Microstructure and properties of Bi(2)O(3) doped 0.8(K(0.52)Na(0.48)) NbO(3)–0.2KSr(2)Nb(5)O(15) lead-free ceramics

Abstract

The 0.8(K(0.52)Na(0.48))NbO(3)–0.2KSr(2)Nb(5)O(15)-yBi(2)O(3) (0.8KNN-0.2KSN-yBi(2)O(3)) lead-free ferroelectric composite ceramics were synthesised using rod-like KSr(2)Nb(5)O(15) (KSN) and isometric (K(0.52)Na(0.48))NbO(3) (KNN) particles as raw material. Effects of Bi(2)O(3) doping content on microstructure, electrical, and optical properties were researched. The results indicated that the addition of Bi(2)O(3) helps to densify 0.8KNN-0.2KSN-y Bi(2)O(3) ceramics within limits without changing phase structure and microstructure. The dielectric constant and phase transition dispersion degree increased with the increase of Bi(2)O(3) while the dielectric loss decreased. Besides, the dielectric tunability was maintained in the range of 43.7∼51.8%, and reached its maximum when Bi(2)O(3) content was 1 wt%. In addition, the remnant polarisation [inline-formula] and coercive field [inline-formula] decreased with the increase of Bi(2)O(3), as well as the optical transmittance of 0.8KNN-0.2KSN, but the transmittance of all samples was above 48%.

Keywords

• bismuth compounds
• ferroelectric ceramics
• dielectric polarisation
• sodium compounds
• potassium compounds
• permittivity
• dielectric losses
• doping
• strontium compounds
• ferroelectric coercive field
• composite materials
• ferroelectric transitions
• crystal microstructure
• densification
• ultraviolet spectra
• visible spectra
• infrared spectra
• lead-free ferroelectric composite ceramics
• doping content
• microstructure
• rod-like particles
• isometric particles
• raw material
• electrical properties
• optical properties
• densification
• dielectric constant
• phase transition dispersion degree
• dielectric loss
• dielectric tunability
• remnant polarisation
• coercive field
• optical transmittance
• (K(0.52)Na(0.48))NbO(3)-KSr(2)Nb(5)O(15):Bi(2)O(3)