Regulating the binder phase of polycrystalline diamond compact by adding tantalum to enhance the mechanical properties

Abstract

In this study, PDC added with tantalum was successfully prepared via high pressure and high temperature (HPHT, 7.7GPa and 1650 °C) with the Cubic-Anvil Press. The effect of tantalum on the mechanical properties and thermal stability was systematically investigated by hardness, abrasion resistance, impact resistance and coefficient of thermal expansion (CTE) tests. The results showed that the hardness, wear ratio, total impact energy and initial expansion temperature increased by 21.7%, 45.5%, 55.2% and 20 °C with the addition of tantalum, respectively. The Ta-PDC material binder phase consisted of Ta-phases (TaC, (Ta,W)CX) and cobalt phase after sintering. In elemental quantification observe that the addition of Ta facilitated cobalt infiltration which was benefit to diamond-diamond bonding. The improvement of mechanical properties and thermal stability can be attributed to the reinforced binder, refined and deagglomerated WC grains at the interface between PCD layer and substrate, and better sintering quality. Further optimization of the Ta additive phase content, mixing methodology, or sintering conditions could be explored to further improve the mechanical properties and thermal stability of this novel PDC material.