Thermal Stability of Poly(ether ether ketone) Composites under Dry-sliding Friction and Wear Conditions

By using X-ray diffraction (XRD), infrared spectrometry (IR) , scanning electron microscope (SEM) and transmission electron microscope (TEM), the worn specimens of poly(ether ether ketone) , (PEEK), composites tested under unlubricated sliding friction and wear conditions at a constant sliding speed were investigated in order to reveal structural changes of polymer as well as wear mechanisms as a function of temperature . The results showed that the PEEK composites exhibited stable friction coefficient and lower wear ratio. The wear mechan ism is that the particle abrasion occurs at low temperature , the adherence abrasion and particle abrasion take place at the temperature between 200-350°C as revealed through wear morphology and wear debris analysis. The thermal degradation of PEEK does not occur until its temperature rises to higher than 350 °. The stainless steel and carbon fibres bind strongly with the matrix PEEK and may be responsible for improving stability of the friction coefficients of the materials. Surface film, transition layer and matrix composed the superficial structure of friction material after wear test. Two kinds of surface film structures are formed: one is cystiform microstructure with PEEK matrix surrounded by single or multicrystal powder of fillers ; the other is meshwork generated by resin base and friction fillings.