Interface Microstructure and Formation Mechanism of Diamond Abrasives Laser Brazed with Ni-Cr Solder

The laser brazing of diamond abrasives was investigated using Ni-based solder in an Ar atmosphere. The microstructure and the phase composition of the interface between diamond abrasives and Ni-based solder were analyzed using scanning electronic microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Meanwhile, the formation mechanism of carbides at the interface between solder and diamond abrasives was discussed. The results indicate that during laser brazing, the Cr-enriched layer around the diamond surface reacts with C in the diamond surface and consequently Cr3C2 is formed. Based on reaction thermodynamic and kinetic analysis, it is revealed that the interface reaction products can be formed via replacement reaction, which realize the tight combination between diamond abrasives and solder.