Toshiba Tungaloy Co., Ltd.

Yasuro Taniguchi

Mitsuo Ueki

Keiichi Kobori

Ko Sasaki

There are disclosed a surface refined sintered alloy body which comprises a hard phase containing at least one selected from the group consissting of carbides, carbonitrides, carbooxides, carbonitrooxides of the metals of the groups 4a, 5a and 6a of the periodic table and a binding phase containing at least one selected from iron group metals, characterized in that the concentration of the binding phase in the surface layer (of from 10 .mu.m to 500 .mu.m from the surface of the sintered alloy) is highest at the outermost surface thereof and approaches the concentration of the inner portion, the concentration of the binding phase decreasing from the outermost surface to a point at least 5 .mu.m from the surface; and a method for making the same by applying decarburization treatment at the surface of the sintered alloy at temperatures within the solid-liquid co-existing region of the binding phase after sintering or in the process of sintering.

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Kawasaki, Japan

Yasuro Taniguchi