Improvement of microwave dielectric properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 ceramics prepared by solid-state reaction

Itaalit, Brahim; Mouyane, Mohamed; Bernard, J.; Reboul, Jean-Michel; Houivet, David

doi:10.1016/j.ceramint.2014.10.063

Cited by 8 publications

(12 citation statements)

References 16 publications

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“…It can be seen that the surface XRD pattern (Figure 2a) can be interpreted as a mixture of Ba(Co0.7Zn0.3)1/3Nb2/3O3 (BCZN) and Ba8(Co,Zn)1Nb6O24 phases. The complex perovskite ceramic Ba8(Co,Zn)1Nb6O24 is isostructural with Ba8Ni1Nb6O24 and Ba8Zn1Nb6O24 [11]. The Co:Zn ratio in Ba8(Co,Zn)1Nb6O24 may be variable.…”

Section: Structural Characterizationmentioning

confidence: 99%

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Itaalit¹,

Mouyane²,

Bernard³

et al. 2015

Applied Sciences

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Abstract:The effects of post-annealing on the crystal structure, microstructure, and microwave dielectric properties for Ba(Co 0.7 Zn 0.3 ) 1/3 Nb 2/3 O 3 ceramics were investigated. The as-prepared materials were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The microwave dielectric properties are measured at 6 GHz using a network analyzer. Ba 5 Nb 4 O 15 and/or Ba 8 (Co,Zn) 1 Nb 6 O 24 secondary phases were found on the surface according to sintering conditions due to volatilization of some Zn and Co elements. The experimental results show that the beneficial effect of the annealing steps to improved the microwave dielectric properties. Excellent microwave dielectric properties were achieved for the coarse-grained microstructures by a higher sintering temperature and with a shorter holding time followed by annealing steps at lower temperatures with a longer holding time. This improvement can be attributed to 1:2 cation ordering within the crystal, which is taking place during annealing process. The Ba(Co 0.7 Zn 0.3 ) 1/3 Nb 2/3 O 3 ceramic could be used successfully for realization of dielectric microwave resonators, since it has a high quality factor Q f value of 123,700 GHz, a high dielectric constant ε r value of 34.5 and a temperature coefficient of the resonant frequency τ f of 0 ppm/ ¥ C.

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Section: Structural Characterizationmentioning

confidence: 99%

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Itaalit¹,

Mouyane²,

Bernard³

et al. 2015

Applied Sciences

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“…The data of these last suspensions show a high initial viscosity which decreases with the pH values. The data also indicate that the nearly Newtonian behavior of the viscosity was observed with the 2 wt% amount of dispersant, indicating a well‐dispersed particle. These results are in agreement with the ζ ‐potential data.…”

Section: Resultsmentioning

confidence: 64%

Sintering behavior of magnesium aluminate spinel MgAl₂O₄ synthesized by different methods

Mouyane

Jaber

Bendjemil

et al. 2019

Int J Applied Ceramic Tech

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This paper is focusing basically on the ceramic technology, of which several methods for the synthesis of MgAl2O4 have been investigated. The synthesis conditions regarding the powders cleanliness, microstructure, and sintering parameters of MgAl2O4 were studied. MgAl2O4 powder was synthesized via conventional solid‐state route using different milling process: vertical attrition milling, WAB as a high‐energy horizontal attrition milling, and Pulverisette as a planetary ball miller, and via solution combustion route using Urea, Glycine, and a mixture of Urea/Glycine. Urea and Glycine was used as fuel. The white powders were obtained for all solid‐state routes and for Urea‐combustion technique. The black and gray powders were obtained in the case of combustion technique, respectively, using a fuel of Glycine and Glycine/Urea mixture. The obtained powders and pellets were characterized by XRD, SEM, and Dilatometry. The results show that, among all the solid‐state route processes, wet attrition milling gives the better and clean spinel phase. The WAB milling and Pulverisette miller introduce a contamination by some yttria‐stabilized zirconia balls in the corresponding powder. Furthermore, the flash combustion technique permit to have nanoparticles with a dense spinel phase of MgAl2O4 and with lower sintering temperature in less time and with no calcination step.

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“…In the case of BCZN, an ordered structure was obtained by an annealing process at 1300 °C for 12 h [6]. In our previous work [3,6], we proved that the improvement of the quality factor QF of such ceramic materials is related to the 1:2 cation ordering in the BCZN crystal that occurs during the annealing process. By adding an annealing step as a second thermal treatment following the initial sintering step, we obtained BCZN materials with excellent dielectric properties (εr 34.5, QF 123 700 GHz, and τf 0 ppm/ °C).…”

Section: Introductionmentioning

confidence: 70%

“…e structure is characterised by a 1:2 arrangement of Co, Zn (B′), and Nb (B″) atomic columns [2]. is 1: 2 cation ordering, which is obtained only by heat treatments at high temperatures, has been shown to be the essential property responsible for the interesting electric properties of this material [3], such as a high quality factor QF (low dielectric loss), a high dielectric constant εr 34.5, and a near zero temperature coe cient of the resonant frequency τf [4,5]. In particular, the QF-factor value is strongly a ected by the degree of cation ordering.…”

Section: Introductionmentioning

confidence: 99%

“…Recently, it has been reported that the disordered BCZN ceramic has a low value of QF (12 000 to 36 000 GHz at 6 GHz), whereas the ordered BCZN ceramic exhibits a higher QF value up to 123 700 GHz [2,6]. In dense BCZN ceramic materials, this kind of ordering is di cult to accomplish without the use of additional procedures such as adding impurities [7][8][9] or the use of a second thermal treatment as an annealing process [2,3,6]. In the case of BCZN, an ordered structure was obtained by an annealing process at 1300 °C for 12 h [6].…”

Section: Introductionmentioning

confidence: 99%

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A Novel Approach to the Sintering Schedule of Ba (Co0.7Zn0.3)1/3Nb2/3O3 Dielectric Ceramics for Microwave Applications

Mouyane

Itaalit

Bernard

et al. 2022

Advances in Materials Science and Engineering

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The present research is devoted to the optimization of the sintering schedule of Ba (Co0.7Zn0.3)1/3Nb2/3O3 (BCZN) dielectric ceramics for microwaves applications. A novel approach to the heat treatment of these ceramics based on the rapid-rate sintering (RRS) technique followed by a lower temperature annealing cycle has been developed. The relationships among the heat treatment process optimization, the structural, microstructural characteristics, and the microwave dielectric properties of the BCZN ceramics were investigated using X-ray diffraction, scanning electron microscopy, energy dispersion analysis, and vector network analysis. The RRS-technique shortens substantially the time required for the elaboration of these components in comparison with conventional sintering techniques and prevents simultaneously the formation of secondary phases as Ba5Nb4O15 and Ba8(Co, Zn) 1Nb6O24 on the surface of the ceramics. All of the sintered and annealed ceramics exhibit a high quality factor QF close to 110 000 GHz at 6 GHz. The high dielectric constant εr of ∼34.5 and a temperature coefficient of the resonant frequency τf of ∼0 ppm.C-1 were obtained in all annealed ceramics.

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Improvement of microwave dielectric properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 ceramics prepared by solid-state reaction

Cited by 8 publications

References 16 publications

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Sintering behavior of magnesium aluminate spinel MgAl₂O₄ synthesized by different methods

A Novel Approach to the Sintering Schedule of Ba (Co0.7Zn0.3)1/3Nb2/3O3 Dielectric Ceramics for Microwave Applications

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Improvement of microwave dielectric properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 ceramics prepared by solid-state reaction

Cited by 8 publications

References 16 publications

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Effect of Post-Annealing on the Microstructure and Microwave Dielectric Properties of Ba(Co0.7Zn0.3)1/3Nb2/3O3 Ceramics

Sintering behavior of magnesium aluminate spinel MgAl2O4 synthesized by different methods

A Novel Approach to the Sintering Schedule of Ba (Co0.7Zn0.3)1/3Nb2/3O3 Dielectric Ceramics for Microwave Applications

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Sintering behavior of magnesium aluminate spinel MgAl₂O₄ synthesized by different methods