Ultra-high Pressure Sintering of Diamond-SiC Nanowire Composites: A Pathway to Superior PDC Cutter Performance

The polycrystalline diamond compact (PDC) cutter consists of a surface polycrystalline diamond (PCD) layer and a tungsten carbide substrate. As oil and gas exploration advances toward deep and ultra-deep wells, the extreme conditions of ultra-depth, high temperature, and high pressure pose significant challenges to the thermal stability and impact toughness of PCD materials. In this study, silicon carbide nanowires (SiCnw) were used as a substitute for metallic cobalt as a binder. A series of SiCnw/PCD composites were synthesized using 1 µm diamond powders under conditions of 15 GPa and 1800-2000 °C, followed by microstructural analysis, Vickers hardness and thermal stability testing. The results indicate that the PCD sample (add 3 vol% SiCnw) with a hardness of 91.5 GPa and a fracture toughness of 15.2 ± 1.0 MPa-mm0.5, significantly outperforming the control sample using Co as the binder. Microscopic observations revealed that microcracks generated during fracture exhibited a wavy pattern, with evidence of nanowire pull-out, crack deflection, and crack bridging, which substantially enhanced the fracture toughness of the composite. Thermogravimetric analysis demonstrated that the SiCnw/PCD composite possesses excellent thermal stability. In summary, sintering polycrystalline diamond composites using SiCnw as a binder under higher pressure and temperature conditions is a feasible and promising approach for investigating its effects on the microstructure and mechanical properties of PCD.