Surface modification of ion implanted ultra high molecular weight polyethylene

The surface modification has been studied for the ultra high molecular weig ht polyethylene (UHMWPE) implanted by 80 keV N-2(+) C3H8+ (40 keV N+, 22 ke V C+) with fluences ranging from 1 x 10(14) to 5 x 10(15) ions/cm(2). Elast ic recoil detection (ERD) and X-ray photoelectron spectroscopy (XPS) have b een employed to characterize the modified surface of the samples. ERD resul ts show that the high energy edge of ERD spectra shifts in the lower energy direction with the increase of implantation fluency, indicating that a hyd rogen deficient surface layer is formed after implantation. XPS result show s that injected nitrogen atoms assist in crosslinking by forming chemical b onds with the polymer chains. KyowA's DF-PM reciprocating tester has been u sed 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.