Control of Metal-Oxide Coatings-Absorbers of Optical Radiation in Solar Power Plants. 1. Methodology

A method has been developed for optical monitoring of spectrally selective solar radiation absorber coatings with a high absorption coefficient obtained by thermal oxidation of metal collectors in an air atmosphere. The methodological basis for processing spectral ellipsometry data for nondestructive testing and further classification of the structure and composition of multilayer films that make up the absorbing coatings-absorbers of solar radiation collectors are presented. The ellipsometric and reflectometric parameters obtained at different wavelengths after processing make it possible to determine the distribution of the composition of the metal-oxide structure over the depth of the coating. This makes it possible to calculate the absorption of radiation in the coating and from here predict the temperature regime of the collector, which determines the efficiency of the solar installation.