Oxidation of Nickel-and Cobalt-Base Superalloys

摘要

This report presents information dealing with the oxidation of nickel- and cobalt-base superalloys. All of the superalloys will oxidize at high temperatures when oxygen is present in the enveloping atmosphere. The rate of oxidation depends upon alloy composition, temperature, oxygen concentration, oxides formed, diffusion rates of the metals in both base metal and oxide, diffusion rate of oxygen in the oxide, solubility of oxygen in the matrix, and a host of other variables. The effects of oxidation can be beneficial or they can be harmful. The first section of this report deals with the fundamentals of the oxidation of Ni-Cr and Co-Cr alloys. Subsequent sections discuss general surface oxidation, intergranular oxidation, other subsurface oxidation, and the effect of stress on the rate of oxidation. Numerous specific alloys are mentioned in the report; as an aid to the reader, the appendix contains an alloy index of the alloys mentioned in the report along with the compositions of the alloys, and the pages on which mention of the alloys is made. (Author)