Frictional properties of C/SiC brake materials

The 3D needle-punched carbon/silicon carbide (C/SiC) brake materials were prepared by chemical vapor infiltration combined with liquid melt infiltration. The structural characteristics of C/SiC brake materials were studied by means of optical microscopy, SEM, XRD, and their frictional properties and wear mechanisms for a full-size aircraft wheel and brake assembly were measured on an electrical simulation dynamometer. The results indicate that the brake materials are composed of 35%-65% C, 25%-55% SiC, and -10% Si. SiC and Si are mostly distributed in the short fiber web layers. Under the same brake pressure, the average friction coefficient increases to the maximum value when braking speed is 150 km/h and then decreases with the increase of initial braking speed. The friction coefficient decreases with the increase of braking pressure at the same initial brake speed. The average wear rate is about 1.0 × 10-3 mm/(side&middottime). The relationship between brake moment and brake speed under normal landing condition matches the landing response of aircraft with anti-skid braking system, which would lead to higher brake efficiency.