Abstract: A liquid coating material curable with actinic radiation, substantially or entirely free from organic solvents and comprising (A) at least two compounds of the general formula I: X—O—Y(—OH)-Z-Gr, ??(I) in which the variables have the following definitions: X is aromatic radical having 6 to 14 carbon atoms, heterocyclic aromatic radical having 5 to 20 ring atoms or alkyl radical having 6 to 30 carbon atoms, Y is trivalent organic radical, Z is linking functional group, and Gr is organic radical having at least one group which can be activated with actinic radiation; with the proviso that at least one of the at least two compounds (A) contains an aromatic or heterocyclic aromatic radical X (=compound A1) and at least one of the at least two compounds (A) contains an alkyl radical X (=compound A2); (B) at least one acidic, corrosion-inhibiting pigment based on polyphosphoric acid, and (C) at least one constituent selected from the group consisting of nanoparticles and electrically conductive pigments