Loading capacity of PEEK blends in terms of wear rate and temperature

Abstract

With the aim to apply thermoplastics as sliding bearing pads against stainless steel runner under heavy loads suffering temporary lack of lubricants, the tribological performance of polyetheretherketone (PEEK) was examined using a pin-on-disk tribometer with a thermocouple embedded in a stainless-steel pin under a dry friction condition. With an increase in specific pressure (from 0.7 to 2.8 MPa) and sliding velocity (from 0.26 to 0.65 m/s), the friction coefficient of the pure matrix increased from 0.06 to 0.60 with measured interface nominal temperature rising from 42 °C to 161 °C, while the PEEK reinforced with carbon fiber (CF)/graphite/polytetrafluoroethylene (PTFE) exhibited a lower friction coefficient between 0.06 and 0.35 and a lower temperature ranging from 29 °C to 53 °C. The interface temperatures play a key role dominating the wear behaviors of PEEK blends. The specific wear rates of PEEK blends increase exponentially when the ambient temperature exceeds 150 °C. It is essential for PEEK blends to keep the interface temperature below the glass transition temperature to achieve remarkable tribological behavior. It is suggested that the CFs provide high thermal conductivity and resistance at the contact deformation in addition to the solid lubrication provided by the graphite/PTFE at the interface.