The structure of iron oxide was controlled by regulating the hydrolytic polymerization of aquo iron complexes with organic
polydentate ligands such as diols. Iron oxides were prepared by calcining the precursor polymers obtained from iron nitrate
nonahydrate and diols. When the diols were 1,2-pentanediol, 1,2-hexanediol and 1,2-octanediol, α-Fe
2O
3 with corundum structure appeared exclusively or as the main crystalline phase, in spite of the amount of diol used and the
calcination temperature. In the case of 1,2-decanediol and 1,2-dodecanediol, when five moles of the diols were used to one
mole of iron nitrate and the calcination temperatures were below 400°C, ψ-Fe
2O
3 with spinel structure appeared as the main phase and, when less than five moles of the diols were used, α-Fe
2O
3 appeared exclusively or as the main phase, irrespective of the calcination temperature. This tendency was also observed in
thin films. Thus, a transparent magnetic film composed of γ-Fe
2O
3 could be prepared by applying a benzene solution of the iron polymer, obtained with 5 equivalents of 1,2-decanediol, on quartz
and calcining the gel film at 350°C.
相似文献