We are trying to improve an industrial process to treat the surface of several grades of stainless steel (electropolishing + passivation on AISI 304, 316, etc.).
I think I read in a study somewhere that nitric acid + bichromate passivation is faster under anodizing conditions, but I can't find it anymore.
I remember seeing that within 3 Volts, immersion time will decrease from 20-30min to 2-3min. Is it really for the purpose of passivation ? Surface chromium oxides should be improved.
What do you think ? Is it relevant to apply an electric field to the passivation bath whereas electropolishing is the previous step of treatment ? We are interested in reducing the time but the final quality of the surface needs to remain the same.
I just managed to find in R. Lévêque's book : Traitements et revêtements de surfaces des métaux (p341) that the passivation under an electric field is appropriate for glueing tools on the stainless steel surface after treatment, which isn't an interesting purpose to us.
Thank you for you help.
I'm sorry, what ?
I just want to know if the process does exist. Unfortunately I am not trying to do R&D, we have to stick to the client's specification.
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