Comparative performance assessment of cenosphere and barium sulphate based friction composites

Friction composites utilising cenosphere and barium sulphate as major fillers were fabricated both separately and in combination. Thermal analysis revealed initial degradation temperature >500 °C irrespective of the composition. Mechanical properties viz. hardness, compressibility and shear strength were found to be well above the standard values as per the industrial practice. Dynamic mechanical response demonstrated improved storage and loss moduli for barium sulphate based composites. Tribological assessment conforming to the regulation-90 as per the Economic Commission for Europe (ECE) norms revealed improved wear resistance, enhanced recovery, lower disc temperature rise and reduced friction fluctuation for cenospheres based composites. Composites containing both fillers showed cenospheres dominated tribological response. Empirical correlation between wear, friction coefficients and dynamic mechanical properties as temperature controlled parameters was developed to predict wear. Worn surface analysis of the brake pads was carried out by scanning electron microscope (SEM) to visually analyse the associated wear mechanism at the braking interface through various topographical attributes viz. primary and secondary contact plateaus.