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-----Acid Zinc Bath Contamination
Q. We have acid zinc plating barrels (chloride based). Since last 2 months we are facing issue of white contamination floating on the solution surface in the morning before starting the bath. Kindly refer the attached photo. Also along with this i see a lot of white substance floating inside the solution, which is also carried to next steps of nitric and Passivation.

I am not able to trace the source and cause; kindly help.
Our process is -
1.Degreasing
2. 2 nos of Water Rinse
3. Acid Pickling
4. Water rinse
5. Acid Activation
6. Barrel plating.

Aniket K
CEO - Maharashtra, India
May 16, 2025
A. Hi Aniket
My initial thought is that this is an extreme example of "oiling out" ⇦ huh?. While awaiting further input here and from your plating process supplier, please see the "Brown sticky slime on surface of chloride zinc plating tank" subheading of thread 400/95.
Luck & Regards,

Ted Mooney, P.E. RET
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