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Transactions of FAMENA, Vol. 42 No. 3, 2018.

Original scientific paper

https://doi.org/10.21278/TOF.42304

Stabilization of Highly Concentrated Alumina Suspensions by Different Dispersants

Ivana Sever orcid id orcid.org/0000-0002-6287-9677 ; Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia
Irena Žmak orcid id orcid.org/0000-0001-7994-3615 ; Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia
Lidija Ćurković orcid id orcid.org/0000-0002-3212-277X ; Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia
Zrinka Švagelj ; Department of Materials, Faculty of Mechanical Engineering and Naval Architecture, University of Zagreb, Zagreb, Croatia

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Abstract

Slip casting is a widely used colloidal technique for consolidation of ceramic powders from a suspension. The colloidal approach ensures homogeneous microstructure of a green body, thereby reducing post-sintering machining and production costs. The process consists of several steps. The first step is to mix the ceramic powder with a liquid, usually water, where the stabilization of the new obtained suspension with different dispersants follows. When an optimum dispersion of particles is achieved, resulting in low slip viscosity, ceramic slurry can finally be poured into a porous mould, usually a gypsum one.
The influence of different dispersants on rheological properties of highly concentrated alumina (Al2O3) suspensions was investigated. The used dispersants were: ammonium polymethacrylate water solution (Darvan C-N), 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt (Tiron) and citric acid. The amount of dispersants was varied from 0.1-1.25 wt. % in order to determine the optimum. Rheological properties of the prepared suspensions were determined by measuring the apparent viscosity at different shear rates. The obtained optimal amount was 0.75 wt. % for Darvan, 0.1 wt. % for Tiron and 0.3 wt. % for citric acid. The obtained results show that the most effective dispersant is 4,5-dihydroxy-1,3-benzenedisulfonic acid disodium salt, given that only 0.1 wt. % was required to stabilize the 70 wt. % Al2O3 suspension.

Keywords

alumina; suspensions; slip casting; stabilization

Hrčak ID:

206944

URI

https://hrcak.srce.hr/206944

Publication date:

19.10.2018.

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