▎ 摘　　要

NOVELTY - Composite brazing filler metal comprises silver, copper, tin and nickel nanoparticle-modified graphene nanosheets. USE - As composite brazing filler metal. ADVANTAGE - The composite brazing filler metal adopts the preparation method that utilizes the self-made nickel nanoparticle modified graphene as a reinforcing material, increases the bonding strength of the interface between the graphene and the brazing filler metal base and improves the strength of the brazing filler metal. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the composite brazing filler metal involving (1) uniformly dispersing graphene oxide in an ethylene glycol solution, (2) adding nickel acetate to obtain a nickel-ethylene glycol chelate/graphene oxide precursor, (3) calcining the precursor in a hydrogen atmosphere to prepare nickel nanoparticle modified graphene, (4) mixing tin-silver-copper alloy powder as a matrix material and mixing with the nickel nanoparticle modified graphite powder obtained in step (3), (5) adding an agate ball to the powder obtained in step (4) and pouring into anhydrous alcohol for mixing, (6) drying the uniformly mixed powder obtained in step (5), putting into a chromium steel mold with a diameter of 10 mm and performing cold pressing to obtain a blank under a pressure of 300-500 MPa under a universal testing machine and (7) sintering the blank obtained in step (6) at 180 degrees C for 2-3 hours in an argon atmosphere and taking out after cooling to room temperature to obtain the product.