The synthesis of LaCrO3 from a stoichiometric mixture of Cr2O3 and La2O3 powder by microwave irradiation was examined using a multi-mode 28 GHz microwave heating system. In the La2O3-Cr2O3 system, Cr2O3 strongly absorbs microwaves while La2O3 is transparent to microwaves. The reaction proceeded rapidly and LaCrO3 could be synthesised within 15 min of irradiation. Surprisingly, the temperature required for the microwave synthesis (440°C) is much lower than that for conventional synthesis (>1200°C) using an electric furnace. The effect of the partial pressure of oxygen in the microwave chamber on the formation of LnCrO3 was investigated. The formation of LnCrO3 is enhanced with increase in the partial pressure of oxygen for Ln = La and Nd, while opposite behavior is seen for Ln = Gd, Tb, Dy and Ho.
ASJC Scopus subject areas
- Materials Chemistry