Preparation and synthesis mechanism of ytterbium monosilicate nano-powders by a cocurrent coprecipitation method

Abstract

In this study, nano-sized Yb2SiO5 powders were prepared by a cocurrent coprecipitation method. The influence of Si/Yb molar ratio and calcination temperature on the phase composition and structure of Yb2SiO5 were investigated, and the synthesis mechanism of Yb2SiO5 was also discussed. Results indicated that the Si/Yb molar ratio has a significant influence on the phase composition of Yb2SiO5 powders. Under nonstoichiometric conditions, trace of Yb2O3 and Yb2Si2O7 will be formed as impurities in the as-prepared Yb2SiO5 powders. In addition, the elevated calcination temperature can promote the formation of stable X2-Yb2SiO5. During the synthesis process, a -[Si-O-Yb]- network structure was formed in the Yb2SiO5 precursors, which resulted from the in-situ replacement of Si by Yb atoms. The -[Si-O-Yb]- network will transformed to a X1-Yb2SiO5 firstly during the calcination process. With the calcination temperature increased, the metastable X1-Yb2SiO5 can convert to a stable X2-Yb2SiO5 gradually through a reconstructive process. Yb2O3 and Yb2Si2O7 may also be formed during the reconstructive process of X1-Yb2SiO5.