Electrochemical Corrosion Behavior and the Related Mechanism of TiSiC/Cu Composites in a Strong Acid Environment.

The electrochemical corrosion behaviors of TiSiC/Cu composites in harsh media including dilute HNO and concentrated HSO were studied in detail and the related corrosion mechanisms were explored. Under open-circuit potential, the corrosion resistance of TiSiC/Cu in dilute HNO was worse than that in concentrated HSO. In dilute HNO, TiSiC/Cu exhibited a typical passivation character with a narrow passivation interval. During the corrosion process, the dissolution of Cu-Si compounds resulted in the destruction of the passivation layer on the surface. Additionally, with the increasing of the potentials, the oxidation of Cu and Si atoms led to the generation of the oxide film again on the surface. In concentrated HSO, the TiSiC/Cu composite was covered by a double-layered passivation layer, which was composed of an internal layer of TiO and an external layer of CuO and SiO. This was because Cu diffused into the surface and was oxidized into CuO, which formed a denser oxidized film with SiO. In addition, it was found that TiSiC/Cu has better corrosion resistance in concentrated HSO.