Preparation of In0.5Sc1.5Mo3O12 Nanofibers and Its Negative Thermal Expansion Property

Orthorhombic In0.5Sc1.5Mo3O12 nanofibers were prepared by electrospinning followed by a heat treatment. The effects of post-annealing temperatures on the phase composition, microstructure and morphology were inves-tigated by XRD, SEM, HRTEM and XPS. Negative thermal expansion (NTE) behaviors of the In0.5Sc1.5Mo3O12 nanofibers were analyzed by high-temperature XRD. Results indicate that the as-prepared In0.5Sc1.5Mo3O12 nanofibers show an amorphous structure with smooth and homogeneous shape. The average diameter of the as-prepared In0.5Sc1.5Mo3O12 nanofibers is around 515 nm. Well crystallized orthorhombic In0.5Sc1.5Mo3O12 nanofibers could be prepared after post-annealing at 550 degrees C for 2 h with an average diameter of about 192 nm. The crystallinity of In0.5Sc1.5Mo3O12 nanofibers gradually improved with the increase of annealing temperature. However, too high post-annealing temperature leads to a damage of sample's fiber structure. The high-temperature XRD results reveal that In0.5Sc1.5Mo3O12 nanofibers show an anisotropic NTE, and the co-efficients of thermal expansion (CTEs) along a-axis and c-axis were-5.95 x 10-6 degrees C- 1 and-3.54 x 10-6 degrees C- 1, while the one along b-axis is 5.61 x 10-6 degrees C- 1. The volumetric CTE of In0.5Sc1.5Mo3O12 nanofibers is-3.90 x 10-6 degrees C- 1 and the linear one is 1.3 x 10-6 degrees C- 1 in 25-700 degrees C.