12039-87-1Relevant articles and documents
Field activated combustion synthesis of the silicides of vanadium
Maglia,Anselmi-Tamburini,Milanese,Bertolino,Munir
, p. 108 - 118 (2001)
The synthesis of vanadium silicides was investigated using the field-activated combustion synthesis technique. For all V-Si compounds, self-sustaining combustion reactions could be obtained when fields above a threshold value were imposed. Monophasic products were obtained only for the starting compositions V:Si=1:2 and V:Si=5:3. For all other compositions the reaction produced a polyphasic mixture. No significant variation of phase composition was observed with an increase in field strength. In contrast with other systems, the field was seen to have a weak effect on the combustion macrokinetic parameters. This was interpreted on the basis of the large electrical conductivity of the reaction products, driving a large part of the electric flux away from the reaction front. The reaction mechanism was investigated through the use of quenching experiments. Only the VSi2 and V5Si3 phases were observed in the leading edge of the combustion front, with the other phases forming from solid-solid interactions in the afterburn. These results have been compared with observations relative to the mechanism of silicides formation in isothermal solid-solid and solid-liquid diffusion couples.
Phase equilibria in the Dy-V-Si system at 1200 K
Morozkin
, p. L4-L6 (2002)
Phase equilibria in the Dy-V-Si system were investigated by X-ray powder diffraction and metallographic analysis. The isothermal cross-section at 1200 K was obtained. It is obvious that the AlB2-type (space group P6/mmm, no. 191) DyV0.1Si1.9 compound [a=0.3817(1) nm, c=0.4114(1) nm] belongs to the extended region of an AlB2-type DySi1.56-based solid solution.
Synthesis and thermal stability of nano-crystalline vanadium disilicide
Ma, Jianhua,Gu, Yunle,Shi, Liang,Chen, Luyang,Yang, Zeheng,Qian, Yitai
, p. 281 - 284 (2004)
Nano-crystalline vanadium disilicide was successfully synthesized using vanadium tetrachloride and silicon as starting materials via reduction-silication route at 650°C in the molten salt solution of magnesium chloride and sodium chloride in an autoclave. X-ray powder diffraction patterns indicated that the product was hexagonal VSi2 (a=4.572A?, c=6.372A?). Transmission electron microscopy images showed that the particle size of the product was in the range of 40-60nm in diameter. There was a strong absorption peak at 271nm in the UV-Vis absorption spectra. The oxidation of nano-crystalline VSi2 began to proceed at the temperature of 400°C in air. But the product had high thermal oxidation stability below 1000°C. It can be used as an antioxidation coating material.
Thermoelectric and magnetic properties of Cr1-xVxSi2 solid solutions
Hohl,Ramirez,Palstra,Bucher
, p. 70 - 76 (1997)
Cr1-xVxSi2 solid solutions have been prepared in the range 0≤x≤1. The thermopowers, resistivities, and magnetic susceptibilities of the solid solutions vary smoothly with composition and reveal a continuous transition from degenerate semiconducting (x = 0) to metallic (x = 1) behavior. S2/ρ ratios of the solid solutions are less than those of pure CrSi2. The thermoelectric properties of the solid solutions can be described in terms of a free-electron model, whereas an effective mass of 15 me has to be assumed in order to explain the results 0 magnetic measurements.
Solid state metathesis synthesis of metal silicides; reactions of calcium and magnesium silicide with metal oxides
Nartowski, Artur M.,Parkin, Ivan P.
, p. 187 - 191 (2008/10/08)
Reactions of transition metal oxides (V2O3, V2O5, Nb2O5, LiNbO3, Ta2O5, LiTaO3, MoO3 and Li2MoO4) with lithium silicide (Li2Si) and calcium silicide-magnesium silicide mix (CaSi2, Mg2Si) could be initiated by grinding, flame, filament or bulk thermal methods to produce a range of single phase transition metal silicides (VSi2, NbSi2 and TaSi2) in good yields (approximately 90%). The silicides were characterised by X-ray powder diffraction, scanning electron microscopy (SEM), energy dispersive analysis by X-rays (EDAX), electron probe, FTIR and microelemental analysis.
Thermodynamics and Kinetics of MSi2 Formation under Shock Compression
Batsanov,Gavrilkin,Markis,Meyers
, p. 103 - 109 (2008/10/08)
Thermodynamic and kinetic features of chemical transformation induced by shock compression are considered using reactions of metals with silicon as a model. The mechanisms and topography of processes that occur under cylindrical geometry of dynamic loading are discussed. The electron microscopy data for the shock compression products are reported.
