A full size carbon ceramic composite brake disc for a car was tested on a full-scale dynamometer by following the AK Master guideline, and microstructural investigation shows the friction surface composition is different from that of a small disc tested on laboratory-scale dynamometer.

The friction surface after bedding is composed of transferred materials (TM) and silicon carbide (SiC), but no carbon and silicon constituent observed.

Transferred materials are compacted densely and subjected to crystallite refinement. No evidence to show that transferred materials have chemical bonding with carbon ceramic composite.

A thin friction layer (FL), composed of nano-sized Fe/Cu oxide crystallites, is developed on top of TM and SiC regions with good coherency.

Debris generated from the pad should be the main source of TM and FL, hence organic pad chemical formulation is essential for friction surface development of a carbon ceramic disc.