β-アルミナ固体電解質を用いたSO2ガスセンサの固体参照極について
1988 年 104 巻 1200 号 p. 89-95
詳細
1988 年 104 巻 1200 号 p. 89-95
The present study was done for the purpose of finding any available solid reference electrode for SO2sensor employingbeta alumina solid electrolyte. In this paper, we tried a few experiments for this sensor using two solid reference electrode, (β+β')-alumina and (α+β)-alumina.
The cells used were as follows: Pt, (β+β')-alumina in air/β'-alumina/Na2SO4/SO2+O2+SO3, Pt (1) Pt, (α+β)-alumina in air/β-alumina/Na2SO4/SO2+O2+SO3, Pt (1)(11) From the present experiments, the following conclusions were obtained.
1) The constant sodium activities in these solid reference electrodes were maintained for a long duration of the experiment.
2) For both cells, good straight lines were obtained between e.m.f.'s and log Pso2 within the temperature ranges from 933 to 1230 K in the cell (1) and from 932 to 1278 K in the cell (11). Especially, in the (β+β')-alumina solid reference electrode, it was shown that the cell using this electrode could be employed to determine concentrations up to a few ppm of SO2 gases at temperatures of 932 to about 1100 K. Consequently, this (β+β')-alumina mixture is recommended for the solid reference electrode ofSO2 sensor employingβ'-alumina solid electrolyte.
3) From e.m.f.'s of these cells, the activities of Na2O in β-Al2O3+β'-Al2O3and α-Al2O3+β-Al2O3coexistences were respectively calculated by considering thermochemical data and compared with the others.
