LEAD-FREE SOLDER FOIL FOR DIFFUSION SOLDERING AND ITS MANUFACTURING METHOD Russian patent published in 2022 - IPC B23K35/02 B23K35/16 B23K35/40 

FIELD: metallurgy.

SUBSTANCE: lead-free solder foil is designed for connection of metal elements by diffusion soldering. Lead-free low-melting solder forms matrix (5), in which, due to the use of rolling cladding in the manufacture of foil, particles (6) of refractory metal component (7) are dispersed. The fraction of low-melting solder of matrix (5) relatively to the fraction of refractory metal component (7) is selected from the condition of complete transition of lead-free low-melting solder (8) of matrix (5) into intermetallic phases (9) having a melting temperature above 400°C. Multilayer foil contains alternately arranged layers of the mentioned lead-free solder foil and intermediate layers (23) of refractory metal component (7) connected by rolling cladding.

EFFECT: lead-free solder foil ensures, during low-temperature soldering, without applying a clamping force and without subsequent heat treatment, the connection of surface layers of soldered elements with the formation of a refractory solder zone in the form of an intermetallic phase with a re-melting temperature above 400°C.

6 cl, 5 dwg