Novel inorganic orange pigments based on BiFeWO₆

Abstract

Bi_1−xLa_xFeWO₆ (0 ≤ x ≤ 0.30) samples were synthesized by a co-precipitation method. Their crystal structure, optical properties, and color of the pigments were characterized as novel inorganic orange pigments. In the case of the La³⁺-doped samples, the target phase was obtained almost in a single-phase form. Strong optical absorption was observed below 550 nm in all samples. As a result, the Bi_1−xLa_xFeWO₆ (0 ≤ x ≤ 0.30) samples exhibited orange colors, and the most vibrant orange hue was obtained at Bi_0.90La_0.10FeWO₆. Although the yellowness value of the Bi_0.90La_0.10FeWO₆ (b* = +37.7) pigment was a little smaller than those of the commercially available orange pigments, the redness value of this pigment (a* = +28.5) was larger. Therefore, this pigment exhibited a reddish orange color as compared with the conventional orange ones. In addition, this pigment was chemically stable. Since the Bi_0.90La_0.10FeWO₆ pigment is composed of non-toxic elements, it could be a new environmentally friendly inorganic orange pigment.