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Al2O3 foil by anodizing

I am interested in possibility of formation thick amorph Al2O3 film on Al foil and then etching the foil down . Maximum thickness achievable? Thanks.

Roman Khait
- Jerusalem,Israel
1999

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Hi Roman, What are the purposes for the process you suggested? You can anodize aluminum first and but do not etch the anodized aluminum, because etching will completely remove the oxide formed on aluminum surface. If you are looking for a process to enhance surface area, I suggest you to follow the process used in producing electrolytic capacitors, in which electrolytic etching is used to generate a highly porous surface on aluminum foil and then the etched foil is anodized in boric acid-based electrolytes to form a thin layer of non-porous aluminum oxide film (<0.5 microns) as a dielectric material. The maximum thickness of the resultant oxide film depends on many factors, such as electrolyte and concentration, temperature, voltage, current density, time, and even material itself (foil thickness). Remember, aluminum oxide is very brittle, so the anodized aluminum foil is very easy to break. I understand you have good ideas on your project, but you need to invest a lot to achieve your goals.

Good luck. Ling

Ling Hao
- Grand Rapids, Michigan
1999