Synthesis of Sc2W3O12/ZrO2 composites with controllable thermal expansion

Sc2W3O12, which exhibits excellent anisotropic negative thermal expansion was synthesized using solid-state reaction. Sc2W3O12/ZrO2 composites were prepared by mixing ZrO2 and Sc2W3O12 at different volume ratios and sintered at 1200°C for 10 h. The crystal structure, fracture surface morphology and thermal expansion properties of the synthesized samples were characterized by XRD, SEM, EDS and dilatometer. The results indicate that the obtained samples contain only orthorhombic Sc2W3O12 and monoclinic ZrO2 phase. All the thermal expansion properties of Sc2W3O12/ZrO2 composites are linear from 30°C to 600°C, and their thermal expansion coefficients can be controlled as positive, negative or even zero by adjusting the volume fraction of Sc2W3O12. 60%Sc2W3O12/ZrO2 composite shows almost zero thermal expansion, and its average thermal expansion coefficient is 0.026×10-6°C-1 from 30°C to 600°C.