Abstract
Coarse grained hafnium samples were oxidized for times up to 432 hr. A remarkable anisotropy of the oxidation rate was observed which persisted to the thick film region. This effect is associated with a variation in the stoichiometry of the oxide films covering the differently oriented grains. The oxygen gradient beneath the oxide film was measured using a technique involving the rate of dissolution of interference colored oxide films. Experimentally determined gradients are in good agreement with a theoretical expression involving the diffusivity, time, and oxide film thickness.

This publication has 0 references indexed in Scilit: