Complex pulse magnetization process and mechanical properties of spark plasma sintered bulk MgB2

Muralidhar, M.; Arvapalli, Sai Srikanth; Sakai, Naomichi; Murakami, Masato; Mochizuki, Hidehiko; Naito, Tomoyuki; Fujshiro, Hiroyuki; Jirsa, M.; Murakami, Akira; Noudem, Jacques

doi:10.1016/j.mseb.2021.115390

Cited by 7 publications

(5 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among superconductors, cost-effectiveness, absence of toxic elements, lack of reliance on rare earth elements, and the ability to transport high critical current across randomly oriented grain boundaries make MgB 2 a good candidate for trapped field applications [ 17 , 18 , 19 ]. In addition, recent progresses in bulk fabrication techniques has allowed for the manufacturing of MgB 2 bulks with high trapped field values even in small-sized samples [ 20 , 21 ]. It was reported that the critical current densities and trapped field depend on the density and homogeneity of the MgB 2 superconducting material and pinning centers [ 19 , 22 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Fracasso,

Gerbaldo,

Ghigo

et al. 2024

Materials

Self Cite

View full text Add to dashboard Cite

Superconductors have revolutionized magnet technology, surpassing the limitations of traditional coils and permanent magnets. This work experimentally investigates the field-trapping ability of a MgB2 disc at various temperatures and proposes new hybrid (MgB2-soft iron) configurations using a numerical approach based on the vector potential (A→) formulation. The experimental characterization consists in measurements of trapped magnetic flux density carried out using cryogenic Hall probes located at different radial positions over the MgB2 sample, after a field cooling (FC) process and the subsequent removal of the applied field. Measurements were performed also as a function of the distance from the disc surface. The numerical modelling of the superconductor required the evaluation of the critical current density dependence on the magnetic flux density (Jc(B)) obtained through an iterative procedure whose output were successfully validated by the comparison between experimental and computed data. The numerical model, upgraded to also describe the in-field behavior of ARMCO soft iron, was then employed to predict the field-trapping ability of hybrid layouts of different shapes. The most promising results were achieved by assuming a hollow superconducting disc filled with a ferromagnetic (FM) cylinder. With such a geometry, optimizing the radius of the FM cylinder while the external dimensions of the superconducting disc are kept unchanged, an improvement of more than 30% is predicted with respect to the full superconducting disc, assuming a working temperature of 20 K.

show abstract

Section: Introductionmentioning

confidence: 99%

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Fracasso,

Gerbaldo,

Ghigo

et al. 2024

Materials

Self Cite

View full text Add to dashboard Cite

show abstract

“…field, due to the absence of flux pinning centers. When the above-mentioned defects were incorporated by chemical doping, ball milling, low-temperature sintering, and spark plasma sintering [3][4][5][6][7], the modified MgB 2 superconductor becomes a compelling candidate for application in magnetic resonance imaging devices, and the refrigeration cost is expected to be reduced by 50% [8][9][10], compared with the conventional Nbbased superconductor.…”

Section: Introductionmentioning

confidence: 99%

Confinement of self-generated Mg(BH₄)₂ particles for simultaneously enhanced flux pinning and grain connectivity in polycrystalline H-doped MgB₂

Cui¹,

Cai²,

Li³

et al. 2023

Supercond. Sci. Technol.

View full text Add to dashboard Cite

The present study reports a simple quenching method to simultaneously improve flux pinning and grain connectivity in polycrystalline H-doped MgB2, which was ex-situ synthesized at 350 oC under the H2 pressure of 3 MPa. Quenching prevented the phase transformation of β-Mg(BH4)2→α-Mg(BH4)2 upon cooling, and the dominant point-pinning effects originated from the self-generated nano-sized β-Mg(BH4)2 particles that were confined within the MgB2 grains. A semi-coherent relationship was found between MgB2(100) and Mg(BH4)2(—11—4) planes. Meanwhile, the precipitation-induced expansion of the MgB2 grains remained at room temperature, leading to an increasing number of contact points as well as grain connectivity. Compared with the un-doped MgB2, the quenched H-doped one exhibited enhanced critical current density over the entire field. These results are expected to guide the design of flux pinning centers for improving the Jc performance of standard type II superconductors.

show abstract

“…Although a lot of efforts have been made in order to fabricate more and more efficient shields, both improving the material properties and optimizing the manufact shape [17][18][19], the SC shield performances can still be weakened by different uncontrolled causes, such as quench phenomena or other thermomagnetic instabilities [20]. In the case of MgB 2 samples, despite the improvements in the fabrication processes, thermomagnetic instabilities such as flux jumps still occur at low operating temperatures.…”

Section: Introductionmentioning

confidence: 99%

Numerical study on flux-jump occurrence in a cup-shaped MgB₂ bulk for magnetic shielding applications

Fracasso

Gömöry

Solovyov

et al. 2023

Supercond. Sci. Technol.

View full text Add to dashboard Cite

MgB2 is one of the most promising materials for superconducting bulk applications. However, thermomagnetic instabilities can arise in the material because of its low heat capacity and thermal conductivity as well as its high critical current density. Being able to predict these phenomena, can guide and optimize MgB2-based devices for magnetic flux shielding or trapping applications. In this work, the flux-jump occurrence in an MgB2 cup-shaped shield is numerically studied using the finite element method by means of the commercial software COMSOL 6.0 Multiphysics®. To this aim, we developed a 2D axial-symmetric model coupling the heat diffusion equation and the magnetic equations based on a magnetic vector-potential A-formulation. The comparison of the computed shielding curves with the experimental ones evidenced a good agreement between the two sets of data at different temperatures and positions along the shield's axis. The as-validated model was then exploited to investigate possible optimization routes via the improvement of both the thermal conductivity of the material and the thermal exchange between the device and the cooling stage.

show abstract

Complex pulse magnetization process and mechanical properties of spark plasma sintered bulk MgB2

Cited by 7 publications

References 35 publications

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Confinement of self-generated Mg(BH₄)₂ particles for simultaneously enhanced flux pinning and grain connectivity in polycrystalline H-doped MgB₂

Numerical study on flux-jump occurrence in a cup-shaped MgB₂ bulk for magnetic shielding applications

Contact Info

Product

Resources

About

Complex pulse magnetization process and mechanical properties of spark plasma sintered bulk MgB2

Cited by 7 publications

References 35 publications

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Comparison of the Field Trapping Ability of MgB2 and Hybrid Disc-Shaped Layouts

Confinement of self-generated Mg(BH4)2 particles for simultaneously enhanced flux pinning and grain connectivity in polycrystalline H-doped MgB2

Numerical study on flux-jump occurrence in a cup-shaped MgB2 bulk for magnetic shielding applications

Contact Info

Product

Resources

About

Confinement of self-generated Mg(BH₄)₂ particles for simultaneously enhanced flux pinning and grain connectivity in polycrystalline H-doped MgB₂

Numerical study on flux-jump occurrence in a cup-shaped MgB₂ bulk for magnetic shielding applications