Search

Abstract: A new method for synthesis of nanocrystalline titanium nitride was developed through the reaction of titanium oxide and sodium amide at 500–600 °C for 12 h in an autoclave. X-ray diffraction (XRD) and electron diffraction (SAED) results indicated the product had a cubic phase with lattice parameter a =4.242 Å. Transmission electron microscopy (TEM) and field emission scanning electron microscopy (FESEM) revealed that the particle sizes were 10 to 40 nm. Quantitative analysis using X-ray photoelectron spectrum (XPS) showed the atomic ratio Ti:N was 1.03:1. [Copyright &y& Elsevier]

Vanadium nitride was synthesized by the reaction of VCl4 and NaNH2 at room temperature. X-ray powder diffraction could be indexed as cubic VN with the lattice constant of a=4.134Å. Transmission electron microscopy image showed particle and hollow sphere morphology. The optical properties of the as-prepared VN were investigated. [Copyright &y& Elsevier]

Ultrafine magnesium diboride (MgB2) powders were successfully synthesized at 600 °C through a solid-state reaction. The synthesis was carried out in an autoclave by using MgCl2 and NaBH4 as the reactants. The X-ray powder diffraction pattern indicates the formation of hexagonal MgB2. Transmission electron microscopy image shows that typical MgB2 crystallites are composed of ultrafine particles with an average size of 300 nm. The superconducting transition of the MgB2 sample occurs at 39 K. [Copyright &y& Elsevier]

Nanocrystalline titanium diboride (TiB2) has been prepared by the reaction of TiCl4 with NaBH4 in the temperature range of 500–700 °C in an autoclave. X-ray powder diffraction (XRD) patterns can be indexed as hexagonal TiB2 with the lattice constants of a=3.032 and c=3.229 A˚. Transmission electron microscopy (TEM) image shows particle morphology, with average size of 15 nm for the powder obtained at 600 °C. Selected area electron diffraction (SAED) pattern confirms the prepared hexagonal TiB2. The oxidation behavior of TiB2 is studied by thermogravimetric analysis (TGA) and differential thermal analysis (DTA). [Copyright &y& Elsevier]

Molybdenum carbide (Mo2C) has been synthesized via a sodium co-reduction of molybdenum pentachloride (MoCl5) and carbon tetrabromide (CBr4) in benzene at 350 °C for 12 h. X-ray diffraction (XRD) pattern indicated that the product was mainly hexagonal Mo2C with a small amount of cubic Mo2C. The lattice constants of the hexagonal Mo2C were a=3.009 and c=4.736 A˚. Transmission electron microscopy (TEM) study showed that the product consisted of slightly conglomerated particles of about 30 nm in size. [Copyright &y& Elsevier]

Abstract: Nanocrystalline neodymium disilicide was synthesized by co-reducing anhydrous neodymium trichloride and sodium fluorosilicate with metallic sodium in an autoclave at 650°C. The as-prepared product was characterized and studied by X-ray powder diffraction, transmission electron microscopy and thermogravimetric analysis. [Copyright &y& Elsevier]

Nanocrystalline vanadium diboride (VB2) were successfully synthesized at 650 °C through a solid state reaction. The synthesis was carried out by reacting VCl4 with NaBH4 and Mg in an autoclave. The X-ray powder diffraction pattern indicates the formation of hexagonal VB2. An atomic ratio of B to V of 2.11:1.0 is determined from X-ray photoelectron spectra. Transmission electron microscopy image shows that typical VB2 crystallites are composed of uniform particles with the grain size in the range of 50–100 nm. [Copyright &y& Elsevier]

Abstract: Niobium diboride (NbB2) nanorods have been successfully synthesized by the reaction of NbCl5 with NaBH4 in the temperature range of 550–650 °C in an autoclave. X-ray diffraction (XRD) and electron diffraction show that the as-prepared products are NbB2. Transmission electron micrographs shows that the average diameter of samples are in the range of 50–60 nm and the length is up to 600 nm. The mechanism for the formation of crystalline NbB2 is proposed. [Copyright &y& Elsevier]