Microstructure evolution and bonding mechanism of ZrO₂ ceramic and Ti-6Al-4V alloy joints brazed by Bi₂O₃-B₂O₃-ZnO glass paste

Ceramics and metal joinings have been widely employed in aerospace, dental implants, and the electronic packaging industry for fabricating multifunctional components. In this study, the 35Bi₂O₃-50B₂O₃-15ZnO (mol.%) glass has been employed for joining the ZrO₂ ceramic and Ti-6Al-4V alloy. The effect of brazing temperature on the microstructure evolution, mechanical properties, and bonding mechanism of brazed joints has been analyzed. The microstructure of the ZrO₂/glass/Ti-6Al-4V joints and the content of Bi₄B₂O₉, Bi₂O₃ and Bi₂₄B₂O₃₉ precipitated crystals in glass were found to be dependent on the brazing temperature. The reaction product of Bi₄Ti₃O₁₂ was identified in the glass/Ti-6Al-4V interface because of the chemical reaction between the oxidized layer of Ti-6Al-4V alloy and glass. A maximum shear strength as high as 48.8 ± 5.2 MPa was obtained. Our work, thus, demonstrates that the 35Bi₂O₃-50B₂O₃-15ZnO glass is an effective bonding material for joining ZrO₂ ceramic and Ti-6Al-4V alloy under low temperature in an ambient atmosphere.