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Problem of white spots after Zinc Plating

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Q. Dear Sir,

We are observing a problem of white spots after zinc plating . Can you please tell a solution for this problem. Thanking You, Yours Truly,

C.D.Agashe
Pune , Maharashtra , India

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Q. We are also facing similar problems occasionally. Answer to this question will help us also.

Regards,

Sonu S Andrews
- Chennai, TN, India

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++ A. I am guessing that the white spots you are referring to is actually white rust, which means that the zinc layer has been corroded. If this happens right after plating, maybe the problem lies in the drying process (not completely dried up), leaving droplets of water on the surface of the plated parts. Other possibilities might be from poor final rinsing and poor chromate dip. Hartarto Ciputra - Surabaya, Indonesia

Zinc Plating by Herb Geduld

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A. This is the common problem in White zinc. The most possible problems are in water rinses after plating & yellow passivation. First these things should be controlled. Secondly drying of the components is very important factor. Please look into that also. Very rarely there can be the problem of contaminations in the plating tank, which can be sorted out by various treatment you must be doing in your normal cleaning times. Please try & let me know.

SANTOSH ZOPE
DUBAI WIRE - DUBAI, U.A.E.

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Dear sir,

Before we attempt to answer your query, it is very important to know what base metal are you plating? What is the pretreatment sequence? What type of zinc plating are you doing? Lastly where does the white spot occur ie HCD, lcd or random? Above will give better insight into the problem.

G.S. Sharma
- India