The high temperature oxidation of beryllium: Part III In carbon dioxide, carbon monoxide and carbon monoxide-carbon dioxide mixtures

Abstract

The kinetics of the oxidation of electrolytic flake beryllium in carbon dioxide, in carbon monoxide and in carbon monoxide-carbon dioxide mixtures have been measured at temperatures from 500° to 750° C. In carbon dioxide, at temperatures up to 700° C, the rate of oxidation continuously decreases with time to reach a very small value (e.g. at 700° C, 0.13 μg/cm 2 h after 300 h) whilst at 750° C the rate first decreases and then increases, indicating breakaway. If the carbon dioxide is admitted to the preheated sample the oxidation is very rapid at first and most of the carbon deposition occurs over this initial period. In carbon monoxide, the oxidation is non-protective above 550° C, the rate of oxidation being considerably greater than in carbon dioxide. When beryllium is heated at 650° C in carbon monoxide-carbon dioxide mixtures containing up to 7.5 % of carbon monoxide, the kinetics are the same as in pure carbon dioxide.