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Effect of sintering temperature on composition, microstructure and electrical properties of K0.5Na0.5NbO3 ceramics

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Title Effect of sintering temperature on composition, microstructure and electrical properties of K0.5Na0.5NbO3 ceramics
 
Creator SINGH, R
KULKARNI, AR
HARENDRANATH, CS
 
Subject Electroceramic
Dielectric:ferroelectric:piezoelectric
PIEZOELECTRIC PROPERTIES
 
Description Lead free potassium sodium niobate (K0.5Na0.5NbO3) ceramic powders were synthesized by colloidal coating method. The calcined powders (800 degrees C) were sintered conventionally at three different temperatures (1050 degrees C, 1100 degrees C and 1150 degrees C) and the effect of sintering temperature on density, microstructure, composition and electrical properties was investigated. All the samples showed a single phase perovskite structure with orthorhombic symmetry similar to KNbO3 ceramics. Microstructure examined under FEG-SEM revealed an optimum microstructure, in terms of grain size, porosity and uniformity, at the sintering temperature of 1100 degrees C, which also showed density of 92% rho(Th). As the sintering temperature increased the X-ray diffraction peaks shifted to lower 2 theta values indicating excess volatilization of Na at higher temperature as compared to K. This was further confirmed through elemental Probe X-ray microanalysis and ICP-AES studies. Dielectric constant (epsilon(r)), dielectric loss (tan delta), ferroelectric (P-E loop) and piezoelectric (d(33)) properties showed considerable improvement and leakage current decreased with increasing sintering temperature. The sample sintered at 1100 degrees C. showed marked improvement in maximum dielectric constant (573) at RT at 1 kHz, minimum tangent loss (0.04) at RT at 1 kHz, maximum remnant polarization (135 mu C/cm(2)), lower leakage current (7.6 x 10(-7) A/cm(2)) and maximum d(33) value (100 pC/N). (C) 2013 Elsevier B.V. All rights reserved.
 
Publisher ELSEVIER SCIENCE BV
 
Date 2014-12-28T16:27:42Z
2014-12-28T16:27:42Z
2014
 
Type Article
 
Identifier PHYSICA B-CONDENSED MATTER, 434139-144
0921-4526
1873-2135
http://dx.doi.org/10.1016/j.physb.2013.10.052
http://dspace.library.iitb.ac.in/jspui/handle/100/16883
 
Language English