Tribological Behavior of High Energy Silicon Ion-Irradiated Ultra High Molecular Weight Polyethylene

Abstract

In order to improve the friction coefficient and the wear resistance on ultra high molecular weight polyethylene (UHMWPE), substrates were irradiated with Si ion. The beam energies were 1.5 and 3.0MeV at a fluence range of 0.5×10¹⁴−1×10¹⁵ ions/cm². The friction coefficient and wear resistance of UHMWPE substrates were measured using the ball-on-disk wear testing method. The ion-irradiated substrates were analyzed using secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. It was found that the friction coefficient of ion-irradiated substrates at a fluence of 5×10¹⁴ or 1×10¹⁵ ions/cm² was lower than that of non-irradiated substrate. Furthermore, the wear resistance was improved at a fluence of 1×10¹⁵ ions/cm². The hardness of the irradiated substrates increased with an increase of ion fluence. The analysis by SIMS and Raman spectroscopy suggested that amorphous carbon was formed in the surface layer by ion-irradiation.