Investigating Negative Thermal Expansion Property of Decahedral Sc2mo3o12 Prepared Via Hydrothermal Method

Orthorhombic Sc 2 Mo 3 O 12 with decahedral structure have been prepared via hydrothermal method. The phase evolution, morphology and negative thermal expansion (NTE) behavior of the decahedral Sc 2 Mo 3 O 12 were investigated using XRD, SEM, TMA and high-temperature XRD. XRD and SEM analyses indicate that orthorhombic Sc 2 Mo 3 O 12 particles with decahedral structure were obtained after annealing at 800 °C. The decahedral Sc 2 Mo 3 O 12 particles are uniform and regular with a size of about 20 μm×20 μm×5 μm. Decahedral Sc 2 Mo 3 O 12 shows stable NTE. TMA analysis shows the coefficient of thermal expansion (CTE) of decahedral Sc 2 Mo 3 O 12 is -4.12×10 -6 °C -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 Sc 2 Mo 3 O 12 are α a =-4.37×10 -6 °C -1 , α b =3.61×10 -6 °C -1 and α c =-2.96×10 -6 °C -1 , respectively. The linear CTE is -1.22×10 -6 °C -1