| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve seat made of iron-base sintered alloy, excellent in wear resistance and reduced in attacks on mating materials. SOLUTION: This valve seat has a composition consisting of, by weight, 15-40% Cu, 0.3-12% Ni, 0.8-3.0% C, and the balance Fe with inevitable impurities and containing, if necessary, 0.1-10% Co and 0.1-10% Cr and also has a structure where a hard particle phase 3 of 500-1700 MHV is dispersed in a matrix formed by binding an Fe-base alloy phase 1 composed essentially of Fe with a Cu-base alloy phase 2 composed essentially of Cu. The Fe-base alloy phase 1 is an Fe alloy phase containing Ni, Cu, and C and also containing >=50 wt.% Fe, and the Cu-base alloy phase 2 is a Cu alloy phase 4 containing Ni, Fe, and C and also containing >=50 wt.% Cu. Further, the concentrations of Ni and C, contained in the Fe-base alloy phase, are higher than the concentrations of Ni and C contained in the Cu-base alloy phase.
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