Investigating negative thermal expansion property of decahedral Sc2Mo3O12 prepared via hydrothermal method

Abstract

Orthorhombic Sc2Mo3O12 with decahedral structure have been prepared via hydrothermal method. The phase evolution, morphology and negative thermal expansion (NTE) behavior of the decahedral Sc2Mo3O12 were investigated using XRD, SEM, TMA and high-temperature XRD. XRD and SEM analyses indicate that orthorhombic Sc2Mo3O12 particles with decahedral structure were obtained after annealing at 800 °C. The decahedral Sc2Mo3O12 particles are uniform and regular with a size of about 20 μm × 20 μm × 5 μm. Decahedral Sc2Mo3O12 shows stable NTE. TMA analysis shows the coefficient of thermal expansion (CTE) of decahedral Sc2Mo3O12 is −4.12 × 10−6 K−1 in 25–700 °C. High-temperature XRD analysis reveals that it displays anisotropic NTE at the same temperature range. The axial CTEs of decahedral Sc2Mo3O12 are αa = −4.37 × 10−6 K−1, αb = 3.61 × 10−6 K−1 and αc = −2.96 × 10−6 K−1, respectively. The linear CTE is −1.22 × 10−6 K−1.