ETCHING SST 316L Hi, I have taken SEM images of SST 316L before and after Etchin

Question

ETCHING SST 316L

Hi, I have taken SEM images of SST 316L before and after Etching [immersed in 10 ml Nitric Acid in 100 ml Ethanol and etched for 1 min, then washed with Ethanol] . Still, even after etching I cannot see grain boundaries.

- Was my etchant too concentrate or not?

- Is 1 min enough for etching or not?

Below are some of my results. Also here is a link to a document about etching: https://www.asminternational.org/documents/10192/1876164/amp16302p032.pdf/3f96696a-ff1b-4980-a12b-0131d52e9c4e

Explanation / Answer

The problem is " The etchant is too concentrate. It is clearly mentioned that nital should not have concentration more than 3%. Since your etchant is 10% nital, complete layer has formed. And you should take little care on polishing as the scratches are not completely removed.

Hope it will satisfy you.

Thank you for your question.

Upvote if you are satisfied.

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