Defect Structure and Electrical Property of Na0.5K0.5NbO3 Lead-Free Piezoceramics

Hitoshi Matsudo; Kenichi Kakimoto; Isao Kagomiya

doi:10.4028/www.scientific.net/KEM.421-422.9

Paper Titles

Preface

Phase Transition and Structural Analysis of (Li,Na,K)NbO₃ Lead-Free Piezoelectric Ceramics
p.3

Defect Structure and Electrical Property of Na_0.5K_0.5NbO₃ Lead-Free Piezoceramics
p.9

Domain Wall Engineering in Lead-Free Piezoelectric Materials
p.13

Crystal Growth and Electrical Properties of Na_0.5Bi_0.5TiO₃-BaTiO₃ Lead-Free Ferroelectric Piezocrystals
p.17

Piezoelectric Properties of c-Axis-Oriented (Sr,Ca)₂NaNb₅O₁₅ Piezoelectric Ceramics with Single-Plate Type and Multilayered Type Fabricated Using Crystal-Oriented Sheet Forming
p.21

Preparation and Characterization of Lead Free Multi-Layer Ceramic Actuators with Ni Inner Electrodes Prepared by Inkjet Printing
p.26

Growth and Characterization of Bismuth Magnesium Titanate Bi(Mg_1/2Ti_1/2)O₃
p.30

Phase Diagram and Microstructure Analysis of Barium Titanate – Potassium Niobate System Piezoelectric Ceramics
p.34

HomeKey Engineering MaterialsKey Engineering Materials Vols. 421-422Defect Structure and Electrical Property of...

Defect Structure and Electrical Property of Na_0.5K_0.5NbO₃ Lead-Free Piezoceramics

Abstract:

Na0.5K0.5NbO3 (NKN) lead-free piezoceramics was synthesized by a solid state reaction method. The d.c. conductivitydc and a.c. impedance of the ceramics were measured at the temperature range from 550 oC to room temperature on cooling process. Thedc decreased linearly with decreasing temperature on Arrhenius plot, and the activation energy at the temperature range from 450 to 390 oC and from 390 to 160 oC were 0.65 and 0.90 eV, respectively. The slope change at 390 oC corresponded to Curie temperature of NKN ceramics so that the carriers of these thermally active conductions were alkali metal or oxygen ions in the NKN crystal structure. The impedance of NKN ceramics at high temperature showed two relaxation processes at high and low frequencies, and the leak current was mainly attributed by the conduction through the grain boundary with low impedance value on lower frequency relaxation.