First, to clarify some terms. If I am correct, by “porcelain” I assume you mean a ceramic coating. By “burn”, I am guessing that you are either referring to contact with skin, or to the car’s paint.
To cover contact with skin, it should not cause any burning, but we do recommend washing it off as quickly as possible. It may cause some light irritation, and if that persists or advances, we recommend contacting a doctor.
If you are referring to the car’s paint job, that also does not cause burning. There would be three ways for this to occur, and only one of them could possibly happen, but not because of the product itself. The first would be a chemical burn. These are caused via an exothermic reaction, in which when mixed together, two chemicals release a significant amount of heat. The materials used in a ceramic coating are inert and are designed not to react with either paint or clear coating.
The other would be a physical burn coming from the curing process. Now, this could possibly burn the underlying paint, but it would be caused by operator error. Some ceramic coatings need to be cured under heat lamps for them to properly harden. In the scenario where this would cause a burn, what would need to happen is for the operator to place the lamp too close to the car for an extended period of time. This could result in a burn to the underlying paint job with enough time.
Last would be the possibility of “buffer burn.” This is when the friction from a buffer builds up so much heat that it causes heat damage to the vehicle. Again, this would be the fault of the operator. Particularly as it requires the operator to consistently press down the buffer in one spot to generate enough heat for this to happen. This usually occurs when someone is trying to buff out a particularly tough spot on a car.
Hopefully, this answer helped!