Ferroelectric KNNT Fibers by Thermoplastic Extrusion Process: Microstructure and Electromechanical Characterization

Actuators

Tony Lusiola¹  Ali Hussain²  Myong Ho Kim²  Thomas Graule¹  Frank Clemens¹ 

[1] Empa - Swiss Federal Laboratories for Materials Science and Technology, High Performance Ceramics, Überlandstrasse 129, CH-8600 Dübendorf, Switzerland; E-Mail:;Changwon National University, Gyeong-Nam 641-773, South Korea; E-Mails:

关键词: KNNT;    fibers;    dielectric constant;    fiber diameter;   

DOI  :  10.3390/act4020099

来源: mdpi

【 摘 要 】

B-site substitution in KNN with tantalum results in a higher d₃₃ and dielectric constant. This higher value makes KNNT interesting for lead-free actuator applications. KNNT fibers with diameters of 300 and 500 μm have been extruded and sintered at 1200 °C in a KNNT-enriched atmosphere. Subsequently, the influence of fiber diameter on the microstructure (porosity and grain size) was investigated. The measurements revealed that with decreasing fiber diameter, the porosity increases, whereas the grain size decreases. The influence of these microstructural differences on the piezoelectric properties was evaluated using a novel characterization procedure for single fibers. The larger diameter fibers show an increase in the electromechanical properties measured, i.e., d₃₃, tanδ, P_r, E_c and the free longitudinal fiber displacement, when compared to smaller diameter fibers. The lower alkali losses result in a larger grain size, a higher density during sintering and lead to higher electromechanical properties.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.