Al_2O_3/Kovar钎焊接头裂纹冶金因素分析

Mechanisms of Cracks Forming in Al_2O_3/Kovar Brazing Joint

为了研究Al2O3陶瓷/Kovar钎焊时出现的裂纹问题,本试验采用Ti-Cu-Ni活性钎料钎焊Al2O3陶瓷/Kovar(可伐合金),通过扫描电镜观察钎焊接头的微观组织并对所含成分进行分析,得出裂纹处的成分组成。分析结果表明:Al2O3/Ti-Cu-Ni/Kovar钎焊接头产生裂纹的主要原因是Kovar中的Fe元素与钎料中的Ti元素相互反应,在界面形成了FexTiy金属间化合物,导致接头产生裂纹,并提出了减少裂纹的2种方法。

To reveal the mechanism of cracks forming in the Al_(2)O_(3)/Kovar joints,the joint specimen made of Kovar based metal,Ti-Cu-Ni active filler metal and Al_(2)O_(3)are adopted in the experiment.The microstructure and microchemistry of the ceramic-metal interface as well as the fracture interface are examined by using scanning electron microscopy (SEM).The component in the cracks position are understood. The results show that there is a reaction in the Ti-Cu-Ni kovar interface with Fe in Kovar and Ti in filler metal.The intermetallic compound Fe_(x)Ti_(y) is formed, and it is the reason of cracks forming in Al_(2)O_(3)/Kovar brazed joints.Two ways are put forward to decrease the posibility of cracks.