THE ROLE OF COPPER-COMPOUNDS AS FILLERS IN THE TRANSFER AND WEAR BEHAVIOR OF POLYETHERETHERKETONE

CuO, CuS and CuF2 have been used as fillers in polyetheretherketone (PEEK) and the influence of these fillers on the friction, wear and transfer behavior of the PEEK composites has been studied. Sliding tests were conducted with a pin-on-disk machine at 1.0 m s-1 speed and 0.65 MPa nominal contact pressure under ambient conditions. The pins were made of polymer composites with a filler content of 35 vol.%. The composites were prepared by compression molding. The disks were machined from tool steel blocks and hardened. Experimental results showed that all these fillers reduced the wear of PEEK. The coefficients of friction of the CuS-PEEK and CuF2-PEEK composites during steady state wear were slightly higher than that of unfilled PEEK, but the coefficient was much higher in the case of the CuO-PEEK composite. The transfer films were studied by optical and scanning electron microscopy and their bonding to the counterface by X-ray photoelectron spectroscopy. It has been argued that the ability of these fillers to reduce wear depends upon their ability to form transfer films of the composites on the counterface which are thin and uniform and are strongly bonded to the substrate.