The Effect of Mn²⁺ on the Microstructure and Mechanical Properties of ZrO₂-Al₂O₃-SiO₂ Ceramic Materials

In this article, we have studied the influence of Mn2+ on the properties (phase composition, porosity, microstructure, three-point bending strength, and microhardness) and sintering of the ZrO2-Al2O3-SiO2 composite ceramic materials. The ZrO2-Al2O3-SiO2 ceramic powder containing 2.5 wt % Al2O3 and 0.5 wt % SiO2 with specific area of 24.7 m(2)/g is synthesized through the coprecipitation method. Three concentrations of Mn2+ are considered: 0.25, 0.50, and 0.75 mol %. The introduction of Mn2+ leads to a significant increase in mechanical properties. The samples are sintered at 1250 and 1300 degrees 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 ZrO2-Al2O3-SiO2 containing 0.75 mol % Mn2+ sintered at 1300 degrees & Scy;. 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 ZrO2-Al2O3-SiO2 composition containing 0.75 mol % Mn2+ sintered at 1250 degrees C.