Low-temperature sintering and microstructure control of mullite-Mo composites

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• 作者：Qingke He ; Yucheng Wang ; ^{wangyc@whut.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Zhengyi Fu ; Rongrong Wang ; Hao Wang ; Weimin Wang ; Jinyong Zhang ; Fan Zhang
• 关键词：A. Sol&ndash ; gel processes ; B. Composites ; Two-stage sintering ; Microstructure
• 刊名：Ceramics International
• 出版年：2016
• 出版时间：March 2016
• 年：2016
• 卷：42
• 期：4
• 页码：5339-5344
• 全文大小：1998 K

文摘

Dense mullite–Mo (45 vol%) composites with homogeneous microstructure have been obtained by plasma activated sintering of a mixture of Mo and mullite precursors at a relatively low temperature (1350 °C) and a pressure of 30 MPa. The mullite precursor was synthesized by a sol–gel process followed by a heat-treatment at 1000 °C. The influence of different mullite precursors on the densification behavior and the microstructure of mullite–Mo composites has been studied. The precursor powder heat-treated at 1000 °C with only Si–Al spinel but no mullite phase shows an excellent sintering activity. Following the sintering shrinkage curves, a two-stage sintering process is designed to enhance the composite densification for further reducing the sintering temperature. The study reveals that viscous flow sintering of amorphous SiO₂ at low temperatures effectively enhances the densification. Moreover, microstructure of these composites can be controlled by selecting different precursors and sintering temperatures.