Evolution of electrical parameters according to pressure

Under a pressure between 10 and lO Pa, and at a temperature in the 300 to 600°C range, analysis of the complex impedance spectrums show that, whatever the studied material (beta-alumina, glass, zirconia), oxygen pressure does not influence at all the parameters T and n which characterize the electrode-material interface. The capacitive effect and charge carrier diffusion in the material stay the same under all oxygen pressme values. 

It is the same for the capacitive effects due to the presence of stractural defects in the materials. 

In fact, oxygen probably does influence the capacitive effect, but it is surely hidden, at least partially, by the charge we placed on the electrodes using the measurement system. It is therefore not surprising that oxygen action on the capacitive effect cannot be measmed. 

We see a very slight decrease in conductivity as oxygen pressure goes up. We have tried to quantify this change using an expression of the following type  

This type of expression is often adopted to express the change in material conductivity according to oxygen pressure. In the simple cases where the gas adsorption reaction is controlled by the adsorbed-phase electron transfer, the value of n depends on whether or not the adsorption process is dissociative. Generally, in the case of oxygen adsorption, n assumes the value 1 if adsorption is not dissociative, and assumes the value 2 if it is. 

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