The phase relations and the mechanism of solid-state synthesis for the Na0.5Bi0.5TiO3–Li3xLa(2/3)-x?(1/3)-2xTiO3 system were investigated using X-ray, SEM, and DTA. The study revealed that the extent of the homogeneity range—which is related to the A-site substitution between (Na0.5Bi0.5)2+ and (Li3xLa(2/3)-x?(1/3)-2x)2+ pseudo cations of a perovskite structure—depends strongly on the ordering of the (Li3xLa(2/3)-x?(1/3)-2x)2+ species. The solid-state reaction of the compounds in the homogeneity range is completed only after multiple high-temperature firings.
COBISS.SI-ID: 21953063
A polyelectrolyte multilayer fabricated by the layer-by-layer self-assembly of weak polyions of polyacrylic acid and polyallylamine was applied as a matrix for the in situ nucleation and growth of pure and Mn-doped ZnS nanocrystallites. The nucleation and growth is initiated by the adsorption and binding of the metal ions to the ionized carboxylic groups of the weak polyions within the matrix, followed by the subsequent precipitation of semiconductor nanocrystallites with Na2S. TEM, AFM and UV–vis spectroscopy were employed to establish the growth characteristics.
COBISS.SI-ID: 22703655
BaO-rich phases with the nominal compositions were synthesized as polycrystalline powders and characterized by X-ray and TEM. Of these powders only the 5L2-Ba6NbxW3-xO15-x/2 (x=2) and 9L-Ba9Nb2W4O26 were obtained as single-phase materials. The formation of 9L-Ba9Nb2W4O26, 12L-Ba4Nb2WO12, and 27L-Ba9Nb6WO27 started with the reaction between the binary compounds and continued over a series of intermediate hexagonal perovskite-type phases lying on the Ba3W2O9–Ba5Nb4O15 tie line.
COBISS.SI-ID: 22912295
The high-T behaviour of K0.5Bi0.5TiO3 was investigated using X-ray, SEM, WDS X-ray spectroscopy and Knudsen effusion combined with mass spectrometry. The results revealed the formation of an off-stoichiometric matrix phase with an excess of Bi and a deficit of K compared to the stoichiometric K0.5Bi0.5TiO3 during the solid-state reaction. During the thermal treatment K and Bi vapours were detected. The losses of the K and Bi components shifted the nominal composition to a 3-phase region, and as a result, K2Ti6O13 and a new Bi-rich ternary phase were formed in the system.
COBISS.SI-ID: 22190631
We used solid-state synthesis to determine the phase relations in the pyrochlore-rich part of the Bi2O3-TiO2- Nd2O3 system at 1100oC. The samples were analyzed using X-ray and SEM with EDS and WDS. A single-phase pyrochlore ceramic was obtained with the addition of 4.5 mol% of Nd2O3. We determined the solubility limits for the three solid solutions: (i) the pyrochlore solid solution Bi(1.6–1.08x)NdxTi2O(6.410.3x), where 0.25?x?0.96; (ii) the solid solution Bi4 xNdxTi3O12, where 0?x?2.6; and (iii) the Nd2 xBixTi2O7 solid solution, where 0?x?0.35.
COBISS.SI-ID: 22993191