AQUEOUS SOLUTION AND METHOD FOR THE FORMATION OF A PASSIVATION LAYER

• Main Authors: ZONE, KEITH RICHARD, VAN SCHAIK, RENE
• Format: Patent
• Language: English; French
• Published: 30.08.2012
• Subjects: APPARATUS THEREFOR; APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TO SURFACES, IN GENERAL; 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; ELECTROFORMING; ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; METALLURGY; PERFORMING OPERATIONS; PROCESSES FOR APPLYING LIQUIDS OR OTHER FLUENT MATERIALS TOSURFACES, IN GENERAL; PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTIONOF COATINGS; SPRAYING OR ATOMISING IN GENERAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION; TECHNICAL SUBJECTS COVERED BY FORMER USPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS; TRANSPORTING

The present invention generally relates to an aqueous solution for the formation of a passivation layer on a zinc layer or zinc-alloy layer. More particularly, the invention relates to the formation of a black passivation layer on a zinc layer or zinc-alloy layer, which passivation layer is substantially free of hexavalent chromium. Furthermore, the present invention relates to method for the formation of a passivation layer on a zinc layer or zinc-alloy layer, as well as a passivation layer on a zinc layer or zinc-alloy layer itself. The solution used contains trivalent chromium ions, nitrate ions, an organic acid and a dithioglycolate. La présente invention concerne de manière générale une solution aqueuse qui permet de former une couche de passivation sur une couche de zinc ou sur une couche d'alliage de zinc. Plus particulièrement, l'invention concerne la formation d'une couche de passivation noire sur une couche de zinc ou sur une couche d'alliage de zinc, ladite couche de passivation étant sensiblement exempte de chrome hexavalent. De plus, la présente invention concerne un procédé de formation d'une couche de passivation sur une couche de zinc ou sur une couche d'alliage de zinc, ainsi qu'une couche de passivation sur une couche de zinc ou sur une couche d'alliage de zinc elle-même. La solution utilisée contient des ions chrome trivalents, des ions nitrate, un acide organique et un dithioglycolate.