Common problem

The galvanized layer of the workpiece has pitted small bubbles, is the alkaline galvanized brightener added too much?

2022-06-08

    In the production process of alkaline galvanizing, sometimes there will be pitted bubbles in the galvanized layer of the workpiece, which will seriously affect the appearance of the workpiece and the performance of the coating, and the customer will not accept it.So does this phenomenon mean that the alkaline galvanizing brightener is used too much?

     Bigolly Technology made an analysis based on the field experience and the characteristics of the product's alkaline galvanizing brightener BZ-515,When the alkaline galvanizing brightener is added excessively, the dispersing ability of the plating solution will be reduced. When the amount is seriously excessive, such pitted small bubbles will appear, and the brittleness of the coating is relatively large.But in addition to the factors of excessive brightener, there may be the following three situations:


    1. The workpiece is not clean in the pretreatment.The workpiece is not thoroughly degreasing or washed with water in the pretreatment, and the residual oil on the surface will foam when galvanized due to the poor bonding force of the coating.Therefore, in our galvanizing production process, the workpiece should be clean before galvanizing, so as to obtain a galvanized layer with good bonding force.

    2. During the galvanizing process, the temperature of the bath is low and the current density is relatively high.In the galvanizing process, the temperature of the bath is low, the conductivity of the bath is poor, and the adsorption capacity of the brightener is relatively poor.If the current density is large, the corners of the workpiece are easy to be scorched, and the coating is easy to be mixed with additives, resulting in increased brittleness and bubbling.Therefore, in the production process of galvanizing, we should control the temperature and current density of the electroplating solution.

    3. There are many organic impurities in the plating solution.When there are many organic impurities in the alkali-zinc plating solution due to the introduction of oil stains or the decomposition of brighteners, the brittleness of the galvanized layer will increase, resulting in streaks, blistering, and blooming.Therefore, in the process of galvanizing production, we should regularly use activated carbon to treat the plating solution to reduce the influence of organic impurities in the plating solution.

    Therefore, the appearance of pitted small bubbles in the coating of the alkali zinc workpiece is not necessarily due to the excessive use of the alkaline galvanizing brightener, or it may be an operation problem.If you are interested in alkaline galvanizing brightener,please contact Bigolly customer service, you can get free samples and detailed technical information!   
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