Li-Chung Lee

Date of Award


Document Type

Dissertation - Restricted

Degree Name

Doctor of Philosophy (PhD)


Electrical and Computer Engineering

First Advisor

Robert N. Blumenthal

Second Advisor

R.F. Brebruck


The purpose of this study is to develop an experimental technique by incorporating an oxygen pump and an oxygen gauge across a gas tight chamber with which an oxide sample was associated. By properly controlling the initial and boundary conditions across this chamber, a steady state or a nonsteady state electrochemical transport was achieved. From the solution of the transport equation and the diffusion equation, the conductivity and mobility of the minor constituent mobile charge carrier o! the oxides sample were determined.

The behavior of the minor constituent charge carrier in a given oxide crystal plays an important role in controlling the rate processes such as chemical diffusion, non-stoichiometric reaction, degradation and mass transport, etc. Thus the polarization technique, which is the only current existing technique !or determining the minor electronic conductivity out of an oxide ionic conductor, has some limitation and difficulties in its performance. A method for direct measurement of the minor ionic conductivity o! an electronic oxide conductor has not been found in the literature.

It is t he objective of this study to develop an experimental technique for determining both the minority conductivities and their mobilities in either ionic or electronic type of charge species. The uniqueness of this novel electrochemical measurement is its capability to reach either steady state or non-steady state oxygen permeation in a single set-up.



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