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Erosion of aluminum thin film during anodizing

2003

Hi all,

I have just started to study the anodization of aluminum thin film and have not experimented with this technique. I am confronted with a problem of erosion of the aluminum layer during anodizing, and I could not reach the applied voltage limit which is in the order of 6V (applied current is 10uA).

Please if you have any idea about what is at the origin of this problem I will really appreciate your help. Elmostafa

El Mostafa
student - Seoul, Asia, Korea

Aluminum is anodized in a particular acid media. This acid will attack (eat) some aluminum and will definitely attack the formed aluminum oxide. It is literally a race between the amount formed and the amount eaten by the acid. At 6 volts, you are not going to form any anodize layer as the acid will eat it as fast as it is formed. For sulfuric acid anodizing, think more of 16 volts with 18 being faster. For each 0.001 of formed anodize, it consumed 0.0005 of the parent aluminum. Subtract the amount the acid ate and you have a net amount. If you are anodizing thin layer aluminum, there is a finite amount of anodize that you will be able to form. IE, you will have to be quick with an abnormally high ramped up voltage.

James Watts
- Navarre, Florida
2003