Non-stoichiometry of Li_2TiO_3 under hydrogen atmosphere condition

摘要

Li_2TiO_3 is one of the most promising candidates for solid breeder materials. In order to control the grain growth at the time of high temperature use, the development of Li_2TiO_3 which has oxide additive is needed. In the present paper, the structure and the non-stoichiometry of Li_2TiO_3 added with some different oxides have been extensively investigated by means of thermogravimetry and X-ray diffractometry (XRD). In the case of the Li_2TiO_3 samples used in this study, Li_2TiO_3 powder and oxide powder (CaO, ZrO_2, Sc_2O_3) in small quantity were mixed in the following molecular ratio: CaO/Li_2TiO_3 =0.20%, ZrO_2/Li_2TiO_3 = 0.44% or Sc_2O_3/Li_2TiO_3 =0.40%. These samples are designated as Ca-Li_2TiO_3, Zr-Li_2TiO_3, and Sc-Li_2TiO_3, respectively. Ca-Li_2TiO_3 and Zr-Li_2TiO_3 exist as double phases, and Sc-Li_2TiO_3 exists as a single phase. In thermogravimetry, Ca-Li_2TiO_3 has fewer oxygen defects than the other kinds of Li_2TiO_3 in the hydrogen atmosphere. The overall results suggest that the oxide additives are able to control not only the growth of the grain size but also the amount of oxygen defects.