On the Reactions Occurring in the CaO?Cr2O3?O2 system

The reactions occurring in the system CaO? Cr₂O₃? O₂ have been investigated. In the mixture of two oxides heated in air to higher temperature calcium chromate and chromite are being formed. The rate and the ratio of the two reactions is very sensitive to the composition of gaseous atmosphere, especially to the partial pressure of oxygen. The formation of spinel was accelerated by a small amount of oxygen but was partly or fully suppressed at a higher oxygen pressure on the expense of chromate formation. The oxidation of CaO? Cr₂O₃ was also studied kinetically. Detailed measurements in different gaseous atmospheres were performed with doped CaO and Cr₂O₃. The results were interpreted in the light of the defect structure of the reacting oxides.