Rapid formation and growth of bixbyite-type (In0.67Fe0.33)(2)O-3 by 28 GHzmicrowave irradiation

(In0.67Fe0.33)(2)O-3 with the bixbyite structure was synthesized via 28 GHz microwave irradiation, using multimode microwave heating equipment. Indium sesquioxide strongly absorbs 28 GHz microwaves, and this strong coupling w ith microwave energy can be used to drive a reaction with iron sesquioxide. A mixture of In2O3 and alpha-Fe2O3 powders (In:Fe ratio of 2:1) was irradi ated with microwaves at a frequency of 28 GHz, The mixture was heated to 14 00 degrees C during the microwave irradiation. The formation of a solid sol ution was completed within a minute, which indicated a drastic enhancement of the reaction rate. Scanning electron microscopy revealed remarkable grai n growth under microwave irradiation.