Potassium, sodium niobate based solid solutions are among the most promising candidates for lead free piezo ceramics. The highest piezoelectric response was found in the vicinity of K0.5Na0.5NbO3. It was explained by the presence of morphotropic phase boundary. Our results show continuous change of crystallographic parameters in composition range KxNa1-xNbO3, (0,4 ? x ? 0,6) meaning absence of morphotropic phase boundary. This is an important results that requires an effort to find a suitable physical background for the enhanced piezo response of K0.5Na0.5NbO3 composition.
COBISS.SI-ID: 22292775
High energy milling is a promising method to synthesis highly chemically homogeneous nano size ceramic powder. There is however very little data on mechanism and kinetic of these reactions. We explained the mechanism of the synthesis f Pb(Mg1/3Nb2/3)O3 by high-energy milling, which occurs via nucleation and growth of the perovskite phase from the amorphous matrix. In contrast, the nuclei of the unstable pyrochlore phase do not grow.
COBISS.SI-ID: 22679335
The article critically analyses the existing models of thin film planar capacitors and give suggestions for the improvements of models and measuring methods. It has been selected by the Journal Editors to feature in iop. select (http://www.iop.org/Select/) for its novelty, significance and potential impact on future research.
COBISS.SI-ID: 22918695
We studied the influence of Li2O on the phase composition, mechanical, and thermal properties of alumina porcelains. We found that Li2O, introduced in the formulation as a mineral spodumene, reacted with the undesired free SiO2, and formed lithium alumosilicate minerals with a higher amount of SiO2. The Li-modified porcelain had more homogeneous microstructure, a lower thermal expansion coefficient, better resistance to thermal shocks and a higher mechanical strength than the standard formulation used in production.
COBISS.SI-ID: 22459175
In this work we investigated the chemica composition and structure of (K0.5Na0.5)NbO3 (KNN) single crystals grown by the solid state crystal growth method. No compositional inhomogeneities within experimental error were encountered in the KNN single crystals. The domain structure of the KNN single crystal, with a monoclinic unit cell, is composed of large 90° domains of up to 100 [mu]m width, which further consist of smaller 180° domains with widths from 50 to 300 nm.
COBISS.SI-ID: 22847527