Influence of laser-induced surface carbonization on the tribological properties of UHMWPE in a seawater environment

Abstract

The influencing mechanism of laser treatment on the tribological behavior of ultrahigh molecular weight polyethylene (UHMWPE) in a seawater environment was studied. The relation between the surface chemical composition and morphology of UHMWPE under different laser processing parameters and tribological properties in seawater environment was obtained. Oxidation and amorphization occurred when UHMWPE was laser-treated at relatively low-power densities (1.92 × 105 and 3.94 × 105 W/cm2), causing the slightly increase in wear rate of UHMWPE. Carbonization occurred after relatively high-power densities laser treatment (6.01 × 105, 8.12 × 105 and 1.00 × 106 W/cm2), causing significantly increase in wear resistance and decrease in friction coefficient. The laser-induced carbonization products were mainly composed of amorphous and graphitic carbon, which served as a solid lubricant during friction, thereby significantly improving the tribological properties of UHMWPE in the seawater environment. A method of laser-induced carbonization was proposed to improve the tribological properties of polymer materials in a seawater environment. Controlling the degrees of surface oxidation and carbonization of UHMWPE effectively regulated its tribological properties in seawater environments.