APPLICATION OF THE HIGH-TEMPERATURE X-RAY-DIFFRACTION METHOD TO THE DIFFUSION STUDY IN THE MGO-AL2O3 SYSTEM

A mathematical model has been developed to study the kinetics of forma tion of spinel (MgAl2O4) using the high-temperature X-ray diffraction method. Experiments have been carried out for the MgO-Al2O3 system on an X-ray diffractometer in the temperature range of 1373 to 1673 K. Eq uimolar mixtures of MgO and Al2O3 powders have been employed as the st arting samples. The interdiffusivity values calculated from the high-t emperature X-ray diffraction data using the present model are in good agreement with those obtained by diffusion couple experiments. The act ivation energy for the interdiffusion process has been found to be 354 .2 kJ/mol in the temperature range 1473 to 1873 K.