Friction and wear in sliding contact of cast iron against phenolic resin composites reinforced with carbonaceous fibres from plantain fibre bundles

Carbonaceous fibres from Colombian plantain crops residues were obtained by slow pyrolysis process to preserve the morphological aspects of the natural fibres. Composite materials were manufactured by thermal press process using carbonaceous fibres and commercial phenolic resin as reinforcement and matrix, respectively. Different reinforcement contents (0-12.5% v/v) were evaluated in a pin-on-disc tribometer to determine the effect on wear and coefficient of friction of this kind of carbonaceous fibres as a potential reinforcement or lubricant filler for tribological applications. Cast iron brake discs were used as counter bodies in all the tests. Worn surfaces of composite pins and metallic discs were analysed in optical and scanning electron microscopes. A decrease in both friction coefficient and mass loss of composites was observed with the increase in fibre volume fraction. The reduction was associated to a beneficial effect of the detachment of carbonaceous material from the worn surface, which remains at the interface between the composite and the cast iron and acts as a solid lubricant. Although adhesion marks were observed, surface fatigue and polymer crazing were identified as principal wear mechanisms of the composites.