Effects of metal-ion implantation on wear properties of polypropylene

Polypropylene was implanted with 100 keV titanium and silver ions to fluences of 1, 10 and 50 x 1019 ions m-2 using a vacuum arc metal-ion source. The implanted specimens were tested for sliding reciprocating wear properties using a nylon counterface, 1 N normal load, 3 mm stroke length and 10 000 sliding cycles. The results of the wear tests showed that there was a dramatic improvement in wear properties for the 50 x 1019 ions m-2 titanium-implanted specimen, to the point that no wear damage was visibly evident after 10 000 cycles. A similar wear improvement was not obtained for the lower fluences for titanium implantation or for the silver-implanted specimens. The improvement in wear properties was related to the mechanisms of linear energy transfer from the incident ions to the polypropylene substrate, and consequent effects on cross-linking, which is responsible for changes in properties. (author)