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Title: Compositional inhomogeneityand segregation in (K0.5Na0.5)NbO3 ceramics

Journal Article · · Ceramics International
 [1];  [1];  [2]
  1. North China Electric Power Univ., Beijing (China)
  2. Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
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The effects of the calcination temperature of (K0.5Na0.5)NbO3 (KNN) powder on the sintering and piezoelectric properties of KNN ceramics have been investigated in this report. KNN powders are synthesized via the solid-state approach. Scanning electron microscopy and X-ray diffraction characterizations indicate that the incomplete reaction at 700 °C and 750 °C calcination results in the compositional inhomogeneity of the K-rich and Na-rich phases while the orthorhombic single phase is obtained after calcination at 900 °C. During the sintering, the presence of the liquid K-rich phase due to the lower melting point has a significant impact on the densification, the abnormal grain growth and the deteriorated piezoelectric properties. From the standpoint of piezoelectric properties, the optimal calcination temperature obtained for KNN ceramics calcined at this temperature is determined to be 800 °C, with piezoelectric constant d33=128.3 pC/N, planar electromechanical coupling coefficient kp=32.2%, mechanical quality factor Qm=88, and dielectric loss tan δ=2.1%.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Organization:
USDOE Office of Science (SC)
Grant/Contract Number:
AC05-00OR22725
OSTI ID:
1261357
Alternate ID(s):
OSTI ID: 1323960
Journal Information:
Ceramics International, Vol. 42, Issue 8; ISSN 0272-8842
Publisher:
ElsevierCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 6 works
Citation information provided by
Web of Science

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Cited By (2)

Effect of chemical inhomogeneity on domains and ferroelectric properties of Fe‐modified 0.77Bi 0.5 Na 0.5 TiO 3 –0.23SrTiO 3 journal May 2018
Harnessing low frequency-based energy using a K 0.5 Na 0.5 NbO 3 (KNN) pigmented piezoelectric paint system journal January 2017

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Related Subjects

36 MATERIALS SCIENCE
Lead-free piezoelectric
Compositional inhomogeneity
Compositional segregation
Liquid phase sintering
Potassium–sodium niobate
Calcination temperature