JPH05339745

PURPOSE:To provide a chromating method and a chromating liquid excellent in prevention of yellow powder. CONSTITUTION:A chromating liquid is applied by direct coating on a galvanized sheet having a plating layer containing total <=0.1% of Pb, Sb and Sn. The chromating liquid is prepared by adding...

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Bibliographic Details
Main Authors KANAMARU TATSUYA, ARAI KATSUTOSHI, SAKAKIBARA YOJI, SUZUKI SHINICHI
Format Patent
LanguageEnglish
Published 21.12.1993
Edition5
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
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Summary:PURPOSE:To provide a chromating method and a chromating liquid excellent in prevention of yellow powder. CONSTITUTION:A chromating liquid is applied by direct coating on a galvanized sheet having a plating layer containing total <=0.1% of Pb, Sb and Sn. The chromating liquid is prepared by adding 3-20g/l phosphoric acid, 0.2-3g/l fluorine compd., and 4-180g/l colloidal silica (calcumated as SiO2) to a partilly reduced chromic acid having 2-30g/l Cr concn. and 0.1-0.7 reduction ratio of Cr<3+>/(Cr<3+>+ Cr<6+>). Then the coated sheet is heated and dried to form a achromate film having 5-90mg/m Cr amt. on the surface. This method has such an effect to surely prevent production of yellow powder after chromate treatment.
Bibliography:Application Number: JP19920146079