Effect of SiC volume fraction and size on dry sliding wear of Fe/SiC/graphite hybrid composites for high sliding speed applications

In this work we investigated the friction and wear properties of Fe/SiC/graphite hybrid composites using a sub-scale dynamometer disk brake testing system. Two particle size ranges (1-30μm and 150-180μm) and three particle volume fractions (10%, 15% and 20%) of SiC were considered. The sliding speed conditions considered in this study (25-35 m/s) were comparable to that experienced by brake materials in high speed braking applications in aircrafts, race car and high speed trains. We examined the effect of coating the SiC particles with BaSO4 to improve interfacial properties and prevent potential undesirable interfacial reactions. The wear loss was found to decrease with increasing volume fraction of SiC for all particulate sizes. At low sliding speeds the composites with large particle sizes and high volume fractions were found to be more effective in controlling wear. On the other hand, at higher sliding speeds the high volume fraction composites were found to be more effective in controlling wear for all particle sizes. This is attributed to a transition in the wear mechanism at higher sliding speeds.