Densification, Microstructure an Electrical Properties of Baruim Titanate (BT) Ceramic Prepared from Ultrasonically De-agglomerated BT Powders

Poster presented at the 10th Conference of the Materials Research Society of Serbia - YUCOMAT 2008, Herceg Novi, Montenegro, September 8-12, 2008

The Electric Conductivity of Molten HgI2-HgBr2 and HgI2-SbI3 Binary Mixtures

The specific electric conductivity of molten HgI2-HgBr2 and HgI2-SbI3 binary mixtures was measured as a function of composition and temperature in the ranges 220 — 540 °C and 180 to 540 °C, respectively. In the HgI2-HgBr2 system negative deviations from additivity are found in mixtures rich in HgBr2, and positive ones in those rich in HgI2. The positive deviations are more pronounced at higher temperatures. In the HgI2-SbI3 system the deviations from additivity are negative throughout.re attractive for optical reflectance studies of electrochemical systems because of the high

Characterization of Barium Titanate Ceramics by Impedance Spectroscopy

Poster presented at the 9th Conference of the Yugoslav Materials Research Society - YUCOMAT 2007, Herceg Novi, Crna Gora, 10-14. septembar 2007

A Conductometric Study of the Bi-HgI2 System

The electric conductivity of the homogeneous liquid Bi-HgI2 System was measured in the temperature range 260—540 °C for several Bi mole fractions ranging from 0.00 to 0.38. The specific conductivity-composition isotherms are indicative of the occurrence of electronic conductivity also before reaching a bismuth concentration sufficient for a complete conversion of HgI2 into Hg2I2. As the temperature rises the share of electronic conductivity in the total conductivity abruptly increases. Comparing the properties of this system with those of the BiI3-Bi System the conclusion is drawn that electronic conductivity in liquids is due to free metal atoms

Ispitivanje reakcije hidriranja legure Zr1.02Ni0.98

The hydriding kinetics of Zr1.02Ni0.98 alloy was examined in dependence on the number of hydriding/dehydriding cycles. The rate constants relating to three subsequent hydriding procedures of an alloy sample, at five temperatures: 423, 448, 473, 498 and 523 K, were determined. The rate constant increases, and the activation energy decreases on each repetition of the hydriding/dehydriding cycle at a given temperature. This behavior was explained by sample crushing, leading to an increase in the surface area accessible to hydrogen.Ispitivna je kinetika hidriranja legure Zr1.02Ni0.98 u zavisnosti od broja ciklusa hidriranja/dehidriranja. Određene su konstante brzina za tri uzastopne reakcije hidriranja na uzorku legure, na pet temperatura: 423, 448, 473, 498 i 523 K. Ponavljanje ciklusa hidriranja/dehidriranja praćeno je stalnim porastom konstante brzine i opadanjem aktivacione energije.Ova pojava je objašnjena usitnjavanjem uzorka,što dovodi do povećanja površine koja je dostupna vodoniku

Gel-combustion synthesis of CoSb2O6 and its reduction to powdery Sb2Co alloy

Sb2Co alloy in powdery form was synthesized via reduction with gaseous hydrogen of the oxide CoSb2O6, obtained by the citrate gel-combustion technique. The precursor was an aqueous solution of antimony nitrate, cobalt nitrate and citric acid. The precursor solution with mole ratio Co(II)/Sb(V) of 1:2 was gelatinized by evaporation of water. The gel was heated in air up to the temperature of self-ignition. The product of gel combustion was a mixture of oxides and it had to be additionally thermally treated in order to be converted to pure CoSb2O6. The reduction of CoSb2O6 by gaseous hydrogen yielded powdery Sb2Co as the sole phase. The process of oxide reduction to alloy was controlled by thermogravimetry, while X-ray diffractometry was used to control the phase compositions of both the oxides and alloys

Structural and Electrochemical Properties of LiFePo4/C Composites Obtained through Ultrasound Assisted Synthesis

Poster presented at PHYSICAL CHEMISTRY 2008. 9th International Conference on Fundamental and Applied Aspects of Physical Chemistry, Belgrade, September 24-26, 200

The study of nanodispersed composite MgH2-Ti: experiment and theory

In order to obtain faster hydrogen sorption kinetics, MgH2-Ti nanocomposites were prepared by high-energy ball milling, under Ar using 10:1 ball to powder ratio and 10% of catalyst. Microstructural and morphological characterization, performed by XRD and optical microscopy analysis, show a correlation with thermal stability and hydrogen desorption properties investigated by DTA. In order to obtain deeper insight into bonding mechanisms of Ti in MgH2 fully relaxed structure, we have performed ab initio electronic structure calculations of MgH2 + Ti system, using Full Potential Linearized Augmented Plane Wave method, as implemented in WIEN2K code.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Zeolit NaX kao templat za dobijanje monoatomski dispergovane platine impregnacijom sa rastvorom Pt(II)-acetilacetonata u acetonu

The incorporation of platinum into the cavities of NaX zeolite was realized by impregnation and thermal decomposition of the organometallic compound Pt(II)-acetylacetonate dissolved in acetone. A high dispersion of platinum to predominantly mono-atomic particles was achieved thanks to the tight fit of the Pt(II)-acetylacetonate molecules in the aperture of the zeolite supercage. Using the high angle annular dark field imaging technique of HRTEM, individual Pt particles situated within the zeolite crystals were, for the first time, clearly visible. This offers new possibilities of studying the distribution of incorporated metal particles along the crystal depth.Platina je ugrađena u kaveze zeolita NaX impregnacijom i termalnim razlaganjem organometalnog jedinjenja Pt(II)-acetilacetonata, rastvrenog u acetonu. Visoka disperznost platine pretežno u vidu jednoatomnih čestica, postignuta je zahvaljujući bliskosti dimenzija molekule Pt(II)-acetilacetonata i prečnika ulaznog otvora supekaveza zeolita. Tehnikom širokougaone difrakcije i tamnog polja ultravisokorezolutivne elektronske mikroskopije, prvi put su učinjene vidljivim individualne čestice platine smeštene unutar kristala zeolita, što otvara nove mogućnosti u proučavanju raspodele ugrađenih metalnih čestica po dubini kristala