This article answers questions raised by industry professionals regarding mold growth on electroplated parts, for your consideration.

1. Is mold growth on electroplated parts a form of corrosion, and is it related to CASS performance?

Answer: Relevant literature indicates that mold growth on electroplated parts is related to plating thickness, potential difference, and the number of micropores. They believe that improving the corrosion resistance of the plating layer can, to some extent, prevent mold growth. We tested the same workpiece, performing a 48-hour CASS test and a mold test separately. Mold appeared on the workpiece after a few days, but the CASS test was qualified/passed, indicating that this mold growth is not directly related to CASS. As mentioned earlier, besides being related to the corrosion resistance of the plating layer, mold growth mainly occurs after electroplating and is more related to post-plating treatment methods, seasonality, and regional temperature conditions.

2. Is mold growth on electroplated parts related to excessive layers of nickel brightener?

Answer: There is no direct connection. Excessive brightener application in multi-layer nickel plating may lead to a decrease in CASS performance, but as mentioned earlier, this is not directly related to CASS performance.

Mold growth on electroplated parts is more common in summer and less common in winter; moreover, mold is more prevalent in the south and extremely rare in the north. Does this mean electroplating technicians prefer to add more brightener in summer, or that southern electroplating technicians prefer to add brightener while northern technicians do not? Logically, this doesn't make sense.

3. Is mold growth on electroplated parts related to the agglomeration of nickel seal particles?

Answer: A Japanese customer suspected that agglomeration of nickel seal particles increased mold growth on electroplated parts. We tried extensively treating the nickel seal and then re-adding the nickel seal particles, and tested the products. We found that mold growth did not improve. Agglomeration of nickel seal particles reduces the number of micropores in the nickel seal, thus decreasing CASS salt spray performance. However, the actual result showed that CASS performance was not affected, confirming that this is unrelated.

4. In conclusion, mold growth on electroplated parts is mainly related to the washing, baking, storage, and transportation conditions after chrome plating. Addressing these aspects can completely solve the mold problem.

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