SELF-DIFFUSION OF OXYGEN IN MAGNETITE . EFFECT OF ANION VACANCY CONCENTRATION AND CATION DISTRIBUTION

The variation of the self-diffusion coefficient of oxygen in magnetite with hydrogen/water ratio and temperature can be expressed as D = 1.8 × 10-13(PH2-PH2O)0.27 exp(-17,000/RT) cm2 sec-1 The variation of D with PH2/-PH2O is compared with the theoretical predictions made by Wagner and Schmalzried for ternary oxides. It is concluded that at temperatures above 500°, the distribution of cations in the magnetite lattice becomes randomized due to electron exchange.