Hi,
   This is Madhav. I am a Research student, working in
University of Arkansas, fayetteville.

I was not able to find a selective chromium etchant.
The etchant should not affect copper and Nickel.
If anyone knows any chromium etchant with such
selectivity, let me know.

Thanks

Regards,
Madhav.
Research Assistant,
University of Arkansas,
Fayetteville.