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One-dimensional negative thermal expansion material has important applications in thermal expansion control and fiber toughened composite. Orthorhombic Al1.6Sc0.4Mo3O12 nanofibers have been prepared by electrospinning. The phase composition, microstructure, morphology, and thermal expansion performance of the samples prepared at various temperatures were investigated. Results show that as-prepared Al1.6Sc0.4Mo3O12 nanofibers are smooth and homogeneous with a fiber diameter of about 370.00 nm, but they show an amorphous structure. Orthorhombic Al1.6Sc0.4Mo3O12 nanofibers can be obtained at 550 ℃ with a diameter of around 140.00 nm. With the increase of post-annealing temperatures, the crystallization of the samples was improved. However, higher post-annealing temperatures will destroy the nanofiber structure of the samples. HTXRD reveals that orthorhombic Al1.6Sc0.4Mo3O12 nanofibers show anisotropic NTE in 25–700 °C. The expansion coefficients αa, αb, and αc of Al1.6Sc0.4Mo3O12 nanofibers are −5.05 × 10–6 °C−1, 4.41 × 10–6 °C−1, and −3.18 × 10–6 °C−1, respectively. The αv is −3.83 × 10–6 °C−1, and the corresponding αl is −1.28 × 10–6 °C−1. [ABSTRACT FROM AUTHOR]

Cubic ZrV 2 O 7 thin films have been synthesized by sol-gel spin-coating method. The influences of annealing temperatures on the phase composition and morphology of ZrV 2 O 7 thin films were investigated using XRD, SEM, and EDX. Negative thermal expansion (NTE) and optical performances of cubic ZrV 2 O 7 thin films were analyzed using variable temperature XRD and UV–Vis spectroscopy. Results indicate that as-deposited ZrV 2 O 7 thin films have an amorphous structure with smooth and dense surface. Cubic ZrV 2 O 7 thin films were prepared after heat treatment at 720 °C for 1 h. It was found that the thin films contained V 2 O 5 impurity with the Zr: V = 1:2 precursor solution. Pure cubic ZrV 2 O 7 thin films were fabricated with the Zr: V = 1.75:2 precursor solution. Cubic ZrV 2 O 7 thin films show isotropic NTE in the temperature range of 100–700 °C. The coefficients of thermal expansion (CTEs) of ZrV 2 O 7 films along the a , b , and c axes are −6.88 × 10−6 °C−1, and the volumetric and linear CTEs are −20.56 × 10−6 °C−1 and -6.85 × 10−6 °C−1, respectively. The transmittance of cubic ZrV 2 O 7 thin film is approximately 80 %. [ABSTRACT FROM AUTHOR]

Orthorhombic Sc 2 (MoO 4) 3 nanofibers have been prepared by ethylene glycol assisted electrospinning method. The effects of annealing temperature, precursor concentration, spinning distance and solvent on the preparation of Sc 2 (MoO 4) 3 nanofibers were characterized by XRD, SEM, HRTEM, EDX and high-temperature XRD. XRD analysis shows as-prepared nanofibers are amorphous. Orthorhombic Sc 2 (MoO 4) 3 nanofibers can be fabricated after annealing at different temperatures in 500–800 °C for 2 h. The crystallinity of Sc 2 (MoO 4) 3 nanofibers improves and the nanofiber diameter decreases gradually as the annealing temperature increases. However, the nanofiber structure was destroyed at the annealing temperature above 700 °C. Higher precursor concentration results in a slight increase of diameter and decrease in destroying temperature of Sc 2 (MoO 4) 3 nanofibers. Spinning distance also affects the diameter of nanofibers, and the nanofiber diameter decreases as the distance increases. One-dimensional orthorhombic Sc 2 (MoO 4) 3 nanofibers exhibit anisotropic negative thermal expansion. In 25–700 °C, the coefficients of thermal expansion (CTE) of α a , α b and α c are −5.81 × 10−6 °C−1, 4.80 × 10−6 °C−1 and -4.33 × 10−6 °C−1, and the α l of Sc 2 (MoO 4) 3 nanofibers is −1.83 × 10−6 °C−1. [ABSTRACT FROM AUTHOR]

Negative thermal expansion (NTE) Sc2(MoO4)3 thin films were fabricated on quartz substrates via facile sol–gel spin coating technique. Effects of process parameters on the phase composition, morphology, thermal expansion behavior and optical property of the Sc2(MoO4)3 thin films were investigated. XRD analysis reveals that as-deposited Sc2Mo3O12 thin films show amorphous phase. Orthorhombic Sc2(MoO4)3 thin films were prepared after annealing in 500–780 °C for 1 h, the crystalline quality of the post-annealed Sc2(MoO4)3 thin films gradually improved, and the grain size also increased as annealing temperature rises. Both as-deposited and post-annealed Sc2(MoO4)3 thin films show a smooth and compact surface. Low heating and cooling rates have contributed to the improvement of quality of the Sc2(MoO4)3 thin films. Orthorhombic Sc2(MoO4)3 thin films show anisotropic NTE. Its coefficient of thermal expansion is − 1.86 × 10−6 °C−1 in 25–700 °C. The transmittance of orthorhombic Sc2(MoO4)3 thin film post-annealed at 780 °C is measured as well and which is about 82% in the visible light range. [ABSTRACT FROM AUTHOR]

Orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 thin films have been synthesized using the sol-gel spin coating. Influences of post-annealing temperatures on crystal structure, morphology, negative thermal expansion (NTE) and optical performances of the thin films were studied using XRD, SEM, XPS, high-temperature XRD and UV–Vis–NIR spectrophotometer. XRD and SEM results show that as-prepared thin film is in an amorphous state with a smooth and dense surface. Orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 thin films were obtained after post-annealing in 550–750 °C. The higher the annealing temperature in 550–750 °C, the better the crystallinity of orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 thin films. In addition, the grain size of the In 0.5 Sc 1.5 Mo 3 O 12 thin film also grows as the annealing temperature increases. The resulting orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 thin films exhibit anisotropic NTE. Its volumetric coefficient of thermal expansion (CTE) is −3.44 × 10−6 °C−1, while the CTEs in a -, b - and c -axis directions are −4.70 × 10−6 °C−1, 5.37 × 10−6 °C−1, and -4.10 × 10−6 °C−1 in 25–700 °C, respectively. In addition, the transmittance of orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 thin films post-annealed at 750 °C is around 87.75 %–95.03 %. [ABSTRACT FROM AUTHOR]

Orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 nanofibers were prepared by electrospinning followed by a heat treatment. The effects of post-annealing temperatures on the phase composition, microstructure and morphology were investigated by XRD, SEM, HRTEM and XPS. Negative thermal expansion (NTE) behaviors of the In 0.5 Sc 1.5 Mo 3 O 12 nanofibers were analyzed by high-temperature XRD. Results indicate that the as-prepared In 0.5 Sc 1.5 Mo 3 O 12 nanofibers show an amorphous structure with smooth and homogeneous shape. The average diameter of the as-prepared In 0.5 Sc 1.5 Mo 3 O 12 nanofibers is around 515 nm. Well crystallized orthorhombic In 0.5 Sc 1.5 Mo 3 O 12 nanofibers could be prepared after post-annealing at 550 °C for 2 h with an average diameter of about 192 nm. The crystallinity of In 0.5 Sc 1.5 Mo 3 O 12 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 In 0.5 Sc 1.5 Mo 3 O 12 nanofibers show an anisotropic NTE, and the coefficients of thermal expansion (CTEs) along a -axis and c -axis were −5.95 × 10−6 °C−1 and -3.54 × 10−6 °C−1, while the one along b -axis is 5.61 × 10−6 °C−1. The volumetric CTE of In 0.5 Sc 1.5 Mo 3 O 12 nanofibers is −3.90 × 10−6 °C−1 and the linear one is 1.3 × 10−6 °C−1 in 25–700 °C. [ABSTRACT FROM AUTHOR]