Superconducting Properties of MgB2 Bulk Shaped by Spark Plasma Sintering

Noudem, Jacques; Dupont, Louis; Gozzelino, Laura; Bernstein, P.

doi:10.1016/j.matpr.2016.01.088

Cited by 11 publications

(11 citation statements)

References 11 publications

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“…We used grade A magnesium diboride from ABCR GmbH as the starting powder, which was loaded into the graphite die and then processed by using the SPS system in DC mode. The pulsed electric current (2000 A, 4 V) was applied under the dynamic vacuum (10 −3 bar) with a uniaxial pressure of 50 MPa [16,17]. The samples were treated at 950 • C and different sintering durations, which include short sintering durations of 15, 30, 45 and 60 min and long sintering durations of 150, 180 and 240 min, corresponding to S1 ∼ S7, respectively.…”

Section: Methodsmentioning

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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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: 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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“…However, the density of the obtained bulks is quite low, about half the value of the theoretical density. Fortunately, some processing techniques can be used to prepare dense MgB 2 samples, especially (i) hot isostatic pressing (HIP), 33 (ii) hot compaction or pressing (HP), 34,35 (iii) high‐pressure sintering (HPS), 36,37 and (iv) spark plasma sintering (SPS) 38‐40 . This last technique SPS, offers the possibility to prepare samples with a complex shape and/or a large size 38,39 .…”

Section: Introductionmentioning

confidence: 99%

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

et al. 2020

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Spark Plasma Sintering (SPS) is a promising rapid consolidation technique that allows a better understanding and optimization of the sintering kinetics and therefore makes it possible to obtain MgB2 bulk superconductor with tailored microstructures consisting of grains with either spherical or elongated morphology. In this contribution, the role of the precursor powders on the superconducting properties of MgB2 is investigated. Three sets of bulk MgB2 material were processed from: (i) a commercially available MgB2 powder; (ii) a mixture of Mg metal and amorphous B using a single‐step solid‐state reaction process and (iii) a mixture of amorphous boron coated with carbon and Mg metal. The samples were prepared in the same SPS processing conditions. The microstructure of the samples was investigated by X‐ray diffraction, SEM and TEM and correlated to their superconducting properties. The critical current density of the best sample at 20K was Jc = 500 kA/cm2 in self‐field, which is one of the highest critical current density reported for MgB2 bulk superconductors.

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“…The sample preparation steps for the SPS sample are described in Ref. [22,23], and the fabrication of the polycrystalline, sintered samples is discussed in Ref. [24].…”

Section: Methodsmentioning

confidence: 99%

Pinning Force Scaling Analysis of Polycrystalline MgB2

Koblischka

Wiederhold

Koblischka-Veneva

et al. 2020

J Supercond Nov Magn

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Flux pinning force scaling $f=F_{p}/F_{p,\max \limits }$ f = F p / F p , max vs. h = Ha/Hirr was performed on a variety of pure MgB2 samples, including a spark plasma sintered (SPS) one and a series of samples sintered at various reaction temperatures ranging between 775 and 950 ∘C. The SPS sample exhibits a well-developed scaling at all temperatures, and also the sintered samples prepared at 950 ∘C; however, the obtained peak positions of the pinning force scalings are distinctly different: The SPS sample reveals dominating pinning at grain boundaries, whereas the dominating pinning for the other one is point-pinning. All other samples studied reveal an apparent non-scaling of the pinning forces. The obtained pinning parameters are discussed in the framework of the Dew–Hughes’ pinning force scaling approach.

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Superconducting Properties of MgB2 Bulk Shaped by Spark Plasma Sintering

Cited by 11 publications

References 11 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

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering

Pinning Force Scaling Analysis of Polycrystalline MgB2

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Superconducting Properties of MgB2 Bulk Shaped by Spark Plasma Sintering

Cited by 11 publications

References 11 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

Improvement of critical current density of MgB2 bulk superconductor processed by Spark Plasma Sintering

Pinning Force Scaling Analysis of Polycrystalline MgB2

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Product

Resources

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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

Improvement of critical current density of MgB₂ bulk superconductor processed by Spark Plasma Sintering