Preparation and characterization of Cr2O3–TiO2–Al2O3–V2O5 green pigment

Green pigments with high near infrared reflectance based on a Cr2O3–TiO2–Al2O3–V2O5 composition have been synthesized. Cr2O3 was used as the host component and mixtures of TiO2, Al2O3 and V2O5 were used as the guest components. TiO2, Al2O3, and V2O5 were mixed into 39 different compositions. The spectral reflectance and the distribution of pigment powder were determined using a spectrophotometer and a scanning electron microscope, respectively. It was found that a pigment powder sample S9 with a Cr2O3–TiO2–Al2O3–V2O5 composition of 80, 4, 14 and 2 wt%, respectively, gives a maximum near infrared solar reflectance of 82.8% compared with 49.0% for pure Cr2O3. The dispersion of pigment powders in a ceramic glaze was also studied. The results show that the pigment powder sample S9 is suitable for use as a coating material for ceramic-based roofs.