Effects of oxide addition on structure and properties of WC–10Co cemented carbide obtained by in situ synthesized powder

Combining spray drying and in situ synthesized technology, WC–10Co cemented carbide with uniform composition was prepared by vacuum sintering. The effects of Al2O3 and additions of different rare‐earth oxides (La2O3, Y2O3 and CeO2) on the microstructure and mechanical properties of WC–10Co were investigated. As the Al2O3 content increased from .5 to 2 wt%, the hardness of the sintered sample increased, whereas the relative density and fracture toughness decreased. Compared with the addition of .5 wt% Al2O3, the WC–10Co alloy with .5 wt% rare‐earth oxides had higher hardness. In addition, compared with the alloy without an inhibitor (.80 μm), after adding .5 wt% Al2O3, La2O3, Y2O3 and CeO2, the WC grain sizes were reduced to .73, .65, .71 and .62 μm, respectively, which indicated that the addition of Al2O3 and rare‐earth oxides could refine WC grain during sintering. Among these additives, CeO2 had the best effect. With the addition of .5 wt% CeO2, the hardness and the fracture toughness increased from 1299 to 1710 HV30 and from 16.18 to 18.90 MPa m1/2, respectively.