Interactions, joining and microstructure of Sn-Ti/ZrO₂ system

Brazing and soldering following pre-metallization were employed to obtain reliable ZrO₂/Sn-Ti/ZrO₂ joints. Both the metallization and brazing depend on the wettability of ZrO₂ by Sn-Ti alloys. The interfacial microstructure of joints was analyzed by SEM, XRD and TEM, and the shear strength of joints was evaluated. Good brazed joints and fully covered metallization layers, leading to good soldered joints, were obtained by the Sn-4Ti and Sn-8Ti alloys, while unsatisfactory results were obtained with Sn-1Ti and Sn-2Ti alloys owing to their limited wettability on ZrO₂. Both kinds of ZrO₂/Sn-Ti/ZrO₂ joints possessed a β-Sn matrix with Ti₆Sn₅ and Ti₂O₃ interfacial layers. A higher Ti concentration per unit area induced the formation of a Ti_11.31Sn₃O₁₀ layer along with the reduction of the Ti₂O₃ layer thickness at the interface in the soldered joints. All the joints exhibited a similar shear strength of 22 ∼ 28 MPa and fractured through the β-Sn matrix.