Determination of the Diffusivity of Oxygen in Liquid Silver by Electrochemical Measurements

Abstract

Following the preceding work, the present study was made in order to find a new method for the measurement of oxygen diffusivity in liquid metal. Using the electrochemical cell, Ar(1% O₂),O(in liquid silver)/ZrO₂(+CaO)/Ar(1% O₂), the diffusivity of oxygen in liquid silver was determined by newly developed potentiostatic titration and e.m.f. methods.
The potentiostatic titration experiment was undertaken by the same procedure as in the previous work except some improvements in the experimental technique. Another e.m.f. experiment was undertaken as follow. Potentiostatic titration was continued until a steady state was obtained and then the change in e.m.f. was measured after electric current was cut off. The diffusivity of oxygen was determined from the change in e.m.f. according to the following relation;
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The results obtained by the above two different methods were in good agreement with the previous results. However the activation energy determined by the e.m.f. method was a little larger than that by the potentiostatic titration method. These experimental results showed that the oxygen diffusivity in liquid metal could be determined accurately by these electrochemical methods. And these experimental methods may be recommended, in particular, for the metal which has a strong affinity with oxygen.