Pe Parameter Measurements and Sensing Properties

A known thermodynamic cm/method was applied to determine the parameter pe . This parameter pe describes the relation between the partial ionic and n-type electronic conductivity of the electrolyte, and is defined as the P02 at which the ionic conductivity and the n-type electronic conductivity of the electrolyte are equal. Basically, it is accepted that this parameter must be consistent and known to a high 

When zirconia-based electrolytes are exposed to the high temperatures (T 1100°C) and low oxygen partial pressures P02 10 ° Pa), usually encountered in metal melts, they exhibit mixed ionic and n-type electronic conductivities. Under these conditions, the solid electrolyte sensor generates cm/that is influenced by the electrical properties of the solid electrolyte. Schmalzried [25] has analyzed the contribution of electronic conductivity in the zirconia electrolytes to the measured emf of an electrochemical cell in the P02 region less than 10 Pa and has shown that, in the presence of n-type electronic conductivity, the emf of the sensor can be expressed as 

Low values of the parameter pe (ionic transference number, is 0.5) indicate low contributions of partial electronic conductivity to the total conductivity, which result in higher ionic conductivities (k) according to the equation 

The investigated HfOj-ZrOj-YjOj electrolyte systems exhibited linear Anhenius plots of the lattice conductivity as a function of tanperature. The difference in ionic conductivities between HfOj-ZrOj-YjOj and ZrOj-YjOj solid electrolytes deCTeases 

The results obtained [11, 18] also indicated that the sensors based on HID2-Z1O2-Y2O3 electrolyte systans have a higher chemical resistivity and thermal shock 

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