Full-ceramic brake systems for high performance friction applications

Ceramic matrix composites (CMC) are promising materials for friction applications. Typically, C/SiC rotors are combined with organic pads (Low Met). Within this work, two types of CMC brake pads were studied, C/SiC SF as well as C/SiC SF 11Coke with 11 vol.% coke as filler, accompanied with the Low Met reference pads. Small brake pads (400 mm2) were applied on a lab-scale and larger pads (12,000 mm2) on a full-scale inertia dynamometer. In both cases, the corresponding rotor was a C/SiC disc with a SiC-rich friction layer. Sliding speeds up to 42.6 m/s and braking pressures up to 8 MPa were applied. The smaller CMC pads show lower wear and higher coefficient of frictions (COF), compared to the reference. This frictional behavior was confirmed on the full-scale dynamometer with mean COFs up to 0.45. However, the wear of the large C/SiC pads was somewhat higher on the full-scale dynamometer.