Citation: BIAN, G. and WU, H., 2015 AbstractWe have examined friction performance, friction surface structure and chemistry of a carbon/silicon carbide ceramic brake disc tested against an organic pad in air, and water sprayenvironment. An average friction coefficient of 0.52 and 0.4 for a braking stop is achieved after bedding in air for a composite disc comprising 53.1% and 17.7% SiC/Si, respectively. It is identified that 100% SiC/Si and ~50% C f /C regions contribute the friction measurement.Tested in water spray, both brakes show a substantial fall of friction coefficient to a level <0.1.Evidences are provided for the existence of hydrodynamic friction. Friction transfer materials removal, SiC region polishing, and lower real contact pressure reinforce hydrodynamic process that a ceramic composite brake can experience.

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Citation: BIAN, G. and WU, H., 2016. Friction surface structure of a Cf/CSiC composite brake disc after bedding testing on a full-scale dynamometer. AbstractWe have examined friction surface structure of a carbon ceramic brake disc tested on a full-scale dynamometer with microscopy techniques. The bedded friction surface is composed of two types of regions: transferred materials (TM) and SiC. The TM regions were formed through the deposition of wear debris into surface voids, followed by compaction and crystallite refinement during braking. A thin friction layer (FL) was developed on top of TM and SiC regions with nano-sized copper/iron oxide crystallites as the primary constituent.Analysis shows that debris generated from pad is the main source of TM and FL. No evidence shows chemical diffusion bonding between TM and composite constituent. On silicon carbide surface, dislocations were activated as the sources of surface fracture.

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