abstract
Current regulations pushing for lead-free piezoelectric alternatives have highlighted potassium-sodium niobate (K0.5Na0.5NbO3, KNN) as a promising candidate. However, conventional sintering of KNN faces challenges like alkali element volatilization and inadequate densification. Ultrafast high-temperature sintering (UHS) offers a solution by rapidly heating ceramics, yielding fine microstructures, with minimal volatile element loss. Here, using a custom UHS equipment we produced undoped KNN ceramics, identifying optimal sintering conditions via a UHS processing map. UHS KNN ceramics sintered for <= 90 s achieved 91 % density, <2 mu m average grain size, and no secondary phases. This study reports also the first dielectric, piezoelectric, and ferroelectric properties of UHS KNN ceramics. Differences between as-UHS and post-annealed ceramics were observed as well, with the latter exhibiting piezoelectric coefficients of similar to 80pC/N. This research enhances understanding of UHS applications and potential of KNN for lead-free piezoelectric uses.
keywords
LEAD-FREE PIEZOCERAMICS; ELECTRICAL-PROPERTIES; CERAMICS; MICROSTRUCTURE; UHS
subject category
Materials Science
authors
Miranda, JL; Ribeiro, C; Tkach, A; Senos, AMOR; Vilarinho, PM
our authors
Ana Maria de Oliveira e Rocha Senos
Collaborator
Oleksandr Tkach
Principal Researcher
Paula Maria Lousada Silveirinha Vilarinho
Vice DirectorProjects
CICECO - Aveiro Institute of Materials (UIDB/50011/2020)
CICECO - Aveiro Institute of Materials (UIDP/50011/2020)
Associated Laboratory CICECO-Aveiro Institute of Materials (LA/P/0006/2020)
acknowledgements
This work was developed within the scope of the project CICECO- Aveiro Institute of Materials, UIDB/50011/2020 (DOI 10.54499/UIDB/50011/2020) , UIDP/50011/2020 (DOI 10.54499/UIDP/50011/2020) & LA/P/0006/2020 (DOI 10.54499/LA/P/0006/2020) , financed by national funds through the FCT/MCTES (PIDDAC) . Alexander Tkach acknowledges FCT for financial support under independent researcher grant 2021.02284.CEECIND/CP1659/CT0018 (DOI 10.544 99/2021.02284.CEECIND/CP1659/CT0018) . Olena Okhay is acknowledged for EDS analysis. Rosario Soares is acknowledged for Rietveld refinement.