Tribological characteristics of nanocomposite materials

Abstract

Multi-walled carbon nanotubes (MWCNTs) were mechanically stirred and dispersed into epoxy matrices to form MWCNT-epoxy nanocomposites by sonication and curing. Using the sessile liquid drop test, micro tribometer, micro indentation test, thermo-gravimetric analysis followed by surface profilometry and microscopic observation, the effects of carbon contents of 0.5, 1, 2 and 3wt% in the nanocomposites were characterized and investigated based on their thermal, mechanical and tribological properties, together with the neat epoxy. The ball-on-disc method was used for the tribological tests with counter balls of different diameters and different materials including aluminum oxide (Al2O3), chromium steel and poly(methyl methacrylate) (PMMA) to compare their differences in friction coefficient and wear resistance, and also with respect to the CNT concentration in the nanocomposites. It was found that the friction coefficients and wear resistances were reduced by adding CNTs into the composites except for 0.5wt% CNT reinforced composite, at the expense of increased surface energy and roughness, weakening of mechanical properties like hardness and Young’s modulus, and poorer structural integrity with possible microvoids in the nanocomposites. The thermal stability of the nanocomposites was also slightly increased by adding more CNTs.