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Microstructure and properties of multiphase and functionally graded materials prepared by chemical vapor deposition

Description: The synthesis of multiphase and functionally graded materials by chemical vapor deposition is discussed from a perspective of controlling their composition and microstructure at a nano-scale level, and ultimately, tailoring their material properties. Prior research is briefly reviewed to address the current state of this novel material concept. Recent experimental results relating to controlling the selected properties of two multiphase systems, TiN + MoS{sub 2} and NiAl + Al{sub 2}O{sub 3}, ar… more
Date: May 1, 1996
Creator: Lee, W.Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Thermal barrier coatings issues in advanced land-based gas turbines

Description: The Department of Energy`s Advanced Turbine Systems (ATS) program is aimed at fostering the development of a new generation of land-based gas turbine systems with overall efficiencies significantly beyond those of current state-of-the-art machines, as well as greatly increased times between inspection and refurbishment, improved environmental impact, and decreased cost. The proposed duty cycle of ATS machines will emphasize different criteria in the selection of materials for the critical compo… more
Date: June 1995
Creator: Parks, W. P.; Lee, W. Y. & Wright, I. G.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Friction and wear of self-lubricating TiN-MoS{sub 2} coatings produced by chemical vapor deposition

Description: The purpose of the work reported here was to develop special chemical vapor deposition (CVD) methods to produce self-lubricating ceramic coatings in which the lubricating and structural phases were co-deposited on Ti-6Al-4V alloy substrates. These novel composite coatings are based on a system containing titanium nitride and molybdenum disulfide. The method for producing these coatings and their sliding behavior against silicon nitride counterfaces, in the temperature range 20--700 C in air, ar… more
Date: December 31, 1994
Creator: Blau, P.J.; Yust, C.S.; Bae, Y.W.; Besmann, T.M. & Lee, W.Y.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Infrared phonon structure in epitaxial films of Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} at low temperatures

Description: We have used both bolometric and cavity techniques to obtain accurate submillimeter and microwave loss data for epitaxial thin films of Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} at low temperatures. These films have {Tc}=121.5 K, are c-axis oriented, contain some volume fraction of the 2:1:2:2 phase, and are characterized by excellent in-plane epitaxy. The absorptivity of these films at 100 cm{sup {minus}1} is a factor of five lower than that obtained by others from a reflectivity measureme… more
Date: February 1, 1992
Creator: Miller, D.; Richards, P. L.; Lee, W. Y.; Newman, N.; Garrison, S. M. & Martens, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Boron nitride coatings and materials for use in aggressive environments

Description: Boron nitride coatings and structures have demonstrated significant resistance to many corrosive environments. These coatings may have application in the protection of sensors needed for measuring a variety of properties such as temperature and chemistry. In addition, boron nitride materials may offer advantages as structural materials in high temperature materials processing. In this study, BN is assessed for use in aluminum smelting.
Date: December 31, 1997
Creator: Besmann, T.M.; Lee, W.Y.; Young, J.P. & Xiao, H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Infrared phonon structure in epitaxial films of Tl sub 2 Ca sub 2 Ba sub 2 Cu sub 3 O sub 10 at low temperatures

Description: We have used both bolometric and cavity techniques to obtain accurate submillimeter and microwave loss data for epitaxial thin films of Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} at low temperatures. These films have {Tc}=121.5 K, are c-axis oriented, contain some volume fraction of the 2:1:2:2 phase, and are characterized by excellent in-plane epitaxy. The absorptivity of these films at 100 cm{sup {minus}1} is a factor of five lower than that obtained by others from a reflectivity measureme… more
Date: February 1, 1992
Creator: Miller, D.; Richards, P. L.; Lee, W. Y.; Newman, N.; Garrison, S. M. & Martens, J. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Corrosion Resistant Coatings for High Temperature Applications

Description: Efforts to increase efficiency of energy conversion devices have required their operation at ever higher temperatures. This will force the substitution of higher-temperature structural ceramics for lower temperature materials, largely metals. Yet, many of these ceramics will require protection from high temperature corrosion caused by combustion gases, atmospheric contaminants, or the operating medium. This paper discusses examples of the initial development of such coatings and materials for p… more
Date: December 1, 1998
Creator: Besman, T. M.; Cooley, K. M.; Haynes, J. A.; Lee, W. Y. & Vaubert, V. M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effects of Platinum Additions and Sulfur Impurities on the Microstructure and Scale Adhesion Behavior of Single-Phase CVD Aluminide Bond Coatings

Description: The adhesion of alumina scales to aluminide bond coats is a life-limiting factor for some advanced thermal barrier coating systems. This study investigated the effects of aluminide bond coat sulfur and platinum contents on alumina scale adhesion and coating microstructural evolution during isothermal and cyclic oxidation testing at 1150 C. Low-sulfur NiAl and NiPtAl bond coats were fabricated by chemical vapor deposition (CVD). Lowering the sulfur contents of CVD NiAl bond coatings significantl… more
Date: February 28, 1999
Creator: Cooley, K. M.; Haynes, J. A.; Lee, W. Y.; Pint, B. A.; Wright, I. G. & Zhang, Y.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Preparation and friction characteristics of self-lubricating TiN- MoS{sub 2} composite coatings

Description: Composite coatings consisting of distinctly discrete phases of TiN and MoS{sub 2} were codeposited on graphite and Ti-6Al-4V substrates from Ti((CH3)2N)4/NH3/MoF6/H2S gas mixtures. Chemical composition and microstructure of the coatings were studied by Auger electron spectroscopy, XRD, and TEM. Friction coefficients at room temperature in air were typically in the range of 0.07 to 0.3; they remained comparable at 573 K, but increased to 0.7 to 1.0 at 673 K. A friction coefficient of {similar_to… more
Date: December 31, 1995
Creator: Bae, Y.W.; Lee, W.Y.; Besmann, T.M.; Yust, C.S. & Blau, P.J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Some effects of metallic substrate composition on degradation of thermal barrier coatings

Description: Comparisons have been made in laboratory isothermal and cyclic oxidation tests of the degradation of oxide scales grown on single crystal superalloy substrates and bond coating alloys intended for use in thermal barrier coatings systems. The influence of desulfurization of the superalloy and bond coating, of reactive element addition to the bond coating alloy, and of oxidation temperature on the spallation behavior of the alumina scales formed was assessed from oxidation kinetics and from SEM o… more
Date: December 1997
Creator: Wright, I. G.; Pint, B. A.; Lee, W. Y.; Alexander, K. B. & Pruessner, K.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Submillimeter and microwave residual losses in epitaxial films of Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O

Description: We have used a novel bolometric technique and a resonant technique to obtain accurate submillimeter and microwave residual loss data for epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8}. For all films we obtain good agreement between the submillimeter and microwave data, with the residual losses in both the Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O films scaling approximately as frequency squared below {approximately}… more
Date: December 1, 1992
Creator: Miller, D; Richards, P. L.; Eom, C. B.; Geballe, T. H.; Garrison, S. M.; Newman, N. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Submillimeter and microwave residual losses in epitaxial films of Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O

Description: We have used a novel bolometric technique and a resonant technique to obtain accurate submillimeter and microwave residual loss data for epitaxial thin films of YBa{sub 2}Cu{sub 3}O{sub 7}, Tl{sub 2}Ca{sub 2}Ba{sub 2}Cu{sub 3}O{sub 10} and Tl{sub 2}CaBa{sub 2}Cu{sub 2}O{sub 8}. For all films we obtain good agreement between the submillimeter and microwave data, with the residual losses in both the Y-Ba-Cu-O and Tl-Ca-Ba-Cu-O films scaling approximately as frequency squared below {approximately}… more
Date: March 1, 1992
Creator: Miller, D.; Richards, P. L.; Garrison, S. M.; Newman, N.; Eom, C. B.; Geballe, T. H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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