INFLUENCE OF MOLYBDENUM DISULFIDE PARTICLE SIZE ON FRICTION AND WEAR CHARACTERISTICS OF NON-ASBESTOS-BASED COPPER-FREE BRAKE FRICTION COMPOSITES

Molybdenum disulfide is a successful solid lubricant because of its cleavage of the basal plane at the time of sliding, which helps to retain the lubrication nature in order to reduce wear and to maintain frictional stability. Thus the present study deals with the development of copper-free brake pads using molybdenum disulfide that possesses different grades based on the particle size, namely, technical (coarse), fine and superfine. The brake pads were developed using conventional manufacturing processes and characterized for its physical, chemical, thermal and mechanical properties as per industrial standards. Thermal stability was measured for the varying ingredients and the developed composites using thermogravimetric analyzer instrument. The tribological studies were done using Chase testing following IS2742 Part-4 standards. The results showed that coarse-sized (technical grade) molybdenum disulfide-based brake pads possess better thermal stability with good fade and recovery characteristics in turn leading to less wear when compared with the other two composites. This is because of its better heat dissipation and superior lubricating nature. Scanning electron microscopy and energy dispersive analysis were helpful in studying the wear behavior of the Chase-tested brake friction composite samples.