Industry news

5 reasons for black spots on workpiece coatings during production using acid zinc plating additives

2022-05-10

    In the production process of using acid zinc plating additives, sometimes small black spots appear on the galvanized layer of the workpiece. What is the reason?

    Bigolly Technology made an analysis based on the field experience and the characteristics of the product acid zinc plating additives BZ-528,There are 5 main reasons:

    1. The workpiece has been pickled for too long or the pickling solution has not been added with a corrosion inhibitor, and the surface has been corroded, resulting in black corrosion spots on the surface of the galvanized layer.

    2. The workpiece is not washed with clean water after pickling, and the residual acid on the surface corrodes the workpiece, resulting in corrosion spots on the surface of the galvanized layer.


    3. In the process of electrogalvanizing, the current density is low, and the galvanized layer is mixed with solid particles to form small black spots.During production, the current density should be appropriately adjusted to within the process range.

    4. The galvanized layer of the workpiece is leak-plated.The workpiece is leak-plated, so that the iron ions penetrate out and become black, which shows the color of the iron substrate.

    5. The performance of the acid zinc plating additive used is too poor.Inferior zinc plating additives will produce more by-products during use, which will affect the quality of the galvanized layer.Therefore, we should choose additives from big brands (such as Bigolly's BZ-528), with stable product quality and less failure rate.

    Therefore, we need to pay attention to these 5 points in the production process of using acid zinc plating additive, which can effectively avoid the phenomenon of black spots on the galvanized layer and reduce the occurrence of failures.If you are interested in acid zinc plating additive, please contact Bigolly customer service, you can get free samples and detailed technical information! 

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