Investigations on the factors assisting a one-step synthesis cum sintering of sodium beta alumina using microwaves

An understanding of a simultaneous microwave synthesis cum sintering taking place in case of MgO stabilized Na-beta"-alumina has been made on the basis of the investigations on the crystal structure of a metastable intermediate called mullite-like-alumina (m-Al2O3). The presence of chemically bonded H2O molecules in the m-Al2O3 intermediate was proposed based on the crystal structure derived and the same verified by other independent techniques. Based on this result, the metastable intermediate can be expected as a microwave active material. The product, Na-beta-alumina is already known to be a good absorber of microwaves. The microwave activity of both the intermediate and the product thus renders possible a direct one-step synthesis cum sintering when the intermediate precursor is exposed to microwaves. (C) 2004 Elsevier B.V. All rights reserved.