Effect of annealing on the structure and phase transformation in ZrO₂–MgO ceramic powders

The structure and phase composition of ZrO₂–MgO powders with the MgO content from 9 to 43 mol % obtained by the plasma chemical method after annealing at 700–1400°С are studied. Differential scanning calorimetry and powder thermogravimetric analysis are carried out. It is found that, in the course of heating, the mass loss and the endothermic reactions energy increase with the increase in the MgO content. In the initial state, the powders containing more than 25 mol % of MgO are supersaturated solid solutions of cubic ZrO₂. Water desorption processes and decomposition of residual nitrates are observed in powders up to 420°С. The endothermic peak at high temperatures is due to the dehydration process and decomposition of the cubic ZrO₂ solid solution.