Friction of a C/SiC composite bearing in air and in combustion environments

A bearing used for the load-carrying hinge was manufactured based on a carbon fiber-reinforced silicon carbide matrix (C/SiC) composite with a SiC coating. Chemical vapor infiltration was applied in the process of the composites. Experiments were conducted by an experimental simulation method that would facilitate testing under coupling stress in air and in combustion environments. Modeling analysis deduced the relationship of applied load, normal contact force, and friction force in the hinge bearing. Friction behavior was comparatively investigated up to 10kN at room temperature in air and at 1800°C in combustion environments. Worn surfaces were observed by scanning electron microscopy, and surface roughness was measured by atomic force microscopy. Reliable thermal load-carrying ability and stable friction performance of the hinge bearing are demonstrated under this testing framework. The oxide products in the combustion environment play an important role in reducing friction by providing a reaction layer to moderate the contact stresses.