Scandium Molybdate Nanofibers with Negative Thermal Expansion for Fabricating Composites with Controllable Coefficients of Thermal Expansion

Abstract

Single-crystal Sc2Mo3O12 nanofibers, an one-dimensional negative thermal expansion (NTE) material, have been successfully synthesized by electrospinning. The crystal structure, morphology, and NTE property of Sc2Mo3O12 nanofibers were characterized using typical X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectroscopy (EDX), and variable-temperature XRD. Results indicate that as-deposited Sc2Mo3O12 nanofibers are amorphous and display a smooth surface and uniform diameter. Single-crystal Sc2Mo3O12 nanofibers are fabricated at 500 °C for 3 h and grown along the (111) orientation with an orthorhombic structure. The average diameter of single-crystal Sc2Mo3O12 nanofibers is ∼100 nm. Sc2Mo3O12 nanofibers exhibit anisotropic NTE with an average volumetric coefficient of thermal expansion (CTE) of −6.53 × 10–6 °C–1 from 25 °C to 700 °C. The average CTEs along the a-, b-, and c-axes are −6.62 × 10–6, 5.33 × 10–6, and −5.21 × 10–6 °C–1, respectively.