Tribo-mechanical behaviour of SiC filled glass-epoxy composites at elevated temperatures

Abstract

Polymer matrix composites are a promising candidate in tribological applications due to possibility of tailoring their properties with special fillers. Several methods have been developed to improve their performance. For instance, the introduction of ceramics such (SiC, Al2O3, TiC, etc.) as within the matrix notably increases the friction coefficient and reduces the wear loss. While glass fibers enhance the toughness of the matrix, silicon carbide shows high hardness, thermal stability and low chemical reactivity, leading to superior friction properties. In this work an attempt was made to evaluate the mechanical properties and tribological behaviour of glass fabric reinforced- epoxy (G-E) composites and silicon carbide filled glass fabric reinforced-epoxy (SiC-G-E) composites. The fabricated wear specimens were tested by using pin-on-disk test rig at various temperatures viz., 30, 60, 90 and 120º C at normal applied loads of 10 N and 20 N. Sliding velocity of the disc of 1.5 m/s was maintained and test was continued for each sample up to a sliding distance of 5000 m. The wear loss in both the composites increases with increase in temperature/applied load and under the same conditions the specific wear rate increases. However, silicon carbide particulate filled G-E composite exhibits lower wear rate with higher coefficient of friction as compared to virgin G-E composite. The elemental composition of worn surface of filler filled composites was quantitatively analyzed by using energy dispersive X-ray spectroscopy. The features of worn surfaces of the specimens tested at higher and lower temperatures at applied normal load of 20 N were examined under scanning electron microscope and also micro mechanism of fractured surfaces were examined through SEM and discussed.

Keywords: Glass fabric-epoxy composites; Silicon carbide; Micro mechanism; wear rate and wear mechanisms.