原位反应制备WSi_2/Si_3N_4复合材料的研究

Study on In-situ Preparation of WSi2/Si3N4 Composite Ceramics

研究了Si3N4/WSi2复合陶瓷材料的特殊制备工艺过程及其显微结构。用XRD、SEM、EDX以及气孔测试仪,对每一制备过程步骤中发生的显微结构变化进行了分析。结果表明预烧过程原位生成了WSi2,氮化反应使Si相几乎全部转化为Si3N4和WSi2,热压使α-Si3N4转化为β-Si3N4,相组成为β-Si3N4、WSi2以及少量的W5Si3。机械强度随温度上升而增加,1200℃强度达988.3MPa。

A new technique for preparation of the Si3N4/WSi2 ceramic composite has been developed in this paper. The microstructure of this material during each step of preparation has been investigated using the XRD, SEM, EDX and pore size tester. The results show that the phase WSi2 forms at its original place during the pre-sintering process. Nitridization leads to the transformation of the Si phase into the Si3N4 and the WSi2 phase. The thermo-pressing sintering results in the transformation of the α-Si3N4 phase into the β-Si3N4 phase, and the system consists of β-Si3N4, WSi2 and a small amount of W5Si3. The mechanical strength increases with increasing temperature, and reaches 988.3 MPa at 1200℃.