THE INVESTIGATION OF THE ACTION OF FILLERS BY XPS STUDIES OF THE TRANSFER FILMS OF PEEK AND ITS COMPOSITES CONTAINING CUS AND CUF2

ne wear behavior of polyetheretherketone (PEEK) and CuS-PEEK composite rubbing at 1 m s-1 speed and 19.6 N load against both the steel and glass disks is examined. While CuS filler decreased considerably the wear rate of PEEK in rubbing against the steel disk, the wear rate of both the filled and unfilled materials in rubbing against the glass disk was almost the same. The wear rate of CuF2-PEEK composite sliding against a steel surface was also considerably lower than that of PEEK. The transfer films of the polymer and its composites containing CuS and CuF2 formed against the steel disk surfaces were studied by X-ray photoelectron spectroscopy (XPS). The analysis of the XPS spectra revealed that both CuS and CuF2 decomposed under the rubbing conditions, because reduced Cu, S, FeF2 and FeSO4 were found in the transfer film. The analysis at two different depths in the transfer film of CuF2-PEEK revealed that the concentrations of Cu and FeF2 were greater close to the transfer film-counterface interface. However, there was no chemical change detected when unfilled PEEK rubbed against the steel disk surface. These results have been used to hypothesize the mechanism for the action of fillers in reducing wear.