Preparation of Y_2W_3O_(12) and Yb_2W_3O_(12) and their Negative Thermal Expansion Property

Liquid precipitation was applied in the production of Y2W3O12 and Yb2W3O12 powders.The room temperature XRD analyses revealed that both Y2W3O12(Space Group:Pnca)and Yb2W3O12(Space Group:Pbcn)enjoy single orthorhombic structure.The structures of the compounds were tested by high temperature XRD from 50 ℃ to 800 ℃.The Retrieved refinement of structures using TOPAS3.0 on PC at different temperature showed that both Y2W3O12 and Yb2W3O12 have negative thermal expansion properties.The overall linear thermal expansion coefficients of Y2W3O12 and Yb2W3O12 are-6.38×10-6 ℃-1 and-4.18×10-6 ℃-1 respectively through calculating.Compared to high temperature solid state reaction,liquid precipitation reduces the synthesis cycle and lowers the synthesis temperature.