Letter 18044

Electropolishing of Nitinol [France] 

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I'm apprentice engineer in materials and I must perform electropolishing on stent made with nitinol. If someone could help me or give me some advice concerning cathode, electrolyte and conditions of the experiments (current density, temperatures or else).

Thank you,

Stephanie Garbez
- France

I do not know what stent is, but nitinol is a titanium-nickel alloy and is a shape memory metal. I think the only way to electropolish this type of metal is to use a perchloric acid based system, but be warned this can be highly explosive, so before you do it, make sure you know EXACTLY what you are doing. A simple solution would be 750-900mls/l acetic acid and 100-250mls/l perchloric acid, operated at 20-100V for between 1 and 5 minutes. There is an alternative process called tampon electropolishing; this can be done on titanium alloys using a mixture of 11mls perchloric acid with 66mls methanol and 24mls butyl cellosolve. A voltage of 26-28V is needed. I would strongly recommend you ask a chemical supply house before embarking on this project.

Trevor Crichton R&D practical scientist - UK

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