Novel copper-impregnated carbon strip for sliding contact materials

Highlights: • The obtention of C/C-Cu by pressureless infiltration technique was described. • The final contact angle decreased because of TiC particles. • The microstructure of C/C–Cu was beneficial for electronic and stress conduction. • The C/C–Cu exhibited high mechanical properties due to the "network conduction". • The C/C–Cu can be appropriately applied to railway current collectors. A carbon/carbon (C/C)–Cu composite reinforced by novel carbon fiber 2.5D-braided preforms was fabricated through pressureless infiltration technique (PLI). The microstructure of the developed composite was characterized by scanning electron microscopy, X-ray diffraction, and energy dispersive spectroscopy. The mechanical, tribological, and electrical properties of the C/C–Cu composite were compared with those of a C/C composite and a carbon/copper (C/Cu) contact strip material. Results showed that the proposed composite formed an excellent network conduction structure. Moreover, the composite exhibited a high flexural strength of 215 MPa, excellent compression strength of 324 MPa, and a particularly low electrical resistivity of 0.63 μΩm, validating its advantages over the C/Cu composite strip in terms of mechanical and electrical properties. The component phases (TiC) of the C/C–Cu composite formed an excellent interconnected structure, which stiffened the interface between the Cu alloy and the pyrocarbon matrix and resulted in excellent mechanical and electrical properties. The friction coefficients of the C/C, C/C–Cu, and C/Cu composites were 0.152, 0.169, and 0.062, respectively. The C/Cu composite exhibited the worst mechanical and electrical performance despite achieving the lowest friction coefficient. Thus, the C/C–Cu composite is a promising new type of sliding electrical contact material.