Nanosized Vanadium Diboride: Synthesis,Structure, and Properties

Russian Journal of General Chemistry - X-ray diffraction, scanning electron microscopic, and X-ray photoelectron spectroscopic examinations, as well as energy dispersive X-ray and elemental...     

Particle size control of alumina nanopowders in microwave plasma-chemical process

The effect of operating parameters of the oxidation of aluminum powder in a stream of air microwave plasma on the particle size of the obtained Al₂O₃ has been studied. The possibility of improving the particle size of the powder by pretreatment the starting aluminum with chemicals activating particle combustion in a reactor has been investigated. Ways of controlling the particle size of produced aluminum oxide nanopowders in the range of 20–80 nm have been found.     

Special features of preparation of nanosized zirconium diboride powders of various dispersity

Products of the zirconium powder reaction with amorphous boron in a Na₂B₄O₇ ionic melt at 650–850°C and those of the ZrCl₄ reaction with NaBH₄ at 300–725°C have been studied by means of X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, thermogravimetry, and elemental analysis. At temperature ≥750°C, single-phase ZrB₂ with the particle size of 60–80 nm is formed in a Na₂B₄O₇ ionic melt, whereas the ZrB₂ powder obtained via the reaction of ZrCl₄ with NaBH₄ at temperature ≥575°C consists of particles differing in the shape, some of which are close to spherical with diameter of 10–35 nm.     

Microwave-assisted chloride process for the production of titanium dioxide

The conditions for the formation of the particle-size and phase composition of titanium dioxide upon the oxidation of titanium tetrachloride in a stream of oxygen-containing microwave discharge plasma have been studied. The possibility of controlling the particle size of the resulting powder in the range of 50–100 nm by changing various operating parameters has been shown. The conditions for obtaining a nearly single-phase powder of the anatase or rutile modification have been found.     

Prospects for Using Photocatalytic Air Cleaning Technology to Provide Safety of Sevoflurane Application to Parturition Anesthesia in Obstetric Hospitals

The product composition of photocatalytic oxidation of vaporized sevoflurane, a next-generation fluorinated inhalation anesthetic, has been studied. It has been found that the final products of oxidation are carbon dioxide and hydrogen fluoride. The possibility of complete chemical absorption of the evolved hydrogen fluoride by a lime absorber during the course of the photocatalytic reaction has been shown. A safe scheme for using photocatalysis is recommended for purifying air to remove vapors of halogen-containing anesthetics under medical hospital conditions.     

Thermally stimulated transformations in brookite-containing TiO<Subscript>2</Subscript> nanopowders produced by the hydrolysis of TiCl<Subscript>4</Subscript>

TiO₂ nanopowder is produced by the low-temperature hydrolysis of TiCl₄. The phase composition of the sample is found to form at a hydrolysis temperature of 30–38°C. Low-temperature annealing (up to 440°C) increases the degree of crystallinity of the phases present in the sample (anatase, brookite) and only weakly affects their ratio. At 500°C, the sample consists of three phases: rutile is detected apart from anatase and brookite. Brookite begins to fail at 600°C; at 700°C, crystalline brookite fails completely.     

Correlation between the E g (1) oscillation frequency and half-width of the (101) peak in the X-ray diffraction pattern of TiO2 anatase nanoparticles

Technical Physics - It is found that the frequency of the E g (1) oscillation in the Raman spectrum of TiO2 anatase nanoparticles increases linearly with the half-width of the (101) peak in the...     

Microwave plasmochemical synthesis of nanopowders in the system Pb-Zr-Ti-O

Conditions for building up the composition and structure of mixed Pb, Zr, and Ti oxides in a microwave plasma-chemical process were studied. As starting substances Pb(C₂H₅)₄, Ti(C₄H₉O)₄, and a 80% Zr(C₄H₉O)₄ solution in 2-propanol were used. To avoid stratification of the components the initial temperature of the flow should not exceed 1000°C. Under these conditions the crystallization of a complex structure requires a combination of a plasma-chemical synthesis with subsequent thermal treatment of the resulting powders. After the thermal treatment an average particle size of lead zirconate-titanate nanopowder was 120 nm.     

Extraction of zinc-containing products from metallurgical sludge of low zinc content using a method of filtration combustion

The possibility of recovery of zinc and zinc-containing compounds from real technogenic waste, metallurgical sludge containing about 1.0% zinc by a filtration combustion method was studied. This method due to its features is distinguished by low energy consumption and can be effectively applied in cases where the use of traditional methods is economically unjustified. In a wide range of control parameters conditions of combustion of slurry samples, the degree of extraction of zinc-containing products were found. The optimal process conditions were determined, under which recovery of zinc from poor sludge (～1.0% Zn) was possible.