Hydrogen Atmosphere Effect on Vaporization of Lithium-Based Oxide Ceramics by Means of High Temperature Mass Spectrometry and Work Function Measurement

摘要

The atmosphere controlled high temperature mass spectrometer has provided vapor pressure data for lithium-based oxide ceramics under condition of low pressure hydrogen introduction. The measured vaporiza- tion behaviors under hydrogen addition of Li_4SiO_4, LiAlO_2, Li_2TiO_3, and Li_2ZrO_3 are summarized. From the experimental data, sum of the partial pressures of lithium containing species was estimated for each oxide. It was pointed out that hydrogen addition seemed to cause the formation of a nonstoichiometric layer at the surfaces of Li_4SiO_4 and Li_2ZrO_3. Work function measurement was employed as a new method for investigation of such oxygen deficient layers. The results of the work function measurements showed the formation of an oxygen deficient surface layer for Li_4SiO_4 and for Li_2ZrO_3, whereas such was not the case for Li_2TiO_3.