Al2O3的W金属化及其与Nb的Pd钎焊研究

在考察Al2O3(95%Al2O3瓷和Al2O3单晶)的W-Y2O3金属化工艺的基础上,制备Al2O3单晶/Pd/Nb的高温钎焊接头,分析Al2O3的W-Y2O3金属化和Al2O3 /Nb的Pd钎焊机制.结果表明:在Al2O3基体和金属化层界面附近存在Y元素的偏聚行为,同时伴随着Al含量的下降.这是由于金属化过程中陶瓷/金属化层界面新生固相产物扩散的结果,且其扩散主要为朝金属化层方向.高温钎焊过程中,金属化层中的W元素和金属Nb扩散进入几乎整个Pd焊料层,这使得在Nb/Pd界面附近及焊料层内形成脆性固溶体或金属间化合物,从而导致微裂纹产生.

Study on Tungsten Metallization of Al2O3 and Pd Brazing of It to Nb

Based on the study of W-Y2O3 metallization process of Al2O3 (including 95% Al2O3 ceramic and Al2O3 single crystal), the high-temperature brazing joints of single crystal Al2O3/Pd/Nb were fabricated. W-Y2O3 metallization mechanism of Al2O3 and Pd brazing mechanism of Al2O3/Nb were analyzed. The results show that there was aggregation behavior of Y near the interface between the Al2O3 substrate and metallizing layer; meanwhile Al content decreased. This resulted from the diffusion of some new solid phase products at the interface of ceramic/metallizing layer during metallization. The diffusion direction was mainly towards the metallizing layer. The W and Nb elements nearly diffused into the whole Pd brazing interlayer during high-temperature brazing, which led to forming of brittle solid solutions or intermetallic compounds in the solder layer and near Nb/Pd interface, resulting in micro-cracks.