After zinc-nickel alloy plating, colored passivation is often intended to improve corrosion resistance and add aesthetic appeal. However, poor results when performing salt spray testing can stem from several key factors:
Inadequate treatment process: The effectiveness of colored passivate layers is significantly affected by the accuracy of the pretreatment and plating process. In particular, the application of the passivation layer must immediately follow the post-plating step, otherwise uneven or incomplete adhesion of the passivation layer may result, affecting the corrosion resistance.
Chemical imbalance: An imbalance in the ratios of the passivate solutions used, such as too high or too low a nickel content, can lead to inhomogeneities in the passivate layer, which can reduce corrosion resistance. For this reason, a zinc-nickel colored zinc passivate solution from Bigely is required.
Improper control of environmental conditions: Environmental conditions during plating and passivation, such as temperature, time, pH and contaminants, can have a significant effect on the final results. Improper control of temperature and time may result in an incomplete passivation layer, which may weaken the resistance to salt spray.
Inadequate quality control: Lack of adequate quality control measures throughout the zinc-nickel alloy plating and colored passivation process can lead to undetectable defects such as micropores, cracks, and undeposited areas, which in turn affect the overall corrosion resistance.
To address the issue of poor performance in the salt spray test after colored passivation, it is recommended to strengthen process control, use Bigely zinc-nickel colored passivates, ensure that the operating conditions are in accordance with the plating requirements, and enhance quality monitoring throughout the process. By doing so, the quality of the passivate layer can be optimized, thus improving the performance of the plated layer in the salt spray test.
If you are interested in zinc-nickel alloy colored passivate, please feel free to contact us.
