, stainless steel (SUS310S), Ni-Mo base alloy (Hastelloy-X), and 4th generation single crystal superalloy (TMS-138) were given. It was noted that creep-rupture life of the SUS310S and Hastelloy-X with the DBC system became longer than those of the bare alloys with or without conventional β-NiAl coatings. This is due to slow creep-deformation of the Re-base alloy layer as the diffusion barrier. A novel concept based on combination of superalloys and coatings was proposed, by taking both the materials science and corrosion science into consideration.

  1. Galvanic Liquid Applied Coating System For Protection of Embedded Steel Surfaces from Corrosion

    NASA Technical Reports Server (NTRS)

    Curran, Joseph; Curran, Jerome; Voska, N. (Technical Monitor)

    2002-01-01

    Corrosion of reinforcing steel in concrete is an insidious problem facing Kennedy Space Center (KSC), other Government Agencies, and the general public. These problems include KSC launch support structures, highway bridge infrastructure, and building structures such as condominium balconies. Due to these problems, the development of a Galvanic Liquid Applied Coating System would be a breakthrough technology having great commercial value for the following industries: Transportation, Infrastructure, Marine Infrastructure, Civil Engineering, and the Construction Industry. This sacrificial coating system consists of a paint matrix that may include metallic components, conducting agents, and moisture attractors. Similar systems have been used in the past with varying degrees of success. These systems have no proven history of effectiveness over the long term. In addition, these types of systems have had limited success overcoming the initial resistance between the concrete/coating interface. The coating developed at KSC incorporates methods proven to overcome the barriers that previous systems could not achieve. Successful development and continued optimization of this breakthrough system would produce great interest in NASA/KSC for corrosion engineering technology and problem solutions. Commercial patents on this technology would enhance KSC's ability to attract industry partners for similar corrosion control applications.

  2. Advanced thermal barrier system bond coatings for use on Ni, Co-, and Fe-base alloy substrates

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1985-01-01

    New and improved Ni-, Co-, and Fe-base bond coatings have been identified for the ZrO2-Y2O3 thermal barrier coatings to be used on NI-, Co-, and Fe-base alloy substrates. These bond coatings were evaluated in a cyclic furnace between 1120 and 1175 C. It was found that MCrAlYb (where M = Ni, Co, or Fe) bond coating thermal barrier systems. The longest life was obtained with the FeCrAlYb thermal barrier system followed by NiCrAlYb and CoCrAlYb thermal barrier systems in that order.

  3. Advanced Oxide Material Systems for 1650 C Thermal/Environmental Barrier Coating Applications

    NASA Technical Reports Server (NTRS)

    Zhu, Dong-Ming; Fox, Dennis S.; Bansal, Narottam P.; Miller, Robert A.

    2004-01-01

    Advanced thermal and environmental barrier coatings (TEBCs) are being developed for low-emission SiC/SiC ceramic matrix composite (CMC) combustor and vane applications to extend the CMC liner and vane temperature capability to 1650 C (3000 F) in oxidizing and water-vapor-containing combustion environments. The advanced 1650 C TEBC system is required to have a better high-temperature stability, lower thermal conductivity, and more resistance to sintering and thermal stress than current coating systems under engine high-heat-flux and severe thermal cycling conditions. In this report, the thermal conductivity and water vapor stability of selected candidate hafnia-, pyrochlore- and magnetoplumbite-based TEBC materials are evaluated. The effects of dopants on the materials properties are also discussed. The test results have been used to downselect the TEBC materials and help demonstrate the feasibility of advanced 1650 C coatings with long-term thermal cycling durability.

  4. Creep Behavior of Hafnia and Ytterbium Silicate Environmental Barrier Coating Systems on SiC/SiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Fox, Dennis S.; Ghosn, Louis J.; Harder, Bryan

    2011-01-01

    Environmental barrier coatings will play a crucial role in future advanced gas turbine engines because of their ability to significantly extend the temperature capability and stability of SiC/SiC ceramic matrix composite (CMC) engine components, thus improving the engine performance. In order to develop high performance, robust coating systems for engine components, appropriate test approaches simulating operating temperature gradient and stress environments for evaluating the critical coating properties must be established. In this paper, thermal gradient mechanical testing approaches for evaluating creep and fatigue behavior of environmental barrier coated SiC/SiC CMC systems will be described. The creep and fatigue behavior of Hafnia and ytterbium silicate environmental barrier coatings on SiC/SiC CMC systems will be reported in simulated environmental exposure conditions. The coating failure mechanisms will also be discussed under the heat flux and stress conditions.

  5. Optimization of a Wcl6 CVD System to Coat UO2 Powder with Tungsten

    NASA Technical Reports Server (NTRS)

    Belancik, Grace A.; Barnes, Marvin W.; Mireles, Omar; Hickman, Robert

    2015-01-01

    In order to achieve deep space exploration via Nuclear Thermal Propulsion (NTP), Marshall Space Flight Center (MSFC) is developing W-UO2 CERMET fuel elements, with focus on fabrication, testing, and process optimization. A risk of fuel loss is present due to the CTE mismatch between tungsten and UO2 in the W-60vol%UO2 fuel element, leading to high thermal stresses. This fuel loss can be reduced by coating the spherical UO2 particles with tungsten via H2/WCl6 reduction in a fluidized bed CVD system. Since the latest incarnation of the inverted reactor was completed, various minor modifications to the system design were completed, including an inverted frit sublimer. In order to optimize the parameters to achieve the desired tungsten coating thickness, a number of trials using surrogate HfO2 powder were performed. The furnace temperature was varied between 930 C and 1000degC, and the sublimer temperature was varied between 140 C and 200 C. Each trial lasted 73-82 minutes, with one lasting 205 minutes. A total of 13 trials were performed over the course of three months, two of which were re-coatings of previous trials. The powder samples were weighed before and after coating to roughly determine mass gain, and Scanning Electron Microscope (SEM) data was also obtained. Initial mass results indicated that the rate of layer deposition was lower than desired in all of the trials. SEM confirmed that while a uniform coating was obtained, the average coating thickness was 9.1% of the goal. The two re-coating trials did increase the thickness of the tungsten layer, but only to an average 14.3% of the goal. Therefore, the number of CVD runs required to fully coat one batch of material with the current configuration is not feasible for high production rates. Therefore, the system will be modified to operate with a negative pressure environment. This will allow for better gas mixing and more efficient heating of the substrate material, yielding greater tungsten coating per trial.

  6. Effects of compositional changes on the performance of a thermal barrier coating system. [yttria-stabilized zirconia coatings on gas turbine engine blades

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1978-01-01

    Currently proposed thermal barrier systems for aircraft gas turbine engines consist of NiCrAlY bond coating covered with an insulating oxide layer of yttria-stabilized zirconia. The effect of yttrium concentration (from 0.15 to 1.08 w/o) in the bond coating and the yttria concentration (4 to 24.4 w/o) in the oxide layer were evaluated. Furnace, natural gas-oxygen torch, and Mach 1.0 burner rig cyclic tests on solid specimens and air-cooled blades were used to identify trends in coating behavior. Results indicate that the combinations of yttrium levels between 0.15 - 0.35 w/o in the bond coating and the yttria concentration between 6 - 8 w/o in the zirconium oxide layer were the most adherent and resistant to high temperature cyclic exposure.

  7. Wear and Corrosion Resistance of Fe-Based Coatings Reinforced by TiC Particles for Application in Hydraulic Systems

    NASA Astrophysics Data System (ADS)

    Bobzin, K.; Öte, M.; Linke, T. F.; Malik, K. M.

    2016-01-01

    Thermally sprayed Fe-based coatings reinforced by TiC particles are a cost-effective alternative to carbide coatings such as WC/CoCr, Cr3C2/NiCr, and hard chrome coatings. They feature a good wear resistance and—with sufficient amount of alloying elements like Cr and Ni—also a high corrosion resistance. In hydraulic systems, the piston is usually coated with hard chrome coatings for protection against corrosion and wear. New water-based hydraulic fluids require an adaption of the coating system. In order to investigate the wear and corrosion resistance of Fe/TiC, a novel powder consisting of a FeCr27Ni18Mo3 matrix and 34 wt.% TiC was applied by HVOF and compared to reference samples made of WC/CoCr (HVAF) and hard chrome. Besides an in-depth coating characterization (metallographic analyses, electron microprobe analyzer-EMPA), wear resistance was tested under reverse sliding in a water-based hydraulic fluid. The novel Fe/TiC coatings showed good wear protection properties, which are comparable to conventional coatings like WC/CoCr (HVAF) and electroplated hard chrome coatings. Corrosion resistance was determined by polarization in application-oriented electrolytes (hydraulic fluid at 60 °C, artificial sea water at RT). The corrosion resistance of the investigated iron-based coatings at 60 °C was superior to the references coatings for both hydraulic fluids. Selected coatings were tested in an application-oriented hydraulic test bench with HFC hydraulic fluid (water polymer solutions) showing comparably good wear and corrosion resistance as the hard chrome-coated reference.

  8. Optimization of antireflection coating design for multijunction solar cells and concentrator systems

    NASA Astrophysics Data System (ADS)

    Valdivia, Christopher E.; Desfonds, Eric; Masson, Denis; Fafard, Simon; Carlson, Andrew; Cook, John; Hall, Trevor J.; Hinzer, Karin

    2008-06-01

    Photovoltaic solar cells are a route towards local, environmentally benign, sustainable and affordable energy solutions. Antireflection coatings are necessary to input a high percentage of available light for photovoltaic conversion, and therefore have been widely exploited for silicon solar cells. Multi-junction III-V semiconductor solar cells have achieved the highest efficiencies of any photovoltaic technology, yielding up to 40% in the laboratory and 37% in commercial devices under varying levels of concentrated light. These devices benefit from a wide absorption spectrum (300- 1800 nm), but this also introduces significant challenges for antireflection coating design. Each sub-cell junction is electrically connected in series, limiting the overall device photocurrent by the lowest current-producing junction. Therefore, antireflection coating optimization must maximize the current from the limiting sub-cells at the expense of the others. Solar concentration, necessary for economical terrestrial deployment of multi-junction solar cells, introduces an angular-dependent irradiance spectrum. Antireflection coatings are optimized for both direct normal incidence in air and angular incidence in an Opel Mk-I concentrator, resulting in as little as 1-2% loss in photocurrent as compared to an ideal zero-reflectance solar cell, showing a similar performance to antireflection coatings on silicon solar cells. A transparent conductive oxide layer has also been considered to replace the metallic-grid front electrode and for inclusion as part of a multi-layer antireflection coating. Optimization of the solar cell, antireflection coating, and concentrator system should be considered simultaneously to enable overall optimal device performance.

  9. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2006-01-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period we tested coated alloy coupons under conditions designed to mimic the conditions in the filter unit after the high-temperature heat recovery unit (HTHRU). The filter unit is another important area where corrosion has caused unscheduled downtime, and the remedy has been the use of sintered metal tubes made of expensive alloys such as inconel. The objective of our test was to determine if those coatings on 400-series steel that were not able to withstand the harsher conditions of the HTHRU, may be sufficiently resistant for use in the filter unit, at the reduced temperatures. Indeed, most of our coatings survived well; the exceptions were the coated porous samples of SS316. We continued making improvements to our coatings apparatus and the procedure began during the last quarter. As a result of these modifications, the coupons we are now producing are uniform. We describe the improved procedure for preparing diffusion coatings. Finally, because porous samples of steel in grades other than SS316 are not readily available, we also decided to procure SS409 powder and fabricate our own sintered porous coupons.

  10. DEMONSTRATION OF A NO-VOC/NO-HAP WOOD KITCHEN CABINET COATING SYSTEM

    EPA Science Inventory

    The report gives results of the development and demonstration of a no-VOC (volatile organic compound)/no-HAP (hazardous air pollutant) wood furniture coating system at two cabinet manufacturing plants: one in Portland, OR, and the other in Redwood City, CA. Technology transfer ef...

  11. Nanocomposite coatings based on quaternary metal-nitrogen and nanocarbon systems

    NASA Astrophysics Data System (ADS)

    Walock, Michael J.

    For this project, CrN-WC coatings are investigated as a hybrid hard and tough material. The use of a hard-carbide with a corrosion-resistant nitride may produce tailored coatings with the desired combination of properties for use as a stand-alone protective coating, or as a basis for nanocrystalline diamond deposition. The work is divided into three stages. The initial study determined the viability of the CrN-WC system, and its use as an interlayer for nanocrystalline diamond. This successful study was followed by a variation of deposition conditions at low deposition temperature. By varying the deposition parameters, the microstructure, chemical, mechanical, and tribological behavior may be optimized. While the system has relatively good adhesion to silicon substrates, its adhesion to steel was lacking. Additionally, the system showed lower than expected mechanical properties. The final step increased the deposition temperature. The aim here was to increase adhesion and improve the mechanical properties. Prior results with other systems show consistent improvement of mechanical properties at elevated deposition temperatures. The high deposition temperature coatings showed marked improvement in various characteristics over their low deposition temperature cousins.

  12. Final Report on NASA Portable Laser Coating Removal Systems Field Demonstrations and Testing

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matthew J; McLaughlin, Russell L.

    2008-01-01

    Processes currently used throughout the National Aeronautics and Space Administration (NASA) to remove corrosion and coatings from structures, ground service equipment, small parts and flight components result in waste streams consisting of toxic chemicals, spent media blast materials, and waste water. When chemicals are used in these processes they are typically high in volatile organic compounds (VOC) and are considered hazardous air pollutants (HAP). When blast media is used, the volume of hazardous waste generated is increased significantly. Many of the coatings historically used within NASA contain toxic metals such as hexavalent chromium, and lead. These materials are highly regulated and restrictions on worker exposure continue to increase. Most recently the Occupational Safety and Health Administration (OSHA) reduced the permissible exposure limit (PEL) for hexavalent chromium (CrVI) from 52 to 5 micrograms per cubic meter of air as an 8-hour time-weighted average. Hexavalent chromium is found in numerous pretreatment and primer coatings used within the Space Shuttle Program. In response to the need to continue to protect assets within the agency and the growing concern over these new regulations, NASA is researching different ways to continue the required maintenance of both facility and flight equipment in a safe, efficient, and environmentally preferable manner. The use of laser energy to prepare surfaces for a variety of processes, such as corrosion and coating removal, weld preparation, and non destructive evaluation (NDE) is a relatively new application of the technology that has been proven to be environmentally preferable and in many cases less labor intensive than currently used removal methods. The novel process eliminates VOCs and blast media and captures the removed coatings with an integrated vacuum system. This means that the only waste generated are the coatings that are removed, resulting in an overall cleaner process. The development of a

  13. Development and in vitro Evaluation of Enteric Coated Multiparticulate System for Resistant Tuberculosis

    PubMed Central

    Rahman, Md. A.; Ali, J.

    2008-01-01

    The multiparticulate formulation of sodium para aminosalicylate for oral administration was developed by extrusion spheronization technique. Microcrystalline cellulose was used as filler in concentration of 14.4% w/w. Pellets were coated with Eudragit L 30 D-55 using fluidized bed processor. Different weight gains of acrylic polymer were applied onto the pellets and evaluated for in vitro dissolution behavior in 0.1 N HCl for two hours and then media was changed to phosphate buffer pH 6.8. A 60% w/w coating level of Eudragit L30 D 55 has produced the most acceptable results against the gastric attack. 3% Seal coat of HPMC E5 was also applied in order to protect the drug from migration into the Eudragit coat and film coat was applied in order to prevent aggregation of pellets in the dissolution media. Morphological characteristics of developed pellets were also investigated by scanning electron microscopy and found to be smooth and spherical. Developed system was found to be suitable for the delivery of Sod PAS in to intestinal region. PMID:20046774

  14. Impact of surface coated magnetite used in magnetic drug delivery system on immune response

    NASA Astrophysics Data System (ADS)

    Oaku, Yoshihiro; Tamada, Junya; Mishima, Fumihito; Akiyama, Yoko; Osako, Mariana Kiomy; Koriyama, Hiroshi; Nakagami, Hironori; Nishijima, Shigehiro

    2015-05-01

    Magnetic drug delivery system (MDDS) is a technique to effectively accumulate drugs, which are combined with ferromagnetic particles, into the affected area using magnetic force control. This study intends to apply MDDS for immunotherapy by enhancing immune responses by a surface treatment of a ferromagnetic particle. The objective of this study is to give the adjuvant effect to a ferromagnetic particle by the surface treatment with alum, which is known as one of the common adjuvants that activates inflammasome pathway. First, magnetite was prepared as a ferromagnetic particle and coated with alum. Alum-coated magnetite increased the expression of caspase-1, which is an activated indicator of inflammasome, in the culture of human monocyte cell (THP-1 cell). To evaluate the potential of the surface coated particles, the particles were subcutaneously injected to mice with a peptide vaccine. As a result, the antibody titer was increased by the surface coated particles as assessed by ELISA. Although a magnetic force has not yet applied in this study, the administration experiment to mice using magnetic force control is our next step. In conclusion, we modified the immune response to magnetite by coating the surface with alum. This can lead to a clinical application for vaccine therapy in future.

  15. [Silica-coated ethosome as a novel oral delivery system for enhanced oral bioavailability of curcumin].

    PubMed

    Li, Chong; Deng, Li; Zhang, Yan; Su, Ting-Ting; Jiang, Yin; Chen, Zhang-Bao

    2012-11-01

    The aim of this study is to investigate the feasibility of silica-coated ethosome as a novel oral delivery system for the poorly water-soluble curcumin (as a model drug). The silica-coated ethosomes loading curcumin (CU-SE) were prepared by alcohol injection method with homogenization, followed by the precipitation of silica by sol-gel process. The physical and chemical features of CU-SEs, and curcumin release were determined in vitro. The pharmacodynamics and bioavailability measurements were sequentially performed. The mean diameter of CU-SE was (478.5 +/- 80.3) nm and the polydispersity index was 0.285 +/- 0.042, while the mean value of apparent drug entrapment efficiency was 80.77%. In vitro assays demonstrated that CU-SEs were significantly stable with improved release properties when compared with curcumin-loaded ethosomes (CU-ETs) without silica-coatings. The bioavailability of CU-SEs and CU-ETs was 11.86- and 5.25-fold higher, respectively, than that of curcumin suspensions (CU-SUs) in in vivo assays. The silica coatings significantly promoted the stability of ethosomes and CU-SEs exhibited 2.26-fold increase in bioavailablity relative to CU-ETs, indicating that the silica-coated ethosomes might be a potential approach for oral delivery of poorly water-soluble drugs especially the active ingredients of traditional Chinese medicine with improved bioavailability. PMID:23387090

  16. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2005-12-01

    Heat exchangers, particle filters, turbines, and other components in an integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high-alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this reporting period, we conducted a simulated gasifier test primarily with TiN-coated steel samples. Although the test showed these coatings to offer significant protection against corrosion, they also revealed a lack of uniformity in the coatings. We spent a considerable amount of effort improving our coatings procedure as well as the fluidized bed reactor and its heater. Based on the results collected thus far, we selected 12 samples and sent them to ConocoPhillips for testing in their gasifier at the Wabash River Energy plant.

  17. Development of strain tolerant thermal barrier coating systems, tasks 1 - 3

    NASA Technical Reports Server (NTRS)

    Anderson, N. P.; Sheffler, K. D.

    1983-01-01

    Insulating ceramic thermal barrier coatings can reduce gas turbine airfoil metal temperatures as much as 170 C (about 300 F), providing fuel efficiency improvements greater than one percent and durability improvements of 2 to 3X. The objective was to increase the spalling resistance of zirconia based ceramic turbine coatings. To accomplish this, two baseline and 30 candidate duplex (layered MCrAlY/zirconia based ceramic) coatings were iteratively evaluated microstructurally and in four series of laboratory burner rig tests. This led to the selection of two candidate optimized 0.25 mm (0.010 inch) thick plasma sprayed partially stabilized zirconia ceramics containing six weight percent yttria and applied with two different sets of process parameters over a 0.13 mm (0.005 inch) thick low pressure chamber sprayed MCrAlY bond coat. Both of these coatings demonstrated at least 3X laboratory cyclic spalling life improvement over the baseline systems, as well as cyclic oxidation life equivalent to 15,000 commercial engine flight hours.

  18. Development of Intermixed Zones of Alumina/Zirconia in Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Stiger, M. J.; Yanar, N. M.; Jackson, R. W.; Laney, S. J.; Pettit, F. S.; Meier, G. H.; Gandhi, A. S.; Levi, C. G.

    2007-04-01

    The mechanisms whereby intermixed zones of alumina and zirconia are formed at the interface between the metallic bond coat and the ceramic top coat (yttria-stabilized zirconia) in thermal barrier coating systems have been investigated. The results lead to the following mechanism for the formation of the zones. The predominant mechanism for intermixed zone formation involves formation of a metastable alumina polymorph ( θ or γ) during TBC deposition, with a significant amount of zirconia dissolved in it. The outward growth also begins to incorporate zirconia particles, which initiates the formation of the intermixed zone. Upon thermal exposure, the metastable TGO continues to grow outward, extending the intermixed zone, and eventually transforms to the equilibrium α-Al2O3. The transformation to α-Al2O3 results in an increase in the volume fraction of zirconia in the intermixed zone as it is rejected from solution. Once the α-Al2O3 appears, subsequent TGO growth produces a columnar zone of the TGO without a second phase. When α-alumina was preformed on the bond coat, prior to TBC deposition, no intermixed zone was formed for Pt-modified aluminide bond coats.

  19. Stress crack resistance of some pigmented and unpigmented tablet film coating systems.

    PubMed

    Okhamafe, A O; York, P

    1985-07-01

    Stress crack resistance parameters--tensile strength: Young's modulus ratio, relative surface energy, and toughness index--have been examined for unpigmented free films of hydroxypropyl methylcellulose containing polyvinyl alcohol, and polyethylene glycols 400 and 1000, as well as similar film systems pigmented with either talc or titanium dioxide. Incorporation of either polyvinyl alcohol or polyethylene glycols 400 and 1000 in hydroxypropyl methylcellulose film coatings eliminated the incidence of edge splitting in the coated tablets. Increase in pigment concentration generally led to a decrease in the crack resistance of pigmented films. There was a relation between the stress crack resistance of pigmented free films and the incidence of edge splitting of corresponding film coatings applied to aspirin tablets--generally, the higher the crack resistance the lower the incidence of edge splitting. A similar relationship applied to the unpigmented films only when the tensile strength: Young's modulus ratio was considered. PMID:2863345

  20. Influence of lithium coating on the optics of Doppler backscatter system.

    PubMed

    Zhang, X H; Liu, A D; Zhou, C; Hu, J Q; Wang, M Y; Yu, C X; Liu, W D; Li, H; Lan, T; Xie, J L

    2015-10-01

    This paper presents the first investigation of the effect of lithium coating on the optics of Doppler backscattering. A liquid lithium limiter has been applied in the Experimental Advanced Superconducting Tokamak (EAST), and a Doppler backscattering has been installed in the EAST. A parabolic mirror and a flat mirror located in the vacuum vessel are polluted by lithium. An identical optical system of the Doppler backscattering is set up in laboratory. The power distributions of the emission beam after the two mirrors with and without lithium coating (cleaned before and after), are measured at three different distances under four incident frequencies. The results demonstrate that the influence of the lithium coating on the power distributions are very slight, and the Doppler backscattering can work normally under the dosage of lithium during the 2014 EAST campaign. PMID:26520951

  1. Influence of lithium coating on the optics of Doppler backscatter system

    SciTech Connect

    Zhang, X. H.; Liu, A. D. Zhou, C.; Hu, J. Q.; Wang, M. Y.; Yu, C. X.; Liu, W. D.; Li, H.; Lan, T.; Xie, J. L.

    2015-10-15

    This paper presents the first investigation of the effect of lithium coating on the optics of Doppler backscattering. A liquid lithium limiter has been applied in the Experimental Advanced Superconducting Tokamak (EAST), and a Doppler backscattering has been installed in the EAST. A parabolic mirror and a flat mirror located in the vacuum vessel are polluted by lithium. An identical optical system of the Doppler backscattering is set up in laboratory. The power distributions of the emission beam after the two mirrors with and without lithium coating (cleaned before and after), are measured at three different distances under four incident frequencies. The results demonstrate that the influence of the lithium coating on the power distributions are very slight, and the Doppler backscattering can work normally under the dosage of lithium during the 2014 EAST campaign.

  2. Galvanic Liquid Applied Coating System for Protection of Embedded Steel Surfaces from Corrosion

    NASA Technical Reports Server (NTRS)

    Curran, Joseph; MacDowell, Louis; Voska, N. (Technical Monitor)

    2002-01-01

    The corrosion of reinforcing steel in concrete is an insidious problem for the Kennedy Space Center, government agencies, and the general public. Existing corrosion protection systems on the market are costly, complex, and time-consuming to install, require continuous maintenance and monitoring, and require specialized skills for installation. NASA's galvanic liquid-applied coating offers companies the ability to conveniently protect embedded steel rebar surfaces from corrosion. Liquid-applied inorganic galvanic coating contains one ore more of the following metallic particles: magnesium, zinc, or indium and may contain moisture attracting compounds that facilitate the protection process. The coating is applied to the outer surface of reinforced concrete so that electrical current is established between metallic particles and surfaces of embedded steel rebar; and electric (ionic) current is responsible for providing the necessary cathodic protection for embedded rebar surfaces.

  3. Structure engineering in vacuum-arc-deposited coatings of the MoN-CrN system

    NASA Astrophysics Data System (ADS)

    Beresnev, V. M.; Sobol', O. V.; Pogrebnjak, A. D.; Grankin, S. S.; Stolbovoi, V. A.; Turbin, P. V.; Meilekhov, A. A.; Arseenko, M. Yu.

    2016-05-01

    The possibilities of structure engineering in multilayer coatings of the MoN-CrN system with relatively low heats of formation of component transition metal nitrides are demonstrated by varying pressure P N of reactive gas (nitrogen) and negative bias voltage- U s applied to a metal substrate. It is established that, by changing P N from 7 × 10-4 to 3 × 10-3 Torr, it is possible to obtain coatings in two significantly different structural-phase states. A multilayer nonisostructural composite with hexagonal crystalline lattice in CrN layers and cubic type lattice in MoN layers is formed at low pressure, whereas an isostructural state with cubic lattice in both nitride layers is formed at high pressure. The existence of two types of structural states allows multilayer coatings with controlled hardness to be obtained, which reaches 38 GPa in the isostructural state.

  4. Electrically insulating coatings for V-Li self-cooled blanket in a fusion system

    SciTech Connect

    Natesan, K.; Reed, C. B.; Uz, M.; Park, J. H.; Smith, D. L.

    2000-05-17

    The blanket system is one of the most important components in a fusion reactor because it has a major impact on both the economics and safety of fusion energy. The primary functions of the blanket in a deuterium/tritium-fueled fusion reactor are to convert the fusion energy into sensible heat and to breed tritium for the fuel cycle. The liquid-metal blanket concept requires an electrically insulating coating on the first-wall structural material to minimize the magnetohydrodynamic pressure drop that occurs during the flow of liquid metal in a magnetic field. Based on the thermodynamics of interactions between the coating and the liquid lithium on one side and the structural V-base alloy on the other side, several coating candidates are being examined to perform the insulating function over a wide range of temperatures and lithium chemistries.

  5. Development of stable low-electroosmotic mobility coatings. [for use in electrophoresis systems in space

    NASA Technical Reports Server (NTRS)

    Vanderhoff, J. W.; Micale, F. J.

    1979-01-01

    Long-time rinsings of the Z6040-methlycellulose coating used successfully on the ASTP MA=011 experiment indicate the permanency of this coating is inadequate for continuous flowing systems. Two approaches are described for developing coatings which are stable under continuous fluid movement and which exhibit finite and predictable electroosmotic mobility values while being effective on different types of surfaces, such as glass, plastics, and ceramic alumina, such as is currently used as the electrophoresis channel in the GE-SPAR-CPE apparatus. The surface charge modification of polystyrene latex, especially by protein absorption, to be used as model materials for ground-based electrophoresis experiments, and the preliminary work directed towards the seeded polymerization of large-particle-size monodisperse latexes in a microgravity environment are discussed.

  6. Mechanisms governing the interfacial delamination of thermal barrier coating system with double ceramic layers

    NASA Astrophysics Data System (ADS)

    Xu, Rong; Fan, Xueling; Wang, T. J.

    2016-05-01

    A systematic study of factors affecting the interfacial delamination of thermal barrier coating system (TBCs) with double ceramic layers (DCL) is presented. Crack driving forces for delaminations at two weak interfaces are examined. The results show that a thicker outermost ceramic layer can induce dramatic increase in crack driving force and make the interface between two ceramic coatings become more prone to delamination. The behavior is shown to be more prominent in TBCs with stiffer outmost coating. The thickness ratio of two ceramic layers is an important parameter for controlling the failure mechanisms and determining the lifetime of DCL TBCs under inservice condition. By accounting for the influences of thickness ratio of two ceramic layers and interfacial fracture toughnesses of two involved interfaces, the fracture mechanism map of DCL TBCs has been constructed, in which different failure mechanisms are identified. The results quanlitatively agree with the aviliable experimental data.

  7. Apatite coating of electrospun PLGA fibers using a PVA vehicle system carrying calcium ions.

    PubMed

    Kim, In Ae; Rhee, Sang-Hoon

    2010-01-01

    A novel method to coat electrospun poly(D,L-lactic-co-glycolic acid) (PLGA) fiber surfaces evenly and efficiently with low-crystalline carbonate apatite crystals using a poly(vinyl alcohol) (PVA) vehicle system carrying calcium ions was presented. A non-woven PLGA fabric was prepared by electrospinning: a 10 wt% PLGA solution was prepared using 1,1,3,3-hexafluoro-2-propanol as a solvent and electrospun under a electrical field of 1 kV/cm using a syringe pump with a flowing rate of 3 ml/h. The non-woven PLGA fabric, 12 mm in diameter and 1 mm in thickness, was cut and then coated with a PVA solution containing calcium chloride dihydrate (specimen PPC). As controls, pure non-woven PLGA fabric (specimen P) and fabric coated with a calcium chloride dihydrate solution without PVA (specimen PC) were also prepared. Three specimens were exposed to simulated body fluid for 1 week and this exposure led to form uniform and complete apatite coating layer on the fiber surfaces of specimen PPC. However, no apatite had formed to the fiber surfaces of specimen P and only inhomogeneous coating occurred on the fiber surfaces of specimen PC. These results were explained in terms of the calcium chelating and adhesive properties of PVA vehicle system. The practical implication of the results is that this method provides a simple but efficient technique for coating the fiber surface of an initially non-bioactive material with low-crystalline carbonate apatite. PMID:20507712

  8. A wideband optical monitor for a planetary-rotation coating-system

    SciTech Connect

    Campanelli, M.B.; Smith, D.J.

    1998-12-01

    A substrate-specific, through-planet, wideband optical coating monitor is being developed to increase production yield and the understanding of physical vapor deposition (PVD) coatings fabricated in the Optical Manufacturing Laboratory at the University of Rochester`s Laboratory for Laser Energetics. In-situ wideband optical monitoring of planetary rotation systems allows direct monitoring of large, expensive substrates with complex layering schemes. The optical monitor discussed here is under development for coating several large (e.g., 80.7 x 41.7 x 9.0 cm) polarizers for the National Ignition Facility. Wideband optical monitoring of the production substrates is used in concert with an array of crystal monitors for process control, film parameter evaluation, and error detection with associated design reoptimization. The geometry of a planetary rotation system, which produces good uniformity across large substrates, makes optical monitoring more difficult. Triggering and timing techniques for data acquisition become key to the process because the optical coating is available only intermittently for monitoring. Failure to properly consider the effects of the system dynamics during data retrieval and processing may result in significant decreases in the spectral data`s reliability. Improved data accuracy allows better determination of film thicknesses, indices, and inhomogeneities and enables in-situ error detection for design reoptimization.

  9. Advanced thermal barrier coating system development: Technical progress report

    SciTech Connect

    1996-08-07

    Objectives are to provide an improved TBC system with increased temperature capability and improved reliability, for the Advanced Turbine Systems program (gas turbine). The base program consists of three phases: Phase I, program planning (complete); Phase II, development; and Phase III (selected specimen-bench test). Work is currently being performed in Phase II.

  10. Application of a production line phosphorescence sensor coating system on a jet engine for surface temperature detection

    NASA Astrophysics Data System (ADS)

    Sollazzo, P. Y.; Feist, J. P.; Berthier, S.; Charnley, B.; Wells, J.; Heyes, A. L.

    2013-09-01

    Thermal Barrier Coatings (TBC) are used to reduce the working temperature of the high pressure turbine blade metal surface and hence permit engines to operate at higher temperatures/ efficiencies. A sensor TBC is an adaptation of existing TBCs to enhance their functionality, such that they become sensors and allow measurement of component temperatures. The sensing capability is introduced by embedding optically active materials into the TBC and by illuminating these coatings with excitation light phosphorescence can be observed. The phosphorescence carries temperature and structural information about the coating. This paper describes the first ever implementation of a sensor coating system on a full-scale jet engine. The system consists of three main components: industrially manufactured coatings, advanced remote detection optics with large stand-off distances and tailored control and readout software. The majority of coatings were based on yttrium stabilized zirconia doped with Dy and Eu, although other coatings were manufactured, too. Coatings were produced on a production line using atmospheric plasma spraying. An advanced optical system was designed, manufactured and operated permitting scanning of coated components using a wide acceptance angle. Successful measurements were taken from the nozzle guide vanes at the inlet to the turbine section and are reported in the paper.

  11. Advanced thermal barrier system bond coatings for use on nickel-, cobalt- and iron-base alloy substrates

    NASA Technical Reports Server (NTRS)

    Stecura, S.

    1986-01-01

    New and improved Ni-, Co-, and Fe-base bond coatings have been identified for the ZrO2-Y2O3 thermal barrier coatings to be used on Ni-, Co-, and Fe-base alloy substrates. These bond coatings were evaluated in a cyclic furnace between 1120 and 1175 C. It was found that MCrAlYb (where M = Ni, Co, or Fe) bond coating thermal barrier systems have significantly longer lives than MCrAlY bond coating thermal barrier systems. The longest life was obtained with the FeCrAlYb thermal barrier system followed by NiCrAlYb and CoCrAlYb thermal barrier systems in that order.

  12. New environmental barrier coating system on carbon-fiber reinforced silicon carbide composites

    NASA Astrophysics Data System (ADS)

    Latzel, S.; Vaßen, R.; Stöver, D.

    2005-06-01

    Carbon-fiber-reinforced silicon carbide composites (C/SiC) are promising materials for high-temperature, light weight structural components. However, a protective coating and environmental barrier coating (EBC) are necessary to prevent the oxidation of the carbon and the reaction of the formed silica scale with water vapor. Current EBC systems use multiple layers, each serving unique requirements. However, any mismatch in the coefficients of thermal expansion (CTE) creates internal stresses and might lead to crack formation. In this case, oxygen and water vapor penetrate through the EBC, reducing the lifetime of the component. Mullite (Al6Si2O13) is used in many known EBC systems on silicon-based ceramics either as an EBC itself or as a bondcoat. Due to its low CTE and its sufficient thermal cycling behavior, mullite was chosen in this investigation as a first layer. As mullite suffers loss of SiO2 when exposed to water vapor at high temperatures, an additional protective top coat is needed to complete the EBC system. Different oxides were evaluated to serve as top coat, especially high-temperature oxides with low coefficients of thermal expansion (LCTE). An EBC containing mullite as bondcoat and the LCTE oxide La2Hf2O7 as a top coat is proposed. Both layers were applied via atmospheric plasma spraying. In this paper, results of the influence of processing conditions on the microstructure of single mullite and LCTE oxide layers as well as mullite/LCTE oxide systems are presented. Special emphasis was directed toward the crystallinity of the mullite layer and, in the top layer, toward low porosity and reduced crack density.

  13. Transparent Si-DLC coatings on metals with high repetition bi-polar pulses of a PBII system

    NASA Astrophysics Data System (ADS)

    Ikeyama, Masami; Sonoda, Tsutomu

    2013-07-01

    Diamond-like carbon (DLC) is widely used because of its good properties. However, the color of DLC is usually dark brown or black. Recently, we have made fairly transparent Si contained DLC (Si-DLC) coatings in visible light region. The fairly transparent Si-DLC was made by using our original bi-polar pulse type plasma based ion implantation (PBII) system, with recently introduced high slew rate pulse power supply. The colors of metal sample surface were uniformly changed as subdued red, yellow, subdued green and subdued blue or violet, with the change of Si-DLC coating's thickness. The colors come from the interference between reflected lights at the surface of the Si-DLC coatings and the surface of the metal samples. The colors were also changed with the angle of glancing. Estimated refractive indexes show well agreements among almost all Si-DLC coatings, instead of the differences of coating conditions. Generally, the longer coating time or slower coating process makes the higher refractive index in near infrared region. Estimated band gap of a Si-DLC coating was about 1.5 eV. The developed Si-DLC coatings must be useful as not only protective but also decorative coatings.

  14. TPB-coated light guides for liquid argon TPC light detection systems

    NASA Astrophysics Data System (ADS)

    Ignarra, C. M.

    2013-10-01

    Light detection systems in Liquid Argon Time Projection Chambers (LArTPCs) require the detection of the 128 nm light produced during argon scintillation. Most detectors use Tetraphenyl Butadiene (TPB) to shift the wavelength of the light into a range visible to Photomultiplier Tubes (PMTs). These proceedings summarize characterizations of light-guides coated with a matrix of TPB in UV transmitting acrylic which are more compact than existing LArTPC light collection systems.

  15. Improved TPB-coated light guides for liquid argon TPC light detection systems

    NASA Astrophysics Data System (ADS)

    Moss, Z.; Bugel, L.; Collin, G.; Conrad, J. M.; Jones, B. J. P.; Moon, J.; Toups, M.; Wongjirad, T.

    2015-08-01

    Scintillation light produced in liquid argon (LAr) must be shifted from 128 nm to visible wavelengths in light detection systems used for liquid argon time-projection chambers (LArTPCs). To date, LArTPC light collection systems have employed tetraphenyl butadiene (TPB) coatings on photomultiplier tubes (PMTs) or plates placed in front of the PMTs. Recently, a new approach using TPB-coated light guides was proposed. In this paper, we report on light guides with improved attenuation lengths above 100 cm when measured in air. This is an important step in the development of meter-scale light guides for future LArTPCs. Improvements come from using a new acrylic-based coating, diamond-polished cast UV transmitting acrylic bars, and a hand-dipping technique to coat the bars. We discuss a model for connecting bar response in air to response in liquid argon and compare this to data taken in liquid argon. The good agreement between the prediction of the model and the measured response in liquid argon demonstrates that characterization in air is sufficient for quality control of bar production. This model can be used in simulations of light guides for future experiments.

  16. Secure and effective gene delivery system of plasmid DNA coated by polynucleotide.

    PubMed

    Kodama, Yukinobu; Ohkubo, Chikako; Kurosaki, Tomoaki; Egashira, Kanoko; Sato, Kayoko; Fumoto, Shintaro; Nishida, Koyo; Higuchi, Norihide; Kitahara, Takashi; Nakamura, Tadahiro; Sasaki, Hitoshi

    2015-01-01

    Polynucleotides are anionic macromolecules which are expected to transfer into the targeted cells through specific uptake mechanisms. So, we developed polynucleotides coating complexes of plasmid DNA (pDNA) and polyethylenimine (PEI) for a secure and efficient gene delivery system and evaluated their usefulness. Polyadenylic acid (polyA), polyuridylic acid (polyU), polycytidylic acid (polyC), and polyguanylic acid (polyG) were examined as the coating materials. pDNA/PEI/polyA, pDNA/PEI/polyU, and pDNA/PEI/polyC complexes formed nanoparticles with a negative surface charge although pDNA/PEI/polyG was aggregated. The pDNA/PEI/polyC complex showed high transgene efficiency in B16-F10 cells although there was little efficiency in pDNA/PEI/polyA and pDNA/PEI/polyU complexes. An inhibition study strongly indicated the specific uptake mechanism of pDNA/PEI/polyC complex. Polynucleotide coating complexes had lower cytotoxicity than pDNA/PEI complex. The pDNA/PEI/polyC complex showed high gene expression selectively in the spleen after intravenous injection into mice. The pDNA/PEI/polyC complex showed no agglutination with erythrocytes and no acute toxicity although these were observed in pDNA/PEI complex. Thus, we developed polynucleotide coating complexes as novel vectors for clinical gene therapy, and the pDNA/PEI/polyC complex as a useful candidate for a gene delivery system. PMID:25148610

  17. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Angel Sanjurjo

    2006-06-01

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. In previous tests, we had frequently encountered problems with our steam generator that were exacerbated by the very low flow rates that we needed. During this period we installed a new computer-controlled system for injecting water into the steam generator that eliminated this problem. We also tested alloy coupons coated by using the improved procedures described in our last quarterly report. Most of these coatings were nitrided Ti and Ta coatings, either by themselves, or sometimes with barrier layers of Al and Si nitrides. The samples were tested for 300 h at 900 C in a gas stream designed to mimic the environment in the high temperature heat recovery unit (HTHRU). Three samples that showed least corrosion were exposed for an additional 100 h.

  18. Stress analysis for multilayered coating systems using semi-analytical BEM with geometric non-linearities

    NASA Astrophysics Data System (ADS)

    Zhang, Yao-Ming; Gu, Yan; Chen, Jeng-Tzong

    2011-05-01

    For a long time, most of the current numerical methods, including the finite element method, have not been efficient to analyze stress fields of very thin structures, such as the problems of thin coatings and their interfacial/internal mechanics. In this paper, the boundary element method for 2-D elastostatic problems is studied for the analysis of multi-coating systems. The nearly singular integrals, which is the primary obstacle associated with the BEM formulations, are dealt with efficiently by using a semi-analytical algorithm. The proposed semi-analytical integral formulas, compared with current analytical methods in the BEM literature, are suitable for high-order geometry elements when nearly singular integrals need to be calculated. Owing to the employment of the curved surface elements, only a small number of elements need to be divided along the boundary, and high accuracy can be achieved without increasing more computational efforts. For the test problems studied, very promising results are obtained when the thickness of coated layers is in the orders of 10-6-10-9, which is sufficient for modeling most coated systems in the micro- or nano-scales.

  19. Enhanced thermal safety and high power performance of carbon-coated LiFePO4 olivine cathode for Li-ion batteries

    NASA Astrophysics Data System (ADS)

    Zaghib, K.; Dubé, J.; Dallaire, A.; Galoustov, K.; Guerfi, A.; Ramanathan, M.; Benmayza, A.; Prakash, J.; Mauger, A.; Julien, C. M.

    2012-12-01

    The carbon-coated LiFePO4 Li-ion oxide cathode was studied for its electrochemical, thermal, and safety performance. This electrode exhibited a reversible capacity corresponding to more than 89% of the theoretical capacity when cycled between 2.5 and 4.0 V. Cylindrical 18,650 cells with carbon-coated LiFePO4 also showed good capacity retention at higher discharge rates up to 5C rate with 99.3% coulombic efficiency, implying that the carbon coating improves the electronic conductivity. Hybrid Pulse Power Characterization (HPPC) test performed on LiFePO4 18,650 cell indicated the suitability of this carbon-coated LiFePO4 for high power HEV applications. The heat generation during charge and discharge at 0.5C rate, studied using an Isothermal Microcalorimeter (IMC), indicated cell temperature is maintained in near ambient conditions in the absence of external cooling. Thermal studies were also investigated by Differential Scanning Calorimeter (DSC) and Accelerating Rate Calorimeter (ARC), which showed that LiFePO4 is safer, upon thermal and electrochemical abuse, than the commonly used lithium metal oxide cathodes with layered and spinel structures. Safety tests, such as nail penetration and crush test, were performed on LiFePO4 and LiCoO2 cathode based cells, to investigate on the safety hazards of the cells upon severe physical abuse and damage.

  20. Hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications

    SciTech Connect

    Seals, Roland D.

    2015-08-18

    The present disclosure relates generally to hardface coating systems and methods for metal alloys and other materials for wear and corrosion resistant applications. More specifically, the present disclosure relates to hardface coatings that include a network of titanium monoboride (TiB) needles or whiskers in a matrix, which are formed from titanium (Ti) and titanium diboride (TiB.sub.2) precursors by reactions enabled by the inherent energy provided by the process heat associated with coating deposition and, optionally, coating post-heat treatment. These hardface coatings are pyrophoric, thereby generating further reaction energy internally, and may be applied in a functionally graded manner. The hardface coatings may be deposited in the presence of a number of fluxing agents, beta stabilizers, densification aids, diffusional aids, and multimode particle size distributions to further enhance their performance characteristics.

  1. Characterization and refinement of carbide coating formation rates and dissolution kinetics in the Ta-C system

    SciTech Connect

    Rodriguez, P.J.

    1996-10-01

    The interaction between carbide coating formation rates and dissolution kinetics in the tantalum-carbon system was investigated. The research was driven by the need to characterize carbide coating formation rates. The characterization of the carbide coating formation rates was required to engineer an optimum processing scheme for the fabrication of the ultracorrosion-resistant composite, carbon-saturated tantalum. A packed-bed carburization process was successfully engineered and employed. The packed-bed carburization process produced consistent, predictable, and repeatable carbide coatings. A digital imaging analysis measurement process for accurate and consistent measurement of carbide coating thicknesses was developed. A process for removing the chemically stable and extremely hard tantalum-carbide coatings was also developed in this work.

  2. Corrosion Resistance Characterization of Coating Systems Used to Protect Aluminum Alloys Using Electrochemical Impedance Spectroscopy and Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Gambina, Federico

    In this study, the corrosion protection provided by of a number of chromate and chromate-free coatings systems was characterized in detail. High-solids SrCrO4-pigmented epoxy primers applied to 2024 and 7075 substrates were subject to salt spray exposure testing for 30 days. Samples were removed periodically and an electrochemical impedance measurement (EIS) was made. Although none of the coatings tested showed visual evidence of corrosion, the total impedance of the samples decreased by as much as two orders of magnitude. An analysis of capacitance showed that the primer coatings rapidly took up water from the exposure environment, but the coating-metal remained passive despite the fact that it was wet. These results support the idea that chromate coatings protect by creating a chromate-rich electrolyte within the coating that is passivating to the underlying metal substrate. They also suggest that indications of metal substrate passivity found in the low-frequency capacitive reactance of the impedance spectra are a better indicator of corrosion protection than the total impedance. The low-frequency capacitive reactance from EIS measurements is also good at assessing the protectiveness of chromate-free coatings systems. Fifteen different coatings systems comprising high-solids, chromate-free primers and chromate-free conversion coatings were applied to 2024 and 7075 substrates. These coatings were subject to salt spray exposure and EIS measurements. All coatings were inferior to coating systems containing chromate, but changes in the capacitive reactance measured in EIS was shown to anticipate visual indications of coating failure. A predictive model based on neural networks was trained to recognize the pattern in the capacitive reactance in impedance spectra measured after 48 hours of exposure and make an estimate of remaining coating life. A sensitivity analysis was performed to prune the impedance inputs. As a result of this analysis, a very simple but highly

  3. Design of the scanning mode coated glass color difference online detection system

    NASA Astrophysics Data System (ADS)

    Bi, Weihong; Zhang, Yu; Wang, Dajiang; Zhang, Baojun; Fu, Guangwei

    2008-03-01

    A design of scanning mode coated glass color difference online detection system was introduced. The system consisted of color difference data acquirement part and orbit control part. The function of the color difference data acquirement part was to acquire glass spectral reflectance and then processed them to get the color difference value. Using fiber for light guiding, the reflected light from surface of glass was transmitted into light division part, and the dispersive light was imaged on linear CCD, and then the output signals from the CCD was sampled pixel by pixel, and the spectral reflectance of coated glass was obtained finally. Then, the acquired spectral reflectance signals was sent to industrial personal computer through USB interface, using standard color space and color difference formula nominated by International Commission on Illumination (CIE) in 1976 to process these signals, and the reflected color parameter and color difference of coated glass was gained in the end. The function of the orbit control part was to move the detection probe by way of transverse scanning mode above the glass strip, and control the measuring start-stop time of the color difference data acquirement part at the same time. The color difference data acquirement part of the system was put on the orbit which is after annealing area in coated glass production line, and the protected fiber probe was placed on slide of the orbit. Using single chip microcomputer to control transmission mechanism of the slide, which made the slide move by way of transverse scanning mode on the glass strip, meanwhile, the color difference data acquirement part of the system was also controlled by the single chip microcomputer, and it made the acquirement part measure color difference data when the probe reached the needed working speed and required place on the glass strip. The scanning mode coated glass color difference online detection system can measure color parameter and color difference of

  4. Blunt Trauma Performance of Fabric Systems Utilizing Natural Rubber Coated High Strength Fabrics

    SciTech Connect

    Ahmad, M. R.; Ahmad, W. Y. W.; Samsuri, A.; Salleh, J.; Abidin, M. H.

    2010-03-11

    The blunt trauma performance of fabric systems against 9 mm bullets is reported. Three shots were fired at each fabric system with impact velocity of 367+-9 m/s and the depth of indentation on the modeling clay backing was measured. The results showed that 18-layer and 21-layer all-neat fabric systems failed the blunt trauma test. However, fabric systems with natural rubber (NR) latex coated fabric layers gave lower blunt trauma of between 25-32 mm indentation depths. Deformations on the neat fabrics upon impact were identified as broken yarns, yarn stretching and yarn pull-out. Deflections of the neat fabrics were more localised. For the NR latex coated fabric layers, no significant deformation can be observed except for peeled-off regions of the NR latex film at the back surface of the last layer. From the study, it can be said that the NR latex coated fabric layers were effective in reducing the blunt trauma of fabric systems.

  5. Amorphous alumina oxidation protective coatings for Zircaloy based on a compositional gradient layer system

    NASA Astrophysics Data System (ADS)

    Park, Sang Tae

    Waterside corrosion of the Zircaloy cladding encasing the uranium oxide pellets is one of the primary factors limiting high "burn up" of nuclear fuel in pressurized water reactors (PWRs). High "burn up" can significantly impact plant safety and economics. Amorphous aluminum oxide coatings with aluminum-based compositional gradient layers (CGLs) were fabricated to develop ceramic coating corrosion protection systems for Zircaloy. Aluminum films were deposited on Zircaloy substrates by electron-beam evaporation, and two-step heat treatments were performed at near the melting temperature of aluminum. Amorphous alumina coatings by rf magnetron sputtering were overcoated on the CGL structures. Morphological and compositional studies were completed using field emission scanning electron microscopy (FE SEM), energy dispersive x-ray analysis (EDX), and auger electron spectroscopy (AES). The AES depth profiles of the annealed coatings showed that gradient compositions of Al, Zr, and O were obtained. Glancing angle x-ray diffraction (GAXRD) analysis showed that a variety of intermetallic and oxide phases (such as Al3Zr, Al2Zr3, Al2O3, ZrO2 and Zr3O) were formed in the coatings during processing. The intermetallic layers improved the adhesion property of the alumina overcoating to Zircaloy substrate, and functioned as oxidation resistant layers. In spite of the successful construction of the compositional gradient layer system with a good adhesion and thermal stability, and the report about the stability of pure alumina and amorphous ceramics in hydrothermal conditions, the amorphous alumina coatings in our study were not stable under nuclear reactor conditions of subcritical water at 350°C and 20.1 MPa (3000 psi). We investigated the behavior of amorphous alumina thin films deposited on Zircaloy substrates in the near-supercritical water. When the coatings were exposed to the subcritical conditions, hydrothermally grown well-faceted crystallite formation was observed

  6. Hybrid Co-Cr/W-WC and Ni-W-Cr-B/W-WC Coating Systems

    NASA Astrophysics Data System (ADS)

    Vernhes, L.; Azzi, M.; Bousser, E.; Schmitt, T.; Lamarre, J. M.; Klemberg-Sapieha, J. E.

    2016-01-01

    The aim of this study was to investigate the effects of subsurface materials on the performance of a wear-resistant thin film. The mechanical, tribological, and corrosion properties were assessed for two hybrid coating systems: (1) W-WC thin film and a laser cladded Co-Cr interlayer applied to a 316 stainless steel substrate and (2) the same W-WC thin film and a spray-and-fused Ni-W-Cr-B interlayer applied to an Inconel® 718 substrate. They were then compared to the same systems without an interlayer. The microstructures were analyzed by XRD, EDS, and SEM. The hardness and surface load-carrying capacity of the coating systems were determined by micro- and macrohardness testing. Rockwell indentation was used to assess coating adhesion (CEN/TS 1071-8). Tribological properties were assessed with a reciprocating tribometer, and corrosion resistance was determined by potentiodynamic polarization and electrochemical impedance spectroscopy. The originality of this work lies in the finding that, except for the Inconel 718/Ni-W-Cr-B/W-WC system, the wear rate decreases with decreasing hardness of the subsurface materials carrying the thin film due to the decreasing contact pressure for a given load. Another novel finding is the stress-induced phase transformation of the Co-Cr interlayer, which occurs beneath the thin film under high load.

  7. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Jordi Perez; Marc Hornbostel; Kai-Hung Lau; Angel Sanjurjo

    2007-05-31

    Advanced electric power generation systems use a coal gasifier to convert coal to a gas rich in fuels such as H{sub 2} and CO. The gas stream contains impurities such as H{sub 2}S and HCl, which attack metal components of the coal gas train, causing plant downtime and increasing the cost of power generation. Corrosion-resistant coatings would improve plant availability and decrease maintenance costs, thus allowing the environmentally superior integrated-gasification-combined-cycle (IGCC) plants to be more competitive with standard power-generation technologies. Heat-exchangers, particle filters, turbines, and other components in the IGCC system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low cost alloy will improve is resistance to such sulfidation attack and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. The Fe- and Ni-based high-temperature alloys are susceptible to sulfidation attack unless they are fortified with high levels of Cr, Al, and Si. To impart corrosion resistance, these elements need not be in the bulk of the alloy and need only be present at the surface layers. In this study, the use of corrosion-resistant coatings on low alloy steels was investigated for use as high-temperature components in IGCC systems. The coatings were deposited using SRI's fluidized-bed reactor chemical vapor deposition technique. Diffusion coatings of Cr and Al were deposited by this method on to dense and porous, low alloy stainless steel substrates. Bench-scale exposure tests at 900 C with a simulated coal gas stream containing 1.7% H{sub 2}S showed that the low alloy steels such SS405 and SS409 coated with {approx

  8. Shuttle active thermal control system development testing. Volume 7: Improved radiator coating adhesive tests

    NASA Technical Reports Server (NTRS)

    Reed, M. W.

    1973-01-01

    Silver/Teflon thermal control coatings have been tested on a modular radiator system projected for use on the space shuttle. Seven candidate adhesives have been evaluated in a thermal vacuum test on radiator panels similar to the anticipated flight hardware configuration. Several classes of adhesives based on polyester, silicone, and urethane resin systems were tested. These included contact adhesives, heat cured adhesives, heat and pressure cured adhesives, pressure sensitive adhesives, and two part paint on or spray on adhesives. The coatings attached with four of the adhesives, two silicones and two urethanes, had no changes develop during the thermal vacuum test. The two silicone adhesives, both of which were applied to the silver/Teflon as transfer laminates to form a tape, offered the most promise based on application process and thermal performance. Each of the successful silicone adhesives required a heat and pressure cure to adhere during the cryogenic temperature excursion of the thermal-vacuum test.

  9. Effect of Coating Process Condition on High-Temperature Oxidation and Mechanical Failure Behavior for Plasma Sprayed Thermal Barrier Coating Systems

    NASA Astrophysics Data System (ADS)

    Takahashi, Satoru; Yoshiba, Masayuki; Harada, Yoshio

    In order to clarify the thermal and/or mechanical failure behavior of the plasma sprayed thermal barrier coating (TBC) system in connection with their coating characteristics depending on the coating process condition, two kinds of the failure analytical tests were conducted for TBC systems processed under different conditions. One was the high-temperature oxidation test, which was conducted at 1100°C under both the isothermal and thermal cycle conditions. The other was the in-situ observation of mechanical failure behavior, which was conducted under the static loadings at ambient temperature; as the most fundamental aspect, by means of an optical microscopy. It was found that the thermal and mechanical failure behavior of TBC system depends strongly on the top-coat (TC)/bond-coat (BC) interfacial condition, the reheat-treatment (RHT) after spraying and so on. For the TBC system with vacuum plasma sprayed (VPS) BC as well as for that with atmospheric plasma sprayed (APS) BC, in particular, the RHT at an appropriate temperature in Ar atmosphere was found to be effective for improving the oxidation property. For the TBC system with APS-BC, however, it was impossible to prevent the crack growth into the BC interior under the tensile loading in spite of conducting the RHT, since the microdefects such as oxides within the APS-BC tend to provide an easy crack propagation path. Furthermore, it was clarified that the smoothening process on the BC surface is able to prevent perfectly the occurrence of the wart-like oxide during oxidation, but at the same time increases also the risk of the TC spalling under the mechanical loading.

  10. Development and characterization of fatty acid-coated microgels within microfluidic systems

    NASA Astrophysics Data System (ADS)

    Kraft, Mary L.

    2003-10-01

    Fatty acid-coated hydrogel microstructures (mugels) were prepared within microfluidic devices and their properties were investigated. A photopolymerization technique was used to position pH-sensitive mugels within microchannels, and lipophilic acid chlorides were covalently grafted to these objects with an in situ process. The resulting hydrophobic coatings served as selectively permeable barriers that enabled pH-sensitive mugels to remain contracted while bathed by buffered solutions that caused expansion in unmodified samples. Modified mugels were capable of swelling once the fatty acid coating was physically disrupted. Barrier permeability was also chemically induced with buffered detergent solutions, triggering complete hydrogel expansion through an asymmetric process. The influence of the fatty acid chain length on the ion gradient stability in the absence of perturbing additives was investigated. In contrast to solid-supported self-assembled monolayers (SAMs), the ion gradient stability of the modified mugels did not increase with increasing chain length, suggesting the structure of the fatty acid coating was inherently different from that of a SAM. The structure of the fatty acid-modified mugels was elucidated through the characterization of comparable hydrogel substrates. Imaging the microstructures with scanning electron microscopy revealed a rough and irregular hydrogel surface, which indicated structural assessment would be challenging since many surface characterization techniques require smooth substrates to acquire depth profiles. The presence of the fatty acid coating was confirmed through investigation of an analogous model system with X-ray photoelectron spectroscopy and secondary ion mass spectrometry. Laser scanning confocal microscopy and the use of a lipophilic fluorescent dye indicated the coating was confined to the periphery of the mugel. Transmission electron microscopy imaging of modified nonionic hydrogels revealed the mugel matrix was

  11. Evaluation of a new photoresist dispense system to detect coating variation

    NASA Astrophysics Data System (ADS)

    Gapin, Florent; Le-Peutrec, Bernard; Stock, Laurent; Hanotte, Marc

    2009-03-01

    A minimal change of dispensed volume will have a severe impact on the film thickness uniformity and in the worst case there might be some lack of resist on the wafer. Therefore it is essential to set-up the photoresist dispense accurately to avoid any dispense variation. In addition, it is important to monitor the dispense conditions real-time to detect problems which may have a direct negative impact on process yield. This paper presents the evaluation of the IntelliGen® Mini dispense system which is manufactured by Entegris, Inc. This new system is able to detect variations like bubbles in the dispense line, changes to the stop suckback valve, and changes in viscosity1. After an explanation of the pump characteristics and the potential root causes of dispense variation and their consequences, the evaluation done in Altis Semiconductor will be presented. The study has been made utilizing different photo-chemicals, including low and mid-range viscosity photo- resists and anti-reflective coatings. The capability of this new product to detect any perturbation of coating will be demonstrated. Then standard tests like coating repeatability, defect density CD uniformity and finally wafer yield inspection will be performed to prove efficiency of the system in a production mode.

  12. Final Report on Portable Laser Coating Removal Systems Field Demonstrations and Testing

    NASA Technical Reports Server (NTRS)

    Rothgeb, Matthew J.; McLaughlin, Russell L.

    2008-01-01

    Processes currently used throughout the National Aeronautics and Space Administration (NASA) to remove corrosion and coatings from structures, ground service equipment and small components results in waste streams consisting of toxic chemicals, spent media blast materials, and waste water. When chemicals are used in these processes they are typically high in volatile organic compounds (VOC) and are considered hazardous air pollutants (HAP). When blast media is used, the volume of hazardous waste generated is increased significantly. Many of the coatings historically used within NASA contain toxic metals such as hexavalent chromium, and lead. These materials are highly regulated and restrictions on worker exposure continue to increase. Most recently the EPA reduced the permissible exposure limit (PEL) for hexavalent chromium. The new standard lowers OSHA's PEL for hexavalent chromium from 52 to 5 micrograms of Cr(V1) per cubic meter of air as an 8-hour time-weighted average. Hexavalent chromium is found in the pretreatment and primer coatings used within the Shuttle Program. In response to the need to continue to protect assets within the agency and the growing concern over these new regulations, NASA is researching different ways to continue the required maintenance of both facility and flight equipment in a safe, efficient and environmentally preferable manner. The use of laser energy to remove prepare surfaces for a variety of processes, such as corrosion and coating removal, weld preparation and non destructive evaluation is a relatively new technology that has shown itself to be environmentally preferable and in many cases less labor intensive than currently used removal methods. The development of a Portable Laser Coating Removal System (PLCRS) started as the goal of a Joint Group on Pollution Prevention (JG-PP) project, led by the Air Force, where several types of lasers in several configurations were thoroughly evaluated. Following this project, NASA decided

  13. Long-Term Anti-Corrosion Performance of a Conducting Polymer-Based Coating System for Steels

    NASA Astrophysics Data System (ADS)

    Pan, Tongyan; Yu, Qifeng

    2016-06-01

    The long-term durability of a two-layer coating system was evaluated by two accelerated corrosion tests, i.e., the ASTM B117 Salt spray test and the ASTM D5894 Cyclic salt fog/UV exposure test, and a series of surface analyses. The coating system was developed for protecting structural steels from corrosion, including a functional primer made of intrinsically conducting polymer (ICP) and a protective topcoat. The standard pull-off test per ASTM D4541 was employed for characterizing the adhesion of the coating systems to substrate, aided by visual examination of the surface deterioration of the samples. The ICP-based systems demonstrated superior long-term anti-corrosion capacity when a polyurethane topcoat is used. The ICP-based primer made of a waterborne epoxy gave poorer anti-corrosion performance than the ICP-based primer made of regular non-waterborne epoxy, which can be attributed to the lower adhesion the waterborne epoxy demonstrated to the substrate surface. The zinc-rich control systems showed good anti-corrosion durability; however, they may produce excessive oxidative products of zinc to cause coating delamination. Based on the test results, the two-layer coating system consisting of an ICP-based primer and a polyurethane topcoat outperforms the conventional zinc-rich coating systems for corrosion protection of steels.

  14. Flow Characteristics in Compact Thermal Spray Coating Systems with Minimum Length Nozzle

    NASA Astrophysics Data System (ADS)

    Seung-Hyun, Kim; Youn-Jea, Kim

    2009-10-01

    In this study, numerical analysis is performed to adopt the equivalence ratio on the high velocity oxygen fuel (HVOF) thermal spray coating systems equipped with a minimum length nozzle. The analysis is applied to investigate the axisymmetric, steady-state, turbulent, and chemically combusting flow both within the torch and in a free jet region between the torch and the substrate to be coated. The combustion is modeled using a single-step and eddy-dissipation model which assumes that the reaction rate is limited by the turbulent mixing rate of the fuel and oxidant. As the diameter of the nozzle throat is increased, the location of the Mach shock disc moves backward from the nozzle exit. As the throat diameter and the divergent portion are 6 mm and 8 mm, respectively, the pressure in the HVOF system is the lowest at the chamber and the expanding gas is steadily maintained with both high velocity and high temperature for different equivalence ratios. Thus, relatively minor amendments of the equivalence ratio and the geometry of HVOF can lead to improved control over coating characteristics.

  15. Sustainable design and manufacturing of multifunctional polymer nanocomposite coatings: A multiscale systems approach

    NASA Astrophysics Data System (ADS)

    Xiao, Jie

    Polymer nanocomposites have a great potential to be a dominant coating material in a wide range of applications in the automotive, aerospace, ship-making, construction, and pharmaceutical industries. However, how to realize design sustainability of this type of nanostructured materials and how to ensure the true optimality of the product quality and process performance in coating manufacturing remain as a mountaintop area. The major challenges arise from the intrinsic multiscale nature of the material-process-product system and the need to manipulate the high levels of complexity and uncertainty in design and manufacturing processes. This research centers on the development of a comprehensive multiscale computational methodology and a computer-aided tool set that can facilitate multifunctional nanocoating design and application from novel function envisioning and idea refinement, to knowledge discovery and design solution derivation, and further to performance testing in industrial applications and life cycle analysis. The principal idea is to achieve exceptional system performance through concurrent characterization and optimization of materials, product and associated manufacturing processes covering a wide range of length and time scales. Multiscale modeling and simulation techniques ranging from microscopic molecular modeling to classical continuum modeling are seamlessly coupled. The tight integration of different methods and theories at individual scales allows the prediction of macroscopic coating performance from the fundamental molecular behavior. Goal-oriented design is also pursued by integrating additional methods for bio-inspired dynamic optimization and computational task management that can be implemented in a hierarchical computing architecture. Furthermore, multiscale systems methodologies are developed to achieve the best possible material application towards sustainable manufacturing. Automotive coating manufacturing, that involves paint spay and

  16. Non Evaporable Getter (NEG) Coatings for Vacuum Systems in Synchrotron Radiation Facilities

    NASA Astrophysics Data System (ADS)

    Manini, Paolo; Conte, Andrea; Raimondi, Stefano; Bonucci, Antonio

    2007-01-01

    Non evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers, have been proposed by CERN to substantially reduce the gas pressure in UHV-XHV systems. The NEG film acts as a conductance-free distributed pump inside a chamber. Being a barrier for gases it also reduces thermal out-gassing, thus allowing the achievement of very demanding pressure conditions. These features are ideal for very narrow, conductance limited chambers, like Insertion Devices, which cannot be always efficiently pumped by ordinary means. Recent investigations have also shown that NEG coatings do present additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment, compared to traditional technical surfaces. Experimental tests, carried out in several high energy machines and synchrotron radiations facilities have so far confirmed the benefits of NEG films in term of better vacuum, longer beam life time and stability, simplified machine design, reduced conditioning time and overall improved machine performances. For these reasons, NEG coating technology is now gaining increasing attention and it is seriously considered for upgrades in a number of machines and for future projects. In the present paper, we report SAES getters experience on NEG coating of chambers of different geometries, materials and sizes for a variety of projects related to synchrotron radiation facilities. Examples of applications in various machines, as well as typical issues related to chambers preparation, film deposition, quality control and characterization, are given.

  17. Non Evaporable Getter (NEG) Coatings for Vacuum Systems in Synchrotron Radiation Facilities

    SciTech Connect

    Manini, Paolo; Conte, Andrea; Raimondi, Stefano; Bonucci, Antonio

    2007-01-19

    Non evaporable Getter (NEG) films, sputter deposited onto the internal surfaces of vacuum chambers, have been proposed by CERN to substantially reduce the gas pressure in UHV-XHV systems. The NEG film acts as a conductance-free distributed pump inside a chamber. Being a barrier for gases it also reduces thermal out-gassing, thus allowing the achievement of very demanding pressure conditions. These features are ideal for very narrow, conductance limited chambers, like Insertion Devices, which cannot be always efficiently pumped by ordinary means. Recent investigations have also shown that NEG coatings do present additional interesting features, like low secondary electron yield and low gas de-sorption rates under ions, electrons and photons bombardment, compared to traditional technical surfaces. Experimental tests, carried out in several high energy machines and synchrotron radiations facilities have so far confirmed the benefits of NEG films in term of better vacuum, longer beam life time and stability, simplified machine design, reduced conditioning time and overall improved machine performances. For these reasons, NEG coating technology is now gaining increasing attention and it is seriously considered for upgrades in a number of machines and for future projects. In the present paper, we report SAES getters experience on NEG coating of chambers of different geometries, materials and sizes for a variety of projects related to synchrotron radiation facilities. Examples of applications in various machines, as well as typical issues related to chambers preparation, film deposition, quality control and characterization, are given.

  18. Diffusion Coatings for Corrosion-Resistant Components in Coal Gasification Systems

    SciTech Connect

    Gopala N. Krishnan; Ripudaman Malhotra; Esperanza Alvarez; Kai-Hung Lau; Jordi Perez-Mariano; Angel Sanjurjo

    2005-03-15

    Heat-exchangers, particle filters, turbines, and other components in integrated coal gasification combined cycle system must withstand the highly sulfiding conditions of the high-temperature coal gas over an extended period of time. The performance of components degrades significantly with time unless expensive high alloy materials are used. Deposition of a suitable coating on a low-cost alloy may improve its resistance to such sulfidation attack, and decrease capital and operating costs. The alloys used in the gasifier service include austenitic and ferritic stainless steels, nickel-chromium-iron alloys, and expensive nickel-cobalt alloys. During this period, we conducted two 300-hour tests. In the first test, we exposed samples at 900 C under conditions simulating the high-temperature heat recovery unit (HTHRU). The second test was at 370 C, corresponding to the filter units following the HTHRU. The tests were showed the resilience of silicon nitride as a coating component, and the new coating procedures better penetrated the pores in sintered metal filter samples. Finally, we also received samples that were exposed in the Wabash River plant. Unfortunately, all these samples, that were prepared last year, were severely eroded and/or corroded.

  19. Health Implications of PAH Release from Coated Cast Iron Drinking Water Distribution Systems in the Netherlands

    PubMed Central

    van de Ven, Bianca M.; de Jongh, Cindy M.

    2013-01-01

    Background: Coal tar and bitumen have been historically used to coat the insides of cast iron drinking water mains. Polycyclic aromatic hydrocarbons (PAHs) may leach from these coatings into the drinking water and form a potential health risk for humans. Objective: We estimated the potential human cancer risk from PAHs in coated cast iron water mains. Method: In a Dutch nationwide study, we collected drinking water samples at 120 locations over a period of 17 days under various operational conditions, such as undisturbed operation, during flushing of pipes, and after a mains repair, and analyzed these samples for PAHs. We then estimated the health risk associated with an exposure scenario over a lifetime. Results: During flushing, PAH levels frequently exceeded drinking water quality standards; after flushing, these levels dropped rapidly. After the repair of cast iron water mains, PAH levels exceeded the drinking water standards for up to 40 days in some locations. Conclusions: The estimated margin of exposure for PAH exposure through drinking water was > 10,000 for all 120 measurement locations, which suggests that PAH exposure through drinking water is of low concern for consumer health. However, factors that differ among water systems, such as the use of chlorination for disinfection, may influence PAH levels in other locations. PMID:23425894

  20. The potential use of novel chitosan-coated deformable liposomes in an ocular drug delivery system.

    PubMed

    Chen, Hongdan; Pan, Hao; Li, Panpan; Wang, Hui; Wang, Xin; Pan, Weisan; Yuan, Yue

    2016-07-01

    In this study, novel chitosan-coated deformable liposomes (DL-CS) were proposed as an ocular drug delivery system to prolong pre-corneal retention, and improve transcorneal penetration and absorption. Flurbiprofen-loaded deformable liposomes (FP-DL) were prepared by a modified ethanol injection method and then coated with chitosan. Both DL and DL-CS exhibited a homogeneous particle size distribution, high encapsulation efficiency and good stability. After coating with 0.1% CS, the zeta potential was shifted from negative to positive. The apparent permeability coefficient of FP-DL-0.1% CS evaluated using isolated rabbit corneas was 1.29-, 1.95- and 4.59- fold greater than that of uncoated FP-DL, conventional liposomes and FP solution (P<0.01), respectively. The in vivo pre-corneal retention time and elimination dynamics were assessed using gamma scintigraphy technology. The area under the remaining activity-time of FP-DL-0.1% CS was prolonged 2.84- and 1.53-fold compared with that of the FP solution and FP-DL groups, respectively. Moreover, the ocular irritation test in vivo revealed that DL-0.1% CS produced no ocular damage or abnormal clinical signs. These results indicate that DL-CS appears to be a novel ophthalmic drug delivery strategy with the potential to overcome the limitations of conventional eye drops. PMID:27037783

  1. Blanch Resistant and Thermal Barrier NiAl Coating Systems for Advanced Copper Alloys

    NASA Technical Reports Server (NTRS)

    Raj, Sai V. (Inventor)

    2005-01-01

    A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.

  2. Influence of EB-PVD TBC Microstructure on Thermal Barrier Coating System Performance Under Cyclic Conditions

    SciTech Connect

    Leyens, C; Pint, B A; Schulz, U; Wright, I G

    1999-04-12

    The lifetimes of electron beam physical vapor deposited (EB-PVD) thermal barrier coating systems (TBCs) with three different microstructures of the Y2O3-stabilized ZrO, YSZ) ceramic top layer were investigated in lh thermal cycles at 1100 and 1150°C in flowing oxygen. Single crystal alloys CMSX-4 and Rene N5 that had been coated with an EB-PVD NiCoCrAlY bond coat were chosen as substrate materials. At 1150°C all samples failed after 80-100, lh cycles, predominantly at the bond coat/alumina interface after cooling down from test temperature. The alumina scale remained adherent to the YSZ after spallation. Despite the different YSZ microstructures no clear tendency regarding differences in spallation behavior were observed at 1150°C. At 1100°C the minimum lifetime was 750 , lh cycles for CMSX-4, whereas the first Rene N5 specimen failed after 1750, lh cycles. The longest TBC lifetime on CMSX-4 substrates was 1250, lh cycles, whereas the respective Rene N5 specimens have not yet failed after 2300, lh cycles. The failure mode at 1100°C was identical to that at 1150°C, i.e. the TBC spalled off the surface exposing bare metal after cooling. Even though not all specimens have failed to date, the available results at 1100°C suggested that both, the substrate alloy chemistry and the YSZ microstructure significantly affect the spallation resistance of the TBC.

  3. EVALUATION OF SORPTIVE PROPERTIES OF VARIOUS CARRIERS AND COATING MATERIALS FOR LIQUISOLID SYSTEMS.

    PubMed

    Vraníková, Barbora; Gajdziok, Jan

    2015-01-01

    The basic principle of liquisolid systems formulation lies in the conversion of the drug in a liquid state into an apparently dry, free-flowing and readily compressible powder by its blending (or spraying) with specific carriers and coating materials. The selection of the most suitable carrier and coating material depends especially on their values of flowable liquid retention potential (Φ), which is defined as the maximum mass of liquid that can be retained per unit mass of powder material, while maintaining an acceptable flowability. The presented work focused on the determination of the maximum amount of propylene glycol (PG), which can be retained by several selected carriers and coating materials while maintaining acceptable flow properties of the liquisolid powder blend. Granulated forms of magnesium aluminometasilicates (Neusilin® US2 and Neusilin® NS2N), dibasic calcium phosphate (Fujicalin®) and microcrystalline cellulose (Avicel® PH 101) were tested due to their frequent use. Powdered forms of magnesium aluminometasilicate (Neusilin® UFL2) and colloidal silica (Aerosil® 200) were used as common coating materials. From the evaluation of liquisolid mixtures with different amounts of liquid, it could be observed that 1 g of Neusilin® US2, Neusilin® UFL2, Neusilin® NS2N, Aerosil® 200, Fujicalin® and Avicel® PH 101 can retain 1.00, 0.97, 0.54, 0.04, 0.25 and 0.12 g of propylene glycol, respectively, while maintaining acceptable flowing properties for further processing. PMID:26642662

  4. Technical and Economical Aspects of Current Thermal Barrier Coating Systems for Gas Turbine Engines by Thermal Spray and EBPVD: A Review

    NASA Astrophysics Data System (ADS)

    Feuerstein, Albert; Knapp, James; Taylor, Thomas; Ashary, Adil; Bolcavage, Ann; Hitchman, Neil

    2008-06-01

    The most advanced thermal barrier coating (TBC) systems for aircraft engine and power generation hot section components consist of electron beam physical vapor deposition (EBPVD) applied yttria-stabilized zirconia and platinum modified diffusion aluminide bond coating. Thermally sprayed ceramic and MCrAlY bond coatings, however, are still used extensively for combustors and power generation blades and vanes. This article highlights the key features of plasma spray and HVOF, diffusion aluminizing, and EBPVD coating processes. The coating characteristics of thermally sprayed MCrAlY bond coat as well as low density and dense vertically cracked (DVC) Zircoat TBC are described. Essential features of a typical EBPVD TBC coating system, consisting of a diffusion aluminide and a columnar TBC, are also presented. The major coating cost elements such as material, equipment and processing are explained for the different technologies, with a performance and cost comparison given for selected examples.

  5. Construction of a novel pH-sensitive drug release system from mesoporous silica tablets coated with Eudragit

    NASA Astrophysics Data System (ADS)

    Xu, Yingpu; Qu, Fengyu; Wang, Yu; Lin, Huiming; Wu, Xiang; Jin, Yingxue

    2011-03-01

    A novel pH-sensitive drug release system has been established by coating Eudragit (Eud) on drug-loaded mesoporous silica (MS) tablets. The release rate of ibuprofen (IBU) from the MS was retarded by coating with Eudragit S-100, and the higher retardation was due to the increase of coating concentration and the coating layers. The target position of the release depended on the pH of the release medium, which was confirmed by the drug release from IBU/MS/Eud increasing rapidly with the change of medium pH from 1.2 to 7.4. This drug delivery system could prohibit irritant drug from leaking in the stomach and make it only release in the intestine. The loaded and unloaded drug samples were characterized by powder X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), N 2 adsorption/desorption, scanning electron microscopy (SEM), and transmission electron microscopy (TEM).

  6. Versatile Coating

    NASA Technical Reports Server (NTRS)

    1990-01-01

    A radome at Logan Airport and a large parabolic antenna at the Wang Building in Massachusetts are protected from weather, corrosion and ultraviolet radiation by a coating, specially designed for antennas and radomes, known as CRC Weathertite 6000. The CRC 6000 line that emerged from Boyd Coatings Research Co., Inc. is a solid dispersion of fluorocarbon polymer and polyurethane that yields a tough, durable film with superior ultraviolet resistance and the ability to repel water and ice over a long term. Additionally, it provides resistance to corrosion, abrasion, chemical attacks and impacts. Material can be used on a variety of substrates, such as fiberglass, wood, plastic and concrete in addition to steel and aluminum. In addition Boyd Coatings sees CRC 6000 applicability as an anti-icing system coated on the leading edge of aircraft wings.

  7. A performance evaluation of various coatings, substrate materials, and solar collector systems

    NASA Technical Reports Server (NTRS)

    Dolan, F. J.

    1976-01-01

    An experimental apparatus was constructed and utilized in conjunction with both a solar simulator and actual sunlight to test and evaluate various solar panel coatings, panel designs, and scaled-down collector subsystems. Data were taken by an automatic digital data acquisition system and reduced and printed by a computer system. The solar collector test setup, data acquisition system, and data reduction and printout systems were considered to have operated very satisfactorily. Test data indicated that there is a practical or useful limit in scaling down beyond which scaled-down testing cannot produce results comparable to results of larger scale tests. Test data are presented as are schematics and pictures of test equipment and test hardware.

  8. Recession Curve Generation for the Space Shuttle Solid Rocket Booster Thermal Protection System Coatings

    NASA Technical Reports Server (NTRS)

    Kanner, Howard S.; Stuckey, C. Irvin; Davis, Darrell W.; Davis, Darrell (Technical Monitor)

    2002-01-01

    Ablatable Thermal Protection System (TPS) coatings are used on the Space Shuttle Vehicle Solid Rocket Boosters in order to protect the aluminum structure from experiencing excessive temperatures. The methodology used to characterize the recession of such materials is outlined. Details of the tests, including the facility, test articles and test article processing are also presented. The recession rates are collapsed into an empirical power-law relation. A design curve is defined using a 95-percentile student-t distribution. based on the nominal results. Actual test results are presented for the current acreage TPS material used.

  9. Durability and CMAS Resistance of Advanced Environmental Barrier Coatings Systems for SiC/SiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming

    2015-01-01

    Environmental barrier coatings (EBCs) and SiCSiC ceramic matrix composites (CMCs) systems will play a crucial role in next generation turbine engines for hot-section component applications because of their ability to significantly increase engine operating temperatures with improved efficiency, reduce engine weight and cooling requirements. This paper will emphasize advanced environmental barrier coating developments for SiCSiC turbine airfoil components, by using advanced coating compositions and processing, in conjunction with mechanical and environment testing and durability validations. The coating-CMC degradations and durability in the laboratory simulated engine fatigue-creep and complex operating environments are being addressed. The effects of Calcium-Magnesium-Alumino-Silicate (CMAS) from road sand or volcano-ash deposits on the degradation mechanisms of the environmental barrier coating systems will be discussed. The results help understand the advanced EBC-CMC system performance, aiming at the durability improvements of more robust, prime-reliant environmental barrier coatings for successful applications of the component technologies and lifing methodologies.

  10. Effects of Chromate and Non-Chromate Coating Systems on Environmentally Assisted Fatigue of an Aluminum Alloy

    NASA Astrophysics Data System (ADS)

    Schubbe, Joel J.; Westmoreland, Sophoria N.

    2014-10-01

    Fatigue crack growth testing of 2024-T3 Aluminum plate was performed using compact tension (CT) specimens with chromate and non-chromate primer paint systems to evaluate the effects of the coatings on fatigue crack growth rates. The tests were conducted in lab air and sea water environments for each of the coating systems. Standard E399 CT specimens were tested to determine the influence level of environmentally assisted cracking (corrosion fatigue) on crack growth rates and cyclic count to prescribed pre-crack and final crack lengths. Increasing stress range (Δ K) tests were conducted at 10 Hz in the range of 6.5 to 26.5 MPa. It was determined that the coated specimens exhibited a 12% shorter total life, on average, than the bare specimens for the lab air cases. In the case of salt water exposure, the coated specimens exhibited approximately 10% life increase over the bare specimens. The number of cycles to the 2.54 mm pre-crack length for the coated specimens was all less than the cycle count for the bare tests. In each case (coated or bare), there was an increased growth rate at the lower stress ranges in the salt water environment, with the chromate system case displaying the smallest change (increase). It can be concluded that the coated specimens initiate cracks and propagate faster than the bare specimens for short cracks at low stress range, but the environmental influence on the specimens is quickly overshadowed as the cracks elongate and the rate of growth increases. The coated specimens exhibited a higher total life cycle count to final crack length for this testing.

  11. Effect of Residual Stresses and Prediction of Possible Failure Mechanisms on Thermal Barrier Coating System by Finite Element Method

    NASA Astrophysics Data System (ADS)

    Ranjbar-Far, M.; Absi, J.; Mariaux, G.; Shahidi, S.

    2010-09-01

    This work is focused on the effect of the residual stresses resulting from the coating process and thermal cycling on the failure mechanisms within the thermal barrier coating (TBC) system. To reach this objective, we studied the effect of the substrate preheating and cooling rate on the coating process conditions. A new thermomechanical finite element model (FEM) considering a nonhomogeneous temperature distribution has been developed. In the results, we observed a critical stress corresponding to a low substrate temperature and high cooling rate during spraying of the top-coat material. Moreover, the analysis of the stress distribution after service shows that more critical stresses are obtained in the case where residual stresses are taken into account.

  12. Corrosion of NiCoCrAlY Coatings and TBC Systems Subjected to Water Vapor and Sodium Sulfate

    NASA Astrophysics Data System (ADS)

    Eriksson, Robert; Yuan, Kang; Li, Xin-Hai; Lin Peng, Ru

    2015-08-01

    Thermal barrier coating (TBC) systems are commonly used in gas turbines for protection against high-temperature degradation. Penetration of the ceramic top coat by corrosive species may cause corrosion damage on the underlying NiCoCrAlY bond coat and cause failure of the TBC system. In the current study, four oxidation/corrosion conditions were tried: (i) lab air, (ii) water vapor, (iii) sodium sulfate deposited on the specimens, and (iv) water vapor + sodium sulfate. The test was done at 750 °C in a cyclic test rig with 48 h cycles. The corrosion damage was studied on NiCoCrAlY-coated specimens, thin APS TBC specimens, and thick APS TBC specimens. Water vapor was found to have very minor influence on the oxidation, while sodium sulfate increased the TGO thickness both for NiCoCrAlY specimens and TBC-coated specimens; the influence of the TBC thickness was found to be very small. Sodium sulfate promoted thicker TGO; more Cr-rich TGO; the formation of Y oxides, and internally, Y sulfides; pore formation in the coating as well as in the substrate; and the formation of a Cr-depleted zone in the substrate.

  13. Drug loaded and ethylcellulose coated mesoporous silica for controlled drug release prepared using a pilot scale fluid bed system.

    PubMed

    Hacene, Youcef Chakib; Singh, Abhishek; Van den Mooter, Guy

    2016-06-15

    The goal of this study was to test the feasibility to load non-ordered, non-spherical mesoporous silica with the model drug paracetamol, and subsequently coat the loaded particles using one single pilot scale fluid bed system equipped with a Wurster insert. Mesoporous silica particles (Davisil(®)) with a size ranging from 310 to 500μm and an average pore diameter of 15nm were loaded with paracetamol to 18.8% drug content. Subsequently, loaded cores were coated with ethylcellulose to obtain controlled drug release. Coating processing variables were varied following a full factorial design and their effect on drug release was assessed. Increasing coating solution feed rate and decreasing fluidizing air temperature were found to increase drug release rates. Increasing pore former level and decreasing coating level were found to increase drug release rates. The release medium's osmolality was varied using different sodium chloride concentrations, which was found to affect drug release rates. The results of this study clearly indicate the potential of non-ordered, non-spherical mesoporous silica as a reservoir carrier for the controlled release of drugs. Although non-spherical, we were able to reproducibly coat this carrier using a bottom spray fluid bed system. However, a major hurdle that needs to be tackled is the attrition the material suffers from during fluid bed processing. PMID:27107901

  14. Optical fiducial timing system for X-ray streak cameras with aluminum coated optical fiber ends

    DOEpatents

    Nilson, David G.; Campbell, E. Michael; MacGowan, Brian J.; Medecki, Hector

    1988-01-01

    An optical fiducial timing system is provided for use with interdependent groups of X-ray streak cameras (18). The aluminum coated (80) ends of optical fibers (78) are positioned with the photocathodes (20, 60, 70) of the X-ray streak cameras (18). The other ends of the optical fibers (78) are placed together in a bundled array (90). A fiducial optical signal (96), that is comprised of 2.omega. or 1.omega. laser light, after introduction to the bundled array (90), travels to the aluminum coated (82) optical fiber ends and ejects quantities of electrons (84) that are recorded on the data recording media (52) of the X-ray streak cameras (18). Since both 2.omega. and 1.omega. laser light can travel long distances in optical fiber with only a slight attenuation, the initial arial power density of the fiducial optical signal (96) is well below the damage threshold of the fused silica or other material that comprises the optical fibers (78, 90). Thus the fiducial timing system can be repeatably used over long durations of time.

  15. Qualification of Target Chamber Vacuum Systems Cleanliness using Sol-Gel Coatings

    SciTech Connect

    Miller, P; Stowers, I F; Ertel, J R

    2006-01-03

    This document defines the procedure necessary to qualify the airborne molecular cleanliness (AMC) of vacuum systems (enclosures or large components) that are placed within the National Ignition Facility (NIF) target chamber or are attached to it and communicate with it during vacuum operation. This test is specific to the NIF target chamber because the allowable time dependent rate of rise in the pore filling of a sol-gel coated SAW sensor is based on some nominal change-out time for the disposable debris shields. These debris shields will be sol-gel coated and thus they represent a means of ''pumping'' AMCs from the target chamber. The debris shield pumping rate sets the allowable change in pore filling with time specified in the test procedure. This document describes a two-part procedure that provides both a static measurement of sol-gel pore filling at the end of a 48-hour test period and a dynamic record of pore-filling measured throughout the test period. Successful qualification of a vacuum system requires that both the static and dynamic measurements meet the criteria set forth in Section 7 of this document.

  16. Structurally Integrated, Damage Tolerant Thermal Spray Coatings: Processing Effects on Surface and System Functionalities

    NASA Astrophysics Data System (ADS)

    Vackel, Andrew

    Thermal Spray (TS) coatings have seen extensive application as protective surfaces to enhance the service life of substrates prone to damage in their operating environment (wear, corrosion, heat etc.). With the advent of high velocity TS processes, the ability to deposit highly dense (>99%) metallic and cermet coatings has further enhanced the protective ability of these coatings. In addition to surface functionality, the influence of the coating application on the mechanical performance of a coated component is of great concern when such a component will experience either static or cyclic loading during service. Using a process mapping methodology, the processing-property interplay between coating materials meant to provide damage tolerant surface or for structural restoration are explored in terms of relevant mechanical properties. Most importantly, the residual stresses inherent in TS deposited coatings are shown to play a significant role in the integrated mechanical performance of these coatings. Unique to high velocity TS processes is the ability to produce compressive stresses within the deposit from the cold working induced by the high kinetic energy particles upon impact. The extent of these formation stresses are explored with different coating materials, as well as processing influence. The ability of dense TS coatings to carry significant structural load and synergistically strengthen coated tensile specimens is demonstrated as a function of coating material, processing, and thickness. The sharing of load between the substrate and otherwise brittle coating enables higher loads before yield for the bi-material specimens, offering a methodology to improve the tensile performance of coated components for structural repair or multi-functionality (surface and structure). The concern of cyclic fatigue damage in coated components is explored, since the majority of service application are designed for loading to be well below the yield point. The role of

  17. Preparation and characterization of 6-mercaptopurine-coated magnetite nanoparticles as a drug delivery system

    PubMed Central

    Dorniani, Dena; Hussein, Mohd Zobir bin; Kura, Aminu Umar; Fakurazi, Sharida; Shaari, Abdul Halim; Ahmad, Zalinah

    2013-01-01

    Background Iron oxide nanoparticles are of considerable interest because of their use in magnetic recording tape, ferrofluid, magnetic resonance imaging, drug delivery, and treatment of cancer. The specific morphology of nanoparticles confers an ability to load, carry, and release different types of drugs. Methods and results We synthesized superparamagnetic nanoparticles containing pure iron oxide with a cubic inverse spinal structure. Fourier transform infrared spectra confirmed that these Fe3O4 nanoparticles could be successfully coated with active drug, and thermogravimetric and differential thermogravimetric analyses showed that the thermal stability of iron oxide nanoparticles coated with chitosan and 6-mercaptopurine (FCMP) was markedly enhanced. The synthesized Fe3O4 nanoparticles and the FCMP nanocomposite were generally spherical, with an average diameter of 9 nm and 19 nm, respectively. The release of 6-mercaptopurine from the FCMP nanocomposite was found to be sustained and governed by pseudo-second order kinetics. In order to improve drug loading and release behavior, we prepared a novel nanocomposite (FCMP-D), ie, Fe3O4 nanoparticles containing the same amounts of chitosan and 6-mercaptopurine but using a different solvent for the drug. The results for FCMP-D did not demonstrate “burst release” and the maximum percentage release of 6-mercaptopurine from the FCMP-D nanocomposite reached about 97.7% and 55.4% within approximately 2,500 and 6,300 minutes when exposed to pH 4.8 and pH 7.4 solutions, respectively. By MTT assay, the FCMP nanocomposite was shown not to be toxic to a normal mouse fibroblast cell line. Conclusion Iron oxide coated with chitosan containing 6-mercaptopurine prepared using a coprecipitation method has the potential to be used as a controlled-release formulation. These nanoparticles may serve as an alternative drug delivery system for the treatment of cancer, with the added advantage of sparing healthy surrounding cells and

  18. Evolving lessons on nanomaterial-coated viral vectors for local and systemic gene therapy.

    PubMed

    Kasala, Dayananda; Yoon, A-Rum; Hong, Jinwoo; Kim, Sung Wan; Yun, Chae-Ok

    2016-07-01

    Viral vectors are promising gene carriers for cancer therapy. However, virus-mediated gene therapies have demonstrated insufficient therapeutic efficacy in clinical trials due to rapid dissemination to nontarget tissues and to the immunogenicity of viral vectors, resulting in poor retention at the disease locus and induction of adverse inflammatory responses in patients. Further, the limited tropism of viral vectors prevents efficient gene delivery to target tissues. In this regard, modification of the viral surface with nanomaterials is a promising strategy to augment vector accumulation at the target tissue, circumvent the host immune response, and avoid nonspecific interactions with the reticuloendothelial system or serum complement. In the present review, we discuss various chemical modification strategies to enhance the therapeutic efficacy of viral vectors delivered either locally or systemically. We conclude by highlighting the salient features of various nanomaterial-coated viral vectors and their prospects and directions for future research. PMID:27348247

  19. Coated Particles Fuel Compact-General Purpose Heat Source for Advanced Radioisotope Power Systems

    NASA Astrophysics Data System (ADS)

    El-Genk, Mohamed S.; Tournier, Jean-Michel

    2003-01-01

    Coated Particles Fuel Compacts (CPFC) have recently been shown to offer performance advantage for use in Radioisotope Heater Units (RHUs) and design flexibility for integrating at high thermal efficiency with Stirling Engine converters, currently being considered for 100 We. Advanced Radioisotope Power Systems (ARPS). The particles in the compact consist of 238PuO2 fuel kernels with 5-μm thick PyC inner coating and a strong ZrC outer coating, whose thickness depends on the maximum fuel temperature during reentry, the fuel kernel diameter, and the fraction of helium gas released from the kernels and fully contained by the ZrC coating. In addition to containing the helium generated by radioactive decay of 238Pu for up to 10 years before launch and 10-15 years mission lifetime, the kernels are intentionally sized (>= 300 μm in diameter) to prevent any adverse radiological effects on reentry. This paper investigates the advantage of replacing the four iridium-clad 238PuO2 fuel pellets, the two floating graphite membranes, and the two graphite impact shells in current State-Of-The-Art (SOA) General Purpose Heat Source (GPHS) with CPFC. The total mass, thermal power, and specific power of the CPFC-GPHS are calculated as functions of the helium release fraction from the fuel kernels and maximum fuel temperature during reentry from 1500 K to 2400 K. For the same total mass and volume as SOA GPHS, the generated thermal power by single-size particles CPFC-GPHS is 260 W at Beginning-Of-Mission (BOM), versus 231 W for the GPHS. For an additional 10% increase in total mass, the CPFC-GPHS could generate 340 W BOM; 48% higher than SOA GPHS. The corresponding specific thermal power is 214 W/kg, versus 160 W/kg for SOA GPHS; a 34% increase. Therefore, for the same thermal power, the CPFC-GPHS is lighter than SOA GPHS, while it uses the same amount of 238PuO2 fuel and same aeroshell. For the same helium release fraction and fuel temperature, binary-size particles CPFC-GPHS could

  20. Oxidation and degradation of a plasma-sprayed thermal barrier coating system

    SciTech Connect

    Haynes, J.A.; Ferber, M.K.; Porter, W.D.

    1996-04-01

    The isothermal oxidation behavior of thermal barrier coating (TBC) specimens consisting of single-crystal superalloy substrates, vacuum plasma-sprayed Ni-22Cr-10Al-1Y bond coatings and air plasma-sprayed 7.5 wt.% yttria stabilized zirconia top coatings was evaluated by thermogravimetric analysis at 1150{degrees}C for up to 200 hours. Coating durability was assessed by furnace cycling at 1150{degrees}C. Coatings and reaction products were identified by x-ray diffraction, field-emission scanning electron microscopy and energy dispersive spectroscopy.

  1. Automated MALDI matrix coating system for multiple tissue samples for imaging mass spectrometry.

    PubMed

    Mounfield, William P; Garrett, Timothy J

    2012-03-01

    Uniform matrix deposition on tissue samples for matrix-assisted laser desorption/ionization (MALDI) is key for reproducible analyte ion signals. Current methods often result in nonhomogenous matrix deposition, and take time and effort to produce acceptable ion signals. Here we describe a fully-automated method for matrix deposition using an enclosed spray chamber and spray nozzle for matrix solution delivery. A commercial air-atomizing spray nozzle was modified and combined with solenoid controlled valves and a Programmable Logic Controller (PLC) to control and deliver the matrix solution. A spray chamber was employed to contain the nozzle, sample, and atomized matrix solution stream, and to prevent any interference from outside conditions as well as allow complete control of the sample environment. A gravity cup was filled with MALDI matrix solutions, including DHB in chloroform/methanol (50:50) at concentrations up to 60 mg/mL. Various samples (including rat brain tissue sections) were prepared using two deposition methods (spray chamber, inkjet). A linear ion trap equipped with an intermediate-pressure MALDI source was used for analyses. Optical microscopic examination showed a uniform coating of matrix crystals across the sample. Overall, the mass spectral images gathered from tissues coated using the spray chamber system were of better quality and more reproducible than from tissue specimens prepared by the inkjet deposition method. PMID:22234508

  2. Pyrolytic carbon-coated stainless steel felt as a high-performance anode for bioelectrochemical systems.

    PubMed

    Guo, Kun; Hidalgo, Diana; Tommasi, Tonia; Rabaey, Korneel

    2016-07-01

    Scale up of bioelectrochemical systems (BESs) requires highly conductive, biocompatible and stable electrodes. Here we present pyrolytic carbon-coated stainless steel felt (C-SS felt) as a high-performance and scalable anode. The electrode is created by generating a carbon layer on stainless steel felt (SS felt) via a multi-step deposition process involving α-d-glucose impregnation, caramelization, and pyrolysis. Physicochemical characterizations of the surface elucidate that a thin (20±5μm) and homogenous layer of polycrystalline graphitic carbon was obtained on SS felt surface after modification. The carbon coating significantly increases the biocompatibility, enabling robust electroactive biofilm formation. The C-SS felt electrodes reach current densities (jmax) of 3.65±0.14mA/cm(2) within 7days of operation, which is 11 times higher than plain SS felt electrodes (0.30±0.04mA/cm(2)). The excellent biocompatibility, high specific surface area, high conductivity, good mechanical strength, and low cost make C-SS felt a promising electrode for BESs. PMID:27058401

  3. Automated MALDI Matrix Coating System for Multiple Tissue Samples for Imaging Mass Spectrometry

    NASA Astrophysics Data System (ADS)

    Mounfield, William P.; Garrett, Timothy J.

    2012-03-01

    Uniform matrix deposition on tissue samples for matrix-assisted laser desorption/ionization (MALDI) is key for reproducible analyte ion signals. Current methods often result in nonhomogenous matrix deposition, and take time and effort to produce acceptable ion signals. Here we describe a fully-automated method for matrix deposition using an enclosed spray chamber and spray nozzle for matrix solution delivery. A commercial air-atomizing spray nozzle was modified and combined with solenoid controlled valves and a Programmable Logic Controller (PLC) to control and deliver the matrix solution. A spray chamber was employed to contain the nozzle, sample, and atomized matrix solution stream, and to prevent any interference from outside conditions as well as allow complete control of the sample environment. A gravity cup was filled with MALDI matrix solutions, including DHB in chloroform/methanol (50:50) at concentrations up to 60 mg/mL. Various samples (including rat brain tissue sections) were prepared using two deposition methods (spray chamber, inkjet). A linear ion trap equipped with an intermediate-pressure MALDI source was used for analyses. Optical microscopic examination showed a uniform coating of matrix crystals across the sample. Overall, the mass spectral images gathered from tissues coated using the spray chamber system were of better quality and more reproducible than from tissue specimens prepared by the inkjet deposition method.

  4. Deformation Microstructures Near Vickers Indentations in SNO2/SI Coated Systems

    NASA Astrophysics Data System (ADS)

    Daria, G.; Evghenii, H.; Olga, S.; Zinaida, D.; Iana, M.; Victor, Z.

    The micromechanical properties (hardness and brittleness) of the hard-on-hard SnO2 / Si-coated system (CS) and their modification depending the on load value has been studied. A nonmonotonic changing of microhardness with load growth was detected. The brittle/plastic behavior of the rigid/hard-on-hard SnO2 / Si CS and its response to concentrated load action explains it.A specific evolution of the indentation-deformed zone vs. load value attributed to the change in the internal stress redistribution between film and substrate was detected. It results in a brittleness indentation size effect (BISE) of the SnO2 / Si CS revealed in this experiment.It was shown that the greater portion of internal stresses under indentation is concentrated in the coating layer at small loads. This fact causes a strong elastic-plastic relaxation in the film and its delamination from substrate. The increase of brittle failure in the indentation-deformed zone with a decrease of indentation load was revealed.

  5. A pH dependent delivery of mesalazine from polymer coated and drug-loaded SBA-16 systems.

    PubMed

    Trendafilova, Ivalina; Szegedi, Ágnes; Yoncheva, Krassimira; Shestakova, Pavletta; Mihály, Judith; Ristić, Alenka; Konstantinov, Spiro; Popova, Margarita

    2016-01-01

    SBA-16 silica was synthesized and modified by post-synthesis method with amino groups. Wet milling in acidic media was applied for loading of poorly soluble drug mesalazine (5-aminosalicylic acid — 5-ASA) in different drug/carrier ratios (1:1; 0.75:1; 0.5:1; 0.25:1). The parent and drug loaded mesoporous silicas were characterized by XRD, TEM,N2 physisorption, thermal analysis, FT-IR and solid state NMR spectroscopy. The drug loaded mesoporous systems were single-coated with Eudragit S or double-coated with Eudragit S and Eudragit RL. The polymer coating significantly modified the rate of mesalazine release fromS BA-16NH2 materials. Applying the double coating method makes possible the sustained delivery of the drug in the intestinal area avoiding the burst release in the gastric fluid. The functionalized, polymer coated mesoporous system could be considered an appropriate oral delivery system for mesalazine. In addition, reduction of mesalazine cytotoxicity on epithelial cells could be achieved by its loading into mesoporous silica particles. PMID:26453768

  6. Microstructure and properties of tungsten carbide coatings sprayed with various high-velocity oxygen fuel spray systems

    NASA Astrophysics Data System (ADS)

    Schwetzke, R.; Kreye, H.

    1999-09-01

    This article reports on a series of experiments with various high-velocity oxygen fuel spray systems (Jet Kote, Top Gun, Diamond Jet (DJ) Standard, DJ 2600 and 2700, JP-5000, Top Gun-K) using different WC-Co and WC-Co-Cr powders. The microstructure and phase composition of powders and coatings were analyzed by optical and scanning electron microscopy and x-ray diffraction. Carbon and oxygen content of the coatings were determined to study the decarburization and oxidation of the material during the spray process. Coatings were also characterized by their hardness, bond strength, abrasive wear, and corrosion resistance. The results demonstrate that the powders exhibit various degrees of phase transformation during the spray process depending on type of powder, spray system, and spray parameters. Within a relatively wide range, the extent of phase transformation has only little effect on coating properties. Therefore, coatings of high hardness and wear resistance can be produced with all HVOF spray systems when the proper spray powder and process parameters are chosen.

  7. Energy Saving Melting and Revert Reduction Technology (E-SMARRT): Development of Surface Engineered Coating Systems for Aluminum Pressure Die Casting Dies: Towards a 'Smart' Die Coating

    SciTech Connect

    Dr. John J. Moore; Dr. Jianliang Lin,

    2012-07-31

    The main objective of this research program was to design and develop an optimal coating system that extends die life by minimizing premature die failure. In high-pressure aluminum die-casting, the die, core pins and inserts must withstand severe processing conditions. Many of the dies and tools in the industry are being coated to improve wear-resistance and decrease down-time for maintenance. However, thermal fatigue in metal itself can still be a major problem, especially since it often leads to catastrophic failure (i.e. die breakage) as opposed to a wear-based failure (parts begin to go out of tolerance). Tooling costs remain the largest portion of production costs for many of these parts, so the ability prevent catastrophic failures would be transformative for the manufacturing industry.The technology offers energy savings through reduced energy use in the die casting process from several factors, including increased life of the tools and dies, reuse of the dies and die components, reduction/elimination of lubricants, and reduced machine down time, and reduction of Al solder sticking on the die. The use of the optimized die coating system will also reduce environmental wastes and scrap parts. Current (2012) annual energy saving estimates, based on initial dissemination to the casting industry in 2010 and market penetration of 80% by 2020, is 3.1 trillion BTU's/year. The average annual estimate of CO2 reduction per year through 2020 is 0.63 Million Metric Tons of Carbon Equivalent (MM TCE).

  8. Development Status and Performance Comparisons of Environmental Barrier Coating Systems for SiCSiC Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Harder, Bryan

    2016-01-01

    Environmental barrier coatings (EBC) and SiCSiC ceramic matrix composites (CMCs) will play a crucial role in future aircraft turbine engine systems, because of their ability to significantly increase engine operating temperatures, reduce engine weight and cooling requirements. This paper presents current NASA EBC-CMC development emphases including: the coating composition and processing improvements, laser high heat flux-thermal gradient thermo-mechanical fatigue - environmental testing methodology development, and property evaluations for next generation EBC-CMC systems. EBCs processed with various deposition techniques including Plasma Spray, Electron Beam - Physical Vapor Deposition, and Plasma Spray Physical Vapor Deposition (PS-PVD) will be particularly discussed. The testing results and demonstrations of advanced EBCs-CMCs in complex simulated engine thermal gradient cyclic fatigue, oxidizing-steam and CMAS environments will help provide insights into the coating development strategies to meet long-term engine component durability goals.

  9. Evaluation of Thermal Control Coatings for Flexible Ceramic Thermal Protection Systems

    NASA Technical Reports Server (NTRS)

    Kourtides, Demetrius; Carroll, Carol; Smith, Dane; Guzinski, Mike; Marschall, Jochen; Pallix, Joan; Ridge, Jerry; Tran, Duoc

    1997-01-01

    This report summarizes the evaluation and testing of high emissivity protective coatings applied to flexible insulations for the Reusable Launch Vehicle technology program. Ceramic coatings were evaluated for their thermal properties, durability, and potential for reuse. One of the major goals was to determine the mechanism by which these coated blanket surfaces become brittle and try to modify the coatings to reduce or eliminate embrittlement. Coatings were prepared from colloidal silica with a small percentage of either SiC or SiB6 as the emissivity agent. These coatings are referred to as gray C-9 and protective ceramic coating (PCC), respectively. The colloidal solutions were either brushed or sprayed onto advanced flexible reusable surface insulation blankets. The blankets were instrumented with thermocouples and exposed to reentry heating conditions in the Ames Aeroheating Arc Jet Facility. Post-test samples were then characterized through impact testing, emissivity measurements, chemical analysis, and observation of changes in surface morphology. The results show that both coatings performed well in arc jet tests with backface temperatures slightly lower for the PCC coating than with gray C-9. Impact testing showed that the least extensive surface destruction was experienced on blankets with lower areal density coatings.

  10. Diamond Coatings

    NASA Technical Reports Server (NTRS)

    1990-01-01

    Advances in materials technology have demonstrated that it is possible to get the advantages of diamond in a number of applications without the cost penalty, by coating and chemically bonding an inexpensive substrate with a thin film of diamond-like carbon (DLC). Diamond films offer tremendous technical and economic potential in such advances as chemically inert protective coatings; machine tools and parts capable of resisting wear 10 times longer; ball bearings and metal cutting tools; a broad variety of optical instruments and systems; and consumer products. Among the American companies engaged in DLC commercialization is Diamonex, Inc., a diamond coating spinoff of Air Products and Chemicals, Inc. Along with its own proprietary technology for both polycrystalline diamond and DLC coatings, Diamonex is using, under an exclusive license, NASA technology for depositing DLC on a substrate. Diamonex is developing, and offering commercially, under the trade name Diamond Aegis, a line of polycrystalline diamond-coated products that can be custom tailored for optical, electronic and engineering applications. Diamonex's initial focus is on optical products and the first commercial product is expected in late 1990. Other target applications include electronic heat sink substrates, x-ray lithography masks, metal cutting tools and bearings.