Preparation of a porous vitrified-bond composite grinding wheel and investigation of the induced reaction mechanism of grinding polycrystalline diamond films

The rough surface grains of polycrystalline diamond (PCD) pose significant grinding difficulties, rendering traditional processing methods inefficient and time-consuming for achieving the desired surface quality for chip cooling substrates. To overcome this problem, a novel composite abrasive wheel capable of inducing reaction with PCD’s surface grains for rapid diamond removal is introduced. The performance of the wheel is optimized through a series of experiments considering sintering temperature, pore-forming agent content, and grinding particle size. Upon sintering under vacuum, the optimal formulation, consisting of 30 wt% Fe and 15 wt% PMMA, yields a tool characterized by high microhardness, bending strength, and porosity. The presence of amorphous carbon and iron carbide is confirmed using various characterization techniques. During processing, Fe particles interact with diamond to form iron carbide, reducing the PCD surface hardness and enhancing the removal efficiency. The PCD film achieves an smooth surface with a roughness as low as 0.49 nm and the thickness of the subsurface damage layer is 2.96 nm. Because the mechanical action of diamond collaborates with the chemical action of iron, subsurface damage is minimized and grinding efficiency is maintained.