Processing of porous cordierite bodies by starch consolidation

Alves, Helena; Tarì, G.; Fonseca, A.T.; Ferreira, José Maria F.

doi:10.1016/s0025-5408(98)00131-7

Cited by 105 publications

(87 citation statements)

References 8 publications

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“…The effect of starch addition on membrane microstructure has been previously described in the membrane literature. Some authors have reported that starch additions higher than 10% give rise to a significant increase in the amount of interconnected pores created by starch burnout [28], [47], [48]. In summary, we can say that the effect of starch addition on the sintered microstructure of clayey compositions manages to counteract the impaired effect (lower porosity, smaller pore size and poor pore interconnectivity) produced by the clay content, even in the case of pieces shaped by extrusion in which the clayey particles are clearly orientated.…”

Section: Membrane Physical Characterizationmentioning

confidence: 99%

Comparison of extruded and pressed low cost ceramic supports for microfiltration membranes

Lorente-Ayza

Mestre

Menéndez

et al. 2015

Journal of the European Ceramic Society

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A comparison has been made between ceramic microfiltration membranes of the same composition obtained by pressing and by extrusion in terms of microstructure and properties.The extruded membranes displayed lower porosity and smaller pore size than pressed membranes. The higher the clay content in the starting composition, the clearer this tendency became. In contrast, the difference tended to disappear when starch was added to the initial composition. The mechanical strength values followed a decreasing exponential variation with porosity, which was influenced by the starting composition and the shaping method.Water permeability reflected the strong effect of the mean pore size. The membranes synthesised from the composition with the higher clay content showed the lowest permeability, while those obtained from the composition including starch showed the highest value. A model derived from the Hagen-Poiseuille equation enabled the tortuosity values to be calculated.

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Section: Membrane Physical Characterizationmentioning

confidence: 99%

Comparison of extruded and pressed low cost ceramic supports for microfiltration membranes

Lorente-Ayza

Mestre

Menéndez

et al. 2015

Journal of the European Ceramic Society

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“…The rounded pores arising from the corn starch had diameters between 7 and 10 μm whereas the pore derived from the potato starch had lengths up to 50 μm. In both cases, the pore sizes were signifi cantly larger than the interstitial voids between the ZrO 2 particles, and consequently they remained stable after sintering [1][2][3][4][5][6][7][8]11 . Densification of the ZrO 2 matrix depended on the sintering temperature.…”

Section: Microstructure Of Sintered Porous Materialsmentioning

confidence: 99%

“…Starch consolidation casting is a suitable method to prepare many porous ceramics including alumina 1,2 , calcium carbonate 3 , cordierite 4 , mullite 5 , electroceramics 6 , silicon nitride 7 and recently, zirconia (ZrO 2 ) 8 . Among other applications, products like filters, catalyst supports and bioceramic materials were successfully processed using the starch consolidation casting.…”

Section: Introductionmentioning

confidence: 99%

Influence of starch type on characteristics of porous 3Y-ZrO2 prepared from a direct consolidation casting method

Garrido¹,

Albano²,

Gênova

et al. 2011

Mat. Res.

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Starch consolidation casting has been successfully used to produce porous ceramics with complex shapes at a relatively low producing cost. In this work, porous 3Y-ZrO 2 ceramics were produced using two types of starch (corn and potato). Concentrated (50-52 vol. (%)) aqueous suspensions of the different 3Y-ZrO 2 -starch mixtures (i.e. starch to zirconia weight ratios between 0.20 and 0.52) were thermally consolidated and the effect of the type and amount of added starch on properties of resultant dried product was examined. After starch granules burnout, the effect of sintering temperature varying between 1000 and 1500 °C on the porosity evolution, interconnection and morphology of pores and microstructure of final ceramic was followed by water absorption measurements, Hg porosimetry and scanning electron microscopy SEM. Typical microstructure of the ceramic sintered at 1500 °C consisted of large nearly spherical pores (created by starch) uniformly distributed in a dense ZrO 2 matrix. As the content of starch in the dried product (expressed as volume fraction) X st is increased from 0.23 to 0.65, porosity of the ceramic sintered at 1500 °C increased from 38 to 52 vol. (%) for corn starch, while it achieved 50 to 54 vol. (%) for potato starch; thus, lower X st of potato starch developed a porous zirconia with higher porosity. In this case, the pore structure contained pores having sizes above 50 μm and resulted completely interconnected while for those prepared using corn starch the pore interconnection occurred for X st above 0.50.

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“…[4] Starch consolidation has been succesfully used in the shaping of ceramic bodies. [5][6][7][8] This technique allows the manufacturing of porous ceramics, [9] Al 2 O 3 , Si 3 N 4 , cordierite, and thermally insulated materials [10] as well as bioceramics. [4] In the field of metal powders, some studies using HSS have already been carried out.…”

Section: Introductionmentioning

confidence: 99%

Starch Consolidation as a New Process for Manufacturing Powder Metallurgy High-Speed Steels

Romano

Velasco

Torralba

2007

Metall Mater Trans A

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The development of a new method called ''starch consolidation,'' suitable for the production of powder metallurgy (P/M) high-speed steel (HSS) components has been studied. Samples have been consolidated using 1.5, 3.5, and 5 vol pct starch and up to 60 vol pct powder. The high solid loading was achieved by stabilizing the repulsive forces with a small addition (0.01 wt pct) of a dispersant (polyacrylic acid) that resulted in accurate fluidity and consolidation of the prepared slurries. After shaping of the samples, the bending strength of the green bodies was evaluated. Debinding cycles were optimized by comparing carbon and oxygen content in argon, in N 2 -5H 2 , and in pure hydrogen. The three atmospheres showed no significant differences in carbon elimination. To determine the influence of H 2 in a nitrogen-rich atmosphere during sintering, tests were performed at 1230°C in a N 2 -5H 2 and in a nitrogen atmosphere. Pure nitrogen resulted in a microstructure formed by smaller carbides. Heat treatments were performed on the samples with the compositions that gave the best combination of properties. A hardness of 800 HV and a bending strength of 1475 MPa were obtained.

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Processing of porous cordierite bodies by starch consolidation

Cited by 105 publications

References 8 publications

Comparison of extruded and pressed low cost ceramic supports for microfiltration membranes

Comparison of extruded and pressed low cost ceramic supports for microfiltration membranes

Influence of starch type on characteristics of porous 3Y-ZrO2 prepared from a direct consolidation casting method

Starch Consolidation as a New Process for Manufacturing Powder Metallurgy High-Speed Steels

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