The Oxidation Kinetics of Zirconium Diboride and Zirconium Carbide at High Temperatures

Kinetic studies have been made of the oxidation of zirconium diboride at 945°–1256°C, and of zirconium carbide at 554°–652°C. The reaction is parabolic throughout the temperature range studied, whereas the reaction is linear. In the former case , together with a molten layer of boron oxide, is formed which protects against further direct attack of oxygen on the , while in the latter, a rather porous film of zirconium oxide is formed which is not protective. The rate of oxidation of is directly proportional to the oxygen partial pressure between 102 and 744 mm.