Reduction or elimination of film defects due to hydrogen evolution during cathodic electrodeposition

摘要

This invention is directed to a method for eliminating or reducing pinhole defects in cataphoretically deposited films without interfering with the electrolysis of water needed for electrodeposition. The method comprises decreasing the evolution of hydrogen gas at the cathode by adding, to the electrodepositable composition, a compound which is reduced by the hydrogen produced at the cathode during the electrodeposition. The hydrogen reacts with this non-gaseous compound rather than becoming hydrogen gas and forming bubbles which lead to pinhole defects.