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X-ray powder diffraction study of chromium-vanadium oxide compounds prepared by “soft chemistry” methods

100%

Pozdnyakova O., Megyeri J., Kuzmann E., Szirtes L.

Open Chemistry

2006

vol. 4

issue 4

760-772

A novel aqueous method was used to synthesise mixed chromium-vanadium oxide hydrates with various chromium content, via the reaction of peroxo-polyacids of chromium and vanadium. The resulting materials are gelatinous. The dehydration of the gels result in a brown coloured amorphous powder. Depending on the chromium content, the compounds have a different characteristic crystallisation temperature upon the further heating. The crystalline compounds, except for the low chromium ones, go on a phase transition and decompose with increasing temperature. By refining the XRPD measurement data of the compounds, the type and parameters of the unit cells were determined. The experimental data were in concordance with the calculated values, using the PWC code. The lattice parameters and the crystalline structure were changed with the variation of chromium content.

Characterization of CaTi0.9Fe0.1O3/La0.98Mg0.02NbO4 composite

100%

Mielewczyk-Gryn A., Lendze T., Gdula-Kasica K., Jasinski P., Krupa A., Kusz B., Gazda M.

Open Physics

2013

vol. 11

issue 2

213-218

A composite of CaTi0.9Fe0.1O3 and electrolyte material, i.e. magnesium doped La0.98Mg0.02NbO4 was prepared and studied. The phase content and the sample microstructure was examined by an X-ray diffraction method and scanning electron microscopy. EDS measurements were done both for composite samples and the diffusion couple. The electrical properties were studied by four terminal DC method. The high-temperature interaction between the two components of the composite has been observed. It has been suggested that lanthanum diffused into the perovskite phase and substituted for calcium whereas calcium and niobium formed the Ca2Nb2O7 pyrochlore phase. At 1500°C very large crystallites of the pyrochlore were observed. Regardless of strong interaction between the composite components, its total conductivity was weakly dependent on the sintering temperature.

Study of solid-solution hardening in binary aluminium-based alloys

75%

Draissia M., Debili M.-Y.

Open Physics

2005

vol. 3

issue 3

395-408

Solid-solution formation in binary aluminium-based alloys is due essentially to the combined effects of the size and valence of solvent and solute atoms, as expected by the four Hume-Rothery rules. The lattice parameter of aluminium in the solid solution of the sputtered Al−Fe films is [Al-a (Å)=4.052−6.6×10−3Y]. The increasing and decreasing evolution of the lattice parameter of copper [Cu-a (Å)=3.612+1.8×10−3Z] and aluminium [Al-a (Å)=4.048−1.6×10−3X] in the sputtered Al-1.8 to 92.5 at. % Cu films is a result of the difference in size between the aluminium and copper atoms. The low solubility of copper in aluminium (<1.8 at % Cu) is due to the valences of solvent and solute atoms in contrast with other sputtered films prepared under similar conditions, such as Al−Mg (20 at. % Mg), Al−Ti (27 at. % Ti), Al−Cr (5at. % Cr) and Al−Fe (5.5 at. % Fe) where the solubility is due to the difference in size.

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2 Open Physics

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1 Debili M.-Y.

1 Draissia M.

1 Gazda M.

1 Gdula-Kasica K.

1 Jasinski P.

1 Krupa A.

1 Kusz B.

1 Kuzmann E.

1 Lendze T.

1 Megyeri J.

1 Mielewczyk-Gryn A.

1 Pozdnyakova O.

1 Szirtes L.

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X-ray powder diffraction study of chromium-vanadium oxide compounds prepared by “soft chemistry” methods

Characterization of CaTi0.9Fe0.1O3/La0.98Mg0.02NbO4 composite

Study of solid-solution hardening in binary aluminium-based alloys