Synthesis and electrical properties of Bi₂Te₃ - based thermoelectric materials doped with Er, Tm, Yb, and Lu

Nanopowders of Bi₂Te₃ and R₀.₁Bi₁.₉Te₃ (where R = Er, Tm, Yb, Lu) are obtained by microwave solvothermal synthesis. The powder-like materials are compacted by cold isostatic compression followed by annealing in argon. The influence of the doping agent on the structure and characteristics of the derived materials are investigate

Cobalt-based ZIF-68 and ZIF-69 as the precursors of non-platinum electrocatalysts for oxygen reduction

We report the microwave-assisted synthesis of Co-based ZIF-68 and ZIF-69 zeolitic imidazolate frameworks, which were enriched with iron(ii) acetate and 1,10-phenanthroline and then pyrolyzed to form heterogeneous catalysts. The materials demonstrated high activity in oxygen reduction and suitability as Pt-free catalysts for low-temperature fuel cell

Synthesis and properties of thermoelectric nanomaterial AgInSe₂ with a chalcopyrite structure

The aim of this study is to develop a simple, efficient, and scalable method for the preparation of nanoparticles of complex chalcogenides using the example of the AgInSe₂ designed to obtain bulk thermoelectric material

Synthesis and electric transportation properties of high-entropy oxides based on cerium oxide

CeGdRLaPrO2-δ (where R: La, Y and Dy) rare-earth high-entropy oxides (HEOx) with the Ia-3 (206) structure were obtained. The structural, microstructural and transport properties of the compounds were studied. All samples exhibiting good homogeneity and electrical conductivity typical of materials for the manufacture of solid electrolyte

Microstructure and thermoelectric properties of the medium-entropy BiSbTe₁.₅Se₁.₅ and PbSnTeSe compounds prepared by reactive spark plasma sintering

Reactive spark plasma sintering (RSPS) is used to obtain single-phase samples of medium-entropy BiSbTe₁.₅Se₁.₅ compounds (low-temperature thermoelectric electronic type of conductivity) and PbSnTeSe (medium temperature hole-type thermoelectric conductor) from a mixture of powders of the corresponding elemental metals. The obtained samples are polycrystalline with lamellar grains with the average size of ~3.3 μm in BiSbTe₁.₅Se₁.₅ and with irregularly shaped grains with the average size of ~18.9 μm in PbSnTeS

Influence of nitriding parameters in radio-frequency inductive discharge plasma on the structural-phase state and properties of H12MF steel

The influence of technological parameters of plasma nitriding on the structural-phase state and mechanical properties of H12MF steel has been investigated in this work. The possibility of improving the corrosion resistance of the reported material was demonstrated by changing the content of nitride phases (Fe3N, Fe4N, CrN) in the surface layer, depending on the nitriding mod

Fracture toughness of Al2O3/ZrSiO4 coatings obtained by multi-chamber gas-dynamic accelerator

In the current work the research of fracture toughness of Al2O3/xZrSiO4 composite coatings have been realized using automatic system for microhardness analysis. Al2O3/xZrSiO4 (x = 0, 3, 25 wt. %) coatings were produced from a mixture of cheap raw materials (alumina and zircon ZrSiO4) on the surface of stainless steels by a new multi-chamber gas-dynamic accelerator. It has been experimentally established that adding of ZrSiO4 increases fracture toughness of alumina coating

Microstructure features of metal-matrix composites based on thermoelectric bismuth telluride matrix and ferromagnetic filler

The formative predictables of the microstructure of metal-matrix composites, obtained using spark plasma sintering and consisting of polycrystalline thermoelectric bismuth telluride Bi₂Te₃(composite matrix) and aferromagnetic filler (Ni or Fe), were examine

Characteristics of ZrB₂-ZrO₂-MoSi₂-Al coating on carbon/carbon composite obtained by a new multi-chamber detonation accelerator

The ZrB₂-ZrO₂-MoSi₂-Al coating was prepared by a new multi-chamber detonation accelerator on carbon/carbon (C/C) composites without adhesion sublayer. The microstructure of the coating showed the laying characteristics of completely molten and partially molten areas had as lamellar-like structure. The coating was dense, homogeneous, and well connected with C/C composite substrate without sublayer. Void content in coating is 0.5±0.05% as determined by image analysi

Processing of rare earth metal oxide for use as a master alloy in the metallurgical industry

This article proposes a method for processing REM oxides for their use as master alloys in ferrous metallurgy products. REMs, in the form of modifiers for steels and alloys, are widely use