Processing a new diamond composite by high pressure and high temperature with improved thermostability using Mo as a binder

Abstract

The current study investigates the effects of powder homogenization on the characteristics of polycrystalline diamond (PCD) sintered with molybdenum (Mo) at high pressure-high temperature (HPHT). PCD combines excellent properties, such as high hardness, wear resistance, and good thermal conductivity. Furthermore, it has greater fracture toughness when compared to a single-crystal diamond, which makes it suitable as a cutting tool. The properties of PCD, however, are sensitive to the preparation conditions, which include the particle size of the initial powders, contaminants, and dispersion of the binder phase. Bearing this in mind, in order to study the effects of the preparation conditions on the properties of PCD, the blends were homogenized by a manual method, such as High-Energy Ball Mills (HEBM), at different times: 30s, 60s, and 90s. Data regarding micromorphology, phase transformations, resulting residual stresses, and thermostability were determined. According to the results, the blends prepared by HEBM showed superior phase dispersion, greater effectiveness in the formation of molybdenum carbides, and good densification. The thermoanalytical data showed that composites with superior thermal performance to commercial PCD were obtained, with thermostability between 802 °C and 837 °C.