Determination of the ATZ ceramics with different SiO$_2$ contents tensile strength by the “brazilian test” method

The possibility of using the “Brazilian test” method to determination the tensile strength sigmat of composite zirconia ceramics small-size samples were demonstrated and the reliability of the obtained sigmat values were confirmed. It was found that the dependence of the tensile strength of alumina toughened zirconia (stabilized by calcium oxide) with silica addition (CaO-ATZ + SiO$_2$ ceramics) on SiO$_2$ concentration in them has a maximum ($\sigma_t$ = 450 MPa, at $C_{\mathrm{SiO_2}}$ = 5 mol.%). The observed toughened is explained by an increase in the transformability of the tetragonal $t$-ZrO$_2$ phase and, accordingly, by an enhanced role of transformation toughening when SiO$_2$ is adding into the ATZ ceramics.