Sintering behaviour and properties of graphene oxide-doped Y-TZP ceramics

Abstract The effect of varying amounts (up to 1 wt%) of graphene oxide (GO), on the densification behaviour of yttria–stabilised tetragonal zirconia (Y-TZP) was investigated. Green bodies were prepared and sintered in air atmosphere over the temperature range of 1200 °C to 1500 °C. Sintered samples were then evaluated to determine bulk density, Vickers's Hardness, fracture toughness, phase stability and grain size. Furthermore, the samples were subjected to hydrothermal ageing in superheated steam at 180 °C/10 bar for up to 200 h to evaluate the ageing-induced tetragonal to monoclinic phase transformation. The results showed that the addition of GO was beneficial in improving densification and mechanical properties of Y-TZP ceramic, particularly at low sintering temperatures. A high hardness of 14.3 GPa and fracture toughness of 5.6 MPa m 1/2 were recorded for GO-doped Y-TZP sintered at 1300 °C and 1400 °C, respectively. Despite the improvement in the sintering properties, the addition of GO was not effective in suppressing the ageing-induced monoclinic phase formation for samples sintered above 1300 °C.