Hydrothermal synthesis of flower-like Sc2Mo3O12 and its investigation into negative thermal expansion property

Abstract

Orthorhombic Sc2Mo3O12 samples have been synthesized using ethylene glycol (EG)-assisted hydrothermal reaction. The influences of hydrothermal temperature, hydrothermal time and additive content of EG on the preparation and negative thermal expansion (NTE) behavior of Sc2Mo3O12 samples were characterized using XRD, SEM, HRTEM, EDX, TMA and HTXRD. Results indicate that flower-like Sc2Mo3O12 with a uniform particle size of 1–2 μm can be synthesized at 120 °C for 2 h by adding 60 ml EG. Hydrothermal temperature, time and additive content of EG have strong influences on the growth and morphology of the Sc2Mo3O12. The average coefficients of thermal expansion (CTEs) of the Sc2Mo3O12 prepared at 120 °C for 2 h and 200 °C for 24 h are tested to be −6.94 × 10−6 °C−1 and -7.18 × 10−6 °C−1 in 25–700 °C using TMA. HTXRD results indicate that the flower-like Sc2Mo3O12 exhibits anisotropic NTE, and the corresponding CTEs along the a, b and c axes are −6.73 × 10−6 °C−1, 4.98 × 10−6 °C−1 and -4.78 × 10−6 °C−1 in 25–700 °C, respectively, and the corresponding linear CTE is −2.21 × 10−6 °C−1.