Chromium-free rust inhibitive treatment method for metal products having zinc surface and metal surface treated thereby

• Main Authors: TAKASE, KENGO, ENDO, YASUHIKO, ADACHI, SHOICHIRO, WATANABE, SHUNJIRO
• Format: Patent
• Language: English; French; German
• Published: 17.12.2014
• Subjects: ADHESIVES; CHEMICAL PAINT OR INK REMOVERS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING COMPOSITIONS, e.g. PAINTS, VARNISHES ORLACQUERS; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; CORRECTING FLUIDS; DIFFUSION TREATMENT OF METALLIC MATERIAL; DYES; FILLING PASTES; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; INKS; METALLURGY; MISCELLANEOUS APPLICATIONS OF MATERIALS; MISCELLANEOUS COMPOSITIONS; NATURAL RESINS; PAINTS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; POLISHES; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; USE OF MATERIALS THEREFOR; WOODSTAINS

Provided is a chromium-free surface treatment method which imparts practical rust inhibitive performance to a metal product having a zinc surface to which it was difficult to impart rust inhibitive performance of practical level. A conversion-coated film of zinc phosphate etc. is formed on the zinc surface of the metal product as pretreatment, and the silica-based film is formed by applying a chromium-free surface treatment agent which uses alcohol or mixture of water and alcohol as a solvent to the conversion-coated film. As a result, when an aqueous surface treatment agent containing alcohol is applied, it is possible to suppress the formation of white rusting for 72 hours or longer in the salt spray test.