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Correction of energy shift in measurements of solute segregation by Rutherford backscattering spectroscopy

Description: Rutherford backscattering spectrometry (RBS) is a sensitive technique for measuring the elemental composition of a specimen in the near-surface region. Studies of radiation effects in materials, such as radiation-induced segregation of solute elements to the external surface, often employ RBS to measure specimen composition because the high-energy ions can be used to produce radiation damage and also serve as the RBS profile ions. When small amounts of segregation are being measured, a shift in… more
Date: February 1, 1991
Creator: Erck, R. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Radiation-induced segregation and precipitation in molybdenum-rhenium alloys

Description: Specimens of Mo-7 at. % Re and Mo-30 at. % Re were irradiated with 1.8 MeV /sup 4/He/sup +/ ions at elevated temperatures. Radiation-induced segregation of Re was measured during irradiation by in situ Rutherford backscattering spectrometry. Segregation of the undersized Re atoms in the same direction as the defect fluxes, i.e., toward the external surface, was observed. The amount of Re enrichment in the near-surface region was measured as a function of temperature and of dose at a calculated … more
Date: February 1, 1986
Creator: Erck, R. A.; Wayman, C. M. & Rehn, L. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Effect of niobium interlayer on high-temperature sliding friction and wear of silver films on alumina

Description: We investigated the effect of a thin Nb bond layer (15--20 mn thick) on the high-temperature sliding friction and wear of silver films ({approx}1.5 {mu}m thick) produced on {alpha}-alumina (Al{sub 2}O{sub 3}) substrates by ion-beam assisted deposition. The friction coefficients of test pairs without an Ag film fluctuated between 0.8 to 1.1, whereas the friction coefficients of pairs with an Ag film were 0.32 to 0.5. The wear of uncoated Al{sub 2}O{sub 3} balls sliding against the Ag-coated flat… more
Date: March 1, 1994
Creator: Erdemir, A. & Erck, R. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Frictional behavior of diamondlike carbon films in vacuum and under varying water vapor pressure.

Description: In this study, we investigated the frictional behavior of both hydrogenated and hydrogen-free diamondlike carbon (DLC) films in high vacuum (10{sup -6} Pa) at room temperature. Water was also introduced into the vacuum chamber to elucidate its effects on DLC film tribology. The hydrogen-free DLC (also referred to as tetrahedral amorphous carbon, or ta-C) was produced by an arc-PVD process, and the highly hydrogenated DLC was produced by plasma-enhanced chemical-vapor deposition. Tribological me… more
Date: March 25, 2002
Creator: Andersson, J.; Erck, R. A. & Erdemir, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Pull-test adhesion measurements of diamondlike carbon films on silicon carbide, silicon nitride, aluminum oxide, and zirconium oxide

Description: Hydrogenated amorphous carbon films or diamondlike carbon (DLC) films were formed by ion-beam deposition of 400 eV methane (CH{sub 4}) ions on several smooth and rough ceramics, as well as on ceramics coated with a layer of Si and Ti. Adhesion was measured by the pin-pull method. Excellent adhesion was measured for smooth SiC and Si{sub 3}N{sub 4}, but adhesion of DLC to Al{sub 2}O{sub 3} and ZrO{sub 2} was negligible. The use of a Si bonding interlayer produced good adhesion to all the substra… more
Date: October 1, 1993
Creator: Erck, R. A.; Nichols, F. A. & Dierks, J. F.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Weibull Analysis Applied to the Pull Adhesion Test and Fracture of a Metal-Ceramic Interface

Description: Various adhesion tests have been developed to measure the mechanical bonding of thin coatings deposited on substrates. In the pull test, pins that have been bonded to the coating under test are pulled with increasing force normal to the coating until the coating is pulled from the substrate. For many systems, large scatter in the data is often observed due to uncontrolled defects in the interface and the brittle nature of the pull test. In this study, the applicability of Weibull statistics to … more
Date: November 1, 1992
Creator: Erck, R. A.; Nichols, F. A. & Schult, D. L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High-temperature tribological characteristics of silver and gold coatings on ceramics prepared by ion-beam-assisted deposition

Description: An ion-beam-assisted deposition (IBAD) system was used to deposit silver and gold coatings on polycrystalline {alpha}-alumina (Al{sub 2}O{sub 3}) substrates for tribological studies at temperatures to 400{degrees}C. The wear tests were performed with an oscillating ball-on-flat type of test apparatus as a partial simulation of ring/liner motion and contact geometry in actual engine systems. The test results showed that without a surface coating, both the wear rates and the friction coefficients… more
Date: April 1, 1992
Creator: Erdemir, A.; Erck, R. A.; Fenske, G. R. & Nichols, F. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High-temperature tribological characteristics of silver and gold coatings on ceramics prepared by ion-beam-assisted deposition

Description: An ion-beam-assisted deposition (IBAD) system was used to deposit silver and gold coatings on polycrystalline {alpha}-alumina (Al{sub 2}O{sub 3}) substrates for tribological studies at temperatures to 400{degrees}C. The wear tests were performed with an oscillating ball-on-flat type of test apparatus as a partial simulation of ring/liner motion and contact geometry in actual engine systems. The test results showed that without a surface coating, both the wear rates and the friction coefficients… more
Date: April 1, 1992
Creator: Erdemir, A.; Erck, R.A.; Fenske, G.R. & Nichols, F.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Hydrogen Pipeline Compressors Annual Progress Report.

Description: The objectives are: (1) develop advanced materials and coatings for hydrogen pipeline compressors; (2) achieve greater reliability, greater efficiency, and lower capital in vestment and maintenance costs in hydrogen pipeline compressors; and (3) research existing and novel hydrogen compression technologies that can improve reliability, eliminate contamination, and reduce cost. Compressors are critical components used in the production and delivery of hydrogen. Current reciprocating compressors … more
Date: July 15, 2011
Creator: Fenske, G. R. & Erck, R. A.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Uses of ion bombardment in thin-film deposition

Description: Use of plasma- and ion-beam-modified surfaces and surface coatings in continually expanding in engineering disciplines. The purpose of these modifications and treatments is to impart favorable properties, such as wear resistance and lubricity, to the surfaces, while at the same time retaining the strength or toughness of the bulk materials. Energetic-ion bombardment can be used to modify the structural and chemical properties of surfaces or applied coatings. Ion-implantation has been used for m… more
Date: October 1, 1990
Creator: Erck, R.A.; Fenske, G.R. & Erdemir, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Top-of-Rail lubricant

Description: Analysis of the volatile and semivolatile fractions collected after use of the TOR lubricant indicated that other than contaminants in the collection laboratory, no compounds on the EPA's Target Compound Lists (Tables 2 and 5) were detected in these fractions. The data of these qualitative analyses, given in the various tables in the text, indicate only the relative amounts of the tentatively identified compounds. The authors recommend that quantitative analysis be performed on the volatile and… more
Date: July 14, 2000
Creator: Alzoubi, M. F.; Fenske, G. R.; Erck, R. A. & Boparai, A. S.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Solid/liquid lubrication of ceramics at elevated temperatures

Description: This study investigates the effect of solid and liquid lubrication on friction and wear performance of silicon nitride (Si{sub 3}N{sub 4}) and cast iron. The solid lubricant was a thin silver film ({approx}2 {mu}m thick) produced on Si{sub 3}N{sub 4} by ion-beam-assisted deposition. A high-temperature polyol-ester-base synthetic oil served as the liquid lubricant. Friction and wear tests were performed with pin-on-disk and oscillating-slider wear test machines at temperatures up to 300{degrees}… more
Date: April 1, 1996
Creator: Erdemir, A.; Erck, R.A.; Fenske, G.R. & Hong, H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of metallic coating properties on the tribology of oil- lubricated coated-ceramics

Description: The friction and wear behavior of zirconia ceramics lubricated with solid coatings (AG, Au, and Nb), deposited by ion-beam-assisted-deposition (IBAD) techniques, and a polyol-ester-based synthetic oil are presented. These results demonstrate that, although the simultaneous use of soft (e.g. Ag and Au) solid lubricants in conjunction with the synthetic lubricant significantly reduces the friction and wear under boundary lubrication at temperatures up to 250{degree}C, the durability of the soft f… more
Date: January 1, 1992
Creator: Ajayi, O.O.; Fenske, G.R.; Erdemir, A.; Erck, R.A.; Hsieh, J.H. & Nichols, F.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Boundary film for structural ceramic materials

Description: Structural ceramic materials, like metals, will require lubrication if they are to be used extensively for tribological applications. The use of thin soft metallic coatings (specifically Ag) as a boundary film during mineral oil lubrication of silicon nitride (Si[sub 3]N[sub 4]) and zirconia (ZrO[sub 2]) ceramic materials was investigated in this study. With a pin-on-flat contact configuration in reciprocating sliding, the steady friction coefficient was reduced by a factor of 2 (0.14 [minus]0.… more
Date: May 1, 1992
Creator: Ajayi, O.O.; Erdemir, A.; Hsieh, J.H.; Erck, R.A.; Fenske, G.R. & Nichols, F.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Boundary film for structural ceramic materials

Description: Structural ceramic materials, like metals, will require lubrication if they are to be used extensively for tribological applications. The use of thin soft metallic coatings (specifically Ag) as a boundary film during mineral oil lubrication of silicon nitride (Si{sub 3}N{sub 4}) and zirconia (ZrO{sub 2}) ceramic materials was investigated in this study. With a pin-on-flat contact configuration in reciprocating sliding, the steady friction coefficient was reduced by a factor of 2 (0.14 {minus}0.… more
Date: May 1, 1992
Creator: Ajayi, O. O.; Erdemir, A.; Hsieh, J. H.; Erck, R. A.; Fenske, G. R. & Nichols, F. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of metallic coating properties on the tribology of oil- lubricated coated-ceramics

Description: The friction and wear behavior of zirconia ceramics lubricated with solid coatings (AG, Au, and Nb), deposited by ion-beam-assisted-deposition (IBAD) techniques, and a polyol-ester-based synthetic oil are presented. These results demonstrate that, although the simultaneous use of soft (e.g. Ag and Au) solid lubricants in conjunction with the synthetic lubricant significantly reduces the friction and wear under boundary lubrication at temperatures up to 250{degree}C, the durability of the soft f… more
Date: April 1, 1992
Creator: Ajayi, O. O.; Fenske, G. R.; Erdemir, A.; Erck, R. A.; Hsieh, J. H. & Nichols, F. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Effect of Metallic-Coating Properties on the Tribology of Coated and Oil-Lubricated Ceramics

Description: Friction and wear behavior was determined for zirconia ceramics lubricated with solid coatings (Ag, Au, and Nb) deposited by ion-beam-assisted-deposition (IBAD) techniques, and a polyol-ester-based synthetic oil. Although the use of soft Ag and Au coatings as solid lubricants in conjunction with the synthetic oil significantly reduced the friction and wear under boundary lubrication at temperatures up to 250[degrees]C, these films had poor durability. In contrast, the Nb coating was more durabl… more
Date: September 1, 1992
Creator: Ajayi, O. O.; Erdemir, A.; Fenske, G. R.; Erck, R. A.; Hsieh, J. H. & Nichols, F. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

High-rate reel-to-reel continuous coating of biaxially textured magnesium oxide thin films for coated conductors

Description: Biaxially textured thin films of magnesium oxide (MgO) were deposited by electron beam evaporation at deposition rates of 0.6 {mu}m/min on moving Ni-based alloy tapes as oriented buffer layers for coated conductors. Moving substrates were inclined with respect to the atomic vapor and translated through collimated dual vapor sources. Growth anisotropy in the MgO and self-shadowing effects due to the inclined angle combine to create biaxial texture in the deposited thin films. MgO films grown to … more
Date: January 12, 2000
Creator: Chudzik, M. P.; Erck, R. A.; Balachandran, U.; Luo, Z. P.; Miller, D. J. & Kannewurf, C. R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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The role of soft (metallic) film in tribological behavior of ceramic materials

Description: The friction coefficient and wear rate in structural ceramic materials are often too high to make them attractive for applications requiring dry sliding. The role of a thin soft silver film in improving the tribological characteristics of silicon nitride materials is investigated in this study. In a pin-on-disc contact configuration in reciprocating motion, the friction coefficient was reduced by about 50% and the wear rate by one to two orders of magnitude. The friction reduction is thought to… more
Date: January 1, 1990
Creator: Ajayi, O.O.; Erdemir, A.; Erck, R.A.; Fenske, G.R. & Nichols, F.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Fabrication of biaxially textured templates for coated conductors by inclined substrate deposition.

Description: YBCO-coated conductors will enable the development of smaller, lighter, more-efficient electric power devices that can be operated at temperatures approaching that of liquid nitrogen. The critical current density (J{sub c}) of YBCO films on flexible metallic substrates has been significantly improved by epitaxially growing the YBCO on biaxially textured template films. Inclined substrate deposition (ISD) offers the potential for rapidly producing high-quality biaxially textured buffer layers th… more
Date: August 21, 2002
Creator: Dorris, S. E.; Ma, B.; Li, M.; Fisher, B. L.; Koritala, R. E.; Erck, R. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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