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Carbon material, because of its high thermal conductivity, ablation resistance and friction resistance, has been widely used in the field of electrical engineering. When confronted strong thermal shock, the interface structure of carbon material would cause thermal shock damage by the rapid temperature difference. In order to systematically and quantificationally study the thermal shock damage of carbon materials, an experimental system that can provide rapid temperature difference was built. The experimental results showed that undergoing a temperature difference of 485 °C, more micro-cracks and holes arose in the pure carbon material, resulting in an increase of porosity by 26.39%, an increase friction coefficient by 48.65%, and a decrease of compressive strength by 23.96%. It was also found the ultrasonic velocity linearly decreased with the increase of porosity and the decrease of the compressive strength caused by thermal shock, which meant the non-destructive ultrasonic testing can be used to conveniently and accurately quantify the thermal shock damage. This conclusion also applies when testing copper-impregnated carbon material, making it a potential method to be used in the maintenance of pantograph which can effectively avoid in rail transit accidents.

Carbon/Copper (C/Cu) composites have been widely used in aerospace, transportation and military products because of their excellent properties of mechanical strength, self-lubrication and electrical conductivities. One of the challenges in preparing C/Cu composites materials is how to overcome the poor wettability between Cu and carbon. In this study, ultrafine iron oxide (Fe2O3), as a precursor, was introduced into the carbon matrix to improve the C/Cu interfacial bonding of C/Cu composites prepared by pressure infiltration. The effect of Fe on the phase composition, microstructure and properties of C/Cu composites were systematically evaluated. The results revealed that the interfacial bonding between Cu and carbon was enhanced by the “bridge architecture” of iron carbide (Fe3C). The wettability between Cu and carbon improved for the contact angle decreased from 124° to 38°. Compared with the unmodified composites, the composites doping 5 wt% Fe2O3 exhibited best performance. The compression and flexural strength increased by 37.4% and 120.4% respectively. Meanwhile, the electrical conductivity improved by 283.7%. It was concluded that the Fe3C layer had an important effect on the electron transport and crack propagation of the C/Cu composites.