Friction and wear of friction composites reinforced by natural fibres

In the present work, friction material composites were proposed to be used as automotive friction materials. The composites were reinforced by agricultural fibres of corn, palm, and sugar bars. The conventional friction materials based on asbestos cause serious lung diseases and being cancerous potential. The aim of the present work is to replace them by the proposed composites because they are environmentally friendly friction material for brake lining and clutch facings. Agricultural wastes of sugar bars, corn and palms fibres were prepared to obtain fibres of length less than 5 mm. The fibre materials were mixed by carbon, barium sulfate, silica, metallic powders and phenol formaldehyde. The proposed composites were pressed in the die at 105°C temperature. The produced specimens were subjected to machining processes to obtain the cylindrical form of 8 mm diameter. Experiments were carried out using test rig designed and manufactured to measure both friction and wear. It consists of a rotating hollow flat disc made of carbon steel, with an outside diameter of 250 mm and 16 mm thickness. The experiments investigated the effect of agriculture fibre wastes (corn, sugar bars, and palms fibres) on friction coefficient and wear. Wear mechanisms of the proposed composites were characterized by scanning electronic microscopy. The tribological properties of the proposed composites materials were compared to three commercial brake linings. Based on the experimental results it was found that, addition of agriculture fibre wastes (corn, sugar bars, and palms fibres) to composites materials increased friction coefficient and decreased wear. Friction coefficient slightly increased, while wear drastically decreased with increasing fibres content. The maximum friction value (0.58) was obtained by composites containing 30 wt.% iron and 25 wt.% sugar bar fibres. The corn fibres were more compatible with aluminum powder where it gave the highest friction coefficient and relatively lower wear compared to other composites. Wear resistance of the tested composites containing bunches and aluminum represented the lowest values among composites containing corn and bunches fibres. The lowest wear values were observed for composites containing 25 wt.% corn fibres and 30 wt.% aluminum and composites containing 20–25 wt.% sugar bar fibres.