Difficulty in electroetching of 1050 aluminum alloy

[materials]

Dear friends
I have tried to electroetch 1050 aluminum alloy by 5ml phosphoric acid + 95ml H2o under 1 to 10 volts. However, it was a complete failure even after etching for 6 min.

Please help me if you know how to overcome this problem.

Thank you very much
Best regards

 

[Lok]

What does failure mean?
All you wish to do is electroetching aluminum?
Why not NaOH
Is the oxide layer thin? I usually get at least electrolysis and some etching with tap water. Are any bubbles coming out?
Are you sure you used the right polarity?

A few startup questions.