Effect of Diamond Particle Size on the Microstructure and Wear Property of High Pressure High Temperature (HPHT) Sintered Polycrystalline Diamond Compact (PDC)

A polycrystalline diamond compact (PDC) is a two-stage sintered body manufactured by placing diamond powders on a WC-Co hard material and then applying the high pressure high temperature (HPHT) sintering process. This study investigated the microstructure and wear properties of the PDC depending on initial diamond particle size. Three different sizes (12-22 mu m, 10-20 mu m, and 8-16 mu m) of initial diamond powders were used to manufacture PDCs with the HPHT sintering process. Some Co and WC were observed along the boundaries between the diamond particles in the three manufactured PDCs. The diamond layer formed using small diamond particles showed finer and more even area distribution of Co along the diamond particles. VTL equipment was used to conduct a granite cutting wear test. The result confirmed that smaller initial diamond particle size leads to greater wear resistance properties. Observation of the PDC wear surface confirmed that the PDC made with larger diamond particles was more prone to be weak along the boundaries between the diamond particles, and there were instances where the diamond particles were displaced as a whole. For PDCs of smaller diamond particle size, abrasive wear occurred where the diamond particles were gradually worn away.