Induction brazing of diamond with Ni-Cr hardfacing alloy under argon atmosphere

Abstract In recent years the brazing of a monolayer of diamond grit to a steel substrate with active filler metals has drawn much attention in industry from the viewpoint of manufacturing tools which can show distinct advantages over conventional electroplated diamond tools in terms of faster cutting and longer tool life. The present study has shown that a commercially available Ni-Cr hardfacing alloy flame sprayed on a steel substrate with an oxyacetylene torch can be used as an active filler material for brazing diamond grit. Induction brazing was carried out in a current of argon. Electron probe microanalyses have shown that during brazing the chromium present in the hardfacing alloy segregated preferentially to the surface of the diamond to form a chromium-rich reaction product, which was readily wetted by the alloy. A simulated grinding test also showed that the wear modes of such a brazed tool were mainly grit fracture and attrition rather than grit dislodgement from the bond.