Keeping METAL fixture from rusting/pitting

I bought some contemporary brackets to be used to hang my pendants. These brackets are brushed nickel and will be close enough to the waterline that they will get some incidental saltwater splatter over time.



I don't want them to pit or rust....



What can I put in the metal to keep it from rusting? like spray painting some sort of clearcoat?!?



I need help to determine how to "prep" these brackets.