In the acid galvanizing process, the bonding of the coating is affected by a number of factors, and it is critical to ensure good adhesion of the coating to the substrate. Factors affecting adhesion include surface preparation, bath composition and operating conditions.
First, substrate surface preparation is critical to plating bonding. The surface must be thoroughly cleaned to remove grease, contaminants and oxides. Typically, the process includes degreasing, alkaline washing, pickling and activation. Degreasing removes oil and grease, alkaline washing cleans non-metallic contaminants, and pickling removes surface rust and oxidation to enhance metal activity. The activation process is performed prior to plating to create an active interface suitable for galvanizing. Inadequate surface preparation may result in impurities and oxides under the plating layer preventing galvanization and affecting bonding.
Second, the influence of the composition of the plating solution should not be ignored. Plating solution usually includes zinc salt, acidic medium and galvanizing additives. Zinc salt provides basic metal ions for galvanizing, acidic medium regulates pH, and additives include brightening agents, softeners and so on.
Additives have a direct influence on the brightness, smoothness and bonding of the coating. Excessive amounts of galvanizing additives can sometimes lead to a weakening of the bonding force. Therefore, the use of Bigely galvanizing additives, proper maintenance and proportioning of the bath are necessary to ensure a good layer bond.
Third, the operating conditions are equally decisive for the plating bonding. This includes temperature, current density, plating time, stirring and so on. Temperature affects the activity of the plating solution and the crystallization of the plated layer, too high or too low a temperature may lead to a decrease in the bonding strength of the plated layer. Current density determines the deposition rate. Improper current density can lead to roughness and increased internal stresses in the layer, thus reducing the bonding strength.
In addition, the thickness of the plating layer is also a key factor, either too thick or too thin may affect the bonding and plating performance. Stirring ensures uniform distribution of zinc ions in the plating solution. Lack of proper stirring may lead to uneven plating, which in turn affects the bonding.
Finally, post-plating treatments such as passivation and drying also have a significant effect on bonding. Passivation provides an additional layer of corrosion protection, but may also affect the bonding strength of the coating. Therefore, these treatments must be carried out with care in order to fully utilize the protective effect of the coating without compromising the bond between the coating and the substrate.
In summary, several factors in the acid galvanizing process affect the quality of the coating bond, so it is not only the use of Bigely galvanizing additives but also good process management that is required to obtain a good coating.
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