Letter 7041

Etching aluminum to reveal microstructure

how can i see the microstructure of aluminium alloy? what is the etching solution for it ?

Ben
- Malaysia

In the metals lab, we use a freshly prepared mixture of 10 parts nitric acid, 1 part hydrofluoric acid, balance distilled water. Use a cotton swab or Q-tip to develop the grain structure on the surface of a highly polished specimen. Use a new swab each time to apply etchant for about 10 seconds only. Rinse and dry to examine. Repeat as necessary. You will develop improved technique with experience. Aluminum alloys will respond vastly different from relatively unalloyed aluminum, also.

W. Carl Erickson
- Rome, New York

You etch aluminum bitn HF acid plus water. You can find in metals handbook (metalography).

Behnam Taki
anodizing - Teheran, Iran

Each alloy of aluminum needs a special solution etch, for example I can see precipitate particle of 2024 by keller solution. for keller composition ref metals hdbk.

HABIBOLAHY
- isfahan-iran

April 12, 2008

Purer version of aluminium alloys require electropolishing prior to electroetching to reveal the grain structure by developing an anodic film. ASTM Metals Hand Book on Metallography gives details on electropolishing & electroetching techniques.

Shankar Nayak
- Mumbai, India

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