The oxygen permeability of solid electrolytes 85.0 mole per cent (m/o) ZrO~ -]-15.0 m/o CaO (I), 90.0 m/o ZrO2 -p 10.0 m/o Y208 (II), 89.0 m/o ZrO2 -t-8.0 m/o Y203 -}-3.0 m/o A120,~ (II1), 90.0 m/o ZrO2 + 10.0 m/o Sc203 (IV) is investigated at temperature range 900~176and partial pressures of oxygen 0.01-1.0 arm. The oxygen permeability in this range of oxygen pressures is proportional to Po21/4. It is shown that the diffusion coefficient of oxygen does not depend on its pressure in a gas atmosphere. Transport numbers of electron boles, which were found to be in limits 1.7 . 10 -a + 5 9 10 -5, were determined from the experimental data. The parameter p i/4 (H e = Ho~-) is also calculated.The oxygen permeability of solid electrolytes with zirconia base, play a big role in the functioning of certain electrochemical devices. However, there are only few investigations on this subject (1-4), and permeability of yttria-and scandia-stabilized zirconia is still not investigated.We investigated the permeability to oxygen of several solid electrolytes: 85.0 mole per cent (m/o) ZrO2 + 15.0 m/o CaO(I), 90.0 m/o ZrO2 -}-10.0 m/o Y208 (II), 89.0 m/o ZrO2 -t-8.0 m/o Y203 -t-3.0 m/o A1203 (III), and 90.0 m/o ZrO2 -I-10.0 m/o Sc203 (IV).The measurements were made by using a cell schematically shown in Fig. 1. We use the principle that the rate J of penetration of gas through a plate diaphragm of area S cm 2 is connected directly with a rate of pressure rise (2P/t) in a calibrated volume (5). The expression which shows this principle isWhere ~, V, p, R, and T are molecular weight, volume, and density of gas at the standard conditions, universal gas constant, and working temperature in ~ respectively. The permeability constant (~l) is given byRTSpAPo21/4 t sec 9 atm 1/4where I is the thickness of diaphragm and -~Po2 is the difference of oxygen pressures on the opposite sides of the diaphragm. The specimens were of oxide solid electrolyte tubes closed at one end. They were placed in an electric resistance furnace in which temperature was precisely controlled and was constant (with accuracy _ 2 ~ along the working length. The tubes were prepared by common technology (a shlicker method). They were 200 mm long, with 9.6 mm outside diameter and about 8.0 mm inside diameter. Porosity was about 5%. Water

Die Sauerstoffdurchlässigkeit der Festelektrolyte 85 (Mol‐%) ZrO2 + 15 CaO, 90 ZrO2 + l0 Y2O3, 89 ZrO2 + 8 Y2O3 + 3 Al2O3, 90 ZrO2 + 10 Sc2O3 wird zwischen 900 und 1250°C und Sauerstoffpartialdrücken von 0,01 bis 1,0 atm untersucht.

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