Characterisation of Large-Sized REBaCuO Bulks for Application in Flux Modulation Machines.

High temperature superconductors (HTSs) are enablers of extensive electrification for aircraft propulsion. Indeed, if used in electrical machines, HTS materials can drastically improve their performance in terms of the power-to-weight ratio. Among the different topologies of superconducting electrical machines, a flux modulation machine based on HTS bulks is of interest for its compactness and light weight.

BiTe-Based Thermoelectric Modules for Efficient and Reliable Low-Grade Heat Recovery.

Bismuth-telluride-based alloy has long been considered as the most promising candidate for low-grade waste heat power generation. However, optimizing the thermoelectric performance of n-type BiTe is more challenging than that of p-type counterparts due to its greater sensitivity to texture, and thus limits the advancement of thermoelectric modules. Herein, the thermoelectric performance of n-type BiTe is enhanced by incorporating a small amount of CuGaTe, resulting in a peak ZT of 1.

Enhanced Thermoelectric Performance of P-Type (Bi,Sb) Te by Incorporating Non-Stoichiometric Ag Te and Refining Te-Se Ratio.

Power generation modules utilizing thermoelectric (TE) materials are suitable for recycling widespread low-grade waste heat (<600 K), highlighting the immediate necessity for advanced Bi Te -based alloys. Herein, the substantial enhancement in TE performance of the p-type Bi Sb Te (BST) sintered sample is realized by subtly incorporating the non-stoichiometric Ag Te and counteractive Se. Specifically, Ag atoms diffused into the BST lattice improve the density-of-states effective mass (m ) and boost the hole concentration for the suppressed bipolar effect.

High Performance Thermoelectric Power of BiSbTe Through Synergistic CuGeSe and Se Incorporations.

BiTe-based alloys are the benchmark for commercial thermoelectric (TE) materials, the widespread demand for low-grade waste heat recovery and solid-state refrigeration makes it imperative to enhance the figure-of-merits. In this study, high-performance BiSbTe (BST) is realized by incorporating CuGeSe and Se. Concretely, the diffusion of Cu and Ge atoms optimizes the hole concentration and raises the density-of-states effective mass (m ), compensating for the loss of "donor-like effect" exacerbated by ball milling.

The Influence of Preparation Temperature on the Different Facets of Bulk MgB Superconductors.

Two MgB samples were prepared using the spark plasma sintering (SPS) technique at different temperatures-950 °C (S1) and 975 °C (S2)-for 2 h under 50 MPa pressure to study the influence of preparation temperature on different facets, namely those perpendicular (PeF) and parallel (PaF) to the compression direction of uniaxial pressure during the SPS of MgB samples. We analyzed the superconducting properties of the PeF and PaF of two MgB samples prepared at different temperatures from the curves of the critical temperature (), the curves of critical current density (), the microstructures of MgB samples, and the crystal size from SEM. The values of the onset of the critical transition temperature, , were around 37.

Comparative Study on the Densification, Microstructure and Properties of WC-10(Ni, Ni/Co) Cemented Carbides Using Electroless Plated and Coprecipitated Powders.

More and more attention is being paid to the influence of powder mixing on the mechanical properties and corrosion resistance of WC-based cemented carbides. In this study, WC was mixed with Ni and Ni/Co, respectively, by chemical plating and co-precipitated-hydrogen reduction, which are labelled as WC-Ni, WC-Ni/Co, WC-Ni and WC-Ni/Co, respectively. After being densified in a vacuum, the density and grain size of CP were denser and finer than those of EP were.

High Critical Current Density of Nanostructured MgB Bulk Superconductor Densified by Spark Plasma Sintering.

In situ MgB superconducting samples were prepared by using the spark plasma sintering method. The density of the obtained bulks was up to 95% of the theoretical value predicted for the material. The structural and microstructural characterizations of the samples were investigated using X-ray diffraction and SEM and correlated to their superconducting properties, in particular their critical current densities, J, which was measured at 20 K.

Enhanced Thermoelectric and Mechanical Performances in Sintered BiSbTe-AgSbSe Composite.

Bismuth telluride alloys have dominated the industrial application of thermoelectric cooling, but the relatively poor mechanical performance of commercial zone-melting material seriously limits the device integration and stability. Here, we exhibit synergistically enhanced thermoelectric and mechanical performances of sintered BiSbTe-AgSbSe composites. It is found that the increased hole concentration improves the σ to 40 μW cm K at room temperature, and the emerged various defects effectively suppress the to 0.

Achieving High Thermoelectric Performance of n-Type BiTeSe Sintered Materials by Hot-Stacked Deformation.

Bismuth telluride has been the only commercial thermoelectric candidate, but the n-type sintered material lags well behind the p-type one in the value, which severely limits the further development of thermoelectrics. Here, we report a promising technique named hot-stacked deformation to effectively improve the thermoelectric properties of n-type BiTeSe + 0.067 wt % BiCl materials based on zone-melting ingots.

Phonon Engineering for Thermoelectric Enhancement of p-Type Bismuth Telluride by a Hot-Pressing Texture Method.

Phonon engineering is a core stratagem to improve the thermoelectric performance, and multi-scale defects are expected to scatter a broad range of phonons and compress the lattice thermal conductivity. Here, we demonstrate obviously enhanced thermoelectric properties in BiSbTe alloy by a hot-pressing texture method along the axial direction of a zone-melted ingot. It is found that a plastic deformation of grain refinement and rearrangement occurs during the textured pressing process.

Anisotropy of Transport Properties Correlated to Grain Boundary Density and Quantified Texture in Thick Oriented Ca₃Co₄O₉ Ceramics.

The misfit-layered Ca₃Co₄O₉ oxide is being seen as a potential thermoelectric (TE) candidate for high-temperature power generation in air. Given the very small size and low strength exhibited by single crystals, grain-oriented Ca₃Co₄O₉ ceramics are worth elaborating to capitalize on their anisotropy. However, the usual textured pellets are too thin to probe the TE properties along their principal crystallographic directions.

Fostered Thermomagnetic Stabilities and Boosted Mechanical Reliability Related to High Trapped Field in Composite Bulk YBa2Cu3O(7-δ) Cryomagnets.

In the quest of YBa2Cu3O(7-δ) (Y123) bulk superconductors providing strong magnetic fields without failure, it is of paramount importance to achieve high thermal stabilities to safeguard the magnetic energy inside them during the trapping-field process, and sufficient mechanical reliability to withstand the stresses derived from the Lorenz force. Herein, we experimentally demonstrate a temperature rise induced by dissipative flux motion inside an Y123 thin-wall superconductor, and a significant thermal exchange in a composite bulk Y123 cryomagnet realized by embedding this superconductor with high thermal-conductivity metal network. It resulted in stimulating the maximum trapped field Bm, which reached 6.