SiC陶瓷/金属钨的SPS扩散焊接

Abstract

本文采用放电等离子烧结(SPS)技术，对用于高温环境下服役的SiC陶瓷和钨的扩散焊接进行了探索研究。结果表明，采用SPS技术可以在1300℃~1500℃实现SiC/W的连接。在SPS扩散焊接条件下SiC和W在界面处会发生化学反应，形成一个主要组分为WC、Si3W5等新相的过渡层，且随着焊接时间延长和温度升高，W持续向SiC层扩散在过渡层和SiC的界面上形成新的反应物，从而导致过渡层的厚度增加。过渡层的厚度对焊接件性能的影响呈现非线性变化，对焊接件的三点弯曲强度测试表明：在1410℃时，保温5 min，材料在界面处的弯曲强度达到最高，约162 MPa。对焊接后金属钨的结构分析显示，高温过程对钨的微结构没有明显的改变，断裂方式仍为延性断裂。显然，SPS可以成为一种快速、有效的SiC陶瓷/金属W扩散焊接技术。 Spark plasma sintering (SPS) as a diffusion welding method was used to bond SiC ceramic and tungsten which was hoped to be used under high temperature environment. Results show that SiC and tungsten could be bonded by SPS technology at the welding temperature during 1300˚C - 1500˚C. And the interfacial microstructure analysis show that an intermediate layer (including new phases WC, W2C, Si3W5) formed rapidly between SiC and tungsten due to the interface chemical reaction under SPS extra field. Thickness of the intermediate layer was found increasing with the welding temperature and duration increasing because of W diffusion through the intermediate layer. Effect of inter- mediate layer thickness on the welded sample performance is nonlinear. The maximum bending strength of bonded SiC/W was 162 MPa with a welding temperature of 1410˚C and a duration of 5 mins. High temperature processing showed no obvious effects on microstructure and fracture behavior of W metal substrate. It seems that SPS could be a fast and effective diffusion welding technology for ceramic (SiC)-high temperature alloy (W).