Fabrication and characterization of highly porous mullite ceramics

She, Jihong; Ohji, Tatsuki

doi:10.1016/s0254-0584(03)00080-4

Cited by 161 publications

(89 citation statements)

References 28 publications

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“…On the other hand, those of lower RD (M-RH 1100 and M-PS 1100 ) could be used as porous structures for thermal insulation or as biological scaffolds. Secondly, the overall level of the RFS values obtained in this work is close to those described in the literature for samples of similar compositions, but produced by more complex compaction techniques (isostatic pressing 3,10,12 ), longer sintering times (longer than 3 h 16,17 ) and higher thermal treatment temperatures (above 1500°C 28,29 ) or with the aid of liquid phase sintering 27,32 . Therefore, for similar levels of flexural strength, a significant energy saving in the processing operations could be achieved by using SASs.…”

Section: Samples Sintered At 1500ºcsupporting

confidence: 84%

“…RFS is the ratio between the experimental results of FS and the theoretical value obtained for a 100% dense sample (for mullite [2][3][4]16,30,34,51 , FS Theoretical = 180 MPa). Such an approach is useful for investigating the mechanical behavior of porous (RD ≤ 50 %) and semi-porous structures (95% ≤ RD > 50 %).…”

Section: Na Siomentioning

confidence: 99%

“…Mullite (3Al 2 O 3 .2SiO 2 or Al 6 Si 2 O 13 ), one of the main raw materials for the ceramic industry [1][2][3][4] , is an input for the production of refractory materials 1,[5][6][7][8][9] , catalyst support 10,11 , electronic and optic devices [12][13][14] , thermal insulators 8,9,15 , hot gas filters (above 600°C) [16][17][18] and biological and biomedical scaffolds [19][20][21] . Its formation is a complex set of high-temperature (800-1400°C) solid state reactions [22][23][24] between silica (SiO 2 ) and alumina (Al 2 O 3 ) [25][26][27][28][29] based on the mutual diffusion of Al 3+ , Si 4+ and O -2 ions amongst particles [30][31][32][33] .…”

Section: Introductionmentioning

confidence: 99%

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Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica

Fernandes

Salomão

2018

Mat. Res.

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The in situ reaction between alumina and silica to obtain mullite (Al 6 Si 4 O 13 ) can be significantly affected by using synthetic amorphous silica (SAS) sources instead of crystalline ones (quartz and cristobalite). For instance, SASs promote early mullite formation (below 1300°C) and greater densification during sintering. This paper reports the "in situ" formation of mullite-alumina structures from fine calcined alumina (α-Al 2 O 3 ) and four grades of SAS of different particles' morphology, specific surface area and internal porosity. After sintering assisted by dilatometry (up to 1500°C), the samples' total porosity, density and flexural strength were measured. The relative density and strength levels of some of these structures were greater than or comparable to other studies in which similar compositions were sintered at higher temperatures (1600-1700°C). Their microstructure assessment indicated that the specific surface area and internal porosity of SAS particles showed a major influence in the development of these physical properties.

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Section: Samples Sintered At 1500ºcsupporting

confidence: 84%

Section: Na Siomentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica

Fernandes

Salomão

2018

Mat. Res.

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“…On the other hand, δ and Δ values of 0.32 ±0.03 and 1.14 ±0.04 mm s −1 were respectively obtained when the sample was prepared under an oxidizing atmosphere (Fig. 3 b-1), suggesting that Fe 3+ ions form tetrahedral FeO 4 sites, substituting for Al 3+ in mullite phase (Al 6 Si 2 O 13 ) [12,13]. It is noted that no magnetic sextet was observed in these samples, indicating that absence of magnetic phase is favourable for the Hagi Porcelain to have higher mechanical strength.…”

Section: Resultsmentioning

confidence: 98%

Mechanically strengthened new Hagi porcelain developed by controlling the chemical environment of iron

et al. 2012

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In order to enhance the mechanical strength of Hagi Porcelain (Hagiyaki), one of the oldest and famous potteries in Japan, new preparation condition was examined. Tempered Hagi porcelain, denominated as 'Hagi Porcelain B', was prepared with the Porcelain clay originating from Daido district, Yamaguchi Prefecture, Japan. Structural change of 'Hagi Porcelain B' was investigated by means of 57 FeMössbauer spectroscopy, X-ray diffractometry (XRD) and three-point bending test. Mechanical strength of the 'original Hagi Porcelain B' was estimated to be 43.1 MPa by means of the three-point bending test, while much larger value of 104.5 MPa could be achieved when tempered by a chemical modification. Mössbauer spectrum of the 'original Hagi porcelain B' was composed of a paramagnetic doublet and a magnetic sextet due to Fe(III) of γ -Fe 2 O 3 (maghemite), while only one paramagnetic doublet due to to octahedral Fe(II)O 6 was observed for the 'tempered Hagi Porcelain B' with isomer shift and quadrupole splitting values of 1.13 and 2.15 mm s −1 , respectively. It is considered that the absence of magnetic phase causes an increase of the mechanical strength because the maghemite phase has a defect spinel structure. These results indicate that mechanical strength of the 'Hagi porcelain B' could be enhanced by controlling the sintering condition.

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“…Many works [17][18][19] have proved that porous mulliteceramics, obtained from clays, are useful refractory materials for water treatment, high-temperature applications due to their high porosity, low thermal expansion coefficient, high creep resistance and corrosion resistance. Indeed, low cost alumina-mullite composites have been produced in [20] via reactive sintering of kaolinite clay and aluminum hydroxide with flexural strength reaching 70 MPa for a sintering at 1600 °C.…”

Section: Materiais Cerâmicos Porosos De Mulita-anortita-albita Foram mentioning

confidence: 99%

Elaboration and characterization of mullite-anorthite-albite porous ceramics prepared from Algerian kaolin

2018

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Mullite-anorthite-albite porous ceramic materials were successfully prepared by a solid-state reaction between kaolin clay and two different additives (CaCO 3 and Na 2 CO 3 ). The starting raw material was characterized by X-ray fluorescence, X-ray diffraction (XRD) and dynamic light scattering techniques. The effect of CaCO 3 and Na 2 CO 3 concentration (10 to 70 wt%) on structure, morphology and thermal properties of the obtained ceramics was investigated by XRD, scanning electron microscopy and differential scanning calorimetry (DSC) techniques. The XRD patterns showed that mullite (3Al 2 O 3 .2SiO 2 ), anorthite (CaO.Al 2 O 3 .2SiO 2 ) and albite (Na 2 O.Al 2 O 3 .6SiO 2 ) were the main crystalline phases present in the materials. The morphology investigation revealed the porous texture of obtained ceramics characterized by the presence of sponge-like structure mainly due to the additive decomposition at high temperatures. The DSC results confirm the presence of four temperature regions related to the kaolin thermal transformations and the formation of minerals. The temperature and enthalpy of mineral formation are additive concentration dependent. As a result, the optimal content of additives which allowed the coexistence of the three phases, a spongelike morphology, and high porosity without cracks corresponded to 15 wt% CaCO 3 , 15 wt% Na 2 CO 3 , and 70 wt% kaolin.

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Fabrication and characterization of highly porous mullite ceramics

Cited by 161 publications

References 28 publications

Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica

Preparation and Characterization of Mullite-Alumina Structures Formed "In Situ" from Calcined Alumina and Different Grades of Synthetic Amorphous Silica

Mechanically strengthened new Hagi porcelain developed by controlling the chemical environment of iron

Elaboration and characterization of mullite-anorthite-albite porous ceramics prepared from Algerian kaolin

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