Crystalline SiO2 bonded coating enhances the high-temperature resistance of γ-Ce2S3 red pigment

Aiming at the critical bottleneck of γ-Ce 2 S 3 red pigment being prone to oxidation and discoloration in high-temperature environments, this study proposes a homogeneous coprecipitation strategy based on the slow release of urea to achieve synchronous hydrolysis-condensation of cerium and silicon sources. An integrated process of homogeneous coprecipitation–pre-sintering–sulfidation–crystallization was adopted to successfully fabricate a γ-Ce 2 S 3 @ c- SiO 2 composite pigment with Si-O-Ce chemical bonding at the core-shell interface. Structural characterization confirms that the γ-Ce 2 S 3 core exhibits high crystallinity, while the c- SiO 2 coating is dense. Performance evaluations demonstrate that the pigment synergistically possesses excellent color rendering properties and high-temperature stability, with initial chromatic parameters of L * = 40.75, a * = 45.90, and b * = 41.00. After calcination at 1000 °C in air for 10 min, its red reflectivity remains above 60%, and the redness value a * is maintained at 30.14. This work elevates the temperature resistance limit of pure γ-Ce 2 S 3 from 350 °C to 1000 °C, laying a solid foundation for the application of this pigment in high-temperature processing fields.