The Oxidation of Ni ‐ 2ThO2 between 900° and 1400°C

Abstract

The oxidation kinetics of nickel containing 2 volume per cent have been studied between 900° and 1400°C. In this temperature range the oxidation rate obeys the relationship Metallographic examination of oxidized specimens showed the oxide to be composed of a dense outer layer and a porous inner layer. Inert markers were found at the boundary between the dense and porous oxide layers. Internal oxidation was also apparent but not to the extent found in pure nickel. X‐ray fluorescence analysis showed to be absent in the dense outer oxide but present in the porous inner oxide. Oxidation of is believed to occur primarily by means of nickel ion diffusion to produce the outer oxide layer and diffusion of oxygen gas to form the inner oxide layer. The oxygen gas required to form the inner oxide layer is produced by decomposition of in the outer oxide layer at the boundary between the inner and outer oxide.