Thermally Sprayed Coating Composites for Film Heating Devices
Direct heated systems in white goods for medium temperature applications (approx. 250° -350° C) can be applied onto glass, glass ceramic and metal substrates by means of thermal spray techniques. Essentially, such a system requires at least two functional layers to work properly: (1) The metal coating that works as the heating element and (2) an insulator coating that electrically separates the substrate from the film heater. Therefore, the heating device combines three materials (substrate, insulator and film heater) with rather different thermophysical properties. An optimized spray deposition process with proper guidance of the heat flow is required to produce coatings that can operate under cyclic thermal load conditions. The paper discusses the influence of thermal spray process parameters as well as the applied spray powders on the electrical properties of the achieved layer structures of the respective insulator and film heater coatings.
A. Killinger and R. Gadow, "Thermally Sprayed Coating Composites for Film Heating Devices ", Advances in Science and Technology, Vol. 45, pp. 1230-1239, 2006