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 Al 2 O 3 and additions of different rare-earth oxides (La 2 O 3 , Y 2 O 3 and CeO 2 ) on the microstructure and mechanical properties of WC–10Co were investigated. As the Al 2 O 3 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% Al 2 O 3 , 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% Al 2 O 3 , La 2 O 3 , Y 2 O 3 and CeO 2 , the WC grain sizes were reduced to .73, .65, .71 and .62 μm, respectively, which indicated that the addition of Al 2 O 3 and rare-earth oxides could refine WC grain during sintering. Among these additives, CeO 2 had the best effect. With the addition of .5 wt% CeO 2 , the hardness and the fracture toughness increased from 1299 to 1710 HV 30 and from 16.18 to 18.90 MPa m 1/2 , respectively.