Diffusion of Iron Oxide into Single Crystal of Magnesia in Reducing Atmosphere
1966 Volume 74 Issue 856 Pages 366-371
Details
1966 Volume 74 Issue 856 Pages 366-371
The diffusion rate coefficients of iron oxide into single crystal of magnesia were investigated in the temperature range of 1300° to 1590°C and under the oxygen partial pressures of 10-9.0atm to 10-6.1atm. The concentration gradients of the diffused iron ion were analysed by using the electron probe X-ray microanalyser (XMA). The diffusion coefficient was 4.5×10-4 exp (-50, 000/RT)cm2/sec in the above atmosphere, while the value 1.3×10-3 exp (-49, 000/RT)cm2/sec in air.
The quenching technique was applied in order to analyse the reaction between single crystal magnesia and iron oxide in such conditions. The specimen was instantly quenched in the reducing atmosphere bydropping it to the bottom of the furnace. The products analysed by X-ray oscillation method were as follows; at 1300°C, Po2=10-9.0atm magnesiowüstite, at 1380°C, Po2=10-8.2atm magnesiowüstite with a small amount of magnesioferrite, at 1490°C, Po2=10-7.1atm and at 1590°C, Po2=10-6.1atm magnesiowüstite and magnesioferrite. They were formed on the host crystal with a high order of topotactic relation.
