Quality and wear behavior of graded polycrystalline diamond compact cutters

The wear behavior of conventional and graded polycrystalline diamond compact cutters was studied using a vertical lathe with mortar counterfaces. Different cutters were considered regarding to their diamond grain size and the high pressure and the high temperature conditions of the manufacturing process (HPHT). On the base of these cutters, a cobalt graduation process was performed on the WC–Co substrates by reactive imbibition. A quality factor developed in previous studies was calculated to evaluate cutters wear performances. The results showed that a controlled HPHT process can act on the wear resistance certainly by improving the diamond grain boundary cohesion. Unexpectedly, the diamond granulometry appeared to be a secondary factor influencing the wear resistance. The reactive imbibition clearly increased the wear resistance, even for cutters with coarse diamond grains (i.e. potentially impact resistant). Finally, a third body approach describes that the quartz particles detached from the mortar rock realizes abrasive scratches on the cutters wear flat. When the wear flat reaches the substrate, the formation of voids in the contact, associated with the trapping of abrasive particles, rises the wear kinetic. As a secondary mechanism, Raman spectroscopy measurements highlighted tribological transformed structures by the formation of graphite and amorphous carbon on the diamond worn surfaces.