Assessment of abrasive powder behaviour during impact-abrasive wear of PCD elements

One of the most suitable renewable energy sources is geothermal energy (providing heating as well as electricity). In order to achieve a suitable depth of drilling (several kilometres), it is required to increase the wear resistance, durability and reliability of key components of the deep drills. The effect of abrasive powders on impact energy transmission and/or damping during wear of Polycrystalline Diamond (PCD) cutting elements was evaluated due to its highest resistance in abrasive conditions. The characteristic features of wear mechanism are presented and discussion is supported by SEM images and EDS maps. The strength of silica sand, quartzite, granite, basalt, marble, limestone, pumice is compared to the force transmitted through the contact zone, damping characteristics and stiffness of abrasive particles. It was found that the laboratory impact-abrasive device enables to initiate damage, characteristic for specific abrasive powder, imitating drilling of such mineral. The mechanism of wear of PCD elements in impact-abrasive conditions depends on the strength and shape of abrasive particles as well as on their behaviour during impact (impact energy damping). The wear of PCD elements in the impact-abrasive conditions was close to zero and their use in new generations of deep drills is expected.