The mechanical properties of carbonized coconut char powder-based friction materials

Carbonized coconut char powder-based friction materials for automotive brakes were produced using hot isostatic pressing machine at 190 °C for 3 h. The amounts of coconut char and magnesium oxide powders used in the mixing were optimized while fixing the compositions of other ingredients (styrene butadiene rubber, stearic acid, sulphur, zinc oxide, bakelite, calcium carbonate, brass, bronze and stainless steel), and effects on microstructure, surface roughness, hardness, wear resistance, and tensile strength were investigated. The powders were used as substitutes for graphite or coal powders. The amount of char used varied between 7–14% of total volume and its chemical analysis was determined using energy dispersive X-ray spectroscopy. The surface roughness, Rockwell hardness number, maximum tensile strength, and specific wear resistance of the materials fabricated are in the range of 1.98–5.16 μm, 34.67–76.06, 0.63–1.67 MPa and 4.13exp−14 to 10.27exp−14 m2/N, respectively.