Need microetchant procedure

I have an alloy which has an composition FE-%34 NI-3.5CR. I used NITAL (%5-%10)and also %45H20+%45H202+%5 HF etc.I also used PICRAL but I couldn't see any microstructure of. Can you recommend a good etchant for this alloy?

Good afternoon: I'm not familiar with this particular alloy, and you didn't mention whether it was a cast or wrought alloy, what microconstituents you were looking for, etc. But if you have access to ASM Handbook, Volume 9, Metallography and Microstructures, you can probably find a good etchant. This handbook has separate sections for cast and wrought heat resistant alloys, as well as etchant recipes.

This alloy will likely be austenitic (FCC crystal structure), which means that nital and picral will not be suitable etchants. Since I am still on vacation, I do not have access to all of my references, but you may want to try Glyceregia as an etchant. It is 3 parts HCl, 2 parts glycerol, and 1 part nitric acid. Also, try posting this question at http://www.metallography.com, which has an "Ask the Experts" forum similar to this site.

Dear Emre,

You can use Vilella's reagent to etch your material.

Vilella's reagent composition 5 ml HCl
1 g picric acid
100 ml methanol [affil link](95%)