Study On The Triboelectrification Of Polymeric Composites And Its Influence On Tribological Performances

In this thesis, the triboelectrification of two kinds of PTFE-based composites (Al2O3/PTFE and FeSi/PTFE) during friction against 45 steel was mainly studied. The influence factors of this phenomenon were investigated. The tribological performances of PTFE-based composites were tested and analysed. The effects on the average thickness of the transfer film were studied when Al2O3/PTFE composite slid against 45 steel. Based on the analysis of the effect of triboelectrification on friction transfer, it is hoped to realize the control of friction transfer by adjusting the triboelectrification in order to optimize and control the tribological performances of the polymeric composites. It may be a new method to control the tribological performances with great significance in theory and application.The main results are as follows:1. Influence factors of triboelectrification of PTFE-based compositesWith the increase of load, the voltage of triboelectrification of the PTFE composites steadily increased. With the velocity’s speeding up, the voltage of triboelectrification increased for Al2O3/PTFE composite and 45 steel couple, but decreased for FeSi/PTFE composite and 45 steel couple. As the increase of filler content, the voltage presented an increasing trend for Al2O3/PTFE, while it lowered for FeSi/PTFE. The triboelectrification of PTFE-based composites with larger particles is more obvious when the filler content is definite.2. Tribological performances of PTFE-based compositesThe average friction coefficient of PTFE-based composites reduced and the wear loss increased linearly along with the enlarged load, while the former decreased slowly and the latter increased rapidly with the increase of velocity. As the increase of the filler content, the average friction coefficient of PTFE-based composite went slightly up and the wear loss went down markedly. The average friction coefficient had a minor decreases adapting to the enlargement of average particle size of filler, but the wear loss was little influenced.3. Friction transfer of Al2O3/PTFE compositeWith the increase of the load, the average thickness of the transfer film first increased and then decreased, the maximum average thickness was 2.568 m, and the load was 3.5MPa. And it increased with the increase of the velocity. With the increase of Al2O3 content, it increased first and then decreased with the maximum value at the content of 10wt%. It increased gradually with the increase of the average particle size of Al2O3, and then turned to down slightly when the average particle size of Al2O3 beyond 63μm.4. Relations between triboelectrification of PTFE-based composite and friction transfer or tribological performancesThere was a positive correlation between the triboelectrification voltage due to the friction of Al2O3/PTFE composite against 45 steel and the average thickness of transfer film. Both the friction coefficient and the wear loss increased with the increase of triboelectrification voltage.