Composition change of the near-surface layer of Li2TiO3 after CO2 absorption observed with accelerator analyses

Abstract Non-Rutherford backscattering spectroscopy (NRBS), which allows for a greatly enhanced cross section for scattering, was used to analyze the atomic composition of Li-containing blanket material, 2.6-MeV proton beams were used as the probe beam to profile the atomic composition in the near-surface region down to about 2 μm. Li 2 TiO 3 ceramics samples of various densities were exposed to CO 2 gas at a pressure of 1 atm at room temperature in a glove box. The absorption of CO 2 was observed to result in the formation of Li 2 CO 3 on these samples in the NRBS spectra. In low and medium density samples, the density ratio of the absorbed CO 2 to Li 2 TiO 3 reached 0.5 after 1800 h and CO 2 absorption showed a saturation tendency of about 1400 h. Li 2 TiO 3 structures without CO 2 were recovered by heating samples to 973 K, with a residual positive volume change of 10%. The structure appeared to have increased capacity for CO 2 absorption with an expanded near-surface layer. This characteristic could present a problem in the process of tritium recovery from the blanket materials.