Freeze casting of iron oxide subject to a tri-axial nested Helmholtz-coils driven uniform magnetic field for tailored porous scaffolds

Nelson, Isaac; Gardner, Levi; Carlson, Krista; Naleway, Steven E.

doi:10.1016/j.actamat.2019.05.003

Cited by 28 publications

(43 citation statements)

References 52 publications

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“…The well aligned cell walls generated by the magnetic field as well as the chitosan bridges that form pillar‐like supports for the cell walls enhance the mechanical performance of the Sendust‐chitosan composite in a similar fashion as previously reported for alumina composites with a nacre‐like structure, [ 23,47 ] in that case generated by freeze casting in the absence of a magnetic field. Comparing our freeze‐cast magnetic flake composites with surface‐magnetized flake‐based materials that were first freeze cast in a magnetic field and then sintered, [ 11,13,16,18 ] we note a superior property enhancement of a factor of 4 in both modulus and strength.…”

Section: Discussionmentioning

confidence: 99%

“…A novel and highly promising approach for the manufacture of low loss magnetic composites with highly aligned flakes is freeze‐casting. [ 11–19 ] Freeze casting, also termed ice‐templating, is based on the directional solidification of water‐based particle slurries. [ 20–24 ] Initially, the process was shown to produce highly aligned, nacre‐like microstructures with alumina platelets in a polymer binder.…”

Section: Introductionmentioning

confidence: 99%

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Superior Mechanical and Magnetic Performance of Highly Anisotropic Sendust‐Flake Composites Freeze Cast in a Uniform Magnetic Field

Yin

Reese

Sullivan

et al. 2020

Adv Funct Materials

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Despite extensive research, the manufacture in the bulk of high‐performance flake‐based magnetic composites with a highly aligned, nacre‐like structure remains challenging. Many challenges can be overcome by freeze casting in an externally applied, uniform magnetic field, which causes both the flakes and the composite walls of the cellular solid to align parallel to the B‐field lines. When appropriately sized, the flakes experience a second alignment parallel to the freezing direction because of a shear flow that occurs due to both the volumetric expansion of the ice phase and mold contraction during the directional solidification. The resulting orthotropic structure of the freeze‐cast magnetic composite is reflected in orthotropic mechanical and magnetic properties of the material. The magnetic composites manufactured by magnetic‐field assisted freeze casting outperform by a factor of 2–4 in terms of stiffness, strength, and toughness materials that are processed in the absence of a magnetic field and do not exhibit a monodomain architecture. Because of the highly aligned microstructure, it is possible to compact the initially lamellar composite with 90% porosity to at least 80% strain. The results presented in this study illustrate the tremendous potential for magnetic freeze casting of magnetic composites for use in power conversion.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Superior Mechanical and Magnetic Performance of Highly Anisotropic Sendust‐Flake Composites Freeze Cast in a Uniform Magnetic Field

Yin

Reese

Sullivan

et al. 2020

Adv Funct Materials

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“…1a). This setup, the construction of which has been previously described, 21,22 has been shown to apply a uniform magnetic field and, therefore, create homogenous porous structures (i.e., eliminate particle agglomeration). 21,28 This setup has also been shown to allow for the magnetic field to be controlled, thus pointing in any direction and/or moving in any direction during the freezing process.…”

Section: Tri-axial Nested Helmholtz Coils-based Freeze-casting Setupmentioning

confidence: 99%

“…21,28 This setup has also been shown to allow for the magnetic field to be controlled, thus pointing in any direction and/or moving in any direction during the freezing process. 22 Examples of the magnetic field aligning particles in the 3 coordinate directions are shown in Fig. 1b-d.…”

Section: Tri-axial Nested Helmholtz Coils-based Freeze-casting Setupmentioning

confidence: 99%

“…[18][19][20] In contrast, the use of Helmholtz coils during freeze casting has been shown to produce a low magnetic field gradient and therefore negates particle agglomeration, enabling the creation of uniform structures. 21,22 In this research, during the formation of ice crystals (i.e., the second step described above), tri-axial nested Helmholtz coils were controlled to apply a magnetic field in helical and Bouligand motions that mimicked the corresponding patterns seen in biological materials. These magnetic field motions JOM, Vol.…”

Section: Introductionmentioning

confidence: 99%

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Helical and Bouligand Porous Scaffolds Fabricated by Dynamic Low Strength Magnetic Field Freeze Casting

Nelson

Varga

Wadsworth

et al. 2020

JOM

Self Cite

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Porous Fe 3 O 4 scaffolds were fabricated while subject to a low (7.8 mT) magnetic field applied in helical and Bouligand motions using a custom-built triaxial nested Helmholtz coils-based freeze-casting setup. This setup allowed for the control of a dynamic, uniform low-strength magnetic field to align particles during the freezing process, resulting in the majority of lamellar walls aligning within ± 30°of the magnetic field direction and a decrease in porosity by up to 42%. Similar to how helical and Bouligand structures in nature promote impact resistance, these magnetic field motions produced structures with improved high strain rate mechanical properties. Strain at failure was increased by up to 2 times as cracks deflected to match the applied angles of rotation of the magnetic field.

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A New Era of Integrative Ice Frozen Assembly into Multiscale Architecturing of Energy Materials

Yeon

Gupta

Bhattacharya

et al. 2022

Adv Funct Materials

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The ice templating assembly has been investigated to construct macroporous channels of functional nanomaterials with well‐defined homogeneous morphology. Recently, this templating method has been revisited integrating with other materials’ synthesis and processing methodologies (such as, spinning, spraying, filtration, hydrothermal, oxygenation, gelation, and 3D printing) for electrochemical energy conversion and storage applications. Herein, the recent progress on “integrative ice frozen assembly” focusing on the hierarchical structures and chemistries of functional nanomaterials such as, organic, inorganic, carbon, and composite materials for a rational design of energy application‐oriented materials is comprehensively reviewed. This integrative process allows functional nanomaterials to be assembled into various dimensions, such as, 0D, 1D, 2D, and 3D macrostructures, as well as, into larger bulk objects such as, fibers, films, monoliths, and powders. The fundamental understanding of the integrative ice frozen assembly is thermodynamically and kinetically discussed with the help of primitive freeze casting domain knowledge and the energy conversion and storage performances of the as‐designed electrodes with their hierarchical structures and chemistries are further correlated. The applications of the as‐assembled electrodes into batteries, supercapacitors, fuel cells, and electrocatalysis are also addressed. Finally, the perspective on the current impediments and future directions in this field is discussed.

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Freeze casting of iron oxide subject to a tri-axial nested Helmholtz-coils driven uniform magnetic field for tailored porous scaffolds

Cited by 28 publications

References 52 publications

Superior Mechanical and Magnetic Performance of Highly Anisotropic Sendust‐Flake Composites Freeze Cast in a Uniform Magnetic Field

Superior Mechanical and Magnetic Performance of Highly Anisotropic Sendust‐Flake Composites Freeze Cast in a Uniform Magnetic Field

Helical and Bouligand Porous Scaffolds Fabricated by Dynamic Low Strength Magnetic Field Freeze Casting

A New Era of Integrative Ice Frozen Assembly into Multiscale Architecturing of Energy Materials

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