Synthesis of Negative Thermal Expansion Sc2W3O12 Thin Film

Orthorhombic Sc2W3O12 thin films were deposited by pulsed laser deposition method. The microstructure, composition and morphology of the Sc2W3O12 ceramic target and thin films were investigated using the X-ray diffraction (XRD) and field emission scanning electron microscope (FESEM). The effects of the substrate temperature and oxygen pressure on the Sc2W3O12 thin films were studied. The negative thermal expansion (NTE) properties of the Sc2W3O12 ceramic target and thin film were characterized using high temperature XRD and thermal mechanical analysis (TMA). Results indicate that the compact orthorhombic Sc2W3O12 ceramic target with excellent NTE can be prepared by sintering at 1000 degrees C for 6 h. The average thermal expansion coefficient of the orthorhombic Sc2W3O12 ceramic target is -5.28x10(-6) K-1 from room temperature to 600 degrees C. All the as-deposited Sc2W3O12 thin films are amorphous. The surface of the as-deposited Sc2W3O12 thin film becomes smoother, but it becomes uneven when the substrate temperature increases. The Sc2W3O12 thin film with excellent NTE is crystallized after annealing at 1000 degrees C for 7 min. The thermal expansion coefficient of the orthorhombic Sc2W3O12 thin film is calculated to be -7.17x10(-6) K-1 in the temperature range from room temperature to 600 degrees C.