Gas permeability and mechanical properties of porous alumina ceramics with unidirectionally aligned pores

Isobe, Toshihiro; Kameshima, Yoshikazu; Nakajima, Akira; Okada, Kiyoshi; Hotta, Yuji

doi:10.1016/j.jeurceramsoc.2006.02.030

Cited by 143 publications

(107 citation statements)

References 16 publications

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“…Zhang et al [79] have reported the use of this method to fabricate porous alumina ceramics with unidirectionally aligned 165 µm continuous pores in a material with 35% porosity and a bending strength of 155 MPa. These properties compare well with those of conventional porous ceramics [70,71].…”

Section: Filament Windingsupporting

confidence: 62%

“…Such anisotropy in the green product is generally unfavorable because it causes inhomogeneous shrinkage in the drying and firing stages, but it can be used intentionally to fabricate unidirectionally porous ceramics using flammable fibers as the pore formers [69][70][71]. Figure 4 shows the microstructures of the cross sections perpendicular and parallel to the extruded directions of porous alumina ceramics prepared using carbon fibers and nylon fibers as the pore formers.…”

Section: Extrusion Using Fibers As the Pore Former (Ef Method)mentioning

confidence: 99%

“…One is a multi-pass extrusion method proposed by Li et al [64][65][66][67][68]. The other is an extrusion method using flammable fibers as the pore formers, reported by Isobe et al [69][70][71].…”

Section: Extrusionmentioning

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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Section: Filament Windingsupporting

confidence: 62%

Section: Extrusion Using Fibers As the Pore Former (Ef Method)mentioning

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

Self Cite

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“…Thus, capillary rise height is inversely proportional to the pore size of lotus ceramics [61]. Despite high water retention and good cooling effects because of the excellent capillary lift of water in the porous ceramics (lotus ceramics) developed by Isobe et al [62][63][64], the applicability of these ceramics will increase even further if they are fabricated using an environmentally friendly process and the requirement for firing at high temperatures will be disregarded. Geopolymers [65] fit all the aforementioned requirements, and thus are excellent choices in the context of this work.…”

Section: Ceramicsmentioning

confidence: 99%

Green Material Prospects for Passive Evaporative Cooling Systems: Geopolymers

et al. 2016

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Passive cooling techniques have been used mostly in countries with hot and arid climates such as Iran, Egypt, and India. However, the use of this important technology has not been seriously considered until a time of energy crisis, and consequently, environmental crisis scenarios, emerge. Scholars have renewed their interest in investigating passive cooling technology, particularly the aspects of new materials, thermal comfort, energy efficiency, new designs, climate, and environmental considerations. This review paper highlights the opportunities to use green materials, such as geopolymers, as evaporative cooling materials with different types of industrial and agricultural waste products as components. Novel ideas for passive cooling design using ancient and nature-inspired concepts are also presented to promote green technology for future applications.

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“…Recently, there has been an increasing interest in the applications of porous ceramics as filters, insulators, catalyst supports, bone replacements and membrane reactors and so on [1][2][3][4][5][6][7]. High porosity and optimization of pore size distribution of the porous ceramics are very essential for the enhancement of the diffusivity of various gaseous and liquid substances through their porous structure.…”

Section: Introductionmentioning

confidence: 99%

Fabrication of porous alumina ceramics having cell windows with controlled size by PMMA template method

et al. 2010

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Highly porous alumina compacts have been prepared by filling alumina slurry into opening of a specially designed template block prepared by cross-linked (cl-) polymethylmethacrylate (PMMA) microspheres (mean particle size: 98.6 m) under reduced pressure, followed by firing to remove the template and then sintering at 1600°C. The template blocks were prepared by utilizing cl-PMMA and acetone solution dissolving noncrosslinked (Ncl-) PMMA as an adhesive to make partial connection among the cl-PMMA microspheres. Furthermore, the effects of the addition of other chemicals (two types of triblockcopolymers and a nonionic surfactant) to the Ncl-PMMA adhesive solution were tested to improve the wettability of the solution to cl-PMMA and then to control the cell windows among the cl-PMMA-originated cells after the firing. By employing the template block prepared with the adhesive solution containing an appropriate amount of triblockcopolymer, a highly porous alumina compact having an open porosity of 77.2%, a mean cell window diameter of 28.8 m and strong alumina skeleton could be fabricated.

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Gas permeability and mechanical properties of porous alumina ceramics with unidirectionally aligned pores

Cited by 143 publications

References 16 publications

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

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

Green Material Prospects for Passive Evaporative Cooling Systems: Geopolymers

Fabrication of porous alumina ceramics having cell windows with controlled size by PMMA template method

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