Oxidation or nitridation behavior of pure chromium and chromium alloys containing 10 mass % Ni or Fe in atmospheric heating

Abstract

The oxidation or nitridation behavior of pure chromium and chromium alloys containing 10 mass%Ni or 10 mass%Fe in atmospheric heating was investigated in the temperature range of 1073 to 1373 K. The formation behavior of the outer oxide phase of Cr 2O 3 and its growth kinetics in both chromium alloys was very similar to that of pure chromium. The nitride layer with the Cr 2N phase was formed beneath the oxide phase at temperatures above 1273 K in pure chromium. Marked internal nitridation with the formation of the Cr 2N phase was observed in the Cr-10 mass%Fe alloy, while the formation of Cr 2N was negligible in the Cr-10 mass%Ni alloy. Neither Ni nor Fe were detected inside the Cr 2O 3 phase, and was enriched in the subsurface layer between the oxide layer and the base alloy in a respective alloy. The Ni-enriched layer in Cr-10 mass%Ni alloy had a relatively narrow width, but a very high concentration of Ni compared with the Fe-enriched layer formed in the Cr-10 mass%Fe alloy. © 2006 The Japan Institute of Metals.