Hybrid effect of ceramic whiskers and graphite flakes on mechanical and dry sliding performance of epoxy composites

This experimental study reports the results of adding ceramic whiskers (15wt%) and graphite flakes (2.5wt%) on mechanical and tribological characteristics of epoxy based polymer composites. Sliding wear experiments were conducted on a pin-on-disc test rig under dry contact conditions. Coefficient of friction and specific wear rate were determined as a function of sliding velocity (0.5m/s, 0.75m/s and 1m/s), normal load (10N, 20N and 30N) and sliding distance (500m, 1000m and 1500m). Density and hardness of epoxy was found to increase with addition of fillers. Strength properties were found to decrease after addition of ceramic whiskers where as it improved after graphite addition. However, both fillers acted to improve the stiffness under tensile and flexural loading conditions. Friction coefficient of polymer was found to increase after whisker addition, and decreased considerably after adding graphite lubricant. Both fillers significantly improved the wear resistance of epoxy composite. Microscopic study of tensile fractured surfaces and worn out surfaces of samples wascarried out to identify different fracture mechanisms.