I am having trouble with etching the heat treated Inconel 625 MIG weld sample. The heat treatment conditions are 980C with 30 mins, 1 hour, 2 hour. I have tried with Glyceregia, Mixed Acid (HCl, HNO3, Acetic Acid). Samples are getting lightly etched at first. Higher Magnification image like 400x are not good enough with this kind of etching. Etching again, I am seeing so many scratch marks (photo attached). If I can even over-etch the sample I can get to see the images in SEM. But during over-etching these scratch marks are occurring.
Anyone know what to do?
Hi Ali,
I also had a problems with etching of Inconel 625 welded samples (the effects were similar to yours). Scratch marks are likely the results of insufficient polishing and the black dots are the precipitates (localized mainly at the grain boundaries) affected by the etchant - in my opinion the sample isn't overetched. In my case I did use the fresh acetic glyceregia (15ml HCl 38%, 10ml acetic acid 99%, 5ml HNO3 65% and 1-2 drops of the glycerin) with etching time of 15 minutes (but maybe in your case, the shorter time will be enough).
Regards,
Robert
Thank you Robert Kosturek . Actually manually polishing and then etching did best with my samples. I used alumina 0.06 micron polisher as a final polisher. The result is really good.
For a somewhat related discussion at this forum: https://www.researchgate.net/post/What_is_the_appropriate_etchant_for_micro-structure_analysis_of_the_Interface_between_Inconel_625_and_Cast_iron/1
- Badges
- Science method
- Similar topics
- Mathematics
- Statistics
- Statistical Techniques
- Structural Equation Modeling