[dingo0722]

I've seen debates back and forth about what is the best acid for passivating stainless. Typically the argument goes between three issues, 1 environmental, 2 chemical reactivity, and 3 alloy specific to the 2 acids.

I was wondering if anyone has set up their own passivation tanks in their shop and if so what acid do you use, best source for the acid and what is your preferred procedure to passivating, like dilution rate, soak time, acid bath temp.

[CaptainVee]

Question is 10 years old and counting, I found it in researching the topic.

So far I found that citric acid is often better.
Requires 4% solution, between 70 and 160 dgr F and more than 120 minutes does not do much extra.

https://ntrs.nasa.gov/api/citations/...0110001362.pdf