Influence of calcium sulfate whiskers on the tribological characteristics of automotive brake friction materials

Abstract Functional fillers enhance the frictional performances of automotive brake friction materials (BFM). The influence of Calcium sulfate whiskers (CaSO 4 ) in BFM’s and its effect as a functional filler on the tribological performances were investigated. Four compositions containing all essential ingredients of BFMs were developed, varying the amount of CaSO 4 whiskers (5%, 10% and 15%) and one composition without CaSO 4 whiskers. The tribological studies were carried out on an inertia brake dynamometer as per JASO C 406 standard. Addition of CaSO 4 whiskers was found to improve the mechanical properties of BFM composites. The inclusion of CaSO 4 whiskers enhanced the frictional performance during fade. Surface analysis of the worn pads was carried out to understand the wear mechanism using scanning electron microscope. The friction materials with the inclusion of calcium sulfate whiskers experienced lesser wear. The composite with 10 wt% of CaSO 4 whiskers exhibited the most stable friction coefficient even at high sliding speeds.