Superconducting cryo-magnets processed by spark plasma sintering and texturing

Noudem, Jacques; Dupont, Louis; Bernstein, P.; Retoux, R.; Chevallier, Geoffroy; Estournès, Claude; Berger, Kévin; Higuchi, Masashi; Muralidhar, M.; Murakami, M.

doi:10.1016/b978-0-12-817744-0.00008-8

Cited by 4 publications

(5 citation statements)

References 47 publications

(51 reference statements)

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“…After polishing, the densities of these samples were measured using the Archimedes method. The densities of about 96% with respect to the theoretical value (2.62 g cm −3 ) have been obtained [16,18]. Specific information about these seven SPSed MgB 2 bulk samples has been shown in table 1.…”

Section: Methodsmentioning

confidence: 76%

“…There are some slender grains in the PeF of S5 with the width about 0.3 µm and the length of 1.6 ∼ 5.6 µm, and we have identified the composition of these slender grains as MgB 2 by the EDS analysis. Such slender MgB 2 grains are formed in the PeF of the S5 may be the result of its suitable preparation condition, because the grain orientation varies with the preparation conditions [18], while other preparation conditions may not be suitable for the formation of such slender MgB 2 grains. For the PeF, there is no significant difference in the micro-morphology except for the slender particles in the S5 mentioned above.…”

Section: Resultsmentioning

confidence: 99%

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The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering

Zhang

Lou

et al. 2021

Supercond. Sci. Technol.

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Seven MgB2 bulk superconductors with good superconductivity and crystallinity were prepared under the pressure of 50 MPa at 950 °C and different sintering durations (15 ∼ 240 min) by spark plasma sintering (SPS), with the onset critical temperature (T c,onset) around 37.5 K. The superconducting properties and microstructure measured from the facets perpendicular (PeF) and parallel (PaF) to the compression direction of the SPSed MgB2 bulk samples were also analyzed to investigate the effect of the sintering duration on the MgB2 bulks and the discrepancy between the PeF and the PaF. The optimum performance was obtained from the sample prepared for 45 min for both facets, and the critical current density (J c) measured from the PeF and the PaF are 364 kA cm−2 and 344 kA cm−2 in self field at 20 K, respectively. The PeF exhibits better Jc performance than the PaF at low fields and the PaF exhibits better J c performance than the PeF at high fields. It can be concluded that the sintering duration affects the properties of the PeF mainly by changing their crystallite size. While for the PaF, the sintering duration mainly affects the microstructural defects, such as cracks, pores and secondary phase particles, thus further affecting their J c performances. In terms of the flux pinning mechanism of the SPSed MgB2 bulk samples, the PaF is less susceptible to sintering duration than the PeF, and the better J c performance of the PaF at high fields is due to the stronger grain boundary pinning. It can be also found that the point pinning being stronger at higher temperature is the result of the decreasing anisotropy of MgB2 bulk samples with the temperature.

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Section: Methodsmentioning

confidence: 76%

Section: Resultsmentioning

confidence: 99%

The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering

Zhang

Lou

et al. 2021

Supercond. Sci. Technol.

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“…The main difference between SPS and conventional or hot-pressing methods is that SPS allows for the preparation of highly dense samples with grain growth control and a decreased processing time [ 13 , 14 , 15 , 16 ]. Concerning MgB 2 , the samples processed by SPS additionally show excellent mechanical properties [ 17 ].…”

Section: Introductionmentioning

confidence: 99%

High Critical Current Density of Nanostructured MgB2 Bulk Superconductor Densified by Spark Plasma Sintering

et al. 2022

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In situ MgB2 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, Jc, which was measured at 20 K. Extremely high critical current densities of up to 6.75 × 105 A/cm2 in the self-field and above 104 A/cm2 at 4 T were measured at 20 K, indicating that vortex pinning is very strong. This property is mainly attributed to the sample density and MgB2 nanograins in connection to the presence of MgO precipitates and areas rich in boron.

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“…The MgB 2 superconductors with a bulk density of about 2.63 g/cm 3 are the lightest materials among practical superconductors. This makes MgB 2 attractive for portable applications [ 143 , 144 , 145 , 146 , 147 , 148 , 149 , 150 , 151 , 152 , 153 , 154 , 155 , 156 , 157 , 158 , 159 , 160 , 161 , 162 , 163 , 164 , 165 , 166 , 167 , 168 , 169 , 170 , 171 , 172 , 173 , 174 , 175 , 176 , 177 , 178 , 179 ], especially for aviation and space technology [ 26 , 146 , 171 ].…”

Section: Application Of Bulk Mgb 2 Superconductorsmentioning

confidence: 99%

Bulk MgB2 Superconducting Materials: Technology, Properties, and Applications

Prikhna,

Sokolovsky,

Moshchil

2024

Materials

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The intensive development of hydrogen technologies has made very promising applications of one of the cheapest and easily produced bulk MgB2-based superconductors. These materials are capable of operating effectively at liquid hydrogen temperatures (around 20 K) and are used as elements in various devices, such as magnets, magnetic bearings, fault current limiters, electrical motors, and generators. These applications require mechanically and chemically stable materials with high superconducting characteristics. This review considers the results of superconducting and structural property studies of MgB2-based bulk materials prepared under different pressure–temperature conditions using different promising methods: hot pressing (30 MPa), spark plasma sintering (16–96 MPa), and high quasi-hydrostatic pressures (2 GPa). Much attention has been paid to the study of the correlation between the manufacturing pressure–temperature conditions and superconducting characteristics. The influence of the amount and distribution of oxygen impurity and an excess of boron on superconducting characteristics is analyzed. The dependence of superconducting characteristics on the various additions and changes in material structure caused by these additions are discussed. It is shown that different production conditions and additions improve the superconducting MgB2 bulk properties for various ranges of temperature and magnetic fields, and the optimal technology may be selected according to the application requirements. We briefly discuss the possible applications of MgB2 superconductors in devices, such as fault current limiters and electric machines.

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Superconducting cryo-magnets processed by spark plasma sintering and texturing

Cited by 4 publications

References 47 publications

The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering

The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering

High Critical Current Density of Nanostructured MgB2 Bulk Superconductor Densified by Spark Plasma Sintering

Bulk MgB2 Superconducting Materials: Technology, Properties, and Applications

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Superconducting cryo-magnets processed by spark plasma sintering and texturing

Cited by 4 publications

References 47 publications

The discrepancies in different facets of MgB2 bulk superconductors prepared under various sintering durations by spark plasma sintering

The discrepancies in different facets of MgB2 bulk superconductors prepared under various sintering durations by spark plasma sintering

High Critical Current Density of Nanostructured MgB2 Bulk Superconductor Densified by Spark Plasma Sintering

Bulk MgB2 Superconducting Materials: Technology, Properties, and Applications

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Product

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The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering

The discrepancies in different facets of MgB₂ bulk superconductors prepared under various sintering durations by spark plasma sintering