Patent ID: 11325210

Abstract:
A micro/nanoparticle-reinforced composite solder for low-temperature soldering and a preparation method thereof belong to the manufacturing field of lead-free low-temperature soldering solders. Micro/nanoparticle-reinforced tin-based alloy solder powder is formed by diffusely mixing micro/nano-sized Cu, Ag and Sb particles with a molten metal tin and atomizing the mixture, and then blended with low-melting-point SnBi-based alloy solder powder and a conventional flux to prepare a micro/nanoparticle-reinforced composite solder. In soldering at a temperature below 200° C., tin atoms in the molten micro/nanoparticle-reinforced tin-based alloy form an intermetallic compound on a soldering pan in preference to the low-melting-point SnBi-based alloy, and the micro/nanoparticles are dispersed in soldered joints to form a “separator effect”, which blocks atoms in the SnBi-based alloy from being precipitated and bonded with the soldering pan, thereby inhibiting the growth of a Bi-rich layer, and solving the problem of brittle and unreliable soldered joints in lead-free low-temperature soldering.