Thermally barrier coatings are designed to slow heat transfer and insulate the substrate. The coating systems used today usually consist of two components: a metallic bond coat (usually an MCrAlY) that also acts as an oxidation resistant layer and a top coat of ceramic (usually a yttrium stabilized zirconium oxide). The coating system has a low rate of thermal conductivity and a high thermal expansion coefficient. These coating systems extend the service life of components or allow components to operate at higher temperatures, increasing thermal efficiency.
Thermal sprayed TBC coatings are used where the insulating layer has to be very thin, follow the contour of the substrate and withstand severe environment service such as gas turbine hot section blades, vanes and combustor components.
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