Microwave-assisted sintering of zircon

Zircon samples were subjected to microwave heating (2.45 GHz and 900 W) in a domestic oven between 4 and 60 min and results compared to conventional heating (1300-1600 degrees C, holding for 120 min). Microwave heating of zircon with susceptor showed a higher temperature for any heating time compared to those heated in the absence of susceptor. To reach almost the same densification, microwave heating reduced the sintering time and temperature (16 min from room temperature to 1280 degrees C) compared to conventional heating (130 min from room temperature to 1300 degrees C and holding for 120 min at this temperature). The results also show that a long microwave heating (higher than 30 min) accelerates the decomposition of zircon. The extra phase formed acts a glassy phase during sintering of the samples; however, a lower average particle size (38.5%) was observed for the microwave-sintered samples. (c) 2007 Elsevier B.V. All rights reserved.