We do this kind of ceramic coating as well. The concern with it is that it is a thermal barrier. That works well with headers where you want the heat to not be absorbed by the pipes (heat soak), but on a solid rotor, you could be trapping in the heat which would not be a good thing. I ceramic coated the brake drums on my '27, but they really don't get hot enough to worry about. A solid rotor for a road race car is different. We do have some other coatings that are thin and handle the heat, but are not ceramic. If there was a concern with the powdercoat, there are higher temp offerings that will go higher that the typical powders.