AN IMROVED SOLAR SELECTIVE ABSORBER COATING WITH EXCELLENT OPTICAL ABSORPTANCE, LOW THERMAL EMISSIVITY AND EXCELLENT CORROSION RESISTANCE PROPERTY AND A PROCESS OF PRODUCING THE SAME

摘要

The invention relates to a solar selective absorber coating with an optical enhanced protective layer having an excellent optical absorptance, low thermal emissive and excellent corrosion resistant property generating over stainless steel substrates (1 a) and a process of producing the same. This can have wider application in solar collectors. The main utility of the present invention is for medium temperature applications particularly in solar steam generators and steam turbines for producing the electricity. Further, it can be employed effectively both in the non evacuated and evacuated environments. The said coating comprise of two layers. The first layer function as the absorber layer (2a) specially having a nanoporous surface morphology! structure and the se cond layer (3a) further enhances the absorptance which acts as a gradient type of antireflective layers. The above said of selective solar collector exhibits high optical properties (abs: 93-95%, thermal emissivity: 0.11-0.14 at 300� C) with high corrosion resistance property (withstand 21 days in salt spray test).