Nickel–tin transient liquid phase sintering with high bonding strength for high-temperature power applications

We performed 30Ni–70Sn (wt%) transient liquid phase sintering (TLPS) bonding with micro-sized Ni and Sn powders for high-temperature power applications. A Ni–Sn paste was fabricated and TLPS bonding was performed. We investigated the interfacial reactions, transformations into Ni 3 Sn 4 intermetallic compound (IMC) phases, and joint strength in this study. The Ni–Sn TLPS bonding was an easy and simple process under a relatively low bonding temperature and short bonding time. After TLPS bonding, low melting point Sn element was completely consumed, and the bonded joint was composed of Ni 3 Sn 4 IMCs and the remaining Ni particles. The Ni 3 Sn 4 IMC joint formed with remaining Ni particles was very stable. All the Ni–Sn TLPS samples had high shear strengths of over 70 MPa, and the shear strength was approximately 32% higher than that of the conventional Sn–3.0Ag–0.5Cu solder joint. The Ni–Sn TLPS bonded joints in the present study were not brittle and exhibited superior adhesion strength. This suggests high applicability of the Ni–Sn TLPS bonding for high-temperature power electronic applications in future EV/HEV systems.