CMC Material Optimization for Aircraft Brake Application

Carbon-carbon (C-C) composites are the state-of-the-art friction material for aircraft brakes. Generally speaking, C-C brake offers low wear and provides excellent frictional performance at high energy conditions such as rejected take off (RTO). However, C-C begins to oxidize at 800 F. C-C brake also yields lower frictional coefficient and tends to vary widely under different environment and landing energy conditions. Ceramic matrix composites (CMC) offer an alternative to C-C composites. In specific, C-SiC has been demonstrated as a possible next-generation brake material. Although the brake performance data of C-SiC are very limited and often kept proprietary, there are enough evidences indicating C-SiC brake may ameliorate many deficiencies associated with their C-C counterpart providing reduced wear rate, higher frictional coefficients, and improved volumetric heat capacity. Under the Phase I effort, full-size CMC brakes along with C-C baselines have been formulated, fabricated and are ready for dynamometer testing. Test results will be compared and performance deficiencies will be identified along with possible. Under the proposed Phase II effort, we plan to conduct two complete development iterations including re-formulation, fabrication of new CMC materials and dynamometer testing to further optimize the material system for selected applications.