Chromatic and near-infrared reflective properties of Fe3+ doped KZnPO4

Abstract This paper adopted the coprecipitation method to prepare a new-type inorganic pigment KZn 1 − x (Fe) x PO 4 ( x  = 0.00, 0.05, 0.10, 0.15) with high near-infrared reflective properties. The reflective properties and structure of the product were investigated by UV–vis–NIR spectrophotometer and XRD. Results showed that after doping with Fe 3+ , the crystal structure of KZnPO 4 did not change; while the color of the sample deepened with the increasing concentration of Fe 3+ ( x  = 0.05–0.15), the band gap decreased from 2.00 eV to 1.95 eV, and the near-infrared reflectance reduced from 74.7% to 67.1%. For the aluminum sheet coated with KZn 0.9 (Fe) 0.1 PO 4 pigment, with coating thickness of 312 μm, the near-infrared reflectance could reach 46.7%, higher than the reflectance of conventional pigment of similar color (32.1%). Therefore, the prepared KZn 1 − x (Fe) x PO 4 pigments can be well served as “cool colorant”.