Multilayer solar selective coating for high temperature solar thermal applications

A multilayer solar selective coating on metallic and non-metallic substrates suitable for high temperature solar thermal power applications. The optimized solar selective coating of the present invention on stainless steel substrate exhibits absorptance of 0.954 and emittance of 0.07. A five layer coating is deposited using the sputtering process, and includes tungsten (W), titanium aluminum nitride (TiAlN), titanium aluminum silicon nitride (TiAlSiN), titanium aluminum silicon oxy-nitride (TiAlSiON), and titanium aluminum silicon oxide (TiAlSiO) layers. The first layer (W) acts an infrared reflector, the second layer (TiAlN), the third layer (TiAlSiN) and the fourth layer (TiAlSiON) act as the absorber layer and the fifth layer (TiAlSiO) acts as the anti-reflection layer. The high-temperature solar selective coating exhibits average emittance of 0.10 at 400° C. on stainless steel substrate in the wavelength range of 2.5-25 μm, thus is suitable for applications in concentrating collectors like evacuated receiver tubes for solar thermal power generatio