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-----Holiday Detection
I am looking for a chemical method to detect iron and/or nickel alloys at microscopic pinholes (holidays) in a nonmetallic coating. Any suggestions?
Larry Hanke
Minneapolis, Minnesota
1999
The most obvious way would be with a spark test if your coating can withstand it; it is done all the time for heavier coatings such as tank linings. Nitric acid porosity tests are used on gold plated items, although I'd be surprised if your coating is impervious to nitric acid.
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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The feroxyl test should work fairly rapidly and not be too tough on the other coating. It's distinctive blue color should be very easy to detect on anything except a cobalt blue color. After acidification, its "pot" life is like one day, and is best used within two hours, according to platers old wives tales.
James Watts- Navarre, Florida
1999
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