The tribological characteristics of A356.2Al alloy/Gr(p) composites

Graphite particulates coated with an electroless copper were introduced into an aluminum alloy by compocasting method to make A356.2 Al/2 wt.%, 4 wt.%, 6 wt.% and 8 wt.% graphite particulate composite. Variations in friction coefficient, wear rate, wear debris and electrical contact resistance were studied related to variations in graphite particulate content under different normal loading and sliding speed. For the 4 wt.% or 6 wt.% graphite particulate contain exhibits the lowest wear rate and friction coefficient, and these properties were insensitive to the variation in sliding speed and normal loading. The wear debris become smaller as the graphite content increased, this is reflected by the lower electric contact resistance. The rest of the tribo-layer consisted of the lamellar graphite films structure, which were elongated over long distances in the direction of sliding, thus, reducing shear stresses transmitted to the sub-surface regions, the amount of graphite film released on the worn surface increases with increasing the graphite particulate content.