Alkaline cyanide-free galvanizing process requires the use of a variety of additives in the production process, the common alkaline cyanide-free galvanizing additives are brightener, carrier brightener, auxiliary brightener, wetting agent and degaussing agent, etc., which can work at the same time, but also can work separately.
Brighteners, also known as main brighteners, do not significantly increase cathodic polarization and must be used in conjunction with carrier brighteners to obtain a bright coating. Brighteners have a greater impact on the physical properties of the coating, and adding more can cause the galvanized layer to blister and increase the brittleness of the coating.
Carrier brightener is also called grain refiner, it has strong adsorption ability on the surface of the substrate, which can increase the cathodic polarization, so as to get the zinc layer electrodeposited with detailed crystals. When the carrier brightener is added alone, the layer is not bright enough and the current density range is narrow, so the main brightener must be used at the same time to make the layer bright.
The auxiliary brightener can enhance the polarization in the low current density area and expand the density range of the bright current, so as to make the galvanized layer fully bright and improve the dispersing ability and covering ability of alkaline zinc plating solution.
The degaussing agent removes the influence of trace metal impurities in the preparation water or raw materials, and promotes a bright and clear galvanized layer without fogging, while suppressing the phenomenon of brittle cracking caused by too much brightener.
These are the types of common alkaline cyanide-free galvanizing additives and their role in the plating solution.
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