Effect of Sintering Temperature on Structures and Properties of High Quality Zirconia Ceramics Under Oscillatory Pressure

Oscillatory pressure sintering technique (OPS) was used to prepare high quality zirconia ceramics. The effects of sintering temperature on the relative density, grain size, microstructure and mechanical properties of zirconia ceramics were investigated. The results show that with the application of oscillatory pressure, the variation of relative densities is not obvious while the grain size significantly increases as the sintering temperature increases. All specimens reach a nearly full density as there is scarcely no pores on the polished surface. The highest hardness and bending strength of 16.6 GPa and 1455 MPa, respectively, are reached when the target temperature reaches 1300 degrees C. Compared with conventional pressureless and hot pressure sintering process, the introduction of oscillatory pressure significantly reduces the densification temperature of zirconia ceramics, and evidently enhances mechanical strength and fracture reliability.