Fabrication and properties of ultra highly porous silicon carbide by the gelation–freezing method

Fukushima, Manabu; Nakata, Masao; Zhou, You; Ohji, Tatsuki; Yoshizawa, Yu‐ichi

doi:10.1016/j.jeurceramsoc.2010.03.018

Cited by 111 publications

(91 citation statements)

References 21 publications

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“…Many techniques, such as partial sintering, 1),2) templating, 3),4) reaction bonding, 5),6) gel casting, 7) gelation-freezing method, 8) and in-situ reaction synthesis, 9), 10) have been developed for fabricating porous SiC ceramics. Among these techniques, the partial sintering is a one-step process for fabrication of porous ceramics using the space formed by necking between the grains.…”

Section: Introductionmentioning

confidence: 99%

Pore-size control in porous SiC ceramics prepared by spark plasma sintering

Hotta

Kita

Matsuura

et al. 2012

J. Ceram. Soc. Japan

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Porous SiC ceramics were prepared at 19002000°C without holding time at 50200°C/min under a pressure of 15 MPa in Ar with Al 2 O 3 , Y 2 O 3 , and AlN additives by spark plasma sintering. The effects of heating rate, heating temperature, and sintering additive on the porosity, pore size, microstructure, and flexural strength of the porous SiC ceramics were investigated. As the heating rate increased, the size of SiC grains in the samples decreased, the porosity increased, and the flexural strength decreased. The strength of the samples increased with an increase in heating temperature. The growth of SiC grains was suppressed in the sample prepared at 1950°C, and the sample had both high porosity (42%) and high strength (95 MPa). In the samples prepared with AlNY 2 O 3 and AlNAl 2 O 3 additives at 1950°C the porosities were 3239%. The addition of AlN to Y 2 O 3 and Al 2 O 3 additives resulted in the inhibition of grain growth and a decrease in the pore size of the samples. The maximum strength was 167 MPa in the prepared porous SiC ceramics.

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Section: Introductionmentioning

confidence: 99%

Pore-size control in porous SiC ceramics prepared by spark plasma sintering

Hotta

Kita

Matsuura

et al. 2012

J. Ceram. Soc. Japan

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“…The cell size decreased with the decrease in the freezing temperature. As the temperature range from 0 to ¹7°C is known as the temperature zone of maximum ice crystal formation, 26) when the time required to pass this zone is short, namely low temperature of cooling medium, the size of ice crystals formed can be reduced. …”

Section: Use Of Sacrificial Ice Fugitivesmentioning

confidence: 99%

Microstructural control of macroporous silicon carbide

Fukushima

2013

J. Ceram. Soc. Japan

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Wide range of porosity in 3090 vol % could be created into silicon carbide by employing carefully selected manufacturing methods. Two fabrication methods have been proposed and reviewed in the present paper: (1) partial sintering of submicrometersized silicon carbide particle with a suitable amount of sintering additive, acting as an inhibition of grain growth during sintering; (2) the use of ice crystals, as sacrificial pore formers, formed by freezing a silicon carbide particle dispersed gel body, leading to highly porous silicon carbide after sublimating ice crystals by vacuum drying and subsequently sintering. Depending on the processing route adopted, average pore size could be modulated in the range from 0.03 to 0.70¯m and 30 to 150¯m by partial sintering and gelation freezing, respectively. All fabrication methods proposed are simple, economical and versatile to produce macroporous body with tailored pore architecture and engineering porosity.

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“…Tert-butyl alcohol (TBA) generates unique unidirectional pores with hexagonal cross sections depending on the structure of the hexamers in the frozen TBA [51]. The porosity of the products can be enhanced by the use of organic pore formers such as polyvinyl alcohol (PVA) [52], polymethyl methacrylate (PMMA) [53], gelatin [54] or polyurethane sponge [55]. In these cases, the ceramic matrix tends to be porous and form a three-dimensional pore network as well as a unidirectionally connected pore structure.…”

Section: Unidirectional Freezingmentioning

confidence: 99%

“…Porosity, pore size and observed and calculated permeability ratio (%) for unidirectional porous ceramics prepared by freeze casting (• [83], : [54], EF, •: [70]), and conventional porous ceramics ( : [84], : [70], ♦: [85]). The solid lines represent the permeability calculated using equation (2).…”

Section: Permeabilitymentioning

confidence: 99%

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Porous ceramics mimicking nature—preparation and properties of microstructures with unidirectionally oriented pores

Okada

Isobe

Katsumata

et al. 2011

Science and Technology of Advanced Materials

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Porous ceramics with unidirectionally oriented pores have been prepared by various methods such as anodic oxidation, templating using wood, unidirectional solidification, extrusion, etc. The templating method directly replicates the porous microstructure of wood to prepare porous ceramics, whereas the extrusion method mimics the microstructures of tracheids and xylems in trees. These two methods are therefore the main focus of this review as they provide good examples of the preparation of functional porous ceramics with properties replicating nature. The well-oriented cylindrical through-hole pores prepared by the extrusion method using fibers as the pore formers provide excellent permeability together with high mechanical strength. Examples of applications of these porous ceramics are given, including their excellent capillary lift of over 1 m height which could be used to counteract urban heat island phenomena, and other interesting properties arising from anisotropic unidirectional porous structures.

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Fabrication and properties of ultra highly porous silicon carbide by the gelation–freezing method

Cited by 111 publications

References 21 publications

Pore-size control in porous SiC ceramics prepared by spark plasma sintering

Pore-size control in porous SiC ceramics prepared by spark plasma sintering

Microstructural control of macroporous silicon carbide

Porous ceramics mimicking nature—preparation and properties of microstructures with unidirectionally oriented pores

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