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Detecting presence of Clear Chromate Alodine Iridite

How can you determine if any of these finishes have been applied. If we do this for a customer how do we show that it was done? - I can't tell by looking at it.

Richard Webb
Quality Engineer - Bloomingdale, Illinois, USA
December 22, 2008

December 23, 2008

Hi, Richard. It was easier when many chromates were yellow and hexavalent. Some people report that a trained eye can detect the slight brown color of TCP coatings, and some manufacturers propose a spot test. But it's obviously not easy. Please see letter 17722 and 39839. letter 19341 might interest you as well.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

How to differentiate between the two parts having white passivation with hexavalent & trivalent plating?

Prashant Jadhav
employee - India
2005First of two simultaneous responsesDecember 25, 2008

Second of two simultaneous responses --

Try website-there are at least 2 patents on that subject (simple spot testing of chromate treated surfaces).Hope it helps and good luck!

Goran Budija
- Cerovski vrh Croatia
December 29, 2008

August 31, 2010

We carry out lot of chromate conversion coatings on aluminium parts. Clear and colour finish.
How to find that chromate conversion is carried out or not? Is there any spot test?
What is the difference between clear chromate and colour chromate?

Chandramanipg Chandramanipg
Manager - Bangalore, Karnataka, India

Hi, Chandramanipg.

We've appended your inquiry to a thread which may partially answer it. As someone who does a lot of clear and colored chromate, I'm sure you know the difference between something that is clear and something that is colored :-) . . . so you obviously are trying to imply a question and I am not understanding what you want to ask; please try to rephrase it. Thanks.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
September 1, 2010

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