Mechanochemical solid reaction of yttrium oxide with alumina leading to the synthesis of yttrium aluminum garnet

Dry grinding of Y2O3 and transition aluminas was conducted, using a planetary ball mill under atmospheric conditions, to synthesize yttrium aluminum garnet (Y3Al5O12, YAG). The Y2O3 reacts mechanochemically with the transition aluminas to form YAlO3 and YAG after 120 min of grinding. No reaction occurs when the Y2O3 was ground with hard corundum or soft gibbsite. Grinding the Y2O3 for 360 min with an alumina prepared by heating at 400 °C leads to a nearly amorphous phase of YAG. A well-crystallized phase of YAG was obtained easily by calcining the ground sample at 700 °C. The calcined YAG fine powders contain agglomerates that consist of nanosized primary grains.