It was recalled that H dissolved in oxides and that, in some acceptor-doped perovskite-type oxides, the solubilities were as high as some mol%. In these oxides, protonic conduction was observed over a certain temperature range. These could be used as proton-conducting solid electrolytes at high temperatures. The mechanism of H incorporation into these oxides was considered here on the basis of the thermodynamics of crystal imperfections. It was suggested that the application of these oxides to electrochemical devices could lead to means for the real-time determination of H potentials in liquid metal, for the measurement of the H content of quenched metal, and to the determination of H permeabilities and diffusivities in these materials.

N.Fukatsu, N.Kurita, T.Yajima, K.Koide, T.Ohashi: Journal of Alloys and Compounds, 1995, 231, 706-12