The fine-pored materials represent a wide range of applications and searches are being continued to develop methods of their manufacturing. In the article, based on measurements on fine-grained powders of Al2O3, TiO2, and SiO2, it has been demonstrated that gelcasting can be relatively simple method of obtaining of nanoporous materials with high values of both specific surface area and open porosity. The powders were dispersed in silica sol, and the gelling initiator was NH4Cl. The usefulness of experiment design theory for developing of fine-pored materials with high porosity and specific surface area was also shown.
Novel siliconized Mo-Re coatings dedicated to applications in the glass industry are shown in this paper. The study aims at the characterization of morphology, phase composition, and oxidation behavior of siliconized Mo-based coatings deposited on a ceramic-metal substrate. Two coatings with different contents of rhenium were prepared using a hybrid process that includes atmospheric plasma spraying and pack siliconizing. The microstructure, chemical, and phase composition of the obtained coatings were characterized and compared to Mo coating. Moreover, a characterization of starting powders was performed. After the description of the coatings' microstructure, oxidation tests were carried out at 1000, 1100, and 1200°C. The surface condition of oxidized coatings was investigated. The structure of Re-containing coatings after the siliconizing process was comparable. Both were composed of Mo and (Mo,Re)Si 2 -ReSi 1.75 layers. However, in the case of Mo-44Re (wt.%) coating, a higher concentration of rhenium silicide was observed compared to that of coating containing 15% Re. The Re-containing silicide layers were characterized by a presence of lower content of hexagonal MoSi 2 compared to that of non-alloyed MoSi 2 . The oxidation resistance of both coatings containing rhenium was comparable; however, the one with a higher amount of Re exhibited slightly higher durability in high-temperature oxidation.
We have reported the synthesis of a new kind of composite combining a rhenium precursor and active carbon. Similarly to other refractory metals, rhenium exhibits several oxidation states that makes it an ideal candidate for redox-type energy storage materials. A simple impregnation of pretreated active carbon with ammonium perrhenate allowed to produce an electrode material with an enhanced specific capacitance. There was not any observed detrimental effect of metal species on the cycle life of the electrode. A small increase in charge transfer resistance was counter-balanced by the improved impedance in the whole examined range.
The purpose of the studies was to determine production parameters of AgW50 composite contact material. Fabrication of contact tips from this material was carried out by powder metallurgy method including preparation of the powder mixture, pressing, sintering and optional repressing under pressure of not less than 600 MPa. This technology enables production of contact tips with different shape and size without application of machining. The required material structure, i.e. uniform distribution of tungsten particles in the silver matrix, was achieved by milling conducted in the planetary ball mill. The further operations of this technological process, i.e. optimization of consolidation parameters, enabled fabrication of material characterized by high density and functional (electrical) properties.
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