Lead-free BFN ceramics doped by chromium, lithium or manganese

Dariusz Bochenek,Przemysław Niemiec,Małgorzata Adamczyk

doi:10.1140/epjb/e2015-60461-2

Dariusz Bochenek, Przemysław Niemiec + Show 1 more

Open Access

https://doi.org/10.1140/epjb/e2015-60461-2

Copy DOI

Abstract

The material of the study was lead-free BaFe0.5Nb0.5O3 ceramics subject to modification. The base composition BaFe0.5Nb0.5O3 as well as the chromium, lithium and manganese modified ones were obtained using conventional mixed oxides and carbonates method. Synthesis was performed by the powder calcination method at high temperature 1250 °C for 4 h, while the densification was carried out by free sintering method under conditions 1350 °C/4 h. The paper presents a complex study of admixtures influence on the crystal structure, microstructure and dielectric properties of the BFN type samples. The mentioned dopants chromium, lithium or manganese in the BFN-type ceramics among other caused the reduction of the electric permittivity maximum as well as significant decrease in value of dielectric loss.

Highlights

The BaFe1/2Nb1/2O3 ceramics (BFN) may be an alternative material to replace lead-based ceramics such as: PbFe1−xNbxO3 (PFN), which, due to its excellent piezoelectric and electromechanical properties, have been widely used for various devices, especially piezoelectric actuators, transformers and transducers [1,2,3,4,5]
The X-ray investigation shows that the pure BFN ceramicstype materials have the monoclinic symmetry with following cell parameters: a = 4.0743 ̊A, b = 4.0388 ̊A, c = 2.8759 ̊A
Such reduction is connected with the increasing porosity of the modified BFN ceramics

Summary

Introduction

The BaFe1/2Nb1/2O3 ceramics (BFN) may be an alternative material to replace lead-based ceramics such as: PbFe1−xNbxO3 (PFN), which, due to its excellent piezoelectric and electromechanical properties, have been widely used for various devices, especially piezoelectric actuators, transformers and transducers [1,2,3,4,5]. The discussed materials have good ferroelectric (high values of dielectric permittivity) and the ferromagnetic properties at low (negative) temperatures, what was widely described in papers [7,8]. In the present paper authors described the influence of chromium, lithium and manganese modifiers on reduction of the dielectric losses of the basic material.

Results

Conclusion