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Abstract: A simple and efficient way to synthesize the SiC/SiO2 nanocables decorated with the laminated porous ceramics by pyrolysis of filter papers impregnated with silicone resins in flowing argon atmosphere has been successfully developed. The phase composition of the laminated porous ceramics was measured by X-ray diffraction. The morphology and microstructure of the samples were analyzed by scanning electron microscopy and transmission electron microscopy. The experimental results show that the nanocables composed of crystalline SiC core coated with a shell of amorphous SiO2 were observed in the interfacial channels and pores of the laminated ceramics. The diameters of SiC cores were 40–80nm and the thicknesses of SiO2 shells were 4–10nm. The increase of the pyrolysis temperature caused an increase in the amount of SiC/SiO2 nanocables. Finally, a vapor–liquid–solid (VLS) process was discussed as the growth mechanism of the nanocables. [Copyright &y& Elsevier]

Abstract: Different acids were used to prepare ZrW2O8 powders at 570°C by the hydrothermal method. The products were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, high-resolution transmission electron microscopy, thermogravimetric and differential scanning calorimetry and Fourier transform infrared absorption spectra. The results indicate that among the chosen acids, only HCl and HNO3 can be used to prepare pure ZrW2O8 powders with high crystallinity and rod-like shape. When the hydrothermal temperature reduces to 160°C, nano-sphere particles with an average diameter of 30nm is obtained, if prepared by HNO3 addition. The results of in situ X-ray diffraction measurement indicate that ZrW2O8 powders prepared by pure HCl or HNO3 have strong negative thermal expansion. [Copyright &y& Elsevier]

Abstract: The microstructure and electrical properties of ZnO–Bi2O3-based varistor ceramics doped with different Sc2O3 content sintered at 1100°C were investigated. The results showed that the nonlinear coefficient of the varistor ceramics with Sc2O3 were in the range of 18–54, the threshold voltage in the range of 250–332V/mm, the leakage current in the range of 0.1–23.0μA, with addition of 0–1.00mol% Sc2O3. The ZnO–Bi2O3-based varistor ceramics doped with Sc2O3 content of 0.12mol% exhibited the highest nonlinearity, in which the nonlinear coefficient is 54, the threshold voltage and the leakage current is 278V/mm and 2.9μA, respectively. The results confirmed that doping with Sc2O3 was a very promising route for the production of the higher nonlinear coefficient of ZnO–Bi2O3-based varistor ceramics, and determining the proper amounts of addition of Sc2O3 was of great importance. [Copyright &y& Elsevier]

Abstract: A composite of Sc2W3O12/Cu where Sc2W3O12, the core, is coated by the Cu shell was synthesized using simple electroless plating method. As-prepared Sc2W3O12/Cu composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and thermomechanical analyzer (TMA) techniques. The study results show that the Pd–Sn activator was successfully formed on the surface of Sc2W3O12 after the sensitization and activation. In the electroless plating process, Cu nanocrystals formed firstly, and then grew together to form a continuous coating. Sc2W3O12/Cu core–shell composites exhibit a negative linear coefficient of thermal expansion CTE=−4.47×10−6 °C−1 from room temperature to 200°C. [Copyright &y& Elsevier]

Abstract: Negative thermal expansion materials ZrW2−x Mo x O8 (0≤ x ≤2) have been successfully synthesized by the reaction of a mixture of ammonium tungstate and ammonium molybdate with zirconium oxynitrate using a hydrothermal method. Effect of substituted ion Mo on the microstructure, α-to-β and cubic to trigonal phase transition in resulting ZrW2−x Mo x O8 powders was examined by the XRD experiments. It was found that the structural phase transition temperature decreased slightly with increasing substituted content. The cubic to trigonal phase transition was also influenced by substituted content. The resulting products decomposed to WO3/MoO3 and ZrO2 as temperature increasing when x ≤0.5 and while x >0.5, the cubic phase transited to trigonal phase. The effect of substituted Mo on the morphology of resulting products was also investigated by SEM experiments. [Copyright &y& Elsevier]