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Evaluation of Selected Spinels and Perovskites as Candidate High- temperature Molybdenum Coatings.
Glenn-ML; Henry-JL; Adams-A
NTIS: PB 295 873 :32 pages
As part of its goal to minimize requirements for mineral commodities through conservation and substitution, the Bureau of Mines conducted research to develop molybdenum as a potential substitute for superalloys containing the strategic and critical materials, nickel, chromium, and cobalt. Since molybdenum requires protection from oxidation at high temperatures, several complex oxides of the spinel and perovskite structure were investigated to determine which possessed the greatest potential for use as oxidation-barrier coatings. Two spinels (mgcr2o4 and mgal2o4) and five perovskites (bahfo3, ycro3, ndcro3, bazro3, and lacro3) were selected for testing. Various high-temperature properties that are important for oxidation-resistant coatings were examined, including diffusion rates of oxygen and molybdenum, recession (vaporization) rates, hardness, erosion resistance, sinterability, reactivity with molybdenum, and ease of application. From the evaluation of high- temperature properties, two spinels (mgcr2o4 and mgal2o4) stand above the other oxides as possible coatings for molybdenum. However, laboratory coatings of mgcr2o4 at 1,360 deg c (2,480 deg f) are equivalent or inferior to currently available mosi2 coatings; laboratory coatings of mgal2o4 may be comparable under limited conditions to currently available mosi2 coatings at the same temperature.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 295 873
Page last reviewed: April 12, 2019
Content source: National Institute for Occupational Safety and Health Education and Information Division