▎ 摘　　要

NOVELTY - Composite solder comprises graphene, copper, silver, tin, zinc and indium, where brazing metal are tin and bismuth. USE - Composite lead free solder used for packing electronic product. ADVANTAGE - The Composite lead free solder has high strength. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing composite lead free solder, which involves: (A) mixing ethyl alcohol, metal and ethyl alcohol; (B) stirring the obtained mixture ultrasonically for 5-10 minutes; (C) adding filler in the obtained mixture; (D) milling the obtained mixture for 10 minutes; (E) drying the obtained mixture in a drying chamber for 150 rotations per minute for 24-36 hours; (F) extruding the obtained mixture for 180 degrees C; (G) sintering the obtained product for 3 hours; and (H) demoulding the obtained product.