SYNTHESIS OF ALUMINA-NITRIDE NANOCOMPOSITES BY SUCCESSIVE REDUCTION-NITRIDATION IN MECHANOCHEMICALLY ACTIVATED REACTIONS

According to our recent study, zircon (ZrSiO4) mineral can be reduced to a zirconium silicide-alumina mixture by mechanochemically induced r eplacement reaction with aluminium. Further milling in nitrogen atmosp here produced zirconium nitride-alumina-silicide ceramic composite. Th is two step procedure can be extended for application to a variety of oxide starting materials. In this paper we present nitridation results for oxides of the group IV metals (Ti, Zr, and Hf). These elements we re successfully nitrided to form compounds with the approximate compos ition MN0.9 (M=metal). Intermediate phases including ternary alloys an d sub-oxides were detected during the milling process. Resulting nitri de-oxide ceramic compositions are compared to those predicted by therm odynamic considerations. (C) 1998 Elsevier Science S.A.