LOW-TEMPERATURE SYNTHESIS OF BETA-ALUMINAS BY A SOL-GEL TECHNIQUE

New intermediates observed in the process of preparing sodium beta-alu minas by a sol-gel method using metal alkoxides as precursors are desc ribed. Results of studies to optimise the conditions for the preparati on by changing parameters such as calcination temperatures and initial concentration of isopropoxides are reported. Based on IR, TG/DTA and XRD studies, different steps in the process leading to the formation o f beta-aluminas are discussed. These studies show that the formation o f beta-alumina starts at as low a temperature as 1273 K possibly throu gh a modified cubic-close-packed gamma-alumina structure stuffed with sodium ions and completes at 1473 K.