## Date of Award

7-1985

## Document Type

Dissertation - Restricted

## Degree Name

Doctor of Philosophy (PhD)

## Department

Mechanical Engineering

## First Advisor

Robert N. Blumenthal

## Second Advisor

Robert F. Brebrick

## Abstract

Steady-state and nonsteady-state oxygen permeation measure- ment have been performed on the ionic conductor, 8 mole % yittria stabilized zirconia, Zr(,.84)Y(,.16)O(,1.92(+OR-)x), as a function of T and P(,O(,2)). The nonstoichiometry, x, in the formular, Zr(,.84)Y(,.16)O(,1.92(+OR-)x), were deter- mined from solid state coulometric titration measurement. The con- ductivity, mobility, diffusivity, and concentration of the n-type and p-type electronic carriers were obtained from the above measure- ments. The results are expressed by the following equations for the temperature (800 - 1050(DEGREES)C) and P(,O(,2)) (1 atm - 10('-17) atm): (UNFORMATTED TABLE FOLLOWS) (sigma)(,ion) = 1.63 x 10('2) e('-0.79/kT )(sigma)(,n) = 1.31 x 10('7) e('-3.88/kT) P(,O(,2))('-1/4) (sigma)(,p) = 2.35 x 10('2) e('-1.67/kT) P(,O(,2))('+1/4) (mu)(,n) = 8.02 x 10('2) e('-1.89/kT) (D(,n) = 2.30 x 10('2) e('-2.00/kT)) (mu)(,p) = 0.853 e('-1.05/kT )(D(,p) = 0.231 e('-1.15/kT)) n = 1.04 x 10('23) e('-1.99/kT) P(,O(,2))('-1/4) p = 1.72 x 10('21) e('-0.62/kT) P(,O(,2))('+1/4) x(,n) = 1.75 e('-1.99/kT) P(,O(,2))('-1/4) x(,p) = 5.84 x 10('-2) e('-0.62/kT) P(,O(,2))('+1/4)(TABLE ENDS) The thermal gap energy (2.61 eV) determined from the product of the electron and hole concentration were found to be in agreement with the gap energy (2.7 - 2.8 eV) obtained from the optical absorp- tion measurement in a single crystal of (YSZ).