Russell,
I think a cursory look in the ASM Handbook helps here as well. But also from experience, this is a pretty classical application case for Vilella's reagent. In general, combination of 2-5% HCl, 1-4g picric acid in ethanol should be all giving you a good etch result in less than a minute, depending on composition, aging condition etc.
The good thing about Vilella's is, that due its high HCl content, you can use if stainless steels as well.
Depending on what you want to highlight in the microstructure, there is Kalling's 1/2, Fry's, Spaeder's, Glyceregia of course, or Murakami's for getting into nice some dark color contrasting of phases.
If you want to perform EBSD, I would go lighter in etch/shorter in time or even avoid altogether. Here, final polish in colloidal silica (pH 9) suffices for accentuation of GBs and relief, even for LOM use.
Thanks
Ben
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Benjamin Adam
Research Assistant Professor
Oregon State University
Corvallis OR
(503) 725-2996
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Original Message:
Sent: 04-06-2023 09:13
From: Russell Cochran
Subject: Grain boundary etchant
What is a good grain boundary etchant for heat treated martensitic steels and stainless steels to determine the grain size? Typical etchants show the martensitic structure which obscures the grain boundaries.
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Russell Cochran
Associate Technical Fellow
Boeing
Maryland Heights MO
(314) 283-5342
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