Dilatometric studies of Y2W3O12 with added Al2O3

Y2W3O12 exhibits negative thermal expansion along the three crystallographic directions due to the transverse thermal vibrations perpendicular to the Y-O-W linkage. It is highly hygroscopic and forms a trihydrate structure at room temperature. Dilatometric studies of Y2W3O12 show large thermal expansion hysteresis due to large grain size and a large initial positive thermal expansion due to the removal of water molecules. Al2O3 has been added to Y2W3O12 upto 10 wt% in an attempt to overcome the hygroscopicity and reduce the particle size and thereby the thermal expansion hysteresis. Thermo gravimetric, dilatometric and electron microscopic studies are presented to support these observations.