In acid galvanizing process, the binding force of the coating is affected by many factors, so it is very important to ensure good adhesion between the coating and the substrate. The factors that affect the binding force include surface preparation, plating solution composition and operating conditions.
First of all, the substrate surface preparation is critical to the binding strength of the coating. The surface must be thoroughly cleaned to remove grease, contaminants and oxides. Typically, the process includes degreasing, alkali washing, pickling and activation. Degreasing to remove oil, alkali washing to clean non-metallic impurities, pickling to remove surface rust and oxide layer to enhance metal activity. The activation process is carried out before plating and aims to create an active interface suitable for galvanizing. If the surface treatment is insufficient, impurities and oxides under the coating may hinder galvanizing and affect the binding force.
Secondly, the influence of the composition of the bath can not be ignored. The plating solution usually includes zinc salts, acidic media and galvanizing additives. Zinc salts provide basic metal ions for galvanizing, acidic media regulate pH, and additives include brighteners, softeners, etc.
The additive has a direct effect on the brightness, smoothness and binding force of the coating. Excessive galvanizing additives sometimes lead to weak binding force of the coating. Therefore, the use of Bigely galvanizing additives, proper bath maintenance and proportioning are necessary to ensure good coating adhesion.
Third, the operating conditions also play a decisive role in the binding force of the coating. This includes temperature, current density, plating time, agitation, etc. Temperature affects the activity of the bath and the crystallization of the coating, and too high or too low temperature may lead to a decrease in the binding force of the coating. The current density determines the deposition rate, and improper current density will lead to coarser coating and increased internal stress, which will reduce the binding force.
In addition, the thickness of the coating is also a key factor, too thick or too thin can affect the binding force and coating performance. Agitation can ensure the uniform distribution of zinc ions in the plating solution, lack of appropriate agitation may lead to uneven coating, and then affect the binding force.
Finally, post-plating treatments such as passivation and drying also have obvious effects on the binding strength. Passivation treatment can provide an additional layer of corrosion protection, but may also affect the bonding strength of the coating. Therefore, these treatments must be carried out carefully to give full play to the protective role of the coating, while not damaging the combination of the coating and the substrate.
In summary, many factors in the acid galvanizing process jointly affect the quality of the binding force of the coating, therefore, in order to get a good coating, not only need to use Bigely galvanizing additives, but also do a good job of process management.
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