Characterization of internal pores in polycrystalline diamond compact after cobalt removal

The thermal stability and wear resistance of PDC under complex operating conditions are affected adversely by the cobalt binder. In this study, an electrolytic method was employed for the removal of cobalt from the polycrystalline layer of PDC. Scanning electron microscope (SEM) was used to observe the microstructure and morphology of the polycrystalline layer before and after cobalt removal. Image J software was used for quantitative analysis of the pores in the polycrystalline layer after cobalt removal. Finally, wear resistance of the samples was evaluated by carrying out wear ratio tests. The results showed a decrease in the mass fraction of cobalt on the surface of PDC polycrystalline layer from the original 5.72–0.65% after electrolytic cobalt removal. Quantitative analysis of the pores in PDC revealed that the percentage of surface pore area relative to the measured surface area was 2.61%, while the percentage of cross-sectional pore area relative to the measured surface area was 3.68%. The wear resistance of PDC after electrolytic removal of cobalt was 40% higher than that of the original PDC. This manuscript provides a new method for quantitative characterization of pores in the PDC polycrystalline layer after cobalt removal.