,; It took a while, but the sheet stainless eventually looked like a
lace
,; curtain. Worse, my solution turned yellow: hexavalent chromium.
,;
,;That's interesting. Did you use one of the standard, weak alkaline
,;solutions?

If you throw the kind of voltages that are used in this process at an
anode something is going to give. You can't pass a current from an
electrode into a solution without a chemical reaction. At the anode it
is either an oxidation of something in solution or an oxidation of the
anode. You must have one or the other to pass a current. If the
current is so high that there is nothing available from the solution
to oxidize then the anode is going to go.

I completely agree that you have to have oxidation at the anode, I just
find it hard to belive that you will produce Cr(VI) and not Cr(III). So
far as I remember my electrochemistry courses, electrolytic dissolution
pretty much always produces the lowest stable oxidation state. I've
done a lot of electropolishing of stainless steel, and those solutions
always turn green, consistent with Cr(III). Have you chemically
verified the presence of hexavalent chromium or did you just trust the
color, which could be due to dissolved rust or other metal ions at low
concentration (no, I didn't on my solutions)?

--
Regards,
Carl Ijames