Microwave preparation and sintering of industrially important perovskite oxides: LaMO3 (M = Cr, Co, Ni)

Abstract

Perovskite oxides LaMO₃ (M = Cr, Co, Ni), have been successfully prepared using microwaves of 2.45 GHz. Microwave preparation is rapid, clean and energy efficient. Preparation of LaCrO₃, LaCoO₃ and LaNiO₃ has been achieved in 3 min, 5 min and 10 min respectively. Direct reaction between component oxides is used for the preparation of LaCrO₃ and LaCoO₃, whereas nitrates are used as starting materials for LaNiO₃ preparation. Products have been characterized using XRD, IR spectroscopy and SEM. Their dc electrical conductivity has also been studied and their fracture behaviour has been examined. All three microwave prepared oxide powders are of submicron size. These perovskite oxides have been sintered to very high densities using microwaves. Possible mechanisms of the microwave–material interaction both during preparation and during sintering have been discussed.