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Neutral salt spray resistance for zinc plating with clear passivation

(-----) 2006

We have analysed a component plated with Zinc plating and clear (blue) passivation for neutral salt spray as per ASTM B117 [affil. link to spec at Techstreet] and didn't find white rust even after 450 hours. Is this possible? What are the factors make this different?

Narasimhun Parthasarathy
auto electricals - Chennai, Tamilnadu, India

First of two simultaneous responses -- 2006

Any thing is possible, at least on a one time basis. Assume that it is a thick coating that has been very well done with an excellent blue chromate and has been handled with care.. My real guess is that they put a very thin coat of clear lacquer or wax on it.

James Watts
- Navarre, Florida

Second of two simultaneous responses -- 2006

Dear Mr Parthasarathy;

Yes its possible with a combination of Alloy Plating, amazing chromate products and really good topcoats.

My plating shop commits 250 hours to white rust for Zinc but delivers much more!

best regards,

Khozem Vahaanwala
Khozem Vahaanwala
Saify Ind
supporting advertiser
Bengaluru, Karnataka, India
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1. I would check all the operating parameters of the salt spray cabinet.

2. 450 hours can be reached with a zinc alloy (zinc cobalt/iron/nickel) with an organic sealer on top of it.

sara michaeli
sara michaeli signature
Sara Michaeli
Tel-Aviv-Yafo, Israel


It is a Zinc plating with clear passivation having thickness of 10-16 microns. And please let me know the methodology to find out the presence of topcoat or sealant by any instrument/chemical test?

Narasimhun Parthasarathy
autoelectricals - Chennai, Tamilnadu, India

Ed. note: We reiterate our editorial standard that it is the obligation of the inquirer to let the readers know what cause their help will advance. Thanks!

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