Particle Characteristics' Influence on FLASH Sintering of Potassium Sodium Niobate: A Relationship with Conduction Mechanisms
authors Serrazina, R; Ribeiro, C; Costa, ME; Pereira, L; Vilarinho, PM; Senos, AMOR
nationality International
author keywords FLASH sintering; K0.5Na0.5NbO3; KNN; FLASH temperature; particle size; impurities; conduction mechanisms; ceramics; single crystals
abstract The considerable decrease in temperature and time makes FLASH sintering a more sustainable alternative for materials processing. FLASH also becomes relevant if volatile elements are part of the material to be processed, as in alkali-based piezoelectrics like the promising lead-free K0.5Na0.5NbO3 (KNN). Due to the volatile nature of K and Na, KNN is difficult to process by conventional sintering. Although some studies have been undertaken, much remains to be understood to properly engineer the FLASH sintering process of KNN. In this work, the effect of FLASH temperature, T-F, is studied as a function of the particle size and impurity content of KNN powders. Differences are demonstrated: while the particle size and impurity degree markedly influence T-F, they do not significantly affect the densification and grain growth processes. The conductivity of KNN FLASH-sintered ceramics and KNN single crystals (SCs) is compared to elucidate the role of particles' surface conduction. When particles' surfaces are not present, as in the case of SCs, the FLASH process requires higher temperatures and conductivity values. These results have implications in understanding FLASH sintering towards a more sustainable processing of lead-free piezoelectrics.
publisher MDPI
isbn 1996-1944
year published 2021
volume 14
issue 5
digital object identifier (doi) 10.3390/ma14051321
web of science category 17
subject category Chemistry, Physical; Materials Science, Multidisciplinary; Metallurgy & Metallurgical Engineering; Physics, Applied; Physics, Condensed Matter
unique article identifier WOS:000628381000001