Abstract
Stainless steel (SS) and Pt are both widely used biomedical materials due to their good biocompatibility and mechanical properties. The ever-growing demand of multifunctional biomedical device calls for the dissimilar joining between SS and Pt. In this work, reliable joining between SS wire and Pt band was realized through a laser micro-brazing process based on the melting of Cu interlayer that was pre-coated on SS wire surface. Micro-brazing process window, joint appearance and interfacial microstructure were investigated. The combination of lower laser peak power and longer pulse duration contributed to the achievement of micro-brazing. The molten Cu showed excellent wettability on Pt surface even towards the antigravity direction. Interdiffusion between Pt and Cu resulted in the formation of Cu-Pt phases in the Pt-side interface. Less interdiffusion was observed in the SS-side interface. By laser micro-brazing, the damage/degradation of SS and Pt (usually caused by a conventional fusion welding process) was greatly reduced.