Friction and wear properties of PTFE irradiated by electron-beam

The friction and wear properties of polytetrafluoroethylene which was irradiated by electron-beam under molten state in nitrogen (irradiated PTFE) were examined under various temperatures, and they were compared with those of unirradiated PTFE. The properties of irradiated PTFE were also investigated with the aid of micro-hardness measurement, X-ray diffraction (XRD), differential scanning calorimetry (DSC), dynamic contact angle measurement, X-ray photoelectron spectroscopy (XPS), and viscoelastometry. The specific wear rates of irradiated PTFE were very low compared with those of unirradiated PTFE more than two orders of magnitude, and they were 3×10-6 mm 3/Nm at room temperature, and around 3×10-8 mm 3/Nm at temperatures from 100 to 200 °C. The low wear rates of irradiated PTFE seem to arise from the repetition of the transfer and back transfer of the irradiated PTFE films. As a result of that repetition, only small wear particles were detected from rubbing surfaces.