Polycrystalline Diamond Cutters with Cobalt–Rhenium Binder for Enhanced Thermal Stability in Rock Cutting

The excellent abrasion resistance and impact resistance of polycrystalline diamond (PCD) make it the material of choice for certain rock cutting applications. For example, a PCD table bonded to a WC/Co substrate forms a cutter suitable for oil and gas drilling. However, the presence of binder in the PCD – infiltrated from the substrate during high pressure, high temperature (HPHT) sintering – severely shortens tool life through thermal degradation mechanisms. Acid leaching this binder from the cutting surface significantly improves its thermal stability, but the use of alternative, more thermally stable binders is also an option. In this work, a novel Co-Re binder was evaluated for thermally stable PCD. Hot-stage XRD confirmed a 200°C delay to the onset of graphitisation in the PCD compared to standard Co binder-based PCD and post-heat treatment crack analysis demonstrated the suitability of this material for thermally demanding drilling applications.