There are several different Aluminium etchants know. Most of them are based
on Phosphoric Acid 85%(about 60 to 90 parts per volume) and Nitric Acid 70%
(about 2 to 10 parts per volume). Sometimes people add Acetic Acid (about
10-30 parts per volume) for better wetting behaviour and lower viskosity.
Merck Corporation has about 10 different Aluminium etchants.

Best regards

Armin Kuebelbeck
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