Tribological behavior of PEEK/PTFE composites reinforced with potassium titanate whiskers

The tribological behavior of polyetheretherketone (PEEK)/polytetrafluoroethylene (PTFE) composites reinforced with potassium titanate whiskers (PTW) has been investigated using the pin-on-disk configuration under dry sliding conditions at different applied loads. It was found that the PTW reinforced PEEK/PTFE composites exhibited much better tribological properties than those without PTW. Both the friction coefficient and the wear rate decreased with the increase of the PTW content. Moreover, the friction coefficient and the wear rate of the composites showed a decreasing tendency with the applied loads increasing from 1.0 MPa to 2.0 MPa. The crystallinity of the composite measured from differential scanning calorimeter (DSC) slightly decreased with the addition of PTW, which might imply that the crystallinity of PEEK was not the dominant factor that influenced the tribological properties of the composites. It was believed that the abrasive effect on the counterface by the whiskers at the initial stage, the formation of a thin, uniform and tenacious transfer film on the counterface, and the embedding of the worn-out free whiskers back into the composite surface during the subsequent frictional process were the main mechanisms to enhance the wear resistance.