Interdiffusion Studies of the System Fe_xO‐MgO

Abstract

The solid-state reaction between Fe,O and MgO is best described as counterdiffusion of the magnesium and iron ions through a relatively rigid oxygen ion lattice of the rock salt structure. A relation between a mutual diffusion coefficient and a controlled cation vacancy concentration was determined by an analysis of the concentration-penetration curve of the Fe,O-MgO solid solution. The diffusion coefficient increased approximately exponentially with a linear increase of the cation vacancy concentration. This may be represented by a linear increase of the entropy of activation with vacancy concentration. The enthalpy of activation for the diffusion reaction, 47.5 kcal per mole, remained independent of vacancy concentration.

Effect of Fe2O3 doping on sintering of yttria-stabilized zirconia

“…29,[33][34][35] The diffusion rate of atomics is proportional to the jump frequency. 34,35 In other words, each position of Fe 3+ substitutent could be a available site for the Zr 4+ ion migration if the interstitial migration of Fe 3+ ions could operate during the sintering process. Therefore, the interstitial defects of Fe 3+ ions partially contribute to an increase in the diffusion coefficient D.…”

Reactions of dense MgO with calcium ferrite-based slags at 1573 K

“…A study of interdiffusion of the Fe x O-MgO system at 1578 K by Rigby and Cutler [15] showed that the mutual diffusion coefficient of Mg 2ϩ and iron ions (Fe 3ϩ and Fe 2ϩ ) increased exponentially with the cation vacancy concentration. Under more oxidized conditions, the counterdiffusion of Mg 2ϩ and iron ions (Fe 3ϩ and Fe 2ϩ ) would be faster.…”

Interdiffusion in a Quasi-Binary Al<SUB>2</SUB>O<SUB>3</SUB>&ndash;Mn<SUB>3</SUB>O<SUB>4</SUB> System in Air

“…So, a tailing of concentration, which usually appears in diffusion phenomena, was not observed. Though these concentration profiles are of an unusual form, the same profile was observed in the system FexO-MgO by Rigby et al (9).…”