Study on Sintering Behavior, Heat and Wear Resistance of Refractory Metal Borides (HfB₂, ZrB₂) and Al-Ni Modified PDC

Polycrystalline Diamond Compacts (PDC) face thermal damage and insufficient wear resistance in complex strata due to the high thermal expansion coefficient of Co binder and its catalysis on diamond graphitization. Existing studies lack a systematic comparison of HfB₂, ZrB₂, and Al-Ni (1.5wt.%Al + 1.5wt.%Ni) on PDC performance under a unified process, and their synergistic mechanism with the PDC matrix remains unclear. Herein, 3wt.% of these additives were incorporated into diamond micropowder to prepare PDC via unified high-temperature and high-pressure (HTHP) sintering. XRD/SEM-EDS characterized the phase/microstructure, while thermal expansion and Vertical Turret Lathe (VTL) tests evaluated their properties. Results: (1) ZrB₂-modified PDC performed the best, with a thermal failure temperature of 800 °C (8.5% higher than the blank group), VTL wear cycles of 110 Pass (22.2% higher), and ZrC (confirmed by XRD) enhancing interface bonding; (2) HfB₂-modified PDC reduced the wear area by 18% (vs. the blank group) via low-expansion HfC (6.5 × 10^-6/°C) and maintained a continuous structure; (3) Al-Ni-modified PDC had a wear ratio of 1.945 × 10⁴ (4.5% higher) but only 60 Pass and structural defects. This study confirms ZrB₂ as the optimal additive for PDC's comprehensive properties, supporting high-performance PDC development for complex downhole environments.