“Cenosphere–Molybdenum Disulfide”–New Filler–Lubricant Combination for Performance Synergism in Composite Friction Materials

Abstract

Short-fiber (e.g., steel wool, rock fibers, and kevlar) reinforced flyash cenosphere–molybdenum disulfide combination-filled phenolic composite materials for friction braking applications were developed and evaluated for their physical (density, void fraction, acetone extraction, and ash content), mechanical (hardness, compressibility, shear strength), and thermal characteristics (thermogravimetric analysis (thermo gravimetric analysis (TGA)/differential thermo gravimetry). Performance correlations between thermomechanical characteristics and friction braking data obtained from Krauss friction testing machine is attempted. The frictional fade (μF) and recovery (μR) behavior vis-a-vis amplitude of friction fluctuations (μmax–μmin) performance were observed to be enhanced due to the incorporation of “cenosphere–molybdenum disulfide” combination. The enhanced wear resistance was attributed to the lower temperature sensitivity of posttemperature degradation kinetics. Analysis of friction and wear data indicated μF and intrinsic material coefficients to be major determinants for μP and wear, respectively. Our study demonstrates the performance synergism due to the incorporation of cenosphere–molybdenum disulfide as the hybrid “filler–lubricant” combination in composite materials for friction braking application.