The influence of corundum content and sintering temperature on the mechanical properties of CaO–ZrO$_{2}$–Al$_{2}$O$_{3}$ ceramic composites

We have studied the mechanical properties (Vickers microhardness $H_V$ and fracture toughness $K_C$) of nanostructured CaO–ZrO$_{2}$–Al$_{2}$O$_{3}$ ceramic composites as dependent on the content of corundum (0 $\le C_{\mathrm{Al}_2\mathrm{O}_3}\le$ 25%) and the temperature of sintering (1250 $\le T_{1}\le$ 1500$^\circ$C). Optimum value of the corundum content ($C_{\mathrm{Al}_2\mathrm{O}_3}$ = 5%) and optimum regime ($T_1$ = 1300$^{\circ}$C, 5 min; $T_2$ = 1200$^{\circ}$C, 4 h) of two-stage sintering are established, which favor attaining the best mechanical characteristics of ceramic composites ($H_V$ = 12.25 GPa, $K_C$ = 8.47 MPa m$^{1/2}$).