An investigation of thermal and tribological behaviors of PTFE-based silicon composites filled with AlN and flake graphite particles

摘要

The thermal and tribological properties of silicon composites were improved by choosing polytetrafluoroethylene (PTFE) as a thickener and alumina nitride (AlN) and flake graphite (FG) as thermal conductive additives, producing AlN-modified, FG-modified, and AlN/FG-modified PTFE-based thermal silicon composites (AlN-PTSC, FG-PTSC, and AlN/FG-PTSC, respectively). Three-dimensional network-configuration representative volume element models were built to investigate the thermal properties of these composites by applying a Monte Carlo, controllable, spatial distribution algorithm. The composites' thermal conductivity and volume resistance were also measured. Tribological tests were conducted using a ball-on-disk reciprocating friction and wear tester. Scanning electron microscopy and energy dispersive spectroscopy were used to analyze the morphologies and elements of worn surfaces. The results showed that AlN/FG-PTSC possessed the best thermal properties, which were ascribed to a compact thermal conductive network; thermal conductivity was 88.8% and 44.8% greater than the highest value of AlN-PTSC and FG-PTSC, respectively. The numerical values of thermal conductivity were in a good agreement with experimental results. The optimal electrical tribological properties of AlN/FG-PTSC were ascribed to the functions of thermal and electrical properties combined, which could be helpful in abating the arc erosion on friction contacts. (c) 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45263.