Improvement of ambient temperature tribological properties of polycrystalline diamond compact treated by cobalt removal

Polycrystalline diamond compact (PDC) is a super-hard composite material sintered under high temperature and high pressure. It has excellent mechanical properties and is widely used in oil and gas drilling and development. For the drill bit and bearing of downhole tools, the graphitization of PDC due to high downhole temperature is the main factor in the failure of PDC. Therefore, we try to change the depth of cobalt removal to explore the friction properties of polycrystalline diamond at ambient temperature. Using Raman spectrometer, X-ray diffractometer (XRD), scanning electron microscope (SEM) and energy spectrometer (EDS) to carry out experimental research, Raman spectroscopy showed that PDC had no graphitization phenomenon. The research results showed that with the increase of the cobalt removal depth, the wear rate and friction coefficient of PDC decrease, and a carbon and silicon transfer films were formed. It was worth noting that the PDC when the cobalt removal depth reaches a certain value, the friction coefficient will be sharply reduced, the wear rate will be reduced, and the friction performance will be significantly improved. These experimental results can promote the life of PDC in bearings and drilling tools, reduce frictional power consumption and improve energy efficiency. [Display omitted] •Decobaltization can improve wear resistance of polycrystalline diamond compact (PDC).•Transfer films and micropores appear in the polycrystalline diamond compact (PDC).•Removal of cobalt can prevent graphitization of polycrystalline diamond compact (PDC).