THE CARBOTHERMAL REDUCTION PROCESS OF A MONTMORILLONITE POLYACRYLONITRILE INTERCALATION COMPOUND

To develop a carbothermal reduction process for the conversion of oxides to nitrides, a montmorillonite-polyacrylonitrile (PAN) intercalation compound was applied as a precursor. Montmorillonite-carbon mixtures were heated as well as the intercalation compound in N2 at 1100 to 1500°C for comparison. From the intercalation compound, β-sialon, AlN and SiC were mainly formed. Oxides were reduced without their crystallization. On the other hand, in the reactions of the mixtures, some oxides and other kinds of nitride were obtained as principal products in addition to these phases. Furthermore, the intercalation compound was more favorable than the mixtures having a larger amount of carbon in terms of the reduction of oxides and the formation of nitrides. These observations suggest that the layered structure of the intercalation compound led to an effective and specific carbothermal reduction process.