I repainted a set of powder coated kitchen chair frames. I degreased, rubbed down with wet & dry paper to take the shine off, and used melamine cupboard paint as I thought that might adhere better to the coating. It did appear to work, but after a few months the paint started rubbing/peeling off.
There may be a paint/primer for the job but melamine paint is not it
. . . but it is excellent on melamine and vinyl covered doors. Not a very helpful post but it might save some wasted time.
Mike.