Gamma irradiation effects on thermal, physical and tribological properties of PEEK under water lubricated conditions

Abstract Effects of gamma irradiation (upto 3 MGy) on thermal, physical and tribological properties of poly-ether-ether ketone (PEEK) were studied. Several studies have presented data on radiation stability of PEEK. However, none have investigated the effects of gamma irradiation on its tribological properties. This work was carried out for applications of precision mechanisms of fuelling machine of Indian Pressurised Heavy Water Reactors (PHWRs). Hence very slow sliding speed and water lubricated environment were selected. Increase in glass transition temperature, melting temperature, hardness and density was observed after exposure to gamma irradiation. Highest glass transition temperature and melting temperature were observed at 0.5 MGy. Tribological properties were also altered after exposure to gamma radiation. Surface stresses generated due to crosslinking have resulted into highest coefficient of friction at 0.5 MGy dose. Reduced probability of fracture has resulted into lowest wear rate at same dose.