HPHT sintering and performance investigation of PDC with high stacking density by dual particle size diamond formulations

The particle size and particle size ratio of the raw diamond powder have a great influence on the stacking density, which is critical to the performance of polycrystalline diamond compact (PDC). In this study, diamond powders with five different particle size of 1 μm, 4 μm, 12 μm, 20 μm and 27 μm were selected. High stacking density diamond powder formulations with three filler particle ratios of 10 wt%, 20 wt% and 30 wt% were designed by using 12 μm, 20 μm and 27 μm diamond as the main particles and 1 μm and 4 μm diamond as the filler particles. The different formulations were evaluated by mechanical property tests and microscopic characterization of PDC samples to find out the optimal filler particle size as well as filler ratio in different main particle series. The results showed that the larger the main particle size in the formulation, the worse the wear resistance and the better the impact toughness of PDC. Adding decent number of fine particles with appropriate particle size could effectively improve the comprehensive performance of PDC. But the match between different main particles and filler particles was not consistent, and the three optimal formulations finally derived under the conditions in this paper were 80 wt%12 μm-20 wt%1 μm, 90 wt%20 μm-10 wt%4 μm, and 80 wt%27 μm-20 wt%4 μm. The rock cutting life of PDC with optimal formulations was all improved by 20 passes and the wear resistance was improved by 62%, 53.8% and 40.4%, respectively, compared with the single particle size control group. The impact toughness was improved by 650 J/68.4%, 1200 J/77.4% and 750 J/20%, respectively. The PDC performance variation pattern of different formulations was highly consistent with that of Co content, indicating that the decrease of Co content caused by the increase of stacking density was the main mechanism for performance enhancement of dual-particle size PDC.