HIGHLY CORROSION-RESISTANT GALVANIZED STEEL SHEET AND ITS PRODUCTION

• Main Authors: NAKAJIMA SEIJI, GOMI SHUJI, NAKAKOUJI NAOMASA, MORITO NOBUYUKI
• Format: Patent
• Language: English
• Published: 24.08.1993
• Subjects: 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 MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION

PURPOSE:To improve the plating adhesion and corrosion resistance by treating a galvanized steel sheet with a soln. contg. a magnesium alkoxide to form a magnesium oxide coating film. CONSTITUTION:A soln. contg. a magnesium alkoxide is applied on a galvanized steel sheet and heat-treated to form a magnesium oxide coating film of 0.1-10.0g/m . Besides, >=1 kind among water, oxygen, oxide ion and hydroxide ion is incorporated into a molten salt bath consisting essentially of a magnesium salt, and a galvanized steel sheet is dipped in the bath to form a magnesium oxide coating film on the surface. Alternately, the galvanized steel sheet is cathodized in a molten salt bath consisting essentially of a magnesium salt and contg. >=1 kind among water, oxygen, oxide ion and hydroxide ion to form a magnesium oxide coating film on the surface.