Originally Posted by frost

There would really be no reason I can think of to do both anodizing and powder coating. The benefits of anodizing a part (color, scratch resistance, strengthening, and protection from elements, including sunlight, rain, chemicals, etc) are pretty much rendered useless if a powder coating is applied on top of it.

Powder coating will provide all these benefits, with the exception of actually strengthening the aluminum alloy, and you will have more options of colors, and the colors will be more consistent.

Since the aluminum will not be in some sort of high abuse area, I actually think PC will be a better option for your particular application.

But to answer your question, anodize coatings, no matter how thick are still subject to cracking (known as crazing in the biz) under extreme temperatures because of the coefficient of expansion in aluminum (aluminum oxide is hard and brittle, the base metal is soft and malleable). So I would probably pick one or the other.