Metallic substrate with a ceramic coating obtained by plasma electrolytic oxidation, resistant to degradation by tribocorrosion of light metals and their alloys, in a liquid and/or semi-solid state with a thickness from 10 to 300 µm and resistant to immersion in said light metals and their alloys without compositional modification of the substrate. Method for obtaining a metallic substrate with a ceramic coating by plasma electrolytic oxidation in which said substrate comprises a core and an outer layer of a metal different from that of the core or of an intermetallic compound, said outer layer being obtained by thermal spraying, laser, solid or liquid diffusion, hot galvanising or cementing. This allows obtaining a ceramic coating applicable to any metallic substrate and resistant to degradation by tribocorrosion.