1.

Hydrothermal conditions for the formation of tetragonal BaTiO[sub]3 particles from potassium titanate and barium salt

This article presents the results of BaTiO3 formation from K2Ti6O13 nano-wires under hydrothermal conditions. The main focus was on determination of the conditions for the formation of BaTiO3 with a high tetragonality. We proved that the growth of BaTiO3 particles occurred via-dissolution-precipitation mechanism. For this reasons the morphology of initial titanate precursor was not preserved. By means of Rietveld analysis, Raman spectroscopy and DSC measurements it was confirmed that higher temperatures of 200-240°C, lower concentrations of precursors and NaOH enable the formation of BaTiO3 with higher tetragonality.

COBISS.SI-ID: 28836903

2.

The effect of BaTiO[sub]3 particle shape on complex permittivity of 0.98MgTiO[sub]3-0.02BaTiO[sub]3 composite powders at GHz frequencies

The elongated BaTiO3 particles (rods) were prepared by topochemical transformation from Na2Ti3O7 rods under hydrothermal conditions at very low concentrations of NaOH. In the continuation such elongated BaTiO3 particles were used to study the effect of the particle shape on the complex permittivity of the 0.98MgTiO3-0.02BaTiO3 composite powders. We found out that even at very low concentrations these elongated BaTiO3 particles significantly increased the permittivity, while this was not the case for spherical particles.

COBISS.SI-ID: 29222695

3.

Tailoring the shape, size, crystal structure, and preferential growth orientation of BaTiO[sub]3 plates synthesized through a topochemical conversion process

In this article, we investigated the mechanism and conditions for topochemical conversion from variously sized (m- and sub-m sized) Bi4Ti3O12 plates to BaTiO3 particles in the molten salt. Key synthetic parameters, which enables the control of domain structure, preferential orientation and consequently the ferroelectric and piezoelectric characteristics have been determined.

COBISS.SI-ID: 30486567

4.

Influence of pulsed-electric-current sintering conditions on the non-stoichiometry and thermoelectric properties of Ti[sub](1+x)S[sub]2

In this paper, we investigated how the non-stoichiometry of Ti1 + xS2 affects the thermoelectric properties of the material. We determined the conditions for achieving high density by sintering with a pulsed- electric-current sintering and suppressing the loss of sulfur in the sintering process. For the Ti1.017S2 composition, prepared at 800 ° C and a pressure of 200 MPa, the best thermoelectric figure of merit ZT equals to 0.32 was obtained at 375 ° C.

COBISS.SI-ID: 30103335

5.

Sub-solidus phase relations and a structure determination of new phases in the CaO-La [sub] 2O [sub] 3-TiO [sub] 2 system

Sub-solidus phase relations in the ternary CaO–La2O3–TiO2 system at 1400 ◦C in air were determined. The multi-phase samples were prepared by a solid-state reaction method, whereas the single-phase samples for the structure analysis of selected solid solutions were prepared by a wet-precipitation method in order to provide good homogeneity of the starting mixtures. The phases in the prepared samples were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The oxides form seven ternary compounds in the equilibrium state, many solid solutions (which extend across a broad concentration region), and a large, single-phase area based on the CaTiO3 solid solution. The structures of several new phases – solid solutions on the tie lines CaTiO3–Ca3La4Ti3O15 and La2TiO5– Ca3La4Ti3O15– were determined in detail.

COBISS.SI-ID: 1536308931