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Evaluation Of Advanced Solid Lubricant Coatings For Foil Air Bearings Operating At 25 And 500 C Nasa Tm 1998 206619 Sep 15 1998
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Book Synopsis Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C by : Christopher DellaCorte
Download or read book Evaluation of Advanced Solid Lubricant Coatings for Foil Air Bearings Operating at 25 and 500 C written by Christopher DellaCorte and published by . This book was released on 1998 with total page 18 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery by : C. DellaCorte
Download or read book Performance and Durability of High Temperature Foil Air Bearings for Oil-Free Turbomachinery written by C. DellaCorte and published by . This book was released on 2000 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 deg C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS 304, is applied to the shaft by plasma spraying. PS304 is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS 304 coating are well suited for advanced high temperature, oil-free turbomachinery applications.
Book Synopsis NAA-SR. by : U.S. Atomic Energy Commission
Download or read book NAA-SR. written by U.S. Atomic Energy Commission and published by . This book was released on 1958 with total page 216 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Reactor Core Materials written by and published by . This book was released on 1960 with total page 304 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Introductory Nuclear Reactor Statics by : Karl Otto Ott
Download or read book Introductory Nuclear Reactor Statics written by Karl Otto Ott and published by . This book was released on 1983 with total page 394 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Thermal Conductivity Measurements by : J. M. Davidson
Download or read book Thermal Conductivity Measurements written by J. M. Davidson and published by . This book was released on 1956 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Transactions and Journal of the British Ceramic Society by : British Ceramic Society
Download or read book Transactions and Journal of the British Ceramic Society written by British Ceramic Society and published by . This book was released on 1912 with total page 426 pages. Available in PDF, EPUB and Kindle. Book excerpt: Vols. for 1971-74, include a separate section with title: British ceramic abstracts, prepared by the British Ceramic Research Association, also issued separately.
Book Synopsis The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings by :
Download or read book The Effect of Journal Roughness and Foil Coatings on the Performance of Heavily Loaded Foil Air Bearings written by and published by . This book was released on 2001 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foil air bearing load capacity tests were conducted to investigate if a solid lubricant coating applied to the surface of the bearing's top foil can function as a break-in coating. Two foil coating materials, a conventional soft polymer film (polyimide) and a hard ceramic (alumina), were independently evaluated against as-ground and worn (run-in) journals coated with NASA PS304, a high-temperature solid lubricant composite coating. The foil coatings were evaluated at journal rotational speeds of 30000 rpm and at 25 deg C. Tests were also performed on a foil bearing with a bare (uncoated) nickel-based superalloy top foil to establish a baseline for comparison. The test results indicate that the presence of a top foil solid lubricant coating is effective at increasing the load capacity performance of the foil bearing. Compared to the uncoated baseline, the addition of the soft polymer coating on the top foil increased the bearing load coefficient by 120 percent when operating against an as-ground journal surface and 85 percent against a run-in journal surface. The alumina coating increased the load coefficient by 40 percent against the as-ground journal but did not have any affect when the bearing was operated with the run-in journal. The results suggest that the addition of solid lubricant films provide added lubrication when the air film is marginal indicating that as the load capacity is approached foil air bearings transition from hydrodynamic to mixed and boundary lubrication.
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721194568 Total Pages :34 pages Book Rating :4.1/5 (945 download)
Book Synopsis Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery by : National Aeronautics and Space Administration (NASA)
Download or read book Performance and Durability of High Temperature Foil Air Bearing for Oil-Free Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-16 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: The performance and durability of advanced, high temperature foil air bearings are evaluated under a wide range (10-50 kPa) of loads at temperatures from 25 to 650 C. The bearings are made from uncoated nickel based superalloy foils. The foil surface experiences sliding contact with the shaft during initial start/stop operation. To reduce friction and wear, the solid lubricant coating, PS304, is applied to the shaft by plasma spraying. PS304, is a NiCr based Cr2O3 coating with silver and barium fluoride/calcium fluoride solid lubricant additions. The results show that the bearings provide lives well in excess of 30,000 cycles under all of the conditions tested. Several bearings exhibited lives in excess of 100,000 cycles. Wear is a linear function of the bearing load. The excellent performance measured in this study suggests that these bearings and the PS304 coating are well suited for advanced high temperature, oil-free turbomachinery applications. DellaCorte, C. and Valco, M. J. and Radil, K. C. and Heshmat, H. Glenn Research Center NASA/TM-1999-209187, NAS 1.15:209187, E-11697
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721641321 Total Pages :32 pages Book Rating :4.6/5 (413 download)
Book Synopsis Friction and Wear Characteristics of Cu-4Al Foil Bearing Coating at 25 and 650 Degree C by : National Aeronautics and Space Administration (NASA)
Download or read book Friction and Wear Characteristics of Cu-4Al Foil Bearing Coating at 25 and 650 Degree C written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: The friction and wear performance of a Cu-4Al top foil coating has been investigated in Generation I foil air bearings. The copper alloy was applied by a novel deposition technique (ion diffusion) and the journal was coated with PS304, a plasma spray deposited high temperature composite solid lubricant coating. The ion diffusion coating process deposits a desirable smooth layer compared to other methods like cathodic arc deposition. The tribological performance of bearings with and without Cu-4Al foil coatings were evaluated through start-stop tests on an air bearing test rig at 25 and 650 C. The results indicate that the Cu-4Al assists during the initial break-in period, gives more stable friction performance with respect to temperature, and appears to prevent top foil wear at high temperature. The measured load capacity coefficient was 0.5, which was comparable to earlier testing of more advanced design Generation III bearings coated with standard cathodic arc deposited Cu-4Al. However, further studies are needed to determine if deeper penetration of the copper alloy into the foil would help make the transition in friction behavior from contact with the Cu-4Al coated foil to contact with the base foil material more gradual. Also, future work is recommended to assess the performance of ion diffusion coatings with different Cu-based alloy compositions and to investigate the effect the coating has on the elastic modulus of the foil material. Stanford, Malcolm K. and DellaCorte, Christopher Glenn Research Center NASA/TM-2004-212972, NAS 1.15:212972, E-14445
Author :National Aeronautics and Space Administration (NASA) Publisher :Createspace Independent Publishing Platform ISBN 13 :9781721530519 Total Pages :34 pages Book Rating :4.5/5 (35 download)
Book Synopsis A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery by : National Aeronautics and Space Administration (NASA)
Download or read book A Systems Approach to the Solid Lubrication of Foil Air Bearings for Oil-Free Turbomachinery written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-20 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Foil air bearings are self-acting hydrodynamic bearings which rely upon solid lubricants to reduce friction and minimize wear during sliding which occurs at start-up and shut-down when surface speeds are too low to allow the formation of a hydrodynamic air film. This solid lubrication is typically accomplished by coating the non-moving foil surface with a thin, soft polymeric film. The following paper introduces a systems approach in which the solid lubrication is provided by a combination of self lubricating shaft coatings coupled with various wear resistant and lubricating foil coatings. The use of multiple materials, each providing different functions is modeled after oil-lubricated hydrodynamic sleeve bearing technology which utilizes various coatings and surface treatments in conjunction with oil lubricants to achieve optimum performance. In this study, room temperature load capacity tests are performed on journal foil air bearings operating at 14,000 rpm. Different shaft and foil coating technologies such as plasma sprayed composites, ceramic, polymer and inorganic lubricant coatings are evaluated as foil bearing lubricants. The results indicate that bearing performance is improved through the individual use of the lubricants and treatments tested. Further, combining several solid lubricants together yielded synergistically better results than any material alone. DellaCorte, Christopher and Zaldana, Antonio R. and Radil, Kevin C. Glenn Research Center NASA/TM-2002-211482, NAS 1.15:211482, E-13250, ARL-TR-2867
