Improving the functional properties of (K0.5Na0.5)NbO3 piezoceramics by acceptor doping

• Published in: Journal of the European Ceramic Society Vol. 35; no. 1; pp. 125 - 130
• Main Authors: Vendrell, X., García, J.E., Bril, X., Ochoa, D.A., Mestres, L., Dezanneau, G.
• Format: Journal Article Publication
• Language: English
• Published: Elsevier Ltd 01.01.2015; Elsevier
• Subjects: (K,Na)NbO3; (NA0.5K0.5)NBO3-LINBO3 CERAMICS; Acceptor doping; Barium titanate; BARIUM-TITANATE CERAMICS; BEHAVIOR; Ceràmica piezoelèctrica; Chemical Sciences; DIELECTRIC-PROPERTIES; Dielèctrics; ELECTRICAL-PROPERTIES; Física; Lead-free piezoceramics; Microestructura; Microstructure; Na)NbO3; Physics; Piezoelectric ceramics; Piezoelectric properties; Potassi; Potassium; Sodi; Sodium; Àrees temàtiques de la UPC; Piezoelectric properties; Lead-free piezoceramics; (K,Na)NbO3; Acceptor doping
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2014.08.033

ZrO2 and TiO2 modified lead-free (K0.5Na0.5)NbO3 (KNN) piezoelectric ceramics are prepared by a conventional solid-state reaction. The effect of acceptor doping on structural and functional properties is investigated. A decrease in the Curie temperature and an increase in the dielectric constant values are observed when doping. More interestingly, an increase in the coercive field Ec and remanent polarization Pr is observed. The piezoelectric properties are greatly increased when doping with small concentrations dopants. ZrO2 doped ceramic exhibits good piezoelectric properties with piezoelectric coefficient d33=134pC/N and electromechanical coupling factor kp=35%. It is verified that nonlinearity is significantly reduced. Thus, the creation of complex defects capable of pinning the domain wall motion is enhanced with doping, probably due to the formation of oxygen vacancies. These results strongly suggest that compositional engineering using low concentrations of acceptor doping is a good means of improving the functional properties of KNN lead-free piezoceramic system.