In fact, given that anodising is a hardening process, are you sure you want to do it to the chainrings?
Won't it just lead to them wearing out faster? IT's your stuff, so it's up to you in the end, of course.
Given time, the anodising will wear off the surfaces (tooth/chain interface) where the hardening effect is beneficial in any case; the rest of it is largely cosmetic.
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