Preparation and Application of High Near-Infrared Reflective Green Pigment for Ceramic Tile Roofs

Complex inorganic green pigments having a high near-infrared (NIR) solar reflectance were synthesized. Chromium oxide (Cr2O3) was used as the host component with mixtures of TiO2, Al2O3, and V2O5 as the guest components. TiO2, Al2O3, and V2O5 were mixed into 39 different compositions. It was found that a sample, denoted by S9, with the composition of Cr2O3, TiO2, Al2O3, and V2O5 are 80, 4, 14, and 2 wt%, respectively, gives a maximum NIR solar reflectance of 82.8% compared with 69.6% of a commercially available cool pigment powder. The comparison study on the effectiveness of the synthesized pigment and a commercial pigment on ceramic glaze and sprayed on ceramic tile roofs show that the new powder has given a better result by keeping the tested room about 2 degrees C cooler. It can be concluded that the new formulated green pigment is a highly thermal effective as an NIR reflective roof coating.