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Porous Alumina Ceramics with Multimodal Pore Size Distributions

Pore networks with multimodal pore size distributions combining advantages from isotropic and anisotropic shaped pores of different sizes are highly attractive to optimize the physical properties of porous ceramics. Multimodal porous Al(2)O(3) ceramics were manufactured using pyrolyzed cellulose fib...

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Autores principales: Biggemann, Jonas, Stumpf, Martin, Fey, Tobias
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232101/
https://www.ncbi.nlm.nih.gov/pubmed/34198712
http://dx.doi.org/10.3390/ma14123294
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author Biggemann, Jonas
Stumpf, Martin
Fey, Tobias
author_facet Biggemann, Jonas
Stumpf, Martin
Fey, Tobias
author_sort Biggemann, Jonas
collection PubMed
description Pore networks with multimodal pore size distributions combining advantages from isotropic and anisotropic shaped pores of different sizes are highly attractive to optimize the physical properties of porous ceramics. Multimodal porous Al(2)O(3) ceramics were manufactured using pyrolyzed cellulose fibers (l = 150 µm, d = 8 µm) and two types of isotropic phenolic resin spheres (d = 30 and 300 µm) as sacrificial templates. The sacrificial templates were homogeneously distributed in the Al(2)O(3) matrix, compacted by uniaxial pressing and extracted by a burnout and sintering process up to 1700 °C in air. The amount of sacrificial templates was varied up to a volume content of 67 Vol% to form pore networks with porosities of 0–60 Vol%. The mechanical and thermal properties were measured by 4-point-bending and laser flash analysis (LFA) resulting in bending strengths of 173 MPa to 14 MPa and heat conductivities of 22.5 Wm(−1)K(−1) to 4.6 Wm(−1)K(−1). Based on µCT-measurements, the representative volume-of-interest (VOI) of the samples digital twin was determined for further analysis. The interconnectivity, tortuosity, permeability, the local and global stress distribution as well as strut and cell size distribution were evaluated on the digital twin’s VOI. Based on the experimental and simulation results, the samples pore network can be tailored by changing the fiber to sphere ratio and the overall sacrificial template volume. The presence pore formers significantly influenced the mechanical and thermal properties, resulting in higher strengths for samples containing fibrous templates and lower heat conductivities for samples containing spherical templates.
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spelling pubmed-82321012021-06-26 Porous Alumina Ceramics with Multimodal Pore Size Distributions Biggemann, Jonas Stumpf, Martin Fey, Tobias Materials (Basel) Article Pore networks with multimodal pore size distributions combining advantages from isotropic and anisotropic shaped pores of different sizes are highly attractive to optimize the physical properties of porous ceramics. Multimodal porous Al(2)O(3) ceramics were manufactured using pyrolyzed cellulose fibers (l = 150 µm, d = 8 µm) and two types of isotropic phenolic resin spheres (d = 30 and 300 µm) as sacrificial templates. The sacrificial templates were homogeneously distributed in the Al(2)O(3) matrix, compacted by uniaxial pressing and extracted by a burnout and sintering process up to 1700 °C in air. The amount of sacrificial templates was varied up to a volume content of 67 Vol% to form pore networks with porosities of 0–60 Vol%. The mechanical and thermal properties were measured by 4-point-bending and laser flash analysis (LFA) resulting in bending strengths of 173 MPa to 14 MPa and heat conductivities of 22.5 Wm(−1)K(−1) to 4.6 Wm(−1)K(−1). Based on µCT-measurements, the representative volume-of-interest (VOI) of the samples digital twin was determined for further analysis. The interconnectivity, tortuosity, permeability, the local and global stress distribution as well as strut and cell size distribution were evaluated on the digital twin’s VOI. Based on the experimental and simulation results, the samples pore network can be tailored by changing the fiber to sphere ratio and the overall sacrificial template volume. The presence pore formers significantly influenced the mechanical and thermal properties, resulting in higher strengths for samples containing fibrous templates and lower heat conductivities for samples containing spherical templates. MDPI 2021-06-14 /pmc/articles/PMC8232101/ /pubmed/34198712 http://dx.doi.org/10.3390/ma14123294 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Biggemann, Jonas
Stumpf, Martin
Fey, Tobias
Porous Alumina Ceramics with Multimodal Pore Size Distributions
title Porous Alumina Ceramics with Multimodal Pore Size Distributions
title_full Porous Alumina Ceramics with Multimodal Pore Size Distributions
title_fullStr Porous Alumina Ceramics with Multimodal Pore Size Distributions
title_full_unstemmed Porous Alumina Ceramics with Multimodal Pore Size Distributions
title_short Porous Alumina Ceramics with Multimodal Pore Size Distributions
title_sort porous alumina ceramics with multimodal pore size distributions
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8232101/
https://www.ncbi.nlm.nih.gov/pubmed/34198712
http://dx.doi.org/10.3390/ma14123294
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