DETERMINATION OF CHEMICAL DIFFUSION COEFFICIENT OF SRFECO0.5OX BY THE CONDUCTIVITY RELAXATION METHOD

摘要

A conductivity relaxation experiment has been conducted on an SrFeCo0.5Ox sample by abruptly changing the oxygen partial pressure in the atmosphere and monitoring the change of conductivity as a function of time. The re-equilibrium process obeys Fick's second law. By fitting the relaxation data to the solution of the diffusion equation with appropriate boundary conditions, we could determine the oxygen chemical diffusion coefficient and the activation energy. The oxygen diffusion coefficient is 8.9 x 10(-7) cm(2)/s at 900 degrees C and it increases with increase in temperature. Measured activation energy is 0.92 eV, which is slightly lower than that of other oxides in the system SrFe1-xCoxOy. [References: 26]