▎ 摘　　要

NOVELTY - Surface coating comprises 10-12 wt.% tin, 0.25-2 wt.% graphene, and copper (balance). The sheet thickness of graphene is 0.35-10 nm. The width of the graphene is 20-400 mu m. USE - The surface coating is useful for hydraulic motor (claimed). ADVANTAGE - The surface coating: contains graphene, which can reduce the coefficient of friction between the friction pair, reduces heat generated by friction and material loss, so as to prolong the service life and use performance of the cylinder body; has conductivity of 84-170W/(m.k), reduces friction coefficient by 15%, has instantaneous maximum temperature of friction pair interface about 200 degrees C to 160 degrees C, and has more smooth temperature distribution. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is also included for preparing surface coating comprising adding tin powder, graphene powder and remaining of reduced copper powder, adding ethanol, carrying out ball milling, placing ball abrasive on the surface of the cylinder, and sintering under reducing atmosphere after pressing to obtain the surface coating.