Low-temperature synthesis of Tb-doped ZrSiO4 yellow pigment via a mechanochemical-assisted in-situ molten salt method: color performance and coloration mechanism

Terbium-doped zircon (ZrSiO 4 ) yellow pigments were synthesized via a mechanochemical-assisted in-situ molten salt method, and their coloration mechanism was investigated. The results show that Tb ions are solid solved in the zircon lattice in mixed Tb 3+ /Tb 4+ valence states. The bright yellow color of the pigment is primarily due to the O 2p → Tb (IV) 4f LMCT transition of Tb 4+ , while the oxygen vacancy mechanism compensates for the charge imbalance from Tb 3+ doping. Under optimal conditions, including a Tb doping amount of 0.07, a Si/Zr molar ratio of 1.05, and calcination at 800 °C for 2 h, the pigment demonstrated superior color performance with chromaticity values of L* = 87.60, a* = −7.43, b* = 72.22, and C* = 72.60. The pigment has uniform particle size distribution and excellent glaze compatibility, maintaining a stable yellow color within a glaze-firing temperature range of 1000–1300 °C, and does not contain harmful elements such as Pb, Cd, or Cr. The mechanochemical-assisted in-situ molten salt method used in this study presents a low-temperature synthesis route for high-performance yellow ceramic pigments, which offers potential for reducing thermal energy consumption.