Abstract: A method is disclosed for preparing a silicon carbide-coated substrate without subjecting the substrate to unnecessary thermal stress. A coating of a silicon carbide precursor polymer is placed on a substrate and the coating is subjected to a laser beam of sufficient energy to raise the temperature of the coating in the area of impingement of the laser beam to approximately 1200.degree. C. to 1600.degree. C. until the coating is converted into a silicon carbide ceramic material. The area of laser beam impingement is located in an inert atmosphere or vacuum while the reaction is taking place.