Effect of iron-powder type on the friction and wear properties of Cu-based P/M friction materials

Copper-based friction materials were made by powder metallurgy (P/M) from copper powder and ferrous powder, which is reduced Fe powder, spongy Fe powder, Fe-Ni alloy powder and Fe-Cr alloy powder, respectively. Their friction and wear properties were investigated by friction testing, scanning electron microscopy and microhardness measurement. When the rubbing speed increases from 3000 to 6200 r·min^-1, the friction coefficient of specimens drops greatly. For specimens with spongy Fe powder, the friction coefficient changes less than 0.024, showing a stable friction coefficient but serious wear. When ferrous powder is strengthened by nickel, the friction coefficient stability of specimens at high rubbing speed improves obviously, and the friction coefficient changes less than 0.027. Specimens with Fe-Cr powder obtain the optimum wear resistance with almost constant wear rate as the rubbing speed increases.