MOSSBAUFR SPECTROSCOPY STUDY OF MgAl_2O_4- MATRIX NANOCOMPOSITE POWDERS CONTAINING CARBON NANOTUBES AND IRON-BASED NANOPARTICLES

摘要

Materials involved in the catalytic formation of carbon nanotubes are first time systema- tically studied by Mossbauer spectroscopy between 11 K and room temperature. Mg_1-xFe_xAl_2O_4(x = 0.1, 0.2,0.3,0.4)solid solutions are transformed into carbon nanotubes-Fe/Fe_3C-MgAl_2O_4 composite powders by reduction in a H_2-CH_4 mixture. The oxides are defective spinels of general formulae (MG~2+_1-xFe~2+_x-3αFe~3+_2α□αAl~3+_2).