A copper alloy sliding material which can bring about superior resistance
to fatigue as well as good anti-seizure property without containing any
Pb. The copper alloy sliding material is made to have the structure in
which both of the hard copper alloy phase and the soft copper alloy phase
coexist in a mixture state. On the surface of the sliding material, the
soft copper alloy phase comes to have a shape more concave than that of
the hard copper alloy phase when receiving a load or when being in a
sliding wear relation, in which concave portions is retained lubricant
with the result that the anti-seizure property is enhanced. Further, since
the soft phase and the hard phase are made of the same copper alloy, the
wettability thereof becomes good, and Ni and etc. contained in the hard
copper alloy phase are diffused into the soft copper alloy phase, so that
the hardness of the boundary portion defined between the phases come to be
gradually varied. Thus, because of the unclear boundary, the load received
in the hard phase comes to be spread in a wide range without being
concentrated at the boundary, so that the fatigue strength is enhanced.