Improved coloristic properties and high NIR reflectance of environment-friendly yellow pigments based on bismuth vanadate

Abstract

© 2018 Elsevier Ltd and Techna Group S.r.l. Herein, fine powders of yellow pigments based on BiVO4 were successfully prepared in two crystalline forms, tetragonal zircon-structured and monoclinic scheelite-structured, through a ethylene glycol-assisted method subjected to a thermal treatment at two different temperatures. The obtained materials were brightly colored with different hues of yellow, exhibited high reflection in the near-infrared region and showed visible luminescence under excitation by UV light. The new preparation method had a considerable effect on chromatic properties of the prepared scheelite-structured BiVO4 pigments. The sample with the most vivid and bright shade of yellow was found to have the L*a*b* and L*C*ab h*ab color coordinates of (87.28, 0.37, 91.53) and (87.28, 91.53, 89.79), which are indicative of exceptionally good chromatic properties superior and/or comparable to those of other inorganic yellow pigments, both commercially available and recently described. In addition, the NIR reflectance of this powder was very high (≥ 80%).