Microstructure and Shear Strength of Diffusion Bonding Joint between Cu-Bi Alloy and ZrO₂ Ceramic

Diffusion bonding between Cu-x%Bi (x=0, 0.5, 1.0, 2.0) alloy and ZrO2 ceramic was carried out under the vacuum condition of 1.3 Pa. The microstructure and shear strength of joint between Cu-Bi alloy and ZrO2 was studied by scanning electron microscopy, electron probe (EPMA) and shear tester. The results show that the Bi elements were squeezed into bonding interface by welding pressure and partial Bi remained on the interface after welding could relax the thermal stress and increase the shear strength of the joint. However, the shear strength of the joint decreased sharply because Bi element on the interface would softened after the using temperature was more than 373 K, so it was difficult that the joint was used in high-temperature environment.