Effects of sulfur impurity on the scale adhesion behavior of a desulfurized Ni-based superalloy aluminized by chemical vapor deposition
- Oak Ridge National Lab., TN (United States)
- Univ. of Tennessee, Knoxville, TN (United States). Dept. of Materials Science and Engineering
The surface of a single-crystal Ni-based superalloy, which contained a bulk sulfur content of {approximately} 0.4 ppmw, was aluminized in a hot-wall chemical vapor deposition (CVD) reactor, using AlCl{sub 3} and H{sub 2} as gaseous precursors, at 1,100 C. The chemical composition and microstructure of the resulting aluminide coating were characterized with particular emphasis on sulfur incorporation as an impurity during aluminizing. Depth profiling by glow-discharge mass spectroscopy (GDMS) was used as a qualitative means of assessing the level of sulfur in the coating structure. Sulfur contamination, which was initially observed at the coating surface and the substrate-coating interface, could be reduced by some minor reactor modifications. With the reduced sulfur content, scale adhesion on the surface of the aluminide grains of the coating was significantly improved during cyclic oxidation, whereas scale spallation at the coating`s grain boundaries became more apparent.
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-96OR22464
- OSTI ID:
- 616438
- Journal Information:
- Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science, Journal Name: Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science Journal Issue: 3 Vol. 29; ISSN 1073-5623; ISSN MMTAEB
- Country of Publication:
- United States
- Language:
- English
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