High near-infrared reflectance Bi2O3-ZnO-CaO yellow pigment system

A novel, eco-friendly yellow mixed oxide inorganic pigment composed of Bi2O3-ZnO-CaO was successfully synthesized using a solid-state reaction. The pigment color was light yellow and rare earth-free. The pigment composition was analyzed by X-ray diffraction (XRD), and the morphology and particle size were analyzed by scanning electron microscopy (SEM). Synthetic pigment samples had superior near-infrared (NIR) solar reflectance (84.2%-91.2%), and the NIR solar reflectance of the pigment-coated Al sheets was more than 50%. The powder samples added to frit glaze improves glaze reflectance.The thermal shielding performance was evaluated by simulating the pigment as a roofing material, and the results indicated that the pigment had an excellent thermal insulation effect. In addition, the pigment had good chemical stability. Therefore, the pigment can be used as a NIR reflection pigment in building coatings to achieve energy-savings by cooling surfaces.