Effects of Binder Composition on the Mechanical Properties of CVDD/PCD Superhard Composite

Abstract

This study prepared superhard composite consisting of CVDD (Chemical vapor deposition diamond) wrapped by PCD (Polycrystalline diamond) through high-temperature and high-pressure (HPHT) sintering, with Ni-Si-B as the binder for the PCD sintering. The effects of different Ni, Si, and B ratios on the properties and microstructure of the composite materials were investigated through hardness testing, wear ratio testing, and scanning electron microscopy (SEM). The results indicated that Ni and B can provide favorable liquid-phase sintering conditions during the sintering process of polycrystalline diamond, mitigating the detrimental effects associated with the brittleness of silicon carbide (SiC). However, as the Ni content increases, the hardness of the outer PCD layer decreases, and the overall performance of the CVDD/PCD composite declines. The composite exhibited optimal overall performance when the binder content of Si, Ni, B were 9.4wt%, 0.5wt%, 0.1wt%. This study provides a foundation for the research and application of CVDD/PCD composite in hard rock drilling.