▎ 摘　　要

NOVELTY - Method for preparing carbon-based nanomaterial modified by metal nanoparticles, involves (i) uniformly dispersing carbon-based nanomaterial with oxygen-containing functional groups in organic alcohol, adding acetate as a metal particle source, and completely stirring and reacting to obtain a precursor, and (ii) placing the precursor obtained in step (i) in a hydrogen-argon atmosphere for calcination and decomposition to obtain the carbon-based nanomaterial modified by metal nanoparticles. USE - The method is used for preparing carbon-based nanomaterial modified by metal nanoparticles for modified composite brazing filler (claimed). ADVANTAGE - The metal nano-particles are uniformly distributed on the surface of the carbon-based nano-material, and the two are combined in the form of chemical bond, which avoids the agglomeration phenomenon in the lead-free solder, the reinforced phase and the solder matrix are dispersed, at the same time, ensuring the interface bonding strength between the reinforcing phase and solder substrate, fully exerting the modified effect in the low-silver SAC composite brazing filler metal. The method can obviously improve the distribution uniformity of the nano-carbon material in solder matrix and the bonding strength of solder matrix interface. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for: (1) a modified composite brazing filler metal comprising: 0.01-0.2 wt.% carbon-based nanomaterials modified by metal nanoparticles, and remaining of low-silver tin-silver-copper (SAC) lead-free solder tin-(0.3-1)silver-(0.5-1)copper; and (2) a method for preparing the modified composite brazing filler metal, which involves (i) taking the carbon-based nanomaterial modified by metal nanoparticles comprising 0.01-0.2 wt.% silver, 0.3-1 wt.% copper, and 0.5-1 wt.% tin to obtain a completely mixed powder, where the particle size is 5-60 microns, and (ii) drying the powder obtained in step (i) and placing in a vacuum hot pressing sintering furnace for hot pressing to obtain a carbon-based nanomaterial reinforced low-silver SAC composite brazing filler metal decorated with metal nanoparticles.