Tribological studies comparison between UHMWPE and PEEK for prosthesis application

This work reports on the tribological and surface hardness modifications of ultrahigh molecular weight polyethylene (UHMWPE) and polyether ether ketone (PEEK) after plasma immersion dual ion implantation of nitrogen, oxygen and helium ions at constant energy and fluence. The results show that the hardness and wear rate can be improved in both polymers by an appropriate combination of the bombarding ions. Wear tests were carried out on modified UHMWPE and PEEK against CoCrMo and Al2O3 counter materials, in an adult bovine serum (ABS) medium at 37 °C. In particular, the dual bombardment with nitrogen and oxygen in a 3:1 ion fluence ratio provides the highest wear rate reduction on both polymers when sliding against CoCrMo. In the case of the test against Al2O3, the averaged low wear rates were obtained using He/N ion fluencies of 3:1. More specifically, the wear performance of plasma treated PEEK is superior to this shown by UHMWPE.