Effect of Co 2+ on the Phase Formation, Mechanical Properties, and In Vitro Behavior of Ceramics in the ZrO 2 –Al 2 O 3 System

The effect of the introduction of Co2+ to ZrO2–10 wt % Al2O3 ceramic materials on their phase composition, porosity, microstructure, strength, microhardness, cytotoxicity, and cytocompatibility was studied. It was shown that the addition of Co2+ stabilizes the tetragonal form of ZrO2, which is the only form in sintering at 1400°С. An increase in the sintering temperature leads to the formation of the monoclinic form of ZrO2 and subsequent increase in its amount. Densely sintered ceramic materials were obtained, which had a strength of more than 860 MPa, a microhardness of up to 11 GPa, and the composition ZrO2–10 wt % Al2O3–3.8 mol % CoO (3 mol % of the introduced Co2+ cation). In vitro tests demonstrated that the materials are cytocompatible. The introduction of cobalt ions to ZrO2–10 wt % Al2O3 ceramics improves the matrix (for cells) properties.