Gd2SiO5纳米粉体的并流化学共沉淀法合成

以Gd₂O₃和正硅酸乙酯(TEOS)为原材料,采用并流化学共沉淀法合成Gd₂SiO₅粉体材料。研究Gd₂SiO₅前驱体的热响应特征、Gd₂SiO₅粉体的物相组成和微观形貌,并对Gd₂SiO₅粉体的合成机理进行初步探讨。结果表明:前驱体的低Gd/Si摩尔比和反应体系的高pH值会导致Gd₂SiO₅粉体生成Gd_9.33(SiO₄)₆O₂杂质相,相反则会导致生成Gd2O3杂质相。当Gd/Si摩尔比为20∶11、pH值为9~10、合成温度为1000~1300℃时,合成的粉体纯度较高,Gd₂SiO₅颗粒呈不规则形貌特征,平均粒度为100~200 nm。Gd₂SiO₅合成过程中,前驱体以一种—[Si—O—Gd]—网络结构存在,在煅烧过程中逐渐转化为Gd₂SiO₅晶体以及Gd_9.33(SiO₄)₆O₂和Gd₂O₃杂相。

Synthesis of Gd2SiO5nano-powders by cocurrent chemical co-precipitation method

In this paper,nano-sized Gd₂SiO₅powder was synthesized by a cocurrent chemical co-precipitation method with Gd2O3 and TEOS as raw materials.The thermal behavior of precursor,phase composition and microstructure of the obtained powder were investigated,the synthesis mechanism was also discussed.The results show that lower Gd:Si molar ratio in precursor and higher pH value in reaction system can lead to the formation of Gd_9.33(SiO₄)₆O₂phase.On the contrary,Gd2O3 impurity is formed in the obtained Gd₂SiO₅powder.In this study,the relatively pure Gd₂SiO₅powder can be synthesized at 1000-1300℃with Gd/Si molar ratio as 20:11 and pH value in the range of 9-10.The obtained powder inhibits irregular morphology with average grain size of 100-200 nm.During the synthesis process,the precursor is generated in the form of—[Si—O—Gd]—network,and then translated to Gd₂SiO₅grains,as well as Gd_9.33(SiO₄)₆O₂and Gd₂O₃impurities.