Carbon Composites for Space Tribology

The intent of this Phase I effort was to examine the feasibility of using C-C composite for possible tribological applications in Space. In the Phase I effort, selected C-C composite materials were modified and tested for both high-speed bearing cage andslip ring/ brush applications under simulated space environments. 2D C-C cage materials were modified to reduce its pore size for lubricant retention. Friction tests revealed comparable frictional coefficient between modified C-C and cotton-phenolicbaseline. 3D C-C was selected for initial brush test based on its isotropic properties. Samples were further metal (silver and copper) impregnated to improve their performances. Frictional coefficient and electrical resistance were measured. C-C basedbrushes exhibited promising results when compared to the performance of Ag-MoS2 baseline.In Phase II, we propose to further optimize C-C based materials for both cage and brush applications. In addition to fine-tune the C-C composite, lubricants will be added to the base composite via filler, coating and material conversion. Prototype cageswill be fabricated and tested for both gyroscope (government) and X-ray Scanner (commercial) applications. Slip Ring brushes will also be fabricated and tested against silver ring using real hardware for both power and signal transmissions.