Preparation and dielectric properties of barium iron niobate by molten-salt synthesis

Tawichai, Nattaya; Sittiyot, Waraporn; Eitssayeam, Sukum; Pengpat, Kamonpan; Tunkasiri, Tawee; Rujijanagul, Gobwute

doi:10.1016/j.ceramint.2011.04.064

Cited by 27 publications

(11 citation statements)

References 11 publications

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“…[23][24][25] Molten-salt method has been widely applied in the preparation of crystalline products with improved thermal, electrical, optical, and other properties. [26][27][28] In the present work, a novel access in combination with DCC and molten-salt method is introduced to fabricate highly porous (44%-61%) alumina ceramics with optimized mechanical properties using alumina fibers as raw material and adding K 2 SO 4 as sintering aid. The influence of various K 2 SO 4 additions on viscosity of alumina suspension at different temperatures was investigated.…”

Section: Introductionmentioning

confidence: 99%

“…Molten‐salt method is an approach to enhance reactions of substrate and generate specific crystals by adding single or composite salts providing a unique ionic liquid circumstance for mass and heat transfer at a particular temperature above melting point (MP) . Molten‐salt method has been widely applied in the preparation of crystalline products with improved thermal, electrical, optical, and other properties . In the present work, a novel access in combination with DCC and molten‐salt method is introduced to fabricate highly porous (44%‐61%) alumina ceramics with optimized mechanical properties using alumina fibers as raw material and adding K 2 SO 4 as sintering aid.…”

Section: Introductionmentioning

confidence: 99%

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Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Liu

Chen

et al. 2017

J Am Ceram Soc

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Flawless porous fibrous alumina ceramics with high performance were fabricated via a novel approach involving direct coagulation casting and lost‐mold method. Stable alumina suspensions were prepared by adding sodium tri‐polyphosphate as dispersant using alumina fibers as raw material and K2SO4 as sintering aid. Resin‐coated sand molds with designed shapes for suspension casting were fabricated through 3D printing with subsequent post‐treatments. Alumina green bodies were obtained by in situ coagulation of the suspension after treating at 90°C within 40 minutes. Porous alumina ceramics were obtained after direct furnace sintering of green bodies without demolding, in which the molds would collapse automatically at around 650°C with less exhaust emission. The effect of various K2SO4 contents and sintering temperatures on mechanical properties of porous ceramics was investigated. The SEM results showed that the fibers interconnected with obvious interfacial bondings on junctions when sintered at 1450°C. The XRD patterns showed that the sample sintered with various K2SO4 additions consisted of different phases, mainly including aluminosilicates. Porosity of ceramic samples increased slightly whereas the compressive strength enhanced significantly with increasing K2SO4 addition. The density of sintered samples with different K2SO4 contents was in accord with the porosity variation tendency. The ceramic samples had uniform pore size distribution with average size from 3.18 to 7.24 μm as increasing K2SO4 addition to 40 wt%. This approach may provide a convenient and general route to fabricate various dense and porous advanced ceramics with complex shapes and good composition homogeneity.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Liu

Chen

et al. 2017

J Am Ceram Soc

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“…Fe-containing complex perovskites A(Fe 0.5 B 0.5 )O 3 (A D Ba, Sr, Ca; B D Nb, Ta, Sb) have attracted much scientific attention due to their giant dielectric response and unique dielectric relaxation behavior [1][2][3][4][5], which are similar to those in CaCu 3 Ti 4 O 12 [6][7][8]. These materials generally exhibit a giant dielectric constant step of the order of (10 3 -10 5 ) over a broad temperature and frequency interval.…”

Section: Introductionmentioning

confidence: 99%

Giant Dielectric Response and Relaxor Behaviors in Ba_0.4Sr_0.6(Fe_0.5Nb_0.5)O₃Ceramics

et al. 2015

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Dielectric relaxations of Ba 0.4 Sr 0.6 (Fe 0.5 Nb 0.5 )O 3 (BSFN) ceramics were investigated. Two dielectric relaxations with strong frequency dispersion and following the Arrhenius law were detected in low and high temperature ranges, respectively. The low temperature dielectric relaxation was proposed to originate from the electronic ferroelectricity and the high temperature dielectric relaxation was attributed to the defect ordering. The formation mechanism of the giant dielectric constant step was just a competing balance result of the low-and high-temperature dielectric relaxations.

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“…Therefore, high dielectric constant in BFN and CCTO systems is considered to be extrinsic in nature. In spite of seemingly important possible dielectric applications, dielectric loss (tan δ) of these ceramics is very high [8]. The major drawback of BFN and CCTO ceramics is the difficulty of obtaining high density and single phase formation by conventional solid state synthesis route [9].…”

Section: Introductionmentioning

confidence: 99%

Microwave assisted sol-gel synthesis of high dielectric constant CCTO and BFN ceramics for MLC applications

Sonia

Chandrasekhar

Kumar³

2017

PAC

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Ba(Fe 1/2 Nb 1/2)O 3 (BFN) and CaCu 3 Ti 4 O 12 (CCTO) ceramic powders were synthesized by microwave assisted sol-gel synthesis technique and sintered at 1100°C and 1000°C, respectively. Calcination and sintering processes were carried out in a microwave furnace. Dielectric constant (ε r) ∼2450 and dielectric loss (tan δ) ∼0.5 at frequency of 1 kHz and 20°C were observed for the BFN ceramic samples. Higher value of ε r ∼ 3600 and lower value of tan δ ∼ 0.07 at frequency of 1 kHz and in 20-60°C temperature range for the CCTO ceramic samples suggested its utility for MLC applications. Sharp decrease of ε r and sharp increase of tan δ at higher frequencies of BFN ceramic samples indicated the presence of Debye like relaxation.

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Preparation and dielectric properties of barium iron niobate by molten-salt synthesis

Cited by 27 publications

References 11 publications

Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Giant Dielectric Response and Relaxor Behaviors in Ba_0.4Sr_0.6(Fe_0.5Nb_0.5)O₃Ceramics

Microwave assisted sol-gel synthesis of high dielectric constant CCTO and BFN ceramics for MLC applications

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Preparation and dielectric properties of barium iron niobate by molten-salt synthesis

Cited by 27 publications

References 11 publications

Effect of K2SO4 additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Effect of K2SO4 additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Giant Dielectric Response and Relaxor Behaviors in Ba0.4Sr0.6(Fe0.5Nb0.5)O3Ceramics

Microwave assisted sol-gel synthesis of high dielectric constant CCTO and BFN ceramics for MLC applications

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Product

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About

Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Effect of K₂SO₄ additions on properties of porous fibrous alumina ceramics prepared by DCC and lost‐mold method

Giant Dielectric Response and Relaxor Behaviors in Ba_0.4Sr_0.6(Fe_0.5Nb_0.5)O₃Ceramics