Study on the surface nonstoichiometry of solid breeder blanket materials by means of work function measurement

The change of contact potential difference (CPD) between Li4SiO4 and Pt was measured in various gas compositions with a high temperature Kelvin probe. The change of the work function of Pt was estimated from the measurement of CPD between Pt and Pt, and that between Au and Pt. From the results, the effect of an oxygen deficient layer near the surface of Li4SiO4 was observed, and the processes of adsorption as H2, and desorption as H2O, were estimated to be dominant when hydrogen was introduced. Moreover, the effect of the oxygen deficient layer on the rate of tritium release as HTO was discussed.