Si3N4/TC4活性钎焊连接机理与性能

针对Si_3N_4/TC4复合结构钎焊连接问题,研究了钎料和母材中活性元素Ti对Si_3N_4/TC4接头润湿性、界面结合机制和力学性能的影响。进行了润湿、接头显微组织分析和剪切强度试验,结果表明:活性元素Ti对于钎料在陶瓷表面的润湿起主要作用,Ag-Cu钎料通过TC4母材中Ti元素的长程扩散进入Si_3N_4界面虽然实现润湿,但形成的反应产物并不明显,陶瓷/钎料界面成为断裂薄弱区域。Ag-Cu-Ti钎料中Ti元素在Si_3N_4一侧界面富集形成TiN+Ti_5Si_3反应层,对钎料在陶瓷界面润湿性和接头断裂脆性都具有改善作用,接头剪切强度达到267.3 MPa。

Active Brazing Mechanism and Properties of Si3N4/TC4

To solve the brazing problem of Si3N4/TC4 composite structure, the effects of the active element Ti in the brazing solder and the base metal on the wettability, the interface bonding mechanism, and the mechanical property of Si3N4/TC4 joint are studied. Wetting, microstructure analysis, and shear strength tests are carried out. The results indicate that, the active element Ti plays a major role in the wetting process of brazing solder on the ceramic surface. The wetting of Ag-Cu brazing solder is realized by the long range diffusion of Ti element from the TC4 base metal into the Si3N4 interface. However, the reaction product is not obvious. The interface of ceramic/brazing solder becomes a weak fracture area. The Ti element of Ag-Cu-Ti brazing solder enriches on the interface at the Si3N4 side to form a TiN+Ti5Si3 reaction layer, which can improve the wettability of the brazing solder on ceramic and weaken the fracture brittleness of the joint, and the shear strength reaches 267.3 MPa.