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Acid Etching Aluminum

What is or are the best etchants to acid etch Aluminum, How should they be treated, i.e. heated like ferric chloride ⇦this on eBay or Amazon [affil links] ? what baumé if any ?


regards,

Peter Vasic

2006

Aluminum is very reactive. Diluted hydrochloric (muriatic) acid, sulfuric acid and ferric chloride ⇦this on eBay or Amazon [affil links] at almost any dilution above 50% will etch it. Strong caustic solutions (NaOH or KOH in water) will also etch it. Room temp.

Guillermo Marrufo

2006

H2SO4 and H3PO4 mixed solution

John Hu

2006

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2006

There is an etch commonly used in the microelectronics industry for etching aluminium. The solution is 80 ml of orthophosphoric acid, 10 ml of nitric acid, 10 ml of acetic acid ⇦this on eBay or Amazon [affil links] and 20 ml of water. The solution works best when heated to about 60 °C.

Dr. Gary Callon
University of Dundee
Arbroath, Scotland

When you say acid etch aluminum, I assume you are not talking about pure aluminum as in 1100, but something in the 3,4,5,6,7XXX. For pure aluminum, you will probably want to use a caustic rather than acid.

James Watts
Navarre, Florida
2006