Comparison of structure and solar-selective absorbance properties of Al2O3 thin films with Al and Ni reflector interlayers

• Published in: Chemical papers Vol. 77; no. 9; pp. 5047 - 5057
• Main Authors: Abdelfatah, Aliaa, Mohamed, Lamiaa Z., Elmahallawi, Iman, Abd El-Fattah, Hanan
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01.09.2023; Springer Nature B.V
• Subjects: Absorbance; Aluminum oxide; Biochemistry; Biotechnology; Chemical composition; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Coating effects; Electron microscopes; Emittance; Energy dispersive X ray analysis; Fourier transforms; Industrial Chemistry/Chemical Engineering; Infrared spectrophotometers; Interlayers; Materials Science; Medicinal Chemistry; Nickel; Optical properties; Original Paper; Physical vapor deposition; Stainless steels; Substrates; Thin films; X ray analysis; Selective solar absorber; SS304L substrate; Magnetron sputtering; Solar thermal energy; Microstructure; Optical properties
• ISSN: 0366-6352; 1336-9075; 2585-7290
• DOI: 10.1007/s11696-023-02842-z

This work aims at evaluating the selective solar absorbance (SSA) of Al 2 O 3 thin films deposited by physical vapor deposition (PVD) with two different metallic reflector interlayers. Al 2 O 3 thin films are deposited on the same substrate stainless steel (SS) 304L, with two different interlayers between the thin film and the substrate, namely, nickel (Ni) and aluminum (Al) are used as the reflector interlayer SS304L/Al/Al 2 O 3 and SS304L/Ni/Al 2 O 3 . A scanning electron microscope (SEM) was utilized to characterize the chemical composition by energy dispersive X-ray analysis (EDX) and surface morphology of the deposited thin films. The phases of the thin films were analyzed and identified by X-ray diffraction (XRD) to detect the present phases. The surface topography and the thickness of the deposited thin films were investigated using an atomic force microscope (AFM). The optical properties of the substrate and the deposited thin films (absorbance & emittance) in two conditions were identified by Fourier transform infrared spectroscopy (FTIR) and spectrophotometer. The obtained results demonstrate that both SS304L/Al/Al 2 O 3 and SS304L/Ni/Al 2 O 3 show good performance, such as high solar absorbance and low thermal emittance. However, the Al/Al 2 O 3 thin film provides high selectivity (absorbance/emittance ( α/ε )) of 0.916/0.05, compared to 0.913/0.15 for the Ni/Al 2 O 3 coating. The effect of different properties and microstructure on the efficiency of deposited thin films showed that the SS304L/Al/Al 2 O 3 has higher absorbance (92%) in visible and ultraviolet (UV) regions; and lower emittance (5%) than the SS304L/Ni/Al 2 O 3 . This work shows that the intermediate IR layer has a more pronounced effect on the emittance properties rather than the absorbance properties of the Al/Al 2 O 3 layer.