Effect of pv factor on carbo-graphite and copper impregnated carbo-graphite material under dry conditions

This study investigates the tribological behaviour of copper-impregnated carbo-graphite (ICG) compared to plain carbo-graphite (CG) under various parameter-product (PV) values and temperatures. Impregnation significantly enhanced ICG's hardness (70%) and reduced porosity (98.6%) compared to CG. The CoF for CG was lower than that for ICG attributed to the formation of a lubricating graphite-rich tribo-film that facilitated easy shearing at the contact interface. The wear mechanisms for CG at elevated temperatures were identified as adhesion, oxidation and delamination, likely exacerbated by the material's softening. In contrast, ICG exhibited superior wear resistance, attributed to its higher hardness and the formation of a protective tribo-layer containing copper and graphite. This tribo-layer offered a low-shear interface at lower PV values, reducing friction. However, at higher PV values, ICG wear increased due to abrasion and adhesion. Overall, copper impregnation offers a promising strategy to improve the wear resistance of carbo-graphite, particularly at elevated temperatures.