High temperature oxidation of nickel

Using a sensitive volumetric technique, a study was made of the kinetics of oxidation of nickel at 1200° C. and 1300° C. Three purities of nickel were used for the investigation which was limited to the initial three hours of reaction. The rate of oxidation of nickel followed the parabolic rate law after an initial period of deviation which lasted up to 40 minutes. No direct correlation was found between the oxide thickness and the end of the period of deviation from the parabolic rate law. The purity of the nickel was found to have a marked effect on the rate of oxidation of nickel which increased as the purity decreased. The color of the oxide on nickel was found to be related to the thickness of the oxide layer. The oxide on high-purity nickel was gray initially but rapidly changed to green and then gradually to black with thickening --Abstract, page 2