resumo
A current challenge for the fabrication of functional oxide-based devices is related with the need of environmental and sustainable materials and processes. By considering both lead-free ferroelectrics of potassium sodium niobate (K0.5Na0.5NbO3, KNN) and aqueous-based electrophoretic deposition here we demonstrate that an eco-friendly aqueous solution-based process can be used to produce KNN thick coatings with improved electromechanical performance. KNN thick films on platinum substrates with thickness varying between 10 and 15 mu m have a dielectric permittivity of 495, dielectric losses of 0.08 at 1 MHz, and a piezoelectric coefficient d(33) of, similar to 70 pC/N. At T-C these films display a relative permittivity of 2166 and loss tangent of 0.11 at 1 MHz. A comparison of the physical properties between these films and their bulk ceramics counterparts demonstrates the impact of the aqueous-based electrophoretic deposition (EPD) technique for the preparation of lead-free ferroelectric thick films. This opens the door to the possible development of high-performance, lead-free piezoelectric thick films by a sustainable low-cost process, expanding the applicability of lead-free piezoelectrics.
palavras-chave
TEMPERATURE-DEPENDENCE; DIELECTRIC-PROPERTIES; FREE PIEZOCERAMICS; DOMAIN-STRUCTURE; CERAMICS; SUSPENSION; OXIDE; EPD; EVOLUTION
categoria
Chemistry; Materials Science
autores
Mahajan, A; Pinho, R; Dolhen, M; Costa, ME; Vilarinho, PM
nossos autores
agradecimentos
This work was developed within the scope of the project CICECO-Aveiro Institute of Materials, POCI-01-0145-FEDER-007679 (FCT ref. UID/CTM/50011/2013), financed by national funds through the FCT/MEC and when appropriate cofinanced by FEDER under the PT2020 Partnership Agreement. A.M. acknowledges the FCT for financial support (SFRH/BD/65415/2009). M.D. is thankful to the University of Limoges for financial support within ERASMUS MUNDUS.