Synthesis of Er2SiO5 nano powders by cocurrent coprecipitation

Abstract

The nano-sized Er2SiO5 powders were prepared by cocurrent coprecipitation method using Er2O3 and tetraethyl orthosilicate (TEOS) as raw materials. The effects of precursor Si/Er molar ratio, calcination temperature, and pH value of reaction system on Er2SiO5 phase composition and microstructure were investigated, and the synthesis mechanism of Er2SiO5 powders was discussed. Results show that pure Er2SiO5 powders with nearly spherical morphology can be obtained from the precursor with Er/Si molar ratio of 20∶12 after being calcined at temperatures at 1300 ℃. Low Er/Si molar ratio can reduce the crystallization temperature of Er2SiO5 and promote the formation of X2-Er2SiO5. The increase of pH value in the reaction system has a certain promotion effect on the formation of ⁅Si—O—Er⁆ structure. During the synthesis process, a ⁅Si—O—Er⁆ network structure is formed in the Er2SiO5 precursor. The ⁅Si—O—Er⁆ network will transform to Er2SiO5 through decomposition and structural reorganization during the calcination process. The Er2O3 impurity is caused by the precipitation of Er3+ of the ⁅Si—O—Er⁆ network structure in the precursor with high Er/Si molar ratio during the crystallization process of Er2SiO5.

Keywords

• er2sio5 powder
• cocurrent coprecipitation method
• er/si molar ratio
• synthesis mechanism