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The electrochemical corrosion behaviors of Ti₃SiC₂/Cu composites in harsh media including dilute HNO₃ and concentrated H₂SO₄ were studied in detail and the related corrosion mechanisms were explored. Under open-circuit potential, the corrosion resistance of Ti₃SiC₂/Cu in dilute HNO₃ was worse than that in concentrated H₂SO₄. In dilute HNO₃, Ti₃SiC₂/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 H₂SO₄, the Ti₃SiC₂/Cu composite was covered by a double-layered passivation layer, which was composed of an internal layer of TiO₂ and an external layer of Cu₂O and SiO₂. This was because Cu diffused into the surface and was oxidized into Cu₂O, which formed a denser oxidized film with SiO₂. In addition, it was found that Ti₃SiC₂/Cu has better corrosion resistance in concentrated H₂SO₄.