Preparation of Industrial Watchcase of 5Y-Tetragonal ZrO2 by Microwave Sintering

The industrial watchcases of 5Y-Tetragonal ZrO2 were prepared by microwave sintering. Samples were sintered in a microwave chamber with TE666 resonant mode at 2.45GHz. The sintering temperature was from 1250°C to 1400°C. XRD and SEM techniques were used to characterize the samples. It is found that microwave sintering improved the phase change from t-ZrO2 to m-ZrO2. Dense and homogeneous microstructure was obtained within the microwave-sintered samples and the average grain size was about 500nm. Compared to conventional sintering, microwave-sintered samples show higher density and hardness. And microwave-sintered samples were performed 130°C lower temperature. Optimized sample with the density of 6.1 g/cm3 and Vickers Hardness of 16.2MPa is microwave-sintered at 1350°C for 30min.