Integration of CMC Brake Disks in Automotive Brake Systems

Since the introduction of the Porsche Ceramic Composite Brake (PCCB) in the Porsche 911 GT2 in 2001, ceramic brake systems provide an exceptional braking power not only in Porsche vehicles but also in high performance cars of other Original Equipment Manufacturers. The ceramic brake disks of these high performance brake systems are based on a special carbon short fibre-reinforced composite material, which is, after the manufacturing of the green body and the pyrolysis, exposed to liquid silicon in a high-temperature vacuum process at approx. 1700°C. The results of this in situ reaction of silicon and carbon to silicon carbide are brake disks, which are significantly lighter, compared to conventional brake disks out of gray cast iron. These brake disks offer higher strength, higher thermal stability and thus lower wear such as higher fading stability. This article discusses on the one hand the advantages of this lightweight brake system and on the other hand essential aspects concerning the integration of ceramic composite brake disks, resulting from vehicle-specific requirements, into the chassis. Furthermore, selected relationships between brake disk design, the manufacturing, the material composition, the assembly and the resulting component properties are explained.