| 摘要 |
PROBLEM TO BE SOLVED: To provide a hard metal of ultra-fine particles for providing a cutting tool which has the long life up to breakage, and high intensity, and shows adequate corrosion resistance and wear resistance, through focusing attention on particle size distribution of WC phases dispersed in a hard phase in a microstructure of the hard metal of the ultra-fine particles, and by removing existing coarse particles as much as possible and improving it into a sintered compact comprising the uniform fine particles. SOLUTION: This hard metal has a composition comprising, by a weight ratio, 5-12% Co and/or Ni, at least two or more of Cr<SB>3</SB>C<SB>2</SB>, VC, TaC, Mo, Ru and Si in a total amount of 0.1-3%, and the balance WC with unavoidable impurities, wherein WC after being sintered has an average particle diameter D which satisfies 0.10≤D≤0.35μm, has a particle size distribution in which a content ratio F of the coarse particles with the particle diameters of 0.70μm or larger satisfies 0<F<10%, and has a deflection strength of 4.5 GPa or higher. COPYRIGHT: (C)2004,JPO
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