The friction and wear characteristics of nanometer SiC and polytetrafluoroethylene filled polyetheretherketone

Abstract

The tribological behavior of polyetheretherketone (PEEK) filled with nanometer SiC and polytetrafluoroethylene (PTFE) was studied. The composite specimens with different filler proportions were prepared by compression molding. The effect of PTFE on the friction and wear properties of nanometer SiC filled PEEK was investigated on a block-on-ring machine by running a plain carbon steel (AISI 1045 steel) ring against the PEEK composite block. The morphologies of the worn surfaces and the transfer film were observed by scanning electron microscopy (SEM) and electron probe microanalysis (EPMA). X-ray photoelectron spectroscopy (XPS) analysis was performed to detect the chemical changes during the wear process. It was found that the friction reduction and wear resistance capacities of nanometer SiC and PTFE were weakened, when nanometer SiC and PTFE were filled together into PEEK. The morphologies of worn surfaces and the properties of transfer films became bad. The reason for this was due to the chemical reaction between the nanometer SiC and PTFE during the compression molding process and the sliding friction process. It was just the formation of the SiF x by depleting some nanometer SiC and the added PTFE that determined the tribological characteristics of the SiC–PTFE–PEEK composites. When the PTFE volume percent was low then the SiF x caused the friction and wear of the SiC–PTFE–PEEK composite to rise since most of the PTFE and nanometer SiC had been altered and their low friction destroyed. However, at high volume percents the low friction PTFE dominated the friction and wear behaviors and the friction decreased as the percentage of PTFE increased.