Influence of linear reciprocating and multi-directional sliding on PEEK wear performance and transfer film formation

Because of their light weight, chemical resistance, and self-lubricating properties, polymers are used in applications ranging from biomedical to aerospace. Some polymers exhibit significant differences in wear resistance based on whether they are in unidirectional or multidirectional sliding. Shear induced polymer chain orientation is believed to be responsible for this behavior. Polyetheretherketone (PEEK) has excellent wear resistance, but its multidirectional sliding behavior has not been thoroughly investigated. A factorial multidirectional pin-on-plate wear study of PEEK was conducted with a focus on molecular weight and sliding path directionality. These factors were studied for their correlation to over all wear performance. Additionally, transfer film thickness was measured at locations along the wear path using white light interferometry. Wear in PEEK was shown to depend significantly on path shape and direction. The lowest wear configuration also resulted in quantifiably thinner and more continuous transfer films. A result of this work has been a greater understanding of PEEK wear mechanisms in various sliding configurations.