Author Topic: cleaning and passifying question  (Read 4339 times)

Offline orangehero

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Re: cleaning and passifying question
« Reply #30 on: September 21, 2013, 01:36:02 AM »
10% w/v citric acid solution heated to 160°F is used as a safe alternative to nitric acid. 10 minutes contact is indicated in the ASTM Metals Handbook, but I like to leave it to cool overnight. You can also save the solution for reuse, just heat it back up. I've also been recommended to use 5% w/v citric acid and 5% w/v ascorbic acid, but ascorbic acid is more expensive.