Optical simulation, corrosion behavior and long term thermal stability of TiC-based spectrally selective solar absorbers

Abstract

This work is a continuation of earlier work where TiC/Al2O3 spectrally selective solar absorbers were deposited onto stainless steel (SS). In this study, the optical simulation, corrosion behavior and long term thermal stability are investigated in detail. A series of TiC and Al2O3 single layers are fabricated by magnetron sputtering using the same deposition parameters as described in the previous work. The optical constants and thicknesses of glass, stainless steel, TiC and Al2O3 layers are obtained by CODE software using the suitable dielectric function model. Then, the structure model of SS/TiC/Al2O3 is constructed and the reflectance spectra of the SS/TiC/Al2O3 solar absorber is successfully simulated using CODE software. The anti-corrosion performance of SS/TiC/Al2O3 solar absorbers is evaluated through electrochemical potentiodynamic polarization measurement and salt spray test. The SS/TiC/Al2O3 solar absorbers have a good thermal stability in vacuum at 500°C for 100h. Raman analysis indicates that the increased sp2 bonds of the coating is the main reason for the degradation of the optical properties.