Laney, Scot Jason
(2004)
Effect of Surface Conditioning of Platinum Aluminide Bond Coats on Thermal Barrier Coating Life.
Master's Thesis, University of Pittsburgh.
(Unpublished)
Abstract
Thermal Barrier Coatings (TBC) have been used for a number of years on components for use in aircraft gas turbine engines. The standard for processing these components includes grit blasting the bond coat prior to TBC deposition by Electron Beam Physical Vapor Deposition (EBPVD). While grit blasting has worked well for industry, it is argued that EBPVD TBC's are able to form strong bonds on smoother surface finishes. This would theoretically improve the component lifetime. This study involved the examination of the performance and failure of several industrially and economically viable alternative surface finishes as well as the effect of pre-oxidation treatments on the lifetime of the TBC. The system used consisted of a substrate of CMSX4 (Ni based superalloy), a platinum modified diffusional aluminide coating, and yttrium stabilized zirconia (YSZ) deposited by EBPVD as the TBC. Surface finishes applied prior to TBC deposition include 120 and 40 minute media finishes, barrel finish, and 3 mm hand polish. The various atmospheres were chosen for the pre-oxidation treatments in order to grow metastable and stable alumina scales. Exposure was done cyclically (1 hour cycles) at 1121oC in laboratory air until failure. Samples with the combination of media finish and mostly a alumina scales had lifetimes up to 1040 cycles. This is well beyond the expected value (~750 cycles) of a grit blasted sample in the same exposure conditions.
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Details
| Item Type: |
University of Pittsburgh ETD
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| Status: |
Unpublished |
| Creators/Authors: |
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| ETD Committee: |
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| Date: |
13 September 2004 |
| Date Type: |
Completion |
| Defense Date: |
3 June 2004 |
| Approval Date: |
13 September 2004 |
| Submission Date: |
19 July 2004 |
| Access Restriction: |
No restriction; Release the ETD for access worldwide immediately. |
| Institution: |
University of Pittsburgh |
| Schools and Programs: |
Swanson School of Engineering > Materials Science and Engineering |
| Degree: |
MSMSE - Master of Science in Materials Science and Engineering |
| Thesis Type: |
Master's Thesis |
| Refereed: |
Yes |
| Uncontrolled Keywords: |
alumina; bond coat; high temperature; oxidation; superalloy; surface roughness; TBC |
| Other ID: |
http://etd.library.pitt.edu/ETD/available/etd-07192004-165714/, etd-07192004-165714 |
| Date Deposited: |
10 Nov 2011 19:52 |
| Last Modified: |
15 Nov 2016 13:46 |
| URI: |
http://d-scholarship.pitt.edu/id/eprint/8442 |
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