In the production process of using chloride zinc galvanizing brightener, we sometimes find that the plating solution contains nitrate impurities. What effect does it have on the plating solution?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product chloride zinc galvanizing brightener BZ-528,The main ways to generate nitrate impurities in the plating solution are:The cleaning before galvanizing and the cleaning after dilute nitric acid after galvanizing share the same cleaning tank;Passivation after galvanizing and galvanizing share hangers or rollers, resulting in the residual passivation solution not being cleaned;Before galvanizing, it contains nitric acid pickling without a good exhaust device, and nitrogen oxide gas drifts into the plating solution;Misuse of nitric acid to lower the pH of the acid zinc bath.
Due to the strong oxidizing properties of nitrate, it will oxidize and destroy some components of chloride zinc galvanizing brightener, especially the main brightener o-chlorobenzaldehyde. This will increase the amount of chloride zinc additive and accelerate the accumulation of organic impurities.
A small amount of nitrate can greatly reduce the deep plating ability of the acid zinc plating solution, so that the plating layer in the low current density area is leaked or very thin (especially barrel plating). In this way, the corrosion resistance of the coating in the low current density area will be greatly reduced.
When the nitrate content in the plating solution is too large, the coating in the high current density area will be roughened, so the nitrate content in the plating solution should be controlled within 0.5g/L.
Therefore, in the production process of using chloride zinc galvanizing brightener, the influence of nitrate impurities on the plating solution is very large, so we need to pay attention.If you are interested in chloride zinc galvanizing brightener, please contact Bigolly customer service, you can get free samples and detailed technical information!