It has been known by the present authors that mechanical properties of WC-Ni alloy were improved towards the values of WC-Co alloy with decreasing grain size of WC, and also the micro-grained WC-Ni alloy could be obtained by the addition of VC, etc., with the result that small pores were apt to appear in the micro-grained WC-Ni alloy in the sintered state, differing from the case of micro-grained WC-Co alloy. Then, the study on this subject, that is, on the reason why small pores often appear in the micro-grained WC-Ni alloy was carried out. The WC-10mass%Ni alloy containing VC up to 5 mass% in binder was used as specimens.
It was suggested that the fact that the Ni rich agglomerates peculiar to WC-Ni alloy (consisting of Ni and fine WC particles) formed during ball-milling of mixture could not perfectly be removed from the ball-milled mixture, and the fact that the temperature at which liquid phase appeared was higher in WC-Ni alloy by about 701C, comparing with in WC-Co alloy, were the most responsible for the above subject.