Vapor species evolved from Li2TiO3 heated at high temperature under various conditions

Li2TiO3 is one of the most promising candidates among proposed solid breeder materials in fusion reactors because of its chemical satiability. Addition of H2 or H2O to inert sweep gas has been proposed for enhancing the release of bred tritium from breeder material in fusion reactors. However, its vaporization characteristic has not been well established. Application of an atmosphere-controlled high-temperature mass spectrometer has provided the vapor pressure data of Li-compounds evolved from Li2TiO3, under individual conditions of vacuum, D2, D2O and O2 atmospheres. The observed characteristics of vapor species evolved from Li2TiO3 under these conditions are presented here. The sum of the partial pressures of Li-containing species was figured out. The highest pressure was obtained in D2 followed by D2O and then, in vacuum, with the lowest being in O2. Furthermore, the temperature dependence of Li vapor pressure indicated that Li-containing species appeared above 1273 K in vacuum and O2 atmosphere, and above 973 K in D2 or D2O atmospheres. After the vapor pressure measurement in D2 atmosphere, the color of the sample changed from white to dark blue. This change of color with the oxygen content decreased, suggested change from Ti4+ to Ti3+ in reduction atmosphere.