抄録
Large dendritic oxide (hematite) was prepared by firing the mixture of a-Fe2O3 and Sb2O3 in the reducing atmosphere with the use of rice-chaff. The mechanism of the dendrite formation was interpreted as follows:
The early stage dissolution of a-Fe2O3 into Sb2O3 melt is followed by the evaporation of Sb2O3 with the increase of temperature, which consequently leads to the precipitation of dendritic nuclei of magnetite (Fe2O4) on the melt surface, because of strongly reducing atmosphere. The mixed melt climbs through the dendrite nuclei by the capillary action, and the successive evaporation of the solvent (Sb2O3) results in the rapid growth of Fe2O4 dendrite. Since the dendrites have large surface area, they are readily reoxidized to ferric oxide (a-Fe2O3) during cooling stage, retaining the skelton structure of the magnetite dendrite.
