Synthesis and tunable thermal expansion property of Al 2−δSc δW 3O 12

Abstract

A series of solid solutions of Al 2−δSc δW 3O 12 ( δ = 0–2) were successfully synthesized by the solid-state reaction with aluminum oxide, scandium oxide and tungsten trioxide as raw materials. The phase composition and structure of the products were analyzed by X-ray powder diffraction and scanning electron microscopy, while the linear thermal expansion coefficients were measured by thermo dilatometer. The results indicate that Al 2−δSc δW 3O 12 with high purity can be successfully prepared by the solid-state method. All samples of different δ values crystallize in the same orthorhombic structure with space group of Pnca. The lattice constants and cell volume increase linearly with increasing Sc content. The average linear thermal expansion coefficients of Al 2−δSc δW 3O 12 measured by thermo dilatometer indicate that the thermal expansion coefficients of the solid solutions could be adjusted to the desired values, such as positive, near zero or negative by simply changing the δ value.