The Role of Atomic Structures on the Oxygen Corrosion of Polycrystalline Copper Surface

AbstractThe mechanical property of materials for pressure vessel, like steel, Ti, Cu and their alloys always turns out to be poor in the severely corrosive environment. The knowledge of oxygen corrosion on metal surface at atomic level is still lack. Using reactive molecular dynamic simulation, the oxygen corrosion behavior on polycrystalline copper is studied at the early stage of oxidation. Results indicate a higher reactivity at the grain boundary. The preferential dissociation of oxygen molecules at grain boundary is ascribed to the diffusion-related trapping effect and dissociation barriers. In addition, the difference of oxygen corrosion between grain boundary and grain on copper surface is elucidated in terms of the atomic-structure-related radial distribution functions. This study directly shows us the origin of intergranular oxygen corrosion and provides us useful information for the corrosion prevention, especially in the situation that the atomic structure changes under the thermal or mechanical loadings