I don't think it will flake off but some consideration of some other things are needed.

In MY experience powder coating is pretty dang tough overall.
The problem will probably come in where the hinges "swivel" or slide together as they open and close. If your powder coating guy puts it on pretty heavy you will have a problem being tight. I had to cut some of the coating out of the edge of a belt tensioner and as Denny Graham would say "it tain't easy"!

I suspect the springs will do better than the hinges....and if you have to strip the powder coating off it is not an easy job. I know, I had to strip a set of big brackets!

Lastly, have a good talk with your powder coating man. He may have some tricks up his sleeve we don't know about.
Just my .02


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