Atomic oxygen erosion behaviors in graphene/copper composite wires: A multi-scale structural and mechanistic study

High flux and kinetic energy atomic oxygen (AO) in low Earth orbit is one of the key environmental factors leading to the performance degradation of spacecraft copper conductors. In this study, the erosion behavior and micro-mechanisms of graphene (Gr)/Cu wires with different Gr content in simulated AO environment were systematically investigated. By using microscopic analysis techniques, the close correlation between Gr content, accompanying with its refined microstructure, and the oxidation behavior of the wires is revealed. The oxidation process of high-content Gr/Cu wire in AO environment is completely different from the continuous-uniform-thick film oxidation process of low-content Gr/Cu wire, which is a controlled diffusion-nucleation-restricted growth process, eventually almost not leading to the degradation of strength and electrical conductivity. These results demonstrate that the high-content Gr/Cu wire, with densely distributed Gr nanoparticles and refined microstructure, exhibits exceptional AO resistance, and hold great promise for long-life spacecraft and satellite applications.