resumo
An alternative sintering methodology, Spark Plasma Texturing (SPT), allowed us to prepare 98.0% dense leadfree piezoelectric (K1-xNax)NbO3 (KNN) ceramics with a homogenous microstructure of small grains. In this work, Resonant Ultrasound Spectroscopy (RUS) was used to measure bulk, K, and shear, G, moduli of SPT KNN for comparison with conventionally sintered (CS) KNN. SPT fabrication resulted in the highest elastic moduli K = 120.3 GPa (127.7 GPa for 100% density) and G = 45.47 GPa (47.2 GPa for 100% density) ever reported for KNN ceramics. Moreover, by collecting RUS data in situ as a function of temperature, phase transitions at temperatures of 464 and 688 K for CS KNN, and 443 and 643 K for SPT KNN ceramics were determined. Low acoustic loss in the stability field of the cubic phase indicated that the ceramics were mechanically robust, while high loss in the stability fields of the tetragonal and orthorhombic structures demonstrated high mobility of ferroelastic domain walls.
palavras-chave
FREE PIEZOELECTRIC CERAMICS; LEAD-FREE PIEZOCERAMICS; CONSTANTS
categoria
Science & Technology - Other Topics; Materials Science; Metallurgy & Metallurgical Engineering
autores
Pinho, R; Tkach, A; Carpenter, MA; Noudem, J; Costa, ME; Vilarinho, PM
nossos autores
Maria Elisabete Jorge Vieira Costa
Colaborador
Oleksandr Tkach
Investigador Auxiliar
Paula Maria Lousada Silveirinha Vilarinho
Vice-Diretor
Rui Manuel de Oliveira Pinho
Estudante de doutoramentoProjectos
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)
Nano-argilas para remoção/captura de fosfatos (P) e sua reutilização como fertilizante (NATURAL)
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, UIDB/50011/2020, UIDP/50011/2020 & LA/P/0006/2020, FLEXIDEVICE project PTDC/CTMCTM/29671/2017, and the scholarship SFRH/BD/12069/2016, financed by national funds through the FCT/MEC (PIDDAC). RUS facilities in Cambridge were established through grants NE/B505738/1, NE/F17081/1 and EP/I036079/1 from the Natural Environment Research Council and the Engineering and Physical Sciences Research Council of Great Britain to MAC.