Metal finishing Q&As since 1989

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Zinc trivalent blue passivation in crs gets white rust

The plating thickness is 8-12 Microns and salt spray test also pass 72 hrs but after 14-15 days the comp will getting white rust so please suggest solution.

If there any problem in cyanide/non-cyanide bath concentration.

Prem Kumar
Employee - Karnataka, India
2007

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Decidedly, it is a problem of passivation or post-treatment. Especially, incorrect the pH or concentration. When it comes to post-treatment, pay your attention on rinsing or drying. Rinse water is often too acidic and it may cause real damages of passivation layer during drying. Some trivalent passivations need drying in really hot air and then conditioning 24 hours before operating. If not - the corrosion resistance is significantly reduced.
Best regards,

Janusz LABEDZ
- Warsaw, Poland
2007

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Hi there,

please check the drying of the component, secondly the porousity of the base material and thirdly the packing material and lastly note the storage components are away from the plating zone where there is lot of acidic fumes.

Regards

Praveen Kumar
plating process supplier
Mumbai, India
2007

adv.