Surface modification of ion implanted ultra high molecular weight polyethylene

The surface modification has been studied for the ultra high molecular weight polyethylene (UHMWPE) implanted by 80 keV N-2(+) C3H8+ (40 keV N+, 22 keV C+) with fluences ranging from 1 x 10(14) to 5 x 10(15) ions/cm(2). Elastic recoil detection (ERD) and X-ray photoelectron spectroscopy (XPS) have been employed to characterize the modified surface of the samples. ERD results show that the high energy edge of ERD spectra shifts in the lower energy direction with the increase of implantation fluency, indicating that a hydrogen deficient surface layer is formed after implantation. XPS result shows that injected nitrogen atoms assist in crosslinking by forming chemical bonds with the polymer chains. KyowA's DF-PM reciprocating tester has been used to measure the wear property before and after implantation. The results show that the wear-resistance of samples after N-2(+), C3H8+ implantation has been improved by 68 and 47.5 times, respectively. Some interpretations are given to explain the observed phenomena. (C) 2000 Elsevier Science B.V. All rights reserved.