Ni-coated graphene nanoplatelets and their application as reinforcements for WC-Co cemented carbides

In the current research, Ni-coated graphene nanoplatelets (Ni-GNPs) were fabricated by electroless Ni plating process. The Co-cemented tungsten carbides (WC-Co) samples doped with Ni-GNPs were obtained by vacuum hot pressing sintering. The effect of various content of Ni-GNPs on the mechanical and frictional properties of as-sintered WC-Co samples was investigated. Vickers hardness of WC-Co samples decreased from 1896 MPa to 1743 MPa with the content of Ni-GNPs varied from 0.0 wt% to 0.4 wt%. The fracture toughness reached to the highest value of 10.85 MPa m(1/2)with 0.05 wt% Ni-GNPs. The friction coefficient dropped from 0.43 of the sample with 0.0 wt% Ni-GNPs to 0.21 of the sample with 0.4 wt% Ni-GNPs. The results revealed that the Ni-GNPs have considerable effect on improving the combination properties of WC-Co cemented carbides. Within the mentioned content range, the optimal content of the Ni-GNPs in WC-Co sample was 0.05 wt%.