High-temperature brazing filler metal preparing method based on foamed silver filled with metal tin

The invention provides a high-temperature brazing filler metal preparing method based on foamed silver filled with metal tin. High-temperature brazing filler metal is a metal sheet formed by the foamed silver with micro and nanoscale pores filled with the metal tin, the foamed silver is filled with liquid metal tin through the capillary action, and preparing of the brazing filler metal is achieved. When the brazing filler metal is used for welding, a finally-formed welding line is composed of an intermetallic compound and remaining foamed silver, low-temperature welding can be achieved, an obtained welding point can be subject to high-temperature service, welding point reliability and welding line stability are greatly improved, and the method can be widely applied to various high-temperature welding fields.