Effect of particle shape on the wear and friction behavior of particle-reinforced epoxy coatings

Epoxy coatings are increasingly becoming popular choices as barriers against acids and alkali for protection of concrete and metal products. In applications, metal containers are often coated with epoxy-based coatings to prevent rusting and corrosion. In this study, an experimental examination was carried out to investigate the effect of particle shape and size on the friction and wear behavior of epoxy coatings. Friction and wear experiments were conducted using a pin-on-disk tribometer. Epoxy resin was filled with four different shapes of glass particles (spherical, flake, rod, and irregular shape) and varying particle sizes. Fillers were settled down and filler surface area fraction through thickness was characterized using microcomputed tomography (micro-CT). The wear mechanisms such as matrix wear, matrix cracking, particle fracture, particle debonding, and pullout and debris formation were studied using scanning electron microscopy. According to observations, it was found that particle shape has an effect on the wear characteristic. Particle fracture and particle pullout mainly dominated the wear in the samples of flake- and rod-shaped fillers, perpendicular matrix cracks occurred in the samples of spherical fillers, large debonding at the particle–matrix interface without particle pullout occurred in the samples of large irregular-shaped fillers (75–150 µm), and matrix cracks dominated the wear as the size of irregular-shaped fillers decreased to 50–75 µm. Further, it was found that friction coefficient depends on the shape of the particle. The samples with spherical- and irregular-shaped fillers had higher friction coefficient as compared to the samples with flake and rod fillers.