Synthesis, sintering, specific heat and magnetism of Eu3S4 by low-temperature CS2-gas sulfurization of Eu2O3 nanospheres

AbstractSingle-phase Eu3S4 was obtained via CS2 gas sulfurization of Eu2O3 nanospheres at 773 K for longer than 0.5 h. The primary particle size of Eu3S4 became larger than that of Eu2O3 during the sulfurization process. Pure synthetic Eu3S4 powders were unstable and transformed to EuS at 873 K under vacuum. Eu3S4 compacts were sintered in temperature range of 773 K to 1173 K and they transformed to EuS at 1473 K during spark plasma sintering. Specific heat of sintered Eu3S4 did not show an anomalous behavior in the range of 2 K to 50 K. The magnetic susceptibility of polycrystalline Eu3S4 followed a Curie-Weiss law from 2 K to 300 K. Magnetization of polycrystalline Eu3S4 was larger than that of single crystal Eu3S4 when the magnetic field was less than 3.5 kOe.

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Structure and Inverse Magnetocaloric Effect of Mn1.2Co0.8Si0.2P0.8 Compound Prepared by SPS

Materials Science Forum ◽

10.4028/www.scientific.net/msf.849.860 ◽

2016 ◽

Vol 849 ◽

pp. 860-864

Author(s):

Lei Ma ◽

Liang Zhou ◽

Lin Li ◽

Zheng Fei Gu ◽

Gang Cheng

Keyword(s):

Magnetocaloric Effect ◽

Single Phase ◽

Vacuum Annealing ◽

Secondary Phase ◽

Ferromagnetic Transition ◽

Plasma Sintering ◽

Spark Plasma ◽

The Magnetic Field ◽

Stoichiometric Proportion ◽

Intrinsic Feature

The single-phase Mn1.2Co0.8Si0.2P0.8 compound was fabricated by the spark plasma sintering (SPS) technology followed by vacuum annealing. The microstructure, Néel temperature (TN) and “inverse” magnetocaloric effect of this compound were investigated. The results show that the structure of Mn1.2Co0.8Si0.2P0.8 compound prepared by SPS is a single phase with precise stoichiometric proportion. Increasing the magnetic field from 0.05 T to 1 T, the TN of the material reduces gradually from 110 k to 45 k, and a splitting of TN appears. The splitting of the antiferro-to-ferromagnetic transition is an intrinsic feature rather than the secondary phase. Though the maxima entropy changes is about 0.6 Jkg-1K-1 at B=5T, the Mn1.2Co0.8Si0.2P0.8 phase synthesized by SPS is more favorable, more overall magnetic moment. In addition to the magnetic refrigeration applications, this compound may be used in thermomagnetic generators.

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Properties of WCCo Composites Produced by the SPS Method Intended for Cutting Tools for Machining of Wood-Based Materials

Materials ◽

10.3390/ma14102618 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2618

Author(s):

Joanna Wachowicz ◽

Tomasz Dembiczak ◽

Grzegorz Stradomski ◽

Zbigniew Bałaga ◽

Marcin Dyner ◽

...

Keyword(s):

Electron Microscopy ◽

Primary Particle ◽

Cutting Tools ◽

Cobalt Content ◽

Primary Particle Size ◽

X Ray Diffraction ◽

X Ray ◽

Plasma Sintering ◽

Spark Plasma ◽

Scanning Electron

This paper presents the possibility of using the Spark Plasma Sintering (SPS) method to obtain WCCo composite materials. Such materials are used as cutting blades for machining wood-based materials. Two series of composites, different in grain size and cobalt content, were analyzed in the paper. The produced materials were characterized using Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and tribological properties were determined. In addition, preliminary tests were carried out on the durability of the blades made of sintered WCCo composites while machining three-layer chipboard. The results of the microstructure analysis proved that the SPS method makes it possible to obtain solid composites. Phase analysis showed the occurrence of the following phases: WC, Co, and Co3W9C4. The lowest friction coefficient value was found in samples sintered using powder with an average primary particle size of 400 nm (ultrafine).

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Synthesis and Thermal Properties of Nanoscale Skutterudite via Cross-Coprecipitation

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.336-338.831 ◽

2007 ◽

Vol 336-338 ◽

pp. 831-833

Author(s):

Ying Chu ◽

Xin Feng Tang ◽

Ling Wan ◽

Qing Jie Zhang

Keyword(s):

Thermal Conductivity ◽

Particle Size ◽

Grain Size ◽

Room Temperature ◽

Single Phase ◽

Antimony Oxide ◽

Hydrogen Atmosphere ◽

Plasma Sintering ◽

Average Grain Size ◽

Spark Plasma

CoSb3 with nanoscale was synthesized by Cross-coprecipitation. A precursor consisting of antimony oxide and cobalt hydrate was prepared by the reaction of CoCl2, SbCl3 and both precipitators at room temperature. The precursor was reduced in thermal treatment under hydrogen atmosphere whereby the CoSb3 was thus obtained. The parameters especially reducing temperature and atmosphere (content of H2) influence the constituent phases and particle size of product significantly. The single phase CoSb3 with the average grain size of 60~70 nm was obtained after reduced at 723 K for 2 h with pure H2. Nanoscale CoSb3 powder was used as starting materials, and bulk CoSb3 compound was prepared by spark plasma sintering (SPS). The effect of grains size on thermal conductivity was investigated.

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Fabrication and Characterization of Quinary High Entropy-Ultra-High Temperature Diborides

Ceramics ◽

10.3390/ceramics4020010 ◽

2021 ◽

Vol 4 (2) ◽

pp. 108-120

Author(s):

Simone Barbarossa ◽

Roberto Orrù ◽

Valeria Cannillo ◽

Antonio Iacomini ◽

Sebastiano Garroni ◽

...

Keyword(s):

High Temperature ◽

Single Phase ◽

Nominal Composition ◽

High Entropy ◽

Chemical Complexity ◽

Alternative Processing ◽

Plasma Sintering ◽

High Temperature Synthesis ◽

Spark Plasma

Due to their inherent chemical complexity and their refractory nature, the obtainment of highly dense and single-phase high entropy (HE) diborides represents a very hard target to achieve. In this framework, homogeneous (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2, (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2, and (Hf0.2Zr0.2Nb0.2Mo0.2Ti0.2)B2 ceramics with high relative densities (97.4, 96.5, and 98.2%, respectively) were successfully produced by spark plasma sintering (SPS) using powders prepared by self-propagating high-temperature synthesis (SHS). Although the latter technique did not lead to the complete conversion of initial precursors into the prescribed HE phases, such a goal was fully reached after SPS (1950 °C/20 min/20 MPa). The three HE products showed similar and, in some cases, even better mechanical properties compared to ceramics with the same nominal composition attained using alternative processing methods. Superior Vickers hardness and elastic modulus values were found for the (Hf0.2Nb0.2Ta0.2Mo0.2Ti0.2)B2 and the (Hf0.2Zr0.2Ta0.2Mo0.2Ti0.2)B2 systems, i.e., 28.1 GPa/538.5 GPa and 28.08 GPa/498.1 GPa, respectively, in spite of the correspondingly higher residual porosities (1.2 and 2.2 vol.%, respectively). In contrast, the third ceramic, not containing tantalum, displayed lower values of these two properties (25.1 GPa/404.5 GPa). However, the corresponding fracture toughness (8.84 MPa m1/2) was relatively higher. This fact can be likely ascribed to the smaller residual porosity (0.3 vol.%) of the sintered material.

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Effect of initial particle size and various composition on the spark plasma sintering of binderless tungsten carbide

Journal of Physics Conference Series ◽

10.1088/1742-6596/1758/1/012022 ◽

2021 ◽

Vol 1758 (1) ◽

pp. 012022

Author(s):

E A Lantsev ◽

N V Malekhonova ◽

V N Chuvil`deev ◽

A V Nokhrin ◽

M S Boldin ◽

...

Keyword(s):

Particle Size ◽

Tungsten Carbide ◽

Spark Plasma Sintering ◽

Initial Particle ◽

Initial Particle Size ◽

Plasma Sintering ◽

Spark Plasma

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Thermoelectric properties of Cu3SbSe3 with intrinsically ultralow lattice thermal conductivity

Journal of Materials Chemistry A ◽

10.1039/c4ta02590c ◽

2014 ◽

Vol 2 (38) ◽

pp. 15829-15835 ◽

Cited By ~ 34

Author(s):

Kriti Tyagi ◽

Bhasker Gahtori ◽

Sivaiah Bathula ◽

A. K. Srivastava ◽

A. K. Shukla ◽

...

Keyword(s):

Thermal Conductivity ◽

Solid State ◽

Spark Plasma Sintering ◽

Thermoelectric Properties ◽

Solid State Reaction ◽

Electrical Transport ◽

Single Phase ◽

Lattice Thermal Conductivity ◽

Plasma Sintering ◽

Spark Plasma

Intrinsically ultra-low thermal conductivity and electrical transport in single-phase Cu2SbSe3 synthesized employing a solid state reaction and spark plasma sintering.

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