Study on the reaction process of LaTiO₃ prepared by spark plasma sintering

Spark plasma sintering was used to sinter lanthanum titanate. Based on the XRD patterns of samples sintered at different temperature, the reaction process of LaTiO₃ 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 Ti³⁺→Ti⁴⁺→Ti³⁺/ Ti⁴⁺→Ti³⁺ because of the change of system environment and the formation of high temperature oxygen vacancies. The LaTiO₃ single phase can't be formed directly by the start materials due to the existence of phase transformation resistance. The intermediate phases of La₂Ti₂O₇, La_2/3TiO₃, La₅Ti₅O₁₇ are formed during the lower temperature stages. The formation of LaTiO₃ occurs during the temperature range of 1400-1550°C, and the LaTiO₃ single phase is obtained at 1550°C.