放电等离子烧结制备LaTiO_3的反应过程研究

Study on the Reaction Process of LaTiO_3 Prepared by Spark Plasma Sintering

采用放电等离子烧结方法制备LaTiO3材料。基于不同温度烧结样品的物相组成变化,对SPS烧结制备LaTiO3的反应过程进行研究。研究结果表明:SPS烧结制备LaTiO3的反应过程可以分为低温、中温和高温三个阶段。随着烧结温度升高,由于系统环境变化和高温氧缺位的形成,Ti的价态经历了Ti3+→Ti4+→Ti3+/Ti4+→Ti3+的转变。由于相变阻力的存在,LaTiO3并不能由原料直接生成,在低温和中温阶段要经历La2Ti2O7,La2/3TiO3,La5Ti5O17等中间相。LaTiO3相的生成主要发生在1400～1550℃,并在1550℃生成单相LaTiO3。

Spark plasma sintering was used to sinter lanthanum titanate. Based on the XRD patterns of samples sintered at different temperature,the reaction process of LaTiO 3 prepared by SPS was studied. The results show that the reaction process is made up of low temperature,medium temperature and high temperature stages. With the increase of sintering temperature,the valence states of Ti go through the transition of Ti 3 + →Ti 4 + →Ti 3 +/Ti 4 + →Ti 3 + because of the change of system environment and the formation of high temperature oxygen vacancies. The LaTiO 3 single phase can't be formed directly by the start materials due to the existence of phase transformation resistance. The intermediate phases of La 2 Ti 2 O 7 , La 2 /3 TiO 3 ,La 5 Ti 5 O 17 are formed during the lower temperature stages. The formation of LaTiO 3 occurs during the temperature range of 1400-1550 ℃ ,and the LaTiO 3 single phase is obtained at 1550 ℃ .