Effects of brazing route and brazing alloy on the interfacial structure between diamond and bonding matrix

Diamond tools with diamond grits of single layer were fabricated by brazing process. When Cu–15Ti–10Sn (wt.%) was utilized as the brazing alloy, a long isothermal hold (5 min) at the brazing temperature in vacuum brazing operation resulted in the formation of a continuous TiC film on the surface of the diamond grits. On the other hand, a short hold at the brazing temperature in laser brazing operation resulted in the formation of discrete TiC grains on the surface of the diamond grits. In addition, segregation of Ti and Sn to the interfaces between the diamond grits and the bonding matrix was significant only for the vacuum brazing operation. When a nickel alloy, Ni–12Cr–4Fe–3Si–2.5B (wt.%), was used as the brazing alloy in a vacuum brazing operation, the surfaces of the diamond grits were catalytically converted into graphite, with chromium carbide being formed near the interface between the graphite layer and the bonding matrix.