Influence of citric acid and EFKA as dispersants on the properties of alumina monoliths produced by tert-butyl alcohol-based freeze-casting

In this paper, EFKA FA 4663 (EFKA) dispersant was used for the first time in the alumina slurries tert -butyl alcohol-based freeze-casting and compared to the commonly used anionic dispersant citric acid (CA). The comparison of both dispersants was analyzed at the beginning of the process at differe...

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Bibliographic Details
Published in:Journal of materials science 2024-04, Vol.59 (16), p.6711-6731
Main Authors: dos Santos, Giovana Magalhães, de Faria, Anna Carolina Britto, da Silva, Saulo Lucas Pereira, Ribeiro, Camila de Lima, Guenka, Tomé Seichi da Nóbrega, de Souza, Rodrigo Nunes, Silva, João Paulo Santiago de Assis, Aiube, Carlos Martins, Athayde, Daniel Dornellas, Lima, Luiz Fernando de Sousa, Rosa, Adriano Possebon, Mohallem, Nelcy Della Santina, Silva, Alysson Martins Almeida
Format: Article
Language:English
Subjects:
Alumina
Aluminum oxide
Butanol
Ceramics
Characterization and Evaluation of Materials
Chemistry and Materials Science
Citric acid
Classical Mechanics
Compressive strength
Crystallography and Scattering Methods
Dispersants
Freezing
Grain size
Materials Science
Polymer Sciences
Pore size
Porosity
Slurries
Solid Mechanics
Stabilization
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Summary:In this paper, EFKA FA 4663 (EFKA) dispersant was used for the first time in the alumina slurries tert -butyl alcohol-based freeze-casting and compared to the commonly used anionic dispersant citric acid (CA). The comparison of both dispersants was analyzed at the beginning of the process at different ultra-low freezing temperatures (− 170 to − 130 °C). The monoliths obtained with EFKA presented promising properties due to its stabilization of alumina particles by both electrostatic interactions and steric impediment, a considerable improvement when compared to the CA that promotes the stabilization of alumina particles only by electrostatic interaction. The use of different dispersants, as well as the control of freezing temperature, significantly influenced the microstructural properties of the monoliths. The monoliths exhibited prismatic pore geometry with high connectivity, forming a complex pore channel with total porosity up to 64.7%, and open porosity up to 48.5%. Results confirmed that the modification of the type of dispersant led to a difference in the grain size (up to 23.1%) and pore size (up to 30.5%) obtained in the materials. The monoliths produced with EFKA dispersant presented a considerable compressive strength resistance up to 11.7 MPa due to its dispersion mechanism that provided the thickening of the walls, confirming that the type of dispersion has a strong influence on the final properties of the materials. Therefore, the type of dispersant proved to be another parameter that allows the refinement of alumina monoliths properties, highlighting the use of EFKA as a promising alternative in the system studied. Graphical Abstract
ISSN:0022-2461
1573-4803
DOI:10.1007/s10853-024-09589-2