Rust preventive composition

摘要

Disclosed is a rust-preventive composition comprising (A) an aromatic compound i) containing a group selected from the group consisting of an -N=N- group, a >C=N- group, a >C=O group and an -N=O group and ii) having an absorption band in a visible region of from 530 nm to 750 nm; (B) a colloidal silica; (C) a film-forming polymeric compound containing in one molecule a group selected from the group consisting of an -OH group and a -COOH group; and (D) an organic solvent. This composition, having been coated on metal surfaces, provides a sufficient corrosion resistance without making any chromating treatment.