| The mechanical properties of sintered WC-Ni alloy are inferior to those of WC-Co alloy because of its poor sinterability. To improve the sintering response we prepared a WC-Ni alloys from WC powders coated with SiC, which were obtained by coating W powder surface with SiO₂ followed by carburizing. The particle size of carburized powders and microsturcture, density, hardness and fracture toughness of sintered alloy were examined in terms of the amount of SiC addition. The particle size of SiC-coated WC coarsened at a lower rate during carburizing than that of uncoated WC powder. While the SiC coated WC-10%Ni cemented carbide with refined particle size showed an abnormal grain growth. With SiC coating by 0.6∼0.8wt.%, the sintered WC alloy showed restrained grain growth and θ phase(Ni₃W₃C) formation. As the amount of added SiC increased, the density, hardness and K_(IC) of the alloy increased. For those with the amount of SiC above 1.0wt.%, however, the hardness increased whereas the density and K_(IC) decreased. |
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