Thermoanalytical study of the solid-state reactions in MgO-Cr2O3 and ZnO-Cr2O3 systems

The solid-state reactions in MgO-Cr₂O₃ and ZnO-Cr₂O₃ systems under atmospheres of oxygen, air and nitrogen were investigated by means of DTA and isothermal kinetic techniques. It was shown that the application of DTA to the solid-state reactions affords useful information with respect to the initial reaction stage: oxidation of Cr₂O₃ to CrO₃ in the presence of MgO or ZnO, followed by the formation of a thin layer of spinel, which consisted of an imperfect lattice, on the surface of the MgO or ZnO grains.