Tribological Behavior of Copper-Graphite Friction Materials

Copper-graphite sintered materials were prepared by powder metallurgy technology. The relationship of the graphite content to the third body topography and the impact of the graphite content on frictional properties of the materials were investigated on a constant speed friction test machine. The results showed that, when less than 15%, the graphite had a significant influence to the material porosity and the friction temperature. The results demonstrated clearly the friction and wear property of the material was closely related to the graphite content and this was due to the effect of the third body containing graphite particles formed on the frictional surface under dry friction condition. The third body derived from low graphite content sintered materials had a high level of metal composition. Plowing effect of the hard metal led to higher friction coefficient and wear rate. With the increase of graphite content, the density and adhesion of the third body reduced because of the increase level of graphite in the third body. The low compactness and easy flow of the third body alleviated the surface plowing, lowered and stabilized the friction coefficient and, therefore, reduced wear rate.