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Abstract: Crystalline tungsten disulphide nanoparticles were successfully synthesized by the chemical vapor condensation (CVC) method. The process performed as decomposition of tungsten hexacarbonyl over sulphur vapor in inert gas flow, where WS2 nanoparticles were synthesized by direct reaction between as formed pure tungsten nanoclusters and sulphur vapor. Influence of experimental parameters on shape, size distribution, structure and phase composition of nanoparticles were evaluated by transmission and scanning electron microscopy and X-ray diffraction analysis. The produced nanoparticles have closely spherical shape with the mean size in the range 20–70nm in diameter dependently of process parameters. Nested “onion-like” structure of nanoparticles was observed. The mean value of interlayer distance in the {0001} direction, is about 0.6358±0.031nm. Due to nanodimensional size, physical properties and layered structure tungsten disulphide nanoparticles have great potential as a solid lubricant material. [Copyright &y& Elsevier]

Abstract: Iron carbide Fe3C nanoparticles were fabricated by a chemical vapor condensation (CVC), and their structural and magnetic properties were investigated. It was found that the formation of iron carbide nanoparticles strongly depended on reaction temperature and pressure. The iron carbide was formed only above 650°C at 101kPa (760Torr) but never formed in vacuum (1.33Pa) regardless of reaction temperature. The fabricated iron carbide nanoparticles were spherical with T c of about 240°C. While the particles formed at 650°C (∼30nm) possessed a typical core–shell structure, those formed at 800°C (∼50nm) did not have such structure. The nanoparticles fabricated at 650°C and 800°C at 101kPa, exhibited M s of ∼125Am2/kg whereas i H c of the former was slightly higher (∼63kA/m) than that of the latter (∼40kA/m). [Copyright &y& Elsevier]

Nanosized #x03B5;-Fe3N and iron-nitrides/α-Fe particles with a core-shell structure were prepared by the chemical vapor condensation. Structure and magnetic properties were studied by means of transmission electron microscopy, X-ray photoelectron spectroscopy and vibrating sample magnetometer. The core consists of iron-nitrides/α-Fe or single #x03B5;-Fe3N nanoparticles, while the shell consists of iron oxides. Magnetic properties of #x03B5;-Fe3N nanoparticles can be improved by varying the experimental conditions. The maximum value of the saturation magnetization reaches 126.1 emu/g for the #x03B5;-Fe3N nanoparticles prepared at 1000°C by a pure 60 sccm NH3 carrier gas. [Copyright &y& Elsevier]

Magnetic Co nanoparticles were synthesized by a chemical vapor condensation method using the precursor of cobalt carbonyl as the source under a flowing inert gas atmosphere. Characteristics of the resulting material were investigated systematically by means of X-ray diffraction, high resolution transmission electron microscopy, TEM, X-ray photoelectron spectroscopy, vibrating sample magnetometer and differential thermal analysis-thermogravimetry. A correlation between the preparation conditions and the resulting microstructure of the nanoparticles was studied. [Copyright &y& Elsevier]

Iron nanoparticles were synthesized by the chemical vapor condensation (CVC) process using the pyrolysis of iron pentacarbonyl (Fe(CO)5). The influence of CVC parameter on the formation of nanoparticle and size distribution was studied. The synthesized nanoparticles consisted of core-shell type structure with nearly spherical shape and 6–25 nm in mean diameter. Obtained particles were studied by transmission electron microscopy and X-ray diffraction methods. The decrease of lattice constant of iron with increasing particle size was explained by the core–shell interaction. [Copyright &y& Elsevier]

Abstract: ε-Fe3N nanoparticles synthesized by chemical vapor condensation (CVC) are covered with shells of disordered Fe3O4 phase, as observed by a transmission electron microscopy. The zero-field cooling and field cooling temperature dependence of magnetization, ac susceptibility as a function of frequency, magnetic hysteresis loops, and the temperature dependence of resistivity of the ε-Fe3N nanoparticles are systematically studied. The results indicate the existence of complex magnetic properties, such as superparamagnetic behavior, exchange bias, magnetic dipole interaction, and the possible coexistence of ferromagnetic and spin-glass-like states and/or disordered surface spins of the shells at low temperatures. The temperature dependence of resistivity ρ(T) for compacted ε-Fe3N nanoparticles in a temperature range of 110K

Abstract: Iron nanoparticles were synthesized without a chilling device in the condensation system of gases vaporized from iron-pentacarbonyls as starting precursors. The size distribution of the synthesized iron particles was wider, ranging from 10 nm to 100 nm, than that of the particles rapidly cooled on the surface of a chiller. The oxide shell thickness and carbon content were analyzed quantitatively in synthesized powders as well as their microstructures and magnetic properties. [Copyright &y& Elsevier]

Iron–cobalt alloyed (Fe1−xCox, x≤50 wt.%) nanoparticles with core–shell structure was prepared by chemical vapor condensation (CVC) process and characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), and vibrating sample magnetometer. The particles having the mean size of 5–25 nm consisted of metallic cores and oxide shells. The nanoparticle size increased with increasing gas flow rate. The saturation magnetization and coercivity increased with increasing Co content, and the saturation magnetization reached its maximum rate at 40 wt.% Co. [Copyright &y& Elsevier]