A customer inquired that the blue white passivation of their own alkaline zinc workpieces is always prone to yellowing, but the passivation solution has been adjusted several times without solving this problem. In fact, this is related to the use of alkaline zinc plating brighteners.
Based on on-site experience and analysis of the characteristics of the alkaline zinc plating brightener BZ-515, Bigley Technology found that selecting an inappropriate alkaline zinc brightener can lead to yellowing of the zinc plating layer after blue white passivation. There are three main situations:
1. The current range of the brightener is narrow. Some brighteners on the market are prone to yellowing in the high current area of workpieces due to issues such as narrow current range, uneven thickness in the high and low areas of the coating, and high brittleness of the coating during production. Therefore, we should choose an alkaline zinc brightener with a wide current range, such as this BZ-515, which can obtain a uniform zinc coating in the range of 0.5-4.0A/dm2.
2. The brightness of the brightener is poor. There are some brighteners on the market, although the brittleness of the coating is low and the uniform plating ability is good, the brightness of the coating is poor. After the workpiece coating is passivated with blue and white, it cannot obtain a clear appearance and is prone to yellowing. Therefore, we should choose alkaline zinc brighteners with good brightness such as BZ-515.
3. The deep plating ability of brighteners is poor. Some brighteners on the market are prone to yellowing after blue white passivation due to poor deep plating ability and thin coating in the low current area of the workpiece. Therefore, we should choose alkaline zinc brighteners with good deep plating ability such as BZ-515.
So, choosing a suitable alkaline zinc plating brightener can effectively prevent yellowing of the workpiece coating after blue white passivation, and reduce the occurrence of faults. If you are interested in alkaline zinc plating brightener, please contact Bigley customer service for free samples and detailed technical information!
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