Nickel-cobalt-based materials for diamond cutting tools

Cobalt is nowadays the most used binding material for diamond cutting tools (DCTs), once it grants a suitable retention of diamond particles during in-service conditions. However, cobalt is an expensive and toxic material, being thus necessary to find effective alternatives that suit the requirements of this tool. In this context, this study focuses on the production of different nickel-cobalt-based materials, aiming to decrease cobalt content in cutting tools. Unreinforced Ni-Co-based materials (Ni-Co; Ni-Co-WC; Ni-Co-Cr3C2) and also Ni-Co-based materials reinforced with 4 wt% of diamond particles were produced by hot pressing, with a sintering temperature of 900 °C, under a pressure of 70 MPa, during 15 min. These materials were characterized regarding their microstructure, hardness, and shear strength. In order to assess these materials, tribological properties, and cutting performance, pin-on-disc wear tests, with the diamond-reinforced Ni-Co-based materials serving as pin and a stone serving as disc, were also performed. Results revealed that the best cutting performance was displayed by diamond-reinforced Ni-Co-WC, having the highest disc/pin wear ratio among the produced materials.