Serrazina, R., Dean, J.S. orcid.org/0000-0001-7234-1822, Reaney, I.M. orcid.org/0000-0003-3893-6544 et al. (3 more authors) (2019) Mechanism of densification in low-temperature FLASH sintered lead free Potassium Sodium Niobate (KNN) piezoelectrics. Journal of Materials Chemistry C, 7 (45). pp. 14334-14341. ISSN 2050-7526
Abstract
Lead-free potassium sodium niobate (K0.5Na0.5NbO3, KNN) piezoelectric ceramics have been densified at temperatures lower than 300 ºC using atmosphere-water assisted FLASH sintering. Transmission electron microscopy (TEM) studies revealed amorphous phase at grain boundaries that resulted from surface melting of the cuboid particles in the presence of segregated impurities. We propose that preferential surface melting of the primary particles is induced in conductive channels of open pores in which water is adsorbed. This creates a network of pathways for the electric current. The resulting liquid phase induces fast densification through sliding of grain boundaries and viscous flow of the liquid driven by minimisation of surface energy. Finite Element Modelling (FEM) revealed that current density and Joule heating were also influenced by the geometry of contact between the cuboid KNN particles with vertex to vertex inducing the maximum current density and consequently creating the greatest volume of amorphous phase in adjacent pores. The lowest current density was predicted for face to face contacts, resulting in only a thin amorphous layer between grains.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2019 Royal Society of Chemistry. This is an author-produced version of a paper subsequently published in Journal of Materials Chemistry C. Uploaded in accordance with the publisher's self-archiving policy. |
Dates: |
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Institution: | The University of Sheffield |
Academic Units: | The University of Sheffield > Faculty of Engineering (Sheffield) > Department of Materials Science and Engineering (Sheffield) |
Depositing User: | Symplectic Sheffield |
Date Deposited: | 07 Nov 2019 11:07 |
Last Modified: | 17 Dec 2021 11:33 |
Status: | Published |
Publisher: | Royal Society of Chemistry (RSC) |
Refereed: | Yes |
Identification Number: | 10.1039/c9tc03117k |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:153167 |