it can be powdercoated but i'd sent it to someone with experience. magnesium 'gasses' out when heated in the powdercoat cure process. so can leave a nasty finish if not done correctly.
you could:
Kephos - (what my linkage is done in, black only)
Cerakote - has to be prepped correctly sorta like powdercoat, but isnt as finicky i dont think.
DOW coatings - easy to get done and probably cheapest, just not the best wear resistance.