(Cr/TiAlCrN/TiAlN/AlsiN/AlSiO) multi layer solar selective coatings for concentrated solar power plant

Abstract

A multi layer solar selective coating Cr/TiAlCrN/TiAlN/AlSiN/AlSiO gives the good absorption (α= 0.95) and low emission (Є= 0.08) over the SS 316 tube for solar thermal applications. In this multi layer solar selective coating each layer has unique properties that mostly depend upon the each layer thickness. Individual layer thickness has been optimized to get high absorbance (α= 0.95) and low emission (Є= 0.08). metal nitride multilayer films display a unique combination of exceptional properties with respect to optical absorption, thermal emission, corrosion resistance, adhesion between coating and surface and thermal stability at high temperatures. The sequence of the Cr/TiAlCrN/TiAlN/AlSiN/AlSiO coating layers was selected based on their relative thickness, which was optimized to get good solar selectivity (α/Є). The multilayer solar selective coating was characterized by using Raman spectrometer, Ultra violet-Visible-NIR spectrophotometer, Scanning electron microscope (SEM), Transmission electron microscopy (TEM) etc. Scratch test was used to find the coating adhesion strength and corrosion tests were also done for these absorber coatings.