Oxidative Vaporization Kinetics of Cr[sub 2]O[sub 3] in Oxygen from 1000° to 1300°C

Rates of oxidative vaporization of on preoxidized resistively heated chromium were determined in flowing oxygen at a pressure of 0.115 Torr for temperatures from 1000° to 1300°C. Reaction controlled rates were obtained from experimental rates by a gold calibration technique, and these rates were shown to agree with those predicted by thermochemical analysis. The activation energy obtained for the oxidative vaporization reaction corresponded numerically with the thermochemical enthalpy of the reaction. A theoretical equation is given for calculating the rate from thermodynamic data using boundary‐layer theory.