Effects of sintering additives on the densification and properties of alumina-toughened zirconia ceramic composites

The effects of manganese oxide, stainless steel and copper oxide doping on the sintering behaviour and mechanical properties of alumina-toughened zirconia (ATZ) were investigated. The prepared ceramic composites were conventionally sintered at 1250 °C, 1350 °C and 1500 °C, using different holding times (1, 12 and 120 min, respectively). The tetragonal phase stability, microstructural evolution, relative density, Vickers hardness and the fracture toughness of the samples were determined. The beneficial effects of sintering additives in aiding the densification of the ATZ, particularly at low temperatures and short holding times were revealed. In particular, the addition of copper oxide was the most beneficial in enhancing the properties of ATZ when sintered at 1250 °C and 1350 °C for short holding times. Sintering at 1500 °C was unnecessary for the copper-doped ATZ to attain the maximum relative density of >98%, Vickers hardness of >12 GPa and fracture toughness of >5 MPa m 1/2 . By contrast, the undoped ATZ required a long holding time and high sintering temperature to achieve similar results as the doped samples. This research showed the viability of using sintering additives in aiding low temperature densification and enhancing the mechanical properties of ATZ through conventional sintering.