The oxidation behavior of tungsten and germanium alloyed molybdenum disilicide coatings [electronic resource].
- Washington, D.C. : United States. Dept. of Defense, 1991.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy.
- Physical Description:
- 29 pages : digital, PDF file
- Additional Creators:
- Pacific Northwest Laboratory
United States. Department of Defense
United States. Department of Energy. Office of Scientific and Technical Information
- A two-step coating process was used to produce a (Mo,W)(Si,Ge)₂ coating on niobium. After exposure to high temperatures, a lower silicide layer forms underneath and is effective in arresting cracks. The oxidation weight-gain kinetics are parabolic following an initial transient period. Test coupons coated with (Mo,W)(Si,Ge)₂ passed 200 one-hour cycles at 1370°C and 60 one-hour cycles at 1540°C. These results, along with evidence of a thick protective glass layer, suggest that the germanium additions help cyclic oxidation resistance. The beneficial effects of the tungsten include the formation of microvoids, which provides a lower effective elastic modulus, and mechanical strengthening. No accelerated low temperature or ``pest`` oxidation was observed in the temperature range between 500--700°C. Thus, a (Mo,W)(Si,Ge) multicomponent silicide coating offers significant promise for the protection of Nb-base alloys exposed to cyclic oxidizing environments over a broad range of temperatures.
- Published through SciTech Connect.
High temperature structural silicides workshop,Gaithersburg, MD (United States),4-6 Nov 1991.
Rapp, R.A.; Mueller, A.; Kircher, T.; Courtright, E.L.; Wang, Ge.
- Funding Information:
View MARC record | catkey: 14456796