Portal de Periódicos da CAPES

Oxygen‐Pressure Dependence of Cation Interdiffusivity in Magnesiowustite Solid Solutions

1982; Wiley; Volume: 65; Issue: 3 Linguagem: Inglês

10.1111/j.1151-2916.1982.tb10386.x

1551-2916

N. Sata, Kazuhiro S. Goto,

Bauxite Residue and Utilization

Cation interdiffusivity in magnesiowustite solid solutions was measured as a function of temperature and oxygen pressure. During diffusion, the local composition of Fe 2+ and Fe 3+ was always equal to the equilibrium composition with the oxygen pressure in the. gas phase. The interdiffusivity is empirically expressed as D=DP 0 P 0 2 1/n expβX Fe . The interdiffusivity increases exponentially with iron mole fraction between 30 and 80 mol% Fe at a given oxygen pressure and temperature. The value of β was between 8 and 10 with the 1/n value 1/2 to 1/5 at 1250° to 1350°C. This oxygen‐pressure dependence of the interdiffusivity is equal to that of the product of defect concentration (Roth‐type cluster) and correlation factor. From the result, iso‐interdiffusivity lines are drawn in the broad range of the magnesiowustite solid solution in the MgO‐FeO‐Fe 2 / 3 O quasi‐ternary system.