Preparation And Investigation Of Colored Solar Selective Absorbing Coating With Ti-AlN Multilayer

The application of solar energy plays a vital role to alleviate the current energy crisis, and the solar selective absorbing film is a key material in solar thermal application. It is very important that the solar absorbing films have different colors and high solar-thermal conversion, because colored solar-thermal collectors have the advantages of architectural integration and color appearance. Therefore, in this dissertation, we fabricated colored solar selective absorbing coating with Ti and AlN multilayer structure by the reactive direct current magnetron sputtering, and the performance variation of the solar selective absorption coating after acid corrosion test has been investigated. The main contents are arranged as follows.First, titanium films were deposited on quartz substrates with different thickness by direct current magnetron sputtering. The effect of thickness on the optical properties and structure of the films was investigated. The results showed that the crystalline performance of the film increases with increasing of thickness. The surface particle size increases and surface roughness decreases as the film thickness increase. In the range of400-2000nm wavelength, transmittance decreases and reflectance increases with the increase of thickness. Refractive index is between2.5and3.4, and extinction coefficient is between0.7and1.4. Both refractive index and extinction coefficient increase with increasing thickness.Second, five colored coatings with a Ti-AIN multilayer structure were designed by the optical multilayer software and fabricated by magnetron sputtering. The color of the five coatings is black, purple, yellowish green, red, and yellowish orange. The energetic performance, chromaticity, and brightness of the coatings were studied and compared. The results show that the solar absorptance of these coatings is between0.82and0.94, the thermal emittance is between0.05and0.27, and the brightness is in the range of0.65%-8.89%. These colored coatings can be produced by a commercial production process, and suitable for the application of building integration.Third, AlN and AlON films have been deposited on quartz substrates by magnetron sputtering technique. The optical constants and thicknesses of the films were calculated from the transmittance or reflectance data. Solar selective absorbing coatings with different surface layer materials (AIN or AlON) have been designed and fabricated. The single layer of AIN layer, AlON layer, and solar selective absorbing coatings with different surface layer materials were eroded by a simulated acid rain corrosion solution. The surface morphologies and optical properties of these coatings after eroding have been studied. The results show that the anti-corrosion performance of the AIN layer is better than that of AlON layer. Accordingly, the anti-corrosion performance of the absorbing coating with AIN surface layer is better than that of the coating with AlON surface layer.