Thermally stable polycrystalline diamond sintered with calcium carbonate

In this study we report on the synthesis and characterisation of thermally stable polycrystalline diamond (PCD) using CaCO3 as a sintering aid. The diamond powder was treated at 8 ± 0.5 GPa and 2000–2200 °C for 10 min in a multi-anvil press. Scanning electron microscopy showed significant intergrowth of the diamond particles sintered in the presence of CaCO3, which remained in the compacts in the form of aragonite and calcite as evident from X-ray diffraction data. The diamond compacts showed no drop in wear resistance, as measured using a machine test, after heat treatment up to 1200 °C in vacuum. This is significantly higher compared to conventional PCDs sintered with a metallic binder. The transmission electron microscopy (TEM) investigation of the samples was carried out in order to gain more knowledge about the role of the carbonate sintering aid in the sintering process.