A new 0.4 mu m WC powder as well as powder-related properties and sintering behavior of 0.6 to 30 mu m WC-Co hardmetals

A new 0.4 mu m WC powder with hardmetal properties based on optimized struc tures and doping additives obtained by sintering is presented. The HV30 har dness of hardmetals made from this new DS40 powder with 10 wt-% Co extends up to 2000 and a hardness of 1870 can be combined with a PALMQVIST toughnes s of 810 N/mm or 10.5 MPa m(1/2). Connections between powder, structure, an d hardmetal properties are established and discussed for the entire range o f WC grain sizes commercially available. Some extrapolations are made to pr edict properties of hardmetals with ultrafine and nanophased structures to be developed ib the near future. As shown by thermoanalytical investigation s, solid-state sintering contributes more than 75% toward the total densifi cation of WC-Co hardmetals and strongly depends on properties and processin g of the starting powder, doping and WC grain size. A model of that solid-s tate sintering prior to the binder melting is proposed.