Thermal conductivity of porous alumina ceramics prepared using starch as a pore-forming agent

Živcová, Z. Vlčková; Gregorová, Eva; Pabst, Willi; Smith, David Stanley; Michot, Aurélie; Poulier, Céline

doi:10.1016/j.jeurceramsoc.2008.06.018

Cited by 210 publications

(94 citation statements)

References 53 publications

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“…Such results can be explained by the morphology of the conventional feedstock, which is a dense "fused and crushed" powder instead of a porous spray-dried material. As a results of its lower porosity it should display a higher thermal conductivity [19][20], leading to an increased melting grade during deposition and thus, to a superior deformability of the droplets when they impact against the substrate, resulting in improved adhesion strength.…”

Section: Coating Mechanical Propertiesmentioning

confidence: 99%

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Vicent

Bannier

Benavente

et al. 2013

Surface and Coatings Technology

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Atmospheric plasma spraying (APS) is an interesting technique to obtain nanostructured coatings due to its versatility, simplicity and relatively low cost. However, nanometric powders can not be fed into the plume using conventional feeding systems, due to their low mass and poor flowability, and must be adequately reconstituted into sprayable micrometric agglomerates.In this work, Al 2 O 3 -13wt%TiO 2 nanostructured and submicron-nanostructured powders were deposited using APS. The feedstocks were obtained by spray drying from two starting suspensions, prepared by mixing two commercial nanosuspensions of Al 2 O 3 and TiO 2 , or by adding nanosized TiO 2 and submicron-sized Al 2 O 3 powders to water. The spray-dried granules were heat-treated to reduce their porosity and the resultant powders were fully characterised.Optimisation of the deposition conditions enabled the reconstituted powders to be successfully deposited, yielding coatings that were well bonded to the substrate. The coating microstructure, characterised by SEM, was formed by semi-molten feedstock agglomerates surrounded by fully molten particles that act as a binder.Moreover, microhardness, adhesion, and tribological behaviour were determined, and the impact of the granule characteristics on these properties was studied. It was found that changing the feedstock characteristics allows to control the coating quality and properties.2

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Section: Coating Mechanical Propertiesmentioning

confidence: 99%

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Vicent

Bannier

Benavente

et al. 2013

Surface and Coatings Technology

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show abstract

“…Therefore we will use exclusively the latter two for comparison with our measured values. The exponential relation, which seems to be the most successful estimator not only for the thermal conductivity [8][9][10] but also for elastic properties (Young's modulus) of porous materials [14,15], will be used in the sequel also to extrapolate low-porosity results to zero porosity, which is necessary to obtain 0 k values for calculating the relative conductivity for the temperature in question. It should be emphasized that equations (4) and (5) are not empirical but can be derived by the differential approach [16] or the functional equation approach [9].…”

Section: Theoreticalmentioning

confidence: 99%

“…That means, the thermal conductivity of ceramics can be very efficiently tailored by controlling the pore volume fraction of ceramics, e.g. by using fugitive pore formers [6][7][8]. It is known that the porosity dependence of ceramics prepared using fugitive pore-formers (i.e.…”

Section: Introductionmentioning

confidence: 99%

Porous alumina and zirconia ceramics with tailored thermal conductivity

Gregorová

Pabst

Sofer

et al. 2012

J. Phys.: Conf. Ser.

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“…Many studies have been made of the relationship between the thermal conductivity (k) and porosity, which can be expressed by the widely used empirical equation [95] …”

Section: Other Propertiesmentioning

confidence: 99%

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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Thermal conductivity of porous alumina ceramics prepared using starch as a pore-forming agent

Cited by 210 publications

References 53 publications

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Influence of the feedstock characteristics on the microstructure and properties of Al2O3–TiO2 plasma-sprayed coatings

Porous alumina and zirconia ceramics with tailored thermal conductivity

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

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