Effects of Platinum on the Hot Corrosion Behavior of Hf-Modified γ′-Ni3Al + γ-Ni-Based Alloys
- 230 Downloads
The establishment of a protective α-Al2O3 scale is critical for providing high temperature protection from oxidation and hot corrosion, thereby improving lifetimes of advanced gas turbine engine components. Recent work by our group has shown that a wide range of Pt + Hf-modified γ′-Ni3Al + γ-Ni alloy compositions form a very adherent and slow-growing Al2O3 scale and exhibit excellent oxidation resistance. The main thrust of the present study was to understand the effects of Pt addition on the Type I (900 °C) and Type II (705 °C) hot corrosion (HC) behavior of model Hf-modified γ′ + γ alloy compositions. The salt used to bring about hot corrosion was Na2SO4. It was found that the Type I HC resistance of γ′ + γ alloys improved with up to about 10 at.% Pt addition, but then decreased significantly with increasing Pt content up to 30 at.% (the maximum level studied); however, under Type II HC conditions the resistance of γ′ + γ alloys progressively improved with increasing Pt content up to 30 at.%. The effect of pre-oxidation on hot corrosion resistance was also examined, and the results indicated that pre-oxidation generally improved Type II HC resistance for the test duration studied.
Keywordsγ′ + γ alloy Platinum effect Pre-oxidation Type I hot corrosion Type II hot corrosion
We thank the Office of Naval Research for sponsoring this research under the contract N00014-04-1-0368, with Program Manager, Dr. Airan Perez.
- 1.F. S. Pettit and G. H. Meier, Superalloys 1984 (Metallurgical Society of AIME, Warrendale, 1984), p. 651.Google Scholar
- 4.K. L. Luthra, Metallurgical Transactions 13A, 1843 (1982).Google Scholar
- 10.D. R. Coupland, C. W. Hall, and I. R. McGill, Platinum Metal Review 26, 186 (1982).Google Scholar
- 11.D. R. Coupland, I. R. McGill, C. W. Corti, and G. L. Selman, Environmental Degradation of High Temperature Materials 2, 26 (1980).Google Scholar
- 14.G. J. Tatlock and T. J. Hurd, Platinum Metals Review 31, 26 (1987).Google Scholar
- 17.N. S. Bornstein, JOM 48, 37 (1996).Google Scholar
- 20.V. Deodeshmukh and B. Gleeson, NACE Corrosion/2005 (Houston, TX, 2005), Paper No. 05446.Google Scholar
- 21.V. Deodeshmukh and B. Gleeson, NACE Corrosion/2006 (San Diego, CA, 2006), Paper No. 06476.Google Scholar
- 22.I. Barin, Thermochemical Data of Pure Substances, Vol. 1–2, 3rd edn. (Weinheim/VCH, New York, 1995).Google Scholar
- 24.Z. F. Gulyanitskaya, N. M. Pavlyuchenko, L. I. Blokhina, and G. N. Zviadadze, Izvestiya Akademii Nauk SSSR, Neorganicheskie Materialy 15-11, 1933 (1979).Google Scholar
- 25.P. Kofstad, High Temperature Corrosion, (Elsevier Applied Science, London, 1988).Google Scholar