Structure and microstructure behavior of iron doped potassium sodium niobate powders

In this paper, the synthesis and characterization of the potassium sodium niobate doped with iron powders have been studied. Solid-state oxide reaction sintering was used. The powders produced in this work exhibit no homogeneous microstructure, which introduced the growth of random cylindrical structures and will can contribute to the increased porosity ceramics. It was observed average particle size of 3μm, besides, also it was observed the formation of agglomerations and an increase in the size of these clusters with the increase in the amount of iron. The calcination temperature was 950 °C. This is slightly higher than other potassium sodium niobate powders systems. In addition to the physical and microstructural properties, structural properties are presented and analyzed for the first-time using Mössbauer spectroscopy as complementary technique in Fe 3+doped potassium sodium niobate powders. This work is important to state solid physics because establishes the influence of iron in the potassium sodium niobate system, and so the future obtaining of multifunctional materials that have piezoelectric and magnetic properties.

Modification of the Structural, Microstructural, and Elastoplastic Properties of Aluminum Wires after Operation

The health of the components that make up the cables of power lines, and hence their service life, is governed at the micro level by changes in their structure and microstructure. In this paper, the structure and microstructure of aluminum wires of overhead power transmission lines (without a steel core) of different service life from 0 to 62 years have been investigated by quantitative techniques of X-ray diffraction, diffraction of back-scattered electrons, and the densitometric method. Elastoplastic properties of the wires have been tested by the acoustic-resonance method. A decrease in the Al material density Δρ/ρ∼−0.165% was found in the near-surface layer of ∼36 μm depth and in the bulk of the wires with an increase in the service life from 0 to 18 years. The density decrease is associated with the accumulation of microcracks. The following density increase (Δρ/ρ∼−0.06%) in wires with a service life of 62 years is attributed to the formation of ∼0.7 vol.% of crystalline Al oxides in the near-surface layers of the wires. The nature of the change in the elastic modulus, microplastic flow stress, and decrement indicates complex structural changes correlating with the results obtained by diffraction methods.

SI JUKI VS. EMPTY WALLET COMIC ANALYSIS. CRITICAL DISCOURSE REVIEW TEUN A VAN DIJK

This study aims to describe the Critical Discourse Review of Teun A Van Dijk in the comic Si Juki vs Dompet Blank”. This research is a qualitative descriptive study. The method used in this research is the method of data collection and documentation. The data sources in this research are macro structure, super structure, and microstructure which are analyzed directly from the comic Si Juki Vs Dompet Blank. The result of this research is the comic Si Juki Vs Dompet Kososng. From the research results, macro structure, theme; to increase public knowledge about mercury investment. Topics; can start moving to learn to manage finances. Super structure, semantics; In the comic Si Juki Vs Dompet Blank there are two different texts, namely descriptive text, and exposition text. Macro structure; semantics: readers can begin to be moved to learn to manage their finances, stylistics; the choice of words used in the comic Si Juki Vs Dompet Blank is easy to understand because the words used are simple and commonly used in public places, the lexicon; office, boarding, and savings.

Enhancement of Dielectric Properties via Crystal Structure and Microstructure Control in the (K0.5Na0.5)NbO3-SrTiO3 System

Solid solutions and composites of a mixture of (K0.5Na0.5)NbO3 (KNN) and SrTiO3 (ST) were respectively synthesized by different process routes using a conventional solid state reaction. All starting materials were mixed simultaneously and calcined at 800 oC for 4 h to obtain the solid solutions of KNN-ST. Meanwhile, the composites of KNN-ST were obtained by mixing the synthesized KNN and synthesized ST, respectively. KNN-ST calcined powders were sintered at 1150, 1250 and 1300 oC for 2 h. The calcined powders, in which all starting materials were mixed at once, showed a single-phase pseudo-cubic structure after sintering. On the other hand, the powders with the mixture of KNN and ST had two phases of cubic ST and orthorhombic KNN as composites. The dielectric loss values of all samples decreased as the sintering temperature increased because of increased densification. The dielectric constants of the solid solutions were increased as the sintering temperature increased, however, the dielectric constants of the composites decreased with increasing sintering temperature. It was concluded that, for enhanced dielectric properties, the dielectric materials should be synthesized as solid solutions.

Effect of a Sulfur Precursor on the Hydrothermal Synthesis of Cu2MnSnS4

Cu2MnSnS4 (CMTS) is acknowledged as an alternative to traditional semiconductors. The structure and microstructure of synthetic CMTS depend on, among other things, the types of sulfur sources used. Traditionally obtained CMTS mostly has a tetragonal structure. In this study, the effect of using thiourea (Tu) or Na2S as a sulfur source on the product structure was compared using hydrothermal synthesis at 190 °C for 7 days (ethylene glycol with water in the presence of poly(vinylpyrollidone) was used as a solvent). When Tu was used, CMTS precipitated in the form of concentric microspheres, 1–1.5 µm in size, consisting of hexagonal (in the cores) and tetragonal (the rims) forms. Most probably, the rapidly formed hexagonal nucleus was later surrounded by a slower-forming rim with a tetragonal structure. In contrast, when Na2S was used as a precursor, microspheres were not formed and a fine crystalline material with a homogeneous tetragonal structure was obtained. This allowed for the choice of micromorphology and product structure during synthesis.