Ceramic Piston for Hydraulic Brakes: Design Study

A design study for ceramic pistons was undertaken in order to address the overheating problems associated with the caliper during aggressive braking using modern C/C-SiC brake discs. The reasoning behind the piston design and the choice of the shaping technology are explained. Zirconia-toughened mullite (ZTM) ceramic was chosen for the pistons, because this material exhibits a low thermal conductivity, sufficiently high mechanical strength and fracture toughness, as well as very good thermal-shock resistance. The manufacturing technology of experimental ceramic brake pistons involved compounding of the selected starting powders to form a high-solids-loadingcontaining feedstock, tooling, shaping of green parts by low-pressure injection molding, extraction of the organic binder, pressure-less sintering in air and final machining. Prototypes brake pistons were fabricated and successfully tested as components of motorcycle brake systems in a test laboratory and on a motorcycle racing track.