EFFECT OF CALCINATION TEMPERATURE ON THE PHASE COMPOSITION AND MAGNETIC PROPERTIES OF THE BOEHMITE WITH ADSORBED FERROCENE

The effect of calcination temperature in air of finely dispersed boehmite powders with ferrocene adsorbed at room temperature from n-hexane solution on X-ray diffraction patterns and EPR spectra of calcined samples was studied. It has been shown that calcination in air of boehmite samples with adsorbed ferrocene leads to the decomposition of ferrocene molecules, stabilization of two types of magnetic centers in the structure of boehmite (at 200 and 400°C) and aluminum oxide (at 600°C) caused by two types of magnetic centers -Fe3+ ions with g-factor values, equal to 4.3 and 2.0. The signal at g = 4.3 is attributed to isolated Fe3+ ions in the structure of boehmite and aluminum oxide in a local field of oxygen anions with a rhombic environment. The signal at g = 2.0 is most likely due to Fe3+ ions bound by dipole interaction for samples with a low concentration of supported ferrocene (<0.1 wt.%) and superpara/ferromagnetic FeOx particles for samples of the calcination product of boehmite with a high content (>0.1 wt.%) of ferrocene. With increasing content of adsorbeded ferrocene, concentrations of Fe3+ ions with g-factor values equal to 4.3 and 2.0 grow disproportionately, and mainly the growth of the concentration of superpara/ferromagnetic FeOx particles on the oxide surface is observed.