| 摘要 |
The present invention relates to a method for at least partly coating an electrically conductive substrate with an electrocoat material, comprising at least contacting the substrate with an aqueous coating composition (A) as step (1), which is carried out in at least two successive stages (1a) and (1b), i.e., first at an applied voltage in a range from 1 to 50 V (1a), which is applied over a duration of at least 5 seconds, and then in a range from 50 to 400 V (1b), the voltage applied in (1b) being greater by at least 10 V than the voltage applied in (1a), with (A) comprising at least one cathodically depositable binder (A1), at least one organic monocarboxylic or polycarboxylic acid which has no nitrogen atom(s), and/or anions thereof (A3) and trivalent bismuth (A4), with (A3) and (A4) each being present in (A) in an amount such that their stoichiometry to one another allows at least 50 mol % of (A4) to be present in the form of a salt and/or complex of components (A3) and (A4), with the molar fractions of any zirconium ions and aminopolycarboxylic acids present in (A) to be lower by a factor in each case of 100 or of 15, respectively, than the molar fraction of (A4) present in (A); to a use of (A) for at least partly coating the substrate with an electrocoat material; to at least partly coated electrically conductive substrates obtainable by the method; and to articles or components produced from such substrates. |
