Microstructure and properties of brazed diamond with Pr-modified Ni Cr filler metals

The aim of this study is to improve the mechanical properties of diamond tools by brazing diamonds with a modified NiCr filler alloy to achieve the reduction of thermal damage. In this paper, rare earth Pr doping into NiCr filler alloy is brazed at 1080 °C under vacuum and tested for organization and properties. The results show that the doping of Pr refines the grain size and carbide. Moreover, Cr7C3 and Cr3C2 are generated at the brazed interface, which realizes the chemical metallurgical bonding and improves the bonding strength of the diamond. The generation of the NiPr phase reduces the thermal damage of brazed diamonds. When the addition of Pr is 1 wt%, the diamond grits have a more complete morphology. The exposed height reaches 46.6 % of its own height and the carbonized layer is thinner. The thermal damage is reduced. In addition, the frictional wear experiments and strength tests also shows that the performance of this filler alloy brazed diamond is better than the unmodified filler alloy brazed diamond.