# Does phosphoric acid remove stainless steel electropolished layer?

Electropolished stainless steel has a high corrosion resistance due to the oxide film that is created during electropolishing. The film mainly consist of chromium(III) oxide.

Phosphoric acid is used as a rust removing agent:

$\ce{2 H3PO4 + Fe2O3 -> 2 FePO4 + 3 H2O}$

My question is: will 5% $\ce{H3PO4}$ solution remove this protective layer as well? It should, but how fast will be the protective layer removed? Does anyone have personal experience?

The phosphoric acid will remove the coating if it's concentrated enough but the time it takes to do this depends on how concentrated the acid is and how much of the acid it is exposed to.

• This has been flagged as very low quality. Could you add some more details and a source to back up your claims. It currently is almost only restating the last part of the question. – Martin - マーチン Jun 23 '15 at 5:33
• I am very sorry to hear that you feel that way. I really do not understand what you mean with "this is getting ridiculous" though. Your question is very specific and it seems, that currently no one is able to answer this to your satisfaction. There are possibilities to raise more awareness for your question though. If you would like to know more, you can come to the chat room and talk about it. – Martin - マーチン Jun 23 '15 at 6:38