Modification and Control of Oxide Structures on Metals and Alloys: (Phase IV)
Final rept. 2 Mar 1973-2 Mar 1974
WESTINGHOUSE ASTRONUCLEAR LAB PITTSBURGH PA
Pagination or Media Count:
Nb-Co-Al and Nb-Fe-Al base alloys have been studied to determine the effects of composition both elemental and constituent i.e., intermetallic alloy compounds used to make alloys on the oxides formed during 1200C oxidation in air. Alloys were formed by both pressing and sintering of intermetallic compounds and elemental powders and by arc melting alloy buttons from intermetallic compounds and elements in powder form. Oxidation kinetics have been measured, and the oxides formed have been examined by x-ray diffraction techniques. In addition, Y and Y2O3 additions were made to several alloys to evaluate the effects of rare earth additions on the oxide structure. In addition to the oxidation kinetics and oxide structure correlation, metallographic techniques were used to evaluate the depth of penetration of oxygen into the various alloys. This study confirmed that rutile type oxides such as NbAlO4, NbFeO4, and NbCrO4 are responsible for improved oxidation performance. Parabolic rate constants were measured for these alloys.
- Physical Chemistry
- Properties of Metals and Alloys