A New Solar Selective Absorbing Structure of Al-Al2O3 Cermet Composite Films by Pulsed Direct Current Magnetron Sputtering

Abstract

Thin films composed of mixtures of metals and dielectric are being considered for use as solar selective coatings for a various applications. By controlling the metal distribution, the solar selective coatings can be designed to have the combined properties of high absorptance, and low infrared emittance. We have studied the preparation of the Al-Al2O3 cermet composite films deposited on the flexible Kapton substrate by pulsed direct current (DC) magnetron sputtering technique. The complex films include infrared reflective layers, interference absorptive layers, and anti-reflective layers. The measurements of the samples show that the spectral absorptance in the region of 0.2~2.5μm and thermal emittance in the region of 2.5~25μm were 92% and 7%, respectively.