Tailoring Alumina Matrix Optical Properties for Colored Solar Thermal Absorber Coatings
Abstract
The paper describes the optimization steps of the alumina matrix to get optical properties and morphology suitable for the pigment layers infiltration to develop efficient colored (yellow and green) solar absorber coatings. The alumina matrices were obtained by the deposition of alumina layer on the Al substrate using two different methods: immersion in and robotic spraying of a diluted sol. The optimized alumina matrix, obtained by immersing the Al substrate in a diluted alumina sol (Al2O3 sol: H2O = 1: 9) for 24 hours, has a porous morphology and promising optical properties: α = 0.16, ε = 0.06.