High-temperature oxidation of the nitrides of the group IV transition metals - II. Oxidation of zirconium and hafnium nitrides

Abstract

1. A study was made of the oxidation of zirconium and hafnium nitrides at temperatures ranging from 400 to 1200°C. 2. It was established that, as the oxide phases forming on these nitrides - ZrO2 and HfO2 - are of the same type and scale formation at the inner phase boundary with both nitrides is a result of oxygen diffusion, the difference in oxidation behavior between zirconium and hafnium nitrides is linked solely with the structural characteristics of the resultant oxynitride phases. The differences in structure between these phases explain why the oxidation resistance of hafnium nitride in the initial and later stages of the process is greater than that of zirconium nitride. © 1976 Plenum Publishing Corporation.