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

Using Sm 2 O 3 as the samarium source, Li 2 CO 3 as the Li + doping source, and CS 2 as the sulfur source, the yellow pigment Li + -doped γ-Sm 2 S 3 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-Sm 2 S 3 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-Sm 2 S 3 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). • Using Sm 2 O 3 , Li 2 CO 3 and CS 2 , the Li + -doped γ-Sm 2 S 3 was obtained at 900 °C for 2 h. • With the increase of n Li / n Sm , phase α has been transformed to γ phase. The color 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 b * reached the highest.