The Effect of Mn 2+ on the Microstructure and Mechanical Properties of ZrO 2 –Al 2 O 3 –SiO 2 Ceramic Materials

In this article, we have studied the influence of Mn 2+ on the properties (phase composition, porosity, microstructure, three-point bending strength, and microhardness) and sintering of the ZrO 2 –Al 2 O 3 –SiO 2 composite ceramic materials. The ZrO 2 –Al 2 O 3 –SiO 2 ceramic powder containing 2.5 wt % Al 2 O 3 and 0.5 wt % SiO 2 with specific area of 24.7 m 2 /g is synthesized through the coprecipitation method. Three concentrations of Mn 2+ are considered: 0.25, 0.50, and 0.75 mol %. The introduction of Mn 2+ leads to a significant increase in mechanical properties. The samples are sintered at 1250 and 1300°C for 2 h. The highest value of strength at three-point bending of 761 ± 36 MPa and microhardness of 9.5 ± 0.5 GPa is demonstrated by the material of the composition ZrO 2 –Al 2 O 3 –SiO 2 containing 0.75 mol % Mn 2+ sintered at 1300°С. The crack resistance of this material is 7.0 MPa m 1/2 . At the same time, the highest values of crack resistance of 9.3 ± 0.5 MPa m 1/2 are shown by materials of the ZrO 2 –Al 2 O 3 –SiO 2 composition containing 0.75 mol % Mn 2+ sintered at 1250°C.