Affiliation:
1. College of Materials and Chemistry & Chemical Engineering, Chengdu University of Technology, Chengdu, China
2. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, School of Material Science and Engineering, Wuhan University of Technology, Wuhan, China
Abstract
In this paper, phase composition, microstructure, dielectric, ferroelectric
and failure behaviour of lead-free (1-x)(Bi0.5Na0.5TiO3-BaTiO3)-xLiNbO3
(BNT-BT-LN, x = 0.01, 0.03, 0.05, 0.07 and 0.10) ceramics were investigated.
The introduction of LiNbO3 did not change the original perovskite crystal
structure of the ceramics with the coexistence of rhombohedral and
tetragonal phases. However, with the increase of x (i.e. LN content), the
characteristic split XRD peaks became more and more symmetrical. It was
observed by scanning electron microscopy that the growth of ceramic grain
size was promoted with the increase of LN content. The dielectric
temperature stability was also effectively improved with addition of LN.
When x = 0.07, the temperature coefficient of capacitance (TCC150 ?C) was
below ?15% in temperature range of 35-400 ?C with moderate permittivity
("r150 ?C = 2050) and low dielectric loss (tan _150 ?C = 0.005). The RC time
constant of this sample was higher than 19.3 s at temperatures up to 245 ?C.
The mean time to failure (TTF) empirical formula for the BNT-BT-LN
dielectrics was established through highly accelerated life test. As
predicted, the TTF could reach 4.67 ? 106 h under the applied electric field
of 7 kV/mm at room temperature.
Publisher
National Library of Serbia