Direct synthesis of La9.33Si6O26 ultrafine powder via sol-gel self-combustion method

作者：Tian Changan; Liu Junliang; Cai Jun; Zeng Yanwei^*

来源：Journal of Alloys and Compounds, 2008, 458(1-2): 378-382.

DOI：10.1016/j.jallcom.2007.03.128

• La9.33Si6O26
• ultrafine powder
• synthesis
• self-combustion

Single phase La9.33Si6O26 ultrafine powder, as a kind of highly activated precursor to prepare medium-to-low temperature electrolyte for solid oxide fuel cells (SOFCs), has been successfully synthesized via a non-aqueous sol-gel and self-combustion approach from the starting materials: lanthanum nitrate (La(NO3)(3)center dot 6H2O), citric acid, ethylene glycol (EG), tetraethyl orthosilicate (TEOS) and ammonium nitrate. The details of gel's self-combustion were investigated by DTA-TG and the structural characterization of as-synthesized powder from self-combustion was performed by XRD and SEM. The results show that La9.33Si6O26 single phase of apatite-type crystal structure can be directly synthesized by sol-gel self-combustion method without further calcinations on the condition that the molar ratio (R) of NO3- to citric acid and ethylene glycol being 6:1. Such powders composed of well-dispersed particles with an average size of 200 nm and a specific surface area of 5.54 m(2)/g. It can be sintered to 90% of its theoretical density at 1500 degrees C for 10h, about 200 degrees C lower than the sintering temperature for the powder derived from traditional solid reactions. The sintered material has a thermal expansion coefficient of 9.2 x 10(-6) K-1 between room temperature and 800 degrees C.

• 出版日期2008-6-30
• 单位南京工业大学