Features of Oxidation of Bismuth by High-Density Water-Oxygen Fluid

The paper presents the results of a study of oxidation of bulk bismuth samples by oxygen, water vapor, and water-oxygen fluid in a reactor heated to 873 K at a rate of 1 K/min with high-density reagents (rho O-2 <= 0.62 and rho H2O <= 5.24 mol/dm(3)). The results include temperature dependences of the pressure of the reaction mixtures. The rate of oxygen consumption is found from these dependences through the Redlich-Kwong equation of state. Formation of dense oxide film during the oxidation of bismuth in the O-2 environment was shown. No oxide formation was detected during treatment of bismuth with water vapor. The combined action of O-2 and H2O molecules enhances the oxidation of bismuth and leads to formation of oxides of different compositions and morphologies. At T>720 K, the bismuth oxidation rate was observed to increase due to the higher pressure of saturated bismuth vapor.