Sintering of Al2O3-ZrO2 Composites Using Millimeter-Wave Radiation

The effect of the millimetre-wave sintering process on the microstructure and mechanical properties of ZrO2-reinforced (5 and 10 wt%) Al2O3 composites was studied. Sintering was performed by 28 GHz millimetre-wave heating. It was found that higher densities than 94% of the theoretical values can be obtained by sintering at 1573 K for 60 min. The sintering temperature for these composites is lowered by about 300 K compared with conventional sintering. It was also shown that only the soaking time of 20-30 min is enough to sinter these composites by millimetre-wave heating. The sintered composites show higher flexural strengths (about 100 MPa) compared with conventionally sintered composites, though they show somewhat lower densities. The results showed that millimetre-wave heating is applicable for rapid and low-temperature sintering of ceramics. 9 refs.