METHOD FOR COATING METALLIC SURFACES FOR PREVENTING PINHOLES ON ZINC-CONTAINING METAL SURFACES

摘要

The invention relates to the use of a silane additive in an aqueous cleaning composition, in an aqueous rinsing liquid or/and in an aqueous activation composition for preventing pinholes on zinc-containing metal surfaces. According to the invention, the silane content in at least one of said aqueous compositions is in the range of 0.001 to 5g/l.