LIU Wei ^{1, 2}, CAO Chun’e ¹, CHEN Yunxia ^{1, 3,} LU Xilong ^{1, 3}, SHI Wei ^{1, 3}

(1. Jingdezhen Ceramic University, Jingdezhen 333403, Jiangxi, China; 2. Ceramic Research Institute of China,Jingdezhen 333001, Jiangxi, China; 3. Key Laboratory of Environmental Ceramic Materials of Jingdezhen,Jingdezhen 333001, Jiangxi, China)

Abstract: Fe-Tb co-doped Y₂Zr₂O₇ orange-red pigment was prepared by using a microwave hydrothermal method. The effects of hydrothermal circumstance on morphology of the Y₂Zr_1.85Fe_0.15O₇ powders and the effects of Tb on the upper doping limit of Fe in Y₂Zr₂O₇ were studied. It is found that the introduction of urea as precipitating agent had a positive effect on dispersibility of the Y₂Zr_1.85Fe_0.15O₇ powders. Monodisperse spherical samples with particle sizes of 1~2 μm n-propanol and water with a volume ratio of 3:1. In addition, when the molar ratio of urea to cation reached 100, the particle size decreased to less than 1 μm and the samples with irregular morphology were no longer generated. The amorphous hydrothermal samples were highly crystallized after heat treatment at 1100 ℃ for 3 h and the monodisperse spherical morphology could be well retained. The upper limit of Fe in Y₂Zr_2-xFe_xO₇ is 0.15, which increased with the introduction of Tb. It is further increased to 0.35 when the content of Tb is increased to 0.25, corresponding to Y_1.75Tb_0.25Zr_1.65Fe_0.35O₇. The Y_1.75Tb_0.25Zr_1.65Fe_0.35O₇ was then mixed with a colorless transparent flux, which showed orange-red tone after heat treatment, with L*, a* and b* values to be 61, 31 and 29, respectively.

Key words: microwave hydrothermal; Fe-Tb co-doped; orange-red pigment; monodisperse; spherical