Surface integrity of PCD composites generated by dynamic friction polishing: Effect of processing conditions

This paper investigates the surface integrity of polycrystalline diamond composites (PCDCs) generated by an efficient abrasive-free dynamic friction polishing. The analysis includes the polishing efficiency, surface roughness, surface damage and residual stress distribution in relation to polishing conditions and microstructures on two types of thermally stable PCDCs. Raman spectroscopy revealed that transformed phases were mainly around grain boundaries, that the magnitudes of residual stresses in polished PCDCs varied across its polished surface, and that stress concentrations over 1 GPa appeared in the vicinity of grain boundaries. It was found that the PCDCs with high percentages of diamond could be polished without cracking at a much large material removal rate of 0.13 mg/s (0.037 mm− 3/s) under a high sliding speed and pressure combination of 35 m/s and 5 MPa, while the PCDCs with low contents of diamond were susceptible to cracking. The underlying mechanisms of sample cracking were discussed.

► Study the relationship of polishing efficiency, surface integrity and polishing conditions
► A very high polishing rate of 0.13 mg/s (0.037 mm− 3/s) has been achieved.
► Surface roughness of PCDCs can be reduced from approximately 4 μm to 0.3 μm Ra in 6 min.
► Stress concentrations over 1 GPa appeared in the vicinity of grain boundaries.
► Discuss the underlying mechanisms of sample cracking