Tribological Behaviours Of CaCO₃ Whisker Filled Peek Composites

No paper is available on the friction and wear behaviour of calcium carbonate(CaCO₃) whisker and polytetrafluoroethylene(PTFE) Filled polyetheretherketone(PEEK) composites. In this work, the composite blocks of CaCO₃/PEEK and CaCO₃/10%PTFE/PEEK with filler were prepared by compression molding. The tribological behaviors of filled PEEK composites were evaluated on MM200 block-on-ring apparatus. The tribological influence of different content of CaCO₃ whisker and the cooperate effect of CaCO₃ whisker and PTFE to composite are researched. The morphologies of the wear traces and the transfer film were observed by scanning electron microscopy(SEM). It was found that CaCO₃/PEEK exhibited considerably lower friction coefficient and wear rate in comparison of the neat PEEK and CaCO₃ /PEEK under dry frictional condition. With an increase in contents, coefficient of friction is continuously decreased ,and the same with the rate of composite wear in low whisker content, the best wear-resistance was obtained with 15wt% CaCO₃ whisker inclusion. And the compositive tribological effect is still valuable when whisker inclusion is 30wt%. Limit PV value of composite is also improved obviously because of CaCO₃ whisker. The composite friction coefficient is decreased and the wearable capability is increased remarkably with 10wt% content of PTFE. When CaCO₃ whisker inclusion is 15wt% to 20 wt%, the specific wear rate of CaCO₃/10%PTFE/PEEK showed minima as low as 3.5x10-7mm3/Nm and a 26 times improvement due to inclusion of CaCO₃ whisker and PTFE, followed by a slow increase for further wshisker addition. The 20wt% CaCO₃/10%PTFE/PEEK composites showed excellent combination of friction coefficient, wear rate and cost. The SEM micrographs of the wear traces of carbon steel ring and PEEK composites indicated that CaCO₃ whisker contributed to abate the scuffing, adhesion and plastic deformation of the filled composites, which conformed to the better wear resistance of the filled PEEK composites than the polymer matrix. meanwhile, a thin, uniform, and tenacious transfer film was formed on the surface of the steel ring because of PTFE's trend to transfer, the tribological behaviors of composite is closely related to the cooperate effect of CaCO₃ whisker and PTFE.