Effect of Li+ doping on the color performance and temperature stability of γ-Sm2S3

Abstract

Using Sm₂O₃ as the samarium source, Li₂CO₃ as the Li⁺ doping source, and CS₂ as the sulfur source, the yellow pigment Li⁺-doped γ-Sm₂S₃ was obtained by solid-phase reaction at 900 °C for 120 min. The effects of different molar ratios of Li and Sm (n_Li/n_Sm = 0–0.20) on the phase composition, color state and temperature stability of γ-Sm₂S₃ were systematically studied. The structure and properties of the pigment were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal gravimetric analysis (TG-DTA). The results showed that the pure α-Sm₂S₃ phase was obtained after vulcanization without adding Li⁺. When the ratio of n_Li/n_Sm is 0.02–0.06, α phase and γ phase exist simultaneously. When the ratio of n_Li/n_Sm is 0.08–0.20, α phase has been completely transformed to γ phase. With the increase of n_Li/n_Sm, the color of the sample gradually changed from light green to yellow-green and then to yellow. When the ratio of n_Li/n_Sm is 0.14, the yellowness value of the sample b* reached the highest (L* = 63.25, a* = 4.63, b* = 67.26).