Solidification microstructure evolution in the presence of inert particles

Sekhar, J. A.; Trivedi, R.

doi:10.1016/0921-5093(91)90800-3

Cited by 82 publications

(66 citation statements)

References 19 publications

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“…The behavior of slurries with ceramic nanoparticles tends to get close to that of the simple system solute/water-a system much simpler to model. In addition, preliminary results [2] indicate that this variation might be dependent on the particle content, as pointed out by the previous studies [3,22].…”

Section: Influence Of Cooling Rate On the Microstructurementioning

confidence: 57%

“…Eventually, it might considerably affect the pattern formation mechanisms. It has previously been shown that the particles themselves may induce morphological transitions, such as dendrites tip splitting or healing during growth before being captured [3]. Ceramic bridges between lamellae may arise from local ice crystal tip splitting and engulfment of particle agglomerates created by particles repelled from the ice-water interface and subsequent tip healing.…”

Section: Ceramic Bridgesmentioning

confidence: 99%

“…Various analyses of this phenomenon in model suspensions [3,19,23] or biological or natural systems like blood [24] or saltwater [25] have been published. All these fundamental investigations were made for suspensions with a very low concentration of particles, so that the interactions of particles with each other were not taken into account.…”

Section: Pattern Formation Mechanisms: the Physics Of Ice And The Intmentioning

confidence: 99%

“…Control of the regularity and size of the patterns is often a key issue with regards to the final properties of the materials. Hence, particular attention has been paid to the control of solidification microstructures in the presence of inert particles [3], both theoretically and experimentally, for its wide application in cast materials. The final microstructure is directly related to the shape and behavior of the solidification front, which can either engulf or repel the inert particles, such as ceramic particles in a solidifying metal.…”

Section: Introductionmentioning

confidence: 99%

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Ice-templated porous alumina structures

2007

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The formation of regular patterns is a common feature of many solidification processes involving cast materials. We describe here how regular patterns can be obtained in porous alumina by controlling the freezing of ceramic slurries followed by subsequent ice sublimation and sintering, leading to multilayered porous alumina structures with homogeneous and well-defined architecture. We discuss the relationships between the experimental results, the physics of ice and the interaction between inert particles and the solidification front during directional freezing. The anisotropic interface kinetics of ice leads to numerous specific morphologies features in the structure. The structures obtained here could have numerous applications including ceramic filters, biomaterials, and could be the basis for dense multilayered composites after infiltration with a selected second phase.

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Section: Influence Of Cooling Rate On the Microstructurementioning

confidence: 57%

Section: Ceramic Bridgesmentioning

confidence: 99%

Section: Pattern Formation Mechanisms: the Physics Of Ice And The Intmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Ice-templated porous alumina structures

2007

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“…It has previously been shown that the particles themselves may induce morphological transitions, such as dendrites tip splitting or healing during growth before being captured. [57] Ceramic bridges between lamellae may arise from local ice crystal tip splitting and engulfment of particle agglomerates created by particles repelled from the ice-water interface and subsequent tip healing. Depending on the magnitude of tip splitting/healing, the entrapped ceramic particles might not bridge completely the gap.…”

Section: Ceramic Bridgesmentioning

confidence: 99%

Freeze‐Casting of Porous Ceramics: A Review of Current Achievements and Issues

2008

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Freeze‐casting, the templating of porous structures by the solidification of a solvent, have seen a great deal of efforts during the last few years. Of particular interest are the unique structure and properties exhibited by porous freeze‐casted ceramics, which opened new opportunities in the field of cellular ceramics. The objective of this review is to provide a first understanding of the process as of today, with particular attention being paid on the underlying principles of the structure formation mechanisms and the influence of processing parameters on the structure. This analysis highlights the current limits of both the understanding and the control of the process. A few perspectives are given, with regards of the current achievements, interests and identified issues.

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Engineering Graphene‐Ceramic 3D Composite Foams by Freeze Drying

et al. 2021

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Nanofillers such as carbon fiber, carbon nanotube (CNT), 2D graphene, and hexagonal boron nitride are a proven reinforcement material at the microscale, leading to enhanced macroscopic property. [1][2][3] However, the augmentation of properties such as superior mechanical strength, increased electrical and thermal properties, and crack confinement in the material matrix is achieved only when the nanofillers are dispersed homogeneously. Until the advent of 2D graphene in 2004, [4,5] CNTs were the dominant nanofiller used in the synthesis of reinforced nanocomposites. CNT's high entanglement affinity, impurities, and challenges associated with processing hindered their application for novel composite materials development. [6][7][8] On the other hand, 2D graphene (Gr), whose material properties are comparable to CNTs, had many other novel physical, chemical, and electronic properties. Experimental and theoretical results boast that a single sheet of 2D graphene formed by the packing of carbon atoms into a honeycomb-like lattice is the strongest material developed to date. [9,10] The 2D graphene exhibits high modulus (%1 TPa), [11] tensile strength (%100 GPa), [11] superior thermal conductivity (3000-5000 W m À1 K À1 ), [12,13] exceptional electron mobility at room temperature (>200 000 cm 2 V À1 s À1 ), [14][15][16] and high transparency (97.7%) to incident light. [17,18] These outstanding physicochemical properties of 2D graphene make it a popular nanofiller for various applications, such as composite engineering materials, sensor, nanoelectronics, biomedical, and catalysis, to name a few. [19] Despite these excellent properties as a nanofiller, 2D graphene results in the aggregation or restacking of sheets due to strong π-π interaction. [20][21][22] Thus, formed nanocomposites exhibit poor mechanical (agglomerates form sites for stress concentration) and deteriorated electrochemical properties due to decreased active surface area. To fully exploit the outstanding properties of 2D graphene, various strategies have been used, such as crumbling the graphene sheets, adding spacers, and stacking 2D graphene into 3D hierarchical architecture. [23,24] Graphene material with 3D architecture, such as foam produced by chemical vapor deposition (CVD), has proved effective against agglomeration, unlike the 2D graphene flakes in the matrix material. The interconnected network of nodes and branches, which is characteristic of a 3D hierarchical structure of graphene foam (GrF), enables uninterrupted pathways to transfer electrons, phonons, and stresses, thus incorporating superior material properties in the reinforced matrix. [25][26][27] The porous 3D architecture in GrF offers low density (<5 mg cm À3 ), high surface area (%850 m 2 g À1 ), stable mechanical properties, accelerated electron and phonon transfer properties due to the reduced inter-sheet junction contact resistance, unlike the 2D graphene sheets.

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Solidification microstructure evolution in the presence of inert particles

Cited by 82 publications

References 19 publications

Ice-templated porous alumina structures

Ice-templated porous alumina structures

Freeze‐Casting of Porous Ceramics: A Review of Current Achievements and Issues

Engineering Graphene‐Ceramic 3D Composite Foams by Freeze Drying

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