IN SITU OBSERVATIONS OF MICROSTRUCTURAL AND MORPHOLOGICCAL CHANGES OF THE REDUCTION PRODUCT OF MAGNETITE IN H_2/Ar GAS MIXTURES
磁铁矿在H2／Ar气氛中还原产物显微结构与形貌变化的原位观测

The microstructural changes occurring on the surface of magnetite samples in H2/Ar gas mixture have been directly recorded using an optical heating stage technique, and the nucleation, growth model and growth rate of iron nuclei under different reduction conditions were discussed. The results show that in the temperature range of 773 -- 1373 K, four kinds of nucleus morphologies and growth models with different characteristics were observed tinder different reduction conditions. Morphology transformation and average growth rate of iron nuclei were found to be closely related to temperature and hydrogen partial pressure.