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Gadolinia-doped ceria ceramic pastes were formulated with different solid loadings and extruded using lab-scale equipment. The force to maintain a constant ram speed of 10 mm/min was recorded. The radial shrinkage after drying was proportional to the solid loading and this allowed the determination of the maximum solid loading by an extrapolation procedure. In order to obtain the apparent viscosity of the pastes, a novel approach based on the analysis of the slope of the extrusion pressure plot versus distance covered by the ram, was formulated for the direct determination of the shear stress upon extrusion. The agreement of the determined maximum solid loading with values calculated by two existing models confirmed that the proposed approach was an alternative and reliable method to identify the upper limit of the solid loading range for the formulation of extrudable ceramic pastes.


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Novel method for the identification of the maximum solid loading suitable for optimal extrusion of ceramic pastes

Show Author's information Andrea AZZOLINI( )Vincenzo M. SGLAVOJohn A. DOWNS
Department of Industrial Engineering, Università di Trento, Via Mesiano 77, 38123, Trento, Italy

Abstract

Gadolinia-doped ceria ceramic pastes were formulated with different solid loadings and extruded using lab-scale equipment. The force to maintain a constant ram speed of 10 mm/min was recorded. The radial shrinkage after drying was proportional to the solid loading and this allowed the determination of the maximum solid loading by an extrapolation procedure. In order to obtain the apparent viscosity of the pastes, a novel approach based on the analysis of the slope of the extrusion pressure plot versus distance covered by the ram, was formulated for the direct determination of the shear stress upon extrusion. The agreement of the determined maximum solid loading with values calculated by two existing models confirmed that the proposed approach was an alternative and reliable method to identify the upper limit of the solid loading range for the formulation of extrudable ceramic pastes.

Keywords:

ceramic extrusion, maximum solid loading, drying shrinkage, rheology
Received: 11 July 2013 Revised: 30 October 2013 Accepted: 12 November 2013 Published: 05 March 2014 Issue date: March 2014
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Publication history
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Publication history

Received: 11 July 2013
Revised: 30 October 2013
Accepted: 12 November 2013
Published: 05 March 2014
Issue date: March 2014

Copyright

© The author(s) 2014

Acknowledgements

A. Azzolini would like to thank INSTM (Consorzio Interuniversitario Nazionale per la Scienza e Tecnologia dei Materiali) for co-funding this project as part of his Ph.D. research.

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