A liquid concentrate for the preparation of the chromating bath with low content of six-valence chromium suitable for the passivation of zinc electroplated coatings deposited from weak acid, alkaline non-cyanide and alkaline cyanide-based baths. The bath creates a yellow and iridescent surface layer which will increase the overall corrosion durability of zinc coatings and is able to run within broad operation times. The chromate coating itself is much less liable to colour change at the transfer time between the chromating and the following operation and, therefore, is convenient for both automatic as well as hand-operated plating lines.
It is a liquid concentrate for the preparation of chromating baths with low content of six-valence chromium. The bath is convenient for the passivation of both zinc galvanized as well as zinc plated coatings deposited from weak acid, alkaline non-cyanide and alkaline cyanide baths. After the application on the zinc galvanized coating, a semi-bright yellow to yellow-brown layer, predominantly suitable to enhance corrosion durability and adhesion of following paints or powder coatings, will be created. If applied, on the other hand, on bright zinc electroplating coatings, a bright yellow iridescent layer appears on the surface to boost corrosion durability and improve appearance. After its drying out and ageing (within about 24 hours) the chromate will get hard without liability to touch and wear.