Brazing of Single Layer Cubic Boron Nitride Wheel with AgCuTi Alloy Under Vacuum Atmosphere

In order to develop new generation monolayer brazing CBN (cubic boron nitride) grinding wheels, two types of active filler alloys (Ni-Cr and Ag-Cu-Ti) were tested in vacuum furnace.The results show that a Ni-Cr alloy fails to wet and bond CBN grits,while a Ag-Cu-Ti alloy exhibits good wetting and bonding towards CBN grits.SEM EDS microanalyses have shown that during brazing Ti in Ag-Cu-Ti alloy segregated preferentially to the surface of the CBN to form a Ti rich reaction product.X-ray diffraction reveals that the wetting and bonding behaviour on CBN surface by Ag-Cu-Ti alloy melt are realized through TiN and TiB which are produced by interaction between Ti atoms of Ag-Cu-Ti alloy and N or B atoms of CBN surface at elevated temperatures.The rupture occurs in Ag-Cu-Ti alloy layer.It can be considered that chemical metallurgic bonding has formed in the interface between CBN grits and Ag-Cu-Ti alloy.Finally a monolayer brazing CBN grinding wheel with regular abrasive distribution was put forward to try a grinding test.The experimental results show distinct advantages over conventional electroplated CBN grinding wheel.