Optimization of graphite contents in PAEK composites for best combination of performance properties

Abstract

Graphite is one of the most widely used solid lubricants in both, anti-friction and friction materials. The influence of particles in the composite mainly depends on its size, amount, its combination with fibers and other fillers etc. No efforts were done to optimize the amount of graphite to achieve very low friction and wear. A series of Polyaryl ether ketone (PAEK) composites with GF (short glass fibers) and increasing amount of graphite particles (10, 15, 20 and 25 wt %) were developed and characterized for various properties such as physical, mechanical, thermal along with adhesive wear performance in severe operating conditions (high pressure and velocity (PV)). Inclusion of graphite led to deterioration in strength and modulus but increase in thermal conductivity. The composites showed very low μ (friction coefficient) in the range of 0.04 and K0 (specific wear rate) (∼2 × 10−16 m3/Nm). Composite with 15 wt % graphite proved to be significantly superior by showing highest PVlimit value (154 MPa m/s) and very low μ (0.04) and K0 (1.91 × 10−16 m3/Nm). The typical inferences were supported by various techniques such as Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), 3D profilometer, Raman spectroscopy on the worn surfaces.