Fabrication of porous alumina ceramics from powder mixtures with sol–gel derived nanometer alumina: Effect of mixing method

Kritikaki, Anna; Tsetsekou, Athena

doi:10.1016/j.jeurceramsoc.2008.10.011

Cited by 49 publications

(22 citation statements)

References 23 publications

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“…The skin layer has remained as the functional layer which decreases the water vapor transfer resistance and increases permeate flux in SGMD. The bending strength of M2 is 25 MPa, which is comparable with ceramic membranes reported in the literature [23,24]. The X-ray diffractograms of the M2 membranes sintered at 1700 are shown in Fig.…”

Section: Membrane Characteristicssupporting

confidence: 82%

Preparation of high-efficiency ceramic planar membrane and its application for water desalination

Tao

et al. 2018

J Adv Ceram

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Highly efficient Si 3 N 4 ceramic planar membrane for water desalination process using membrane distillation was prepared by the dual-layer phase inversion tape casting and sintering method. In comparison with typical phase inversion tape casting method, the green tape was formed using Si 3 N 4 slurry on the top and graphite slurry on the bottom. After consuming away the graphite structure, a ceramic membrane consisting of a two-layered structure (skin and finger-like layers) was obtained. The skin layer was relatively tight, and thus could act as a functional layer for separation, while the finger-like layer contained straight open pores with a diameter of 100 μm, acting as a support with low transport resistance. For comparison, typical Si 3 N 4 ceramic membrane was fabricated by phase inversion technique without graphite substrate, resulting in a three-layered structure (skin, finger-like, and sponge layers). After membrane modification from hydrophilic to hydrophobic with polymer derived nanoparticle method, the water desalination performance of the membranes was tested using the sweeping gas membrane distillation (SGMD) with different NaCl feed solutions. With the increase of salt content from 4 to 12 wt%, the water flux decreased slightly while rejection rate maintained over 99.99%. Comparing with typical three-layered Si 3 N 4 membrane, an excellent water flux enhancement of over 83% was resulted and the rejection rate remained over 99.99%.

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Section: Membrane Characteristicssupporting

confidence: 82%

Preparation of high-efficiency ceramic planar membrane and its application for water desalination

Tao

et al. 2018

J Adv Ceram

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“…It could be concluded that the improvement of bending strength was largely contributed to the aligned alumina platelets in the surface layer. Ray et al 23) reported about 14 MPa for the bending strength of porous alumina with the porosity of about 48% and the average particle size of 7¯m, and Kritikaki et al 24) did about 22 MP for that of porous alumina with the porosity of 52% and the average particle size of 5¯m. Note that the particles of these materials are isotropic ones.…”

mentioning

confidence: 99%

Fabrication and characterization of porous alumina with a surface layer composed of alumina platelet by direct-foaming method

Shimamura

Fukushima

Hotta

et al. 2017

J. Ceram. Soc. Japan

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Porous alumina with the surface layer was fabricated from an alumina platelet/novolac-HexaMethyleneTetramine (HMT) composite. HMT was used as a blowing agent as well as a curing one for the novolac binder. When the alumina platelet/novolac composite was heated with covering its surface with filter papers, a porous structure formed inside the composite due to blowing from HMT. On the other hand, the blowing gas near the surface was evolved outward through the filter paper, which resulted in the formation of the surface layer composed of the aligned alumina platelets. Effect of the surface layer on the mechanical strength was examined by three-point bending measurement. The bending strength of the obtained porous alumina increased by 94% compared to the porous alumina without the surface layer.©2017 The Ceramic Society of Japan. All rights reserved.Key-words : Alumina, Porous, Platelets [Received November 7, 2016; Accepted January 29, 2017] Porous ceramics have numerous industrial applications, including structural components, thermal insulators, absorbents, and filters, 1)6) due to a variety of specific properties, such as their heat and corrosion resistance, lightness, and low thermal conductivity. 7),8) Among these specific properties, the lightness is one of the most important properties in the porous ceramics. While increasing porosity reduces the weight, it also degrades mechanical strength, which is critically important where the porous ceramics is used as structural materials.We have previously proposed a direct-foaming approach for porous ceramics from ceramic/novolacHexaMethyleneTetramine (HMT) composite, 9),10) and using this approach we have fabricated porous alumina with the relatively dense surface layer. 11) In this study, HMT was used as a blowing agent and as a curing one for the novolac resin. A gas blown from HMT led to the formation of a porous structure in the alumina/ novolac composite with the expansion of the composite body, while it also resulted in swelling of the surface. This problem can be solved by covering the surface with a proper sheet and constraining the swelling using a mold during blowing. When using a plastic sheet for this purpose, coarse pores formed on the surface because the blowing gas accumulated around the surface, which led to degradation of mechanical strength. Instead, when employing a paper filter for the sheet, relatively dense layer was obtained since the blowing gas near the surface was released to the outside and to keep the surface flat, improving the mechanical strength 30% compared to that of porous alumina without the surface layer.It has been known that dense alumina with microstructure of aligned platelets exhibits excellent mechanical property when stress is applied in the alignment direction. 12)17) Therefore, if the surface layer composed of aligned alumina platelets parallel to the surface can be fabricated, then we can anticipate increase of the mechanical strength. However, to the best of our knowledge, there have been no studies on controlling mi...

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“…[1][2][3] Indeed, these materials present a lot of interesting properties such as lightness, thermal insulation, thermal shock resistance or high specific surface area. This kind of materials often exhibits open porosity and high roughness that is necessary for some applications such as filtration or catalyst but could be not compatible with some others.…”

Section: Introductionmentioning

confidence: 99%

Fabrication and characterization of composite sol–gel coatings on porous ceramic substrate

Touzin

béclin

2011

Journal of the European Ceramic Society

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Fabrication of porous alumina ceramics from powder mixtures with sol–gel derived nanometer alumina: Effect of mixing method

Cited by 49 publications

References 23 publications

Preparation of high-efficiency ceramic planar membrane and its application for water desalination

Preparation of high-efficiency ceramic planar membrane and its application for water desalination

Fabrication and characterization of porous alumina with a surface layer composed of alumina platelet by direct-foaming method

Fabrication and characterization of composite sol–gel coatings on porous ceramic substrate

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