Synthesis and tunable thermal expansion properties of Sc2−xYxW3O12 solid solutions

Abstract A new series of rare earth solid solutions Sc 2− x Y x W 3 O 12 was successfully synthesized by the conventional solid-state method. Effects of doping ion yttrium on the crystal structure, morphology and thermal expansion property of as-prepared Sc 2− x Y x W 3 O 12 ceramics were investigated by X-ray diffraction (XRD), thermogravimetric analysis (TG), field emission scanning electron microscope (FE-SEM) and thermal mechanical analyzer (TMA). Results indicate that the obtained Sc 2− x Y x W 3 O 12 samples with Y doping of 0≤ x ≤0.5 are in the form of orthorhombic Sc 2 W 3 O 12 -structure and show negative thermal expansion (NTE) from room temperature to 600 °C; while as-synthesized materials with Y doping of 1.5≤ x ≤2 take hygroscopic Y 2 W 3 O 12 ·nH 2 O-structure at room temperature and exhibit NTE only after losing water molecules. It is suggested that the obvious difference in crystal structure leads to different thermal expansion behaviors in Sc 2− x Y x W 3 O 12 . Thus it is proposed that thermal expansion properties of Sc 2− x Y x W 3 O 12 can be adjusted by the employment of Y dopant; the obtained Sc 1.5 Y 0.5 W 3 O 12 ceramic shows almost zero thermal expansion and its average linear thermal expansion coefficient is −0.00683×10 −6 °C −1 in the 25–250 °C range.