Microstructure and Thermal Stability of Cu/Ti_xSi_yN/AlSiN Solar Selective Absorbing Coating

An oxygen-free solar selective absorbing coating of Cu/Ti_xSi_yN/AlSiN was prepared on a Cu buffered stainless steel substrate by magnetron sputtering. This coating was prepared using a single target for each layer. A spectrophotometer, Fourier transform infrared spectrophotometer, scanning electron microscopy, X-ray diffractometer and atomic force microscopy were used to characterize the optical properties, crystalline structure, morphology and composition of these coatings. The coating of Cu/Ti_xSi_yN/AlSiN has good optical properties (average absorption of 0.941 and emittance of 0.058) and excellent thermal stability. The performance criterion (PC) is 0.0365, when the solar selective absorbing coating is heated in air at 200 °C for 1200 h.