Interface microstructure and bonding performance of brazed W-coated diamonds using Ni–Cr alloy

To enhance the comprehensive bonding performance of brazed diamond joints, W-coated diamonds were developed instead of conventional uncoated diamonds. This study focused on the interface bonding performance of induction-brazed W-coated diamonds when used with Ni–Cr alloy. Under the influence of tungsten coating, the brazed W-coated diamond joints had an optimised bonding interface with a refined microstructure and significantly reduced interface cracks. The disordered and discrete morphology of the intermetallic compound Cr 3 C 2 at the brazed W-coated diamond particle/Ni–Cr alloy interface alleviated the internal residual stress and the maximum residual compressive stress of the W-coated diamond joints by 16.35%. The degree of graphitisation and erosion of the W-coated diamond particles improved significantly. The brazed W-coated diamond bits exhibited superior processing performance. In the drilling process, the wear pattern of the W-coated diamond particles was dominated by mild particle micro-fractures rather than unfavourable particle macro-fractures or brittle intergranular fractures.