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ALUMINUM ANODIZED PART BAKING TEST FAILED

May 22, 2009

I've anodized camera parts, material 5056 series. Color is black, thickness about 5 - 6 micron. Anodizing solution type II, temperature 20 degree.Concentration 180 g/L to 200 g/L. Dipping time is 35 minutes, constant current used 0.45 cc.

Recently my customer complained of color peel off when they did baking test 180 degree, 2 hours. I wonder what going on with my process?

I'm searching all information about peel off of anodizing, but in all articles mentioned, anodizing should not create peel off. Can any one give me idea, why this happened?

Salinah Masri salinah
plating shop employee - Selangor, Malaysia

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First of two simultaneous responses --

At 80C to 100C the aluminum metal expands 5 times more than the aluminum oxide coating, hence cracking.

Robert H Probert
Robert H Probert Technical Services

Garner, North Carolina

May 26, 2009

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Second of two simultaneous responses --

If that 180 degrees is in Celsius, I know of no black dye that will withstand that temperature.

Marc Green
anodizer - Boise, Idaho
May 27, 2009

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If you do a similar bake test and it fails, then there is something wrong with your anodize process. Think of all of the pots and pans that are hard anodized. While yours is type II and not hard anodize, it still should not peel.
by the way, what is 0.45cc? I assume that cc is constant current, but what are the units?

James Watts
- Navarre, Florida
May 27, 2009

I had not considered the 180 as being centigrade. Organic dye will not stand up to that as Marc stated. So, is it the color burning off or is it the anodize layer peeling as with a knife?

James Watts
- Navarre, Florida
May 27, 2009