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Sealing inhibitors

2007

Question:
1- can sealing be performed in tap water?
2- how can I maintain a good DI water in the sealing tank ? if with filters , what type and how can I calculate the exact size?
3- what type of quality control I can use to test the additives performance for sealing baths? (test description)
5- what are the main ingredients of the conventional smut preventives(ammonium citrate?
4- what are the advantages and disadvantages of using nickel acetate sealing smut?
5- is it possible to have a good sealing at temperature lower than 96 °C....if yes how?
Any reliable information would be gratefull............many thanks.

Elie Kattar
- Jounieh, Lebanon

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2007

Hello, Elie. Yes, DI water should be used and specialist purveyors of deionization equipment for seal tanks will have sufficient experience that they will be able to help size it based on volume of the tank and throughput.

Questions 3 through 5 are addressed very well in "Sealing Processes of Anodic Coatings--Past, Present and Future" by Ling Hao and B. Rachel Cheng, published in the Dec. 2000 issue of Metal Finishing magazine. But each of your five questions would be good titles for subchapters in an anodizing book, and together they could comprise the whole chapter, so it may be best to get a book like "The Surface Treatment and Finishing of Aluminum and its Alloys" and then use a dialog here to clarify a confusing passage or confirm that some particular procedure is an industry standard.

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