Low temperature synthesis of Ba(Zr0.2Ti0.8)O3–0.5(Ba0.7Ca0.3)TiO3 nanopowders by solution based auto combustion method

Mezzane

Superlattices and Microstructures

et al. 2019

Lead-free Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) ceramics had attracted much attention for the fabrication of microelectronic devices by virtue of their excellent dielectric, ferroelectric and piezoelectric properties. To understand the effects of both mean grain size and grain size distribution on the dielectric properties of lead-free Ba 0.85 Ca 0.15 Ti 0.9 Zr 0.1 O 3 (BCZT) ferroelectric relaxors, an original method was proposed. It is based on the surfactant-assisted solvothermal processing coupled with lowtemperature conventional sintering at 1250 °C. In this way, three highly dense BCZT with different mean grain size and dissimilar grain size distribution were designed. A significant increase of dielectric properties was obtained by a control of grain size and densification process. The dielectric constants measured were ranged from 5370 to 9646 and the dielectric loss was enhanced by 70%. Surprisingly, it was evidenced that there is unequivocal link between mean grain size with dielectric properties. Indeed, it was found that the presence of high density of refined grains leads to an improvement of dielectric 2 properties due to an enhancement of densification. This work may provide a new strategy to design ferroelectric materials with enhanced properties.

Section: Phase Characterization Of Nanopowdersmentioning

confidence: 57%

Enhancement of dielectric properties of lead-free BCZT ferroelectric ceramics by grain size engineering

Mezzane

Superlattices and Microstructures

et al. 2019

“…1b)and the formation of triplet at 65.8°(Fig. 1c) indicate the formation of BCZT ceramic at the Morphotropic Phase Boundary (MPB) with the coexistence of orthorhombic (Amm2) and tetragonal phases (P4mm)[1,[24][25][26]. (a) Room-temperature XRD pattern, (b) enlarged peaks splitting around 2θ ≈45° and (c) around 2θ ≈ 65.8°.…”

mentioning

confidence: 99%

Phase transitions, energy storage performances and electrocaloric effect of the lead-free Ba0.85Ca0.15Zr0.10Ti0.90O3 ceramic relaxor

Mezzane

J Mater Sci: Mater Electron

et al. 2019

Lead-free Ba0.85Ca0.15Zr0.10Ti0.90O3 (BCZT) ceramic exhibits excellent dielectric, ferroelectric and piezoelectric properties at the Morphotropic Phase Boundary (MPB). Previously, we demonstrated that the use of the anionic surfactant Sodium Dodecyl Sulfate (SDS, NaC12H25SO4) could enhance the dielectric properties of BCZT ceramic using surfactant-assisted solvothermal processing [1]. In the present study, structural, dielectric, ferroelectric properties, as well as electrocaloric effect and energy storage performances of this BCZT ceramic were thoroughly investigated. X-ray diffraction (XRD) measurements revealed the presence of single perovskite phase at room temperature with the coexistence of orthorhombic and tetragonal symmetries. In-situ Raman spectroscopy results confirmed the existence of all phase transitions from rhombohedral through orthorhombic and tetragonal to cubic symmetries when the temperature varies as reported in undoped-BaTiO3. Evolution of energy storage performances with temperature have been investigated. BCZT ceramic exhibits a high energy storage efficiency of ~80% at 120 °C. In addition, the electrocaloric responsivity was found to be 0.164×10 -6 K.m/V at 360 K.

“…Crystalline structure of BCZT powder was performed by X-ray diffraction [19]were observed at 2θ ≈ 45° ( Fig. 1(b)) and 65.5° (Fig.…”

Section: Characterizationmentioning

confidence: 99%

Very-low temperature synthesis of pure and crystalline lead-free Ba .85 Ca .15 Zr .1 Ti .9 O 3 ceramic

Ablouh

et al. 2018

Ceramics International

The site-doping strategy of barium titanate (BaTiO3) is a promising way to develop new lead-free materials for energy with enhanced dielectric and piezoelectric properties.A novel strategy to elaborated pure and crystalline Ba0.85Ca0.15Zr0.1Ti0.9O3(BCZT) ferroelectric powders at low temperature is proposed. It is based on sol-gel method followed by a hydrothermal reaction. The effects of preparation temperature on structure, crystallinity, purity, morphology and particles size distribution of BCZT powders were studied. It was clearly shown that pure and crystalline BCZT could be obtained over 80°C. Furthermore, the BCZT particles exhibit a spherical shape whose mean size increases from 145 nm at 40°C to 160 nm at 80°C.The present study may provide a new strategy to design lead-free ferroelectric materials with enhanced structure and microstructure properties at very low temperature. 2