Does ceramic coating prevent rust?

Not on its own. A ceramic coating can help repel water, salt and road grime from painted surfaces and wheels, which makes them easier to keep clean, but it is not a rust-proofing treatment. Rust usually starts where the paint is already chipped, at seams and on the underbody, where a paint coating offers little or no protection. Repair stone chips promptly, rinse salt off regularly in winter and use dedicated underbody corrosion protection where rust is a concern.