Preceramic Paper‐Derived Ceramics

Travitzky, Nahum; Windsheimer, Hans; Fey, Tobias; Greil, Peter

doi:10.1111/j.1551-2916.2008.02752.x

Cited by 100 publications

(99 citation statements)

References 62 publications

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“…Además, indican que 191). Esta técnica de síntesis mimética utiliza preformas de origen natural o biomáscaras para generar cerámicas morfológicamente estructuradas, que encuentra aplicación en muy diferentes áreas: electrónica, magnética, fotónica, biotecnología, ingeniería tisular, transducción, filtración y catálisis (192)(193)(194), así como en la síntesis de composites derivados del carbón (195). Una extensa y completa revisión bibliográfica sobre la mineralización de elementos naturales es la realizada por Fan y col. (193).…”

Section: Revisión Del Estado Del Arte En La Síntesis De Alúmina Por Bunclassified

Alúminas porosas: El método de bio-réplica para la síntesis de alúminas estables de alta superficie específica

Guerrero¹,

Maqueda²,

Castro³

et al. 2013

Bol. Soc. Esp. Ceram. Vidr.

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INTRODUCCIÓNEn general, la síntesis de estructuras cerámicas porosas con una alta estabilidad térmica y de elevada resistencia, tanto física como química, atraen cada vez una mayor atención en multitud de áreas, especialmente en tecnologías relacionadas con la energía y medioambiente, como separadores gas/líquido, filtros, electrodos porosos para celdas de combustible de óxido sólido (SOFCs), soportes de catalizadores, membranas de micro y ultrafiltración, sensores químicos, así como también en sistemas de aireación de líquidos, sistemas de intercambio iónico, diálisis, separación cromatográfica, sistemas optoelectrónicos, liberación controlada de fármacos y biomateriales para implantes (1-4).En concreto, las cerámicas porosas de alúmina, por sus excelentes propiedades intrínsecas (bajo peso específico, elevada superficie específica, alta permeabilidad y estabilidad térmica, resistencia a la corrosión) y su bajo coste de producción, presentan un gran interés tecnológico en diversos campos. Destaca su empleo como refractarios, como membranas de separación (5-7) usadas por ejemplo en componentes de filtros de metales fundidos (8) y de gases de alta temperatura (9), y como membranas catalíticas (10) encontrando utilidad tanto en la eliminación de compuestos contaminantes de efluentes gaseosos (11-13) como del agua En las últimas décadas el desarrollo de alúminas porosas viene siendo objeto de numerosas investigaciones por las propiedades intrínsecas que tiene el óxido de aluminio, como elevado punto de fusión, baja conductividad térmica, inercia química y resistencia a la corrosión, a las que se unen una elevada superficie específica y permeabilidad, que hacen que encuentren aplicación en multitud de sectores industriales y técnicos. En aquellos procesos en los que intervengan temperaturas altas, la estabilidad cristalográfica y textural de las alúminas adquiere una importancia significativa; sin embargo, la mayoría de los métodos de preparación conducen hacia la generación de óxidos metaestables, que no encuentran aplicabilidad en procesos de elevada temperatura debido a su transformación hacia la fase alfa, con la consiguiente reducción de superficie. El presente artículo realiza una revisión de distintas vías de obtención de alúmina porosa de elevada superficie específica, incluyendo los métodos y estrategias que han tenido por objeto la síntesis de alfa-alúmina de alta superficie. Dentro de este marco, el trabajo analiza los resultados obtenidos hasta el momento a través de la bio-réplica de lignocelulósicos, tecnología que permite mimetizar con exactitud la compleja jerarquía estructural de las máscaras hasta diferentes niveles. Porous Aluminas: The biotemplate method for the synthesis of stable high surface area aluminas Development of porous alumina has been the objective of numerous studies in recent decades, due to the intrinsic properties of aluminium oxide, such as high melting point, low thermal conductivity, chemical inertness and corrosion resistance which, in addition to a high surface area and perme...

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Section: Revisión Del Estado Del Arte En La Síntesis De Alúmina Por Bunclassified

Alúminas porosas: El método de bio-réplica para la síntesis de alúminas estables de alta superficie específica

Guerrero¹,

Maqueda²,

Castro³

et al. 2013

Bol. Soc. Esp. Ceram. Vidr.

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“…In addition to the main components, coagulation and flocculation agents are added to the suspension. The suspension is then fed into a paper machine, which produces a continuous sheet of preceramic paper by a dewatering process, [2] for technical details.…”

Section: Introductionmentioning

confidence: 99%

Thermal shock behaviour of paper‐derived alumina ceramics

Kluthe¹,

Kollenberg²

2013

Materialwissenschaft Werkst

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Micro-scaled alumina filled preceramic papers are used to produce paper-derived alumina ceramics. The thin (0.6 -0.7mm) and porous ceramics fabricated by this process can be, besides other possible applications, potentially utilized as setter plates on cordierite kiln furniture to avoid contact between the cordierite and powder metal substrate during sintering. The SiO 2 of the cordierite causes objectionable reactions with the powder metal. For this application it is important to investigate the thermal shock behaviour of the paper-derived alumina ceramics especially focusing the residual strength, because fast cooling is a common technique in the metal sintering industry to avoid cost and save production time. Two differently processed types of paper were investigated: calendered (additionally rollpressed) and uncalendered paper. Their remaining strength has been measured by the B3B-test after thermal shocks of a temperature difference DT = 100 K up to DT = 1000 K to evaluate the critical temperature difference DT C and the type of crack growth according to the method of Hasselman. In order to determine the cyclic thermal shock behaviour, at a temperature difference DT of 400 K and 600 K the ceramics have been quenched up to 5 times. The results of these investigations have been compared to the properties of tape casted alumina ceramics, a material already commercially used as setter plates. The initial strength of calendered paper-derived ceramics was 240 MPa. After quenching at a temperature difference DT = 600 -700 K, 50% strength decrease was observed. Temperature differences of more than 800 K caused A90% strength reduction. Uncalendered paper-derived ceramics have 185 MPa strength. Between thermo shocks of temperature differences DT = 700 -800 K, 50% of the strength reduction was measured. With thermo shocks of a temperature difference DT = 800 K only 10% of the initial strength remains. Generally the uncalendered ceramics showed a more stable crack growth than the calendered samples. Cyclic shocking at 400 K causes strength losses for both kinds of paper. But they differ in magnitude. While uncalendered paper only lost 7% strength, calendered paper strength was reduced by 20%, compared to their initial strength. This observation gets even more significant by shocking about 600 K. Calendered ceramics start with a higher initial strength and end up with a lower residual strength than the uncalendered ceramics. Only 30 MPa remain after five cycles of shocking, while the uncalendered paper-derived ceramics have 90 MPa remaining strength. Uncalendered ceramics show a better thermal stress resistance, which can be correlated to their higher porosity and therefore their increased crack deflection in the microstructure. Tape-casted alumina ceramics show a lower initial strength and lesser thermal shock resistance against simple and cyclic shocking. SEM pictures of the tape-casted alumina ceramics show large amounts of small, spherical shape pores, while paper-derived alumina microstructures show long cylindrical...

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“…Biomorphous carbide ceramics are interesting candidates for advanced engineering applications due to their anisotropic cellular structures [16]. The anisotropic mechanical properties of these materials were thoroughly investigated [33][34][35][36]. Biomorphous ceramics exhibit a higher strength at similar porosities with respect to conventional materials due to their uniaxial directed cellular microstructure.…”

Section: Biomorphous Carbide Ceramics From Cardboardmentioning

confidence: 99%

Biotemplating: polysaccharides in materials engineering

Zollfrank¹

2010

WIT Transactions on Ecology and the Environment

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The generation of biominerals and hard tissue in nature is directed and templated by biomacromolecules. In many systems, polysaccharides play a significant role during the assembly of the inorganic phase. Polysaccharides exhibit a hierarchical multiscale order as well as self-assembly properties and they appear in a large variety of structures. The directed deposition of inorganic phases on polysaccharide templates is an interesting approach for the manufacturing of patterned functional materials. This paper highlights our recent developments on the bioinspired deposition and formation of inorganic phases on polysaccharide templates. Polysaccharides can be used at various structural levels from the molecular scale to three-dimensional parts in the millimetre range. The versatility of polysaccharide templating capabilities will be shown on onedimensional cellulose nanocrystals for formation of luminescent inorganic nanotubes for optoelectronic applications. The replication of complex plant tissue and processed lignocellulosic materials such as paper and cardboard into carbide based engineering and functional ceramics will be presented. The developed methods for the mineralisation of inorganic phases on polysaccharides are adapted for an innovative bioinspired route involving phototactic microorganisms, which are useful for the light-induced fabrication of hierarchically structured functional materials.

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Preceramic Paper‐Derived Ceramics

Cited by 100 publications

References 62 publications

Alúminas porosas: El método de bio-réplica para la síntesis de alúminas estables de alta superficie específica

Alúminas porosas: El método de bio-réplica para la síntesis de alúminas estables de alta superficie específica

Thermal shock behaviour of paper‐derived alumina ceramics

Biotemplating: polysaccharides in materials engineering

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