Improvement in varistor properties of CaCu3Ti4O12 ceramics by chromium addition

Grzebielucka, Edson Cezar; Monteiro, João Frederico Haas Leandro; Souza, Éder Carlos Ferreira de; Borges, Christiane Philippini Ferreira; Andrade, André Vitor Chaves de; Cordoncillo, Eloísa; Antunes, Sandra Regina Masetto

doi:10.1016/j.jmst.2019.08.055

Cited by 36 publications

(16 citation statements)

References 55 publications

(95 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For Equation 4, β can be obtained by plotting a graph of ln J vs ffi ffi ffi E p and taking the gradient of the best-fit line. Consequently, the Schottky barrier height, Φ B may be estimated by first plotting the values of ln J obtained across different T in the absence of an electrical field, i.e., E = 0 against T −1 and then calculating the gradient of the best-fit line [19]. Figure 1 shows the diffraction patterns for samples with varying concentrations of SLS glass.…”

Section: Methodsmentioning

confidence: 99%

Effect of soda lime silica glass doping on ZnO varistor ceramics: dry milling method

Ismail

Saat

Zaid

2020

Journal of Asian Ceramic Societies

View full text Add to dashboard Cite

There is a lack of reports where dry milling methods have been used in the preparation of varistor based ceramics. Dry milling methods have been demonstrated to be able to produce fine and homogeneous sample powders. Soda lime silica (SLS) glass powder have also been used as dopants in ZnO varistor ceramics. This work focuses on the effect of dry milling on the microstructural and electrical properties of ZnO 0.98-x-SLS x-CoO 0.02. The sample mixtures were prepared via a solid state method with x = 0.5, 1.0, 1.5, and 2.0 mol%. XRD managed to detect Zn 2 SiO 4 as secondary phase in the sintered samples. The results show that the average grain size decreased from 26.1 to 21.6 µm and densities of the varistor samples increased as x increased. The varistor sample that was sintered at 1100°C and doped with 2 mol% SLS glass powder shows good electrical properties with nonlinear coefficient, (α) 6.97, breakdown voltage 261.1 V/cm and leakage current (J L) 4.87 µA/cm 2 .

show abstract

Section: Methodsmentioning

confidence: 99%

Effect of soda lime silica glass doping on ZnO varistor ceramics: dry milling method

Ismail

Saat

Zaid

2020

Journal of Asian Ceramic Societies

View full text Add to dashboard Cite

show abstract

“…These values were rescaled by a specific factor (ε 0 /10 3 , 20 × D) individually to a factor for the values of ε 0 and D, respectively, to highlight and showcase their impressive performance. Categorically, one could observe that these reported materials in the literature possess either lower D values associated with significantly lower ε 0 values [46][47][48][49][50][51] or higher ε 0 values with higher D values, [52][53][54][55] while ZnO-CCTO and SnO 2 -CCTO are found to exhibit pronounced improvement in all the values of ε 0 , D, and α, which are technologically critical for varistor applications. Observed values sourced from various studies and the concerned references therein and the present study are illustrated in Table S1 in the supplementary material.…”

Section: F I-v Characteristicsmentioning

confidence: 96%

“…To better appraise the dielectric and nonlinear properties of ZnO/SnO 2 diffused ceramics, we compare ε 0 , D, and α values in the current study with that of the recent reports on CCTO-based ceramics. [46][47][48][49][50][51][52][53][54][55] Figure 11 shows the comparison bars comprised of normalized values of ε 0 , D, and α. These values were rescaled by a specific factor (ε 0 /10 3 , 20 × D) individually to a factor for the values of ε 0 and D, respectively, to highlight and showcase their impressive performance.…”

Section: F I-v Characteristicsmentioning

confidence: 99%

Superior dielectric and varistor properties of ZnO or SnO2 diffused calcium copper titanate ceramics

Dhavala

Muthukumar

Sai

et al. 2023

Journal of Applied Physics

View full text Add to dashboard Cite

Sub-micrometer-sized (0.33 μm) polycrystalline powders of calcium copper titanate (CCTO) were synthesized via the solgel method. Compacted calcined powders were sintered at 900 °C/2h to obtain porous (<80% density) pellets. Subsequently, ZnO or SnO2 pastes (∼10 μm grain size) were smeared on either side of the pellets and sintered at 1100 °C/15 h, which yielded dense (>95% density) ceramics. X-ray structural investigations revealed the presence of ZnO or SnO2 traces in the bulk of the CCTO ceramics. Scanning electron microscopy and energy dispersive spectroscopic studies confirmed the diffusion and the segregation of these oxides at the grain boundaries. The dielectric and varistor properties of the ZnO or SnO2 diffused samples were found to be superior to that of pristine CCTO ceramics. For instance, the dielectric constant (ɛ′) of ZnO diffused ceramics exhibited a value as high as 2.4 × 104 (1 kHz, at room temperature) and a dielectric loss (D) of 0.059. Similarly, SnO2 diffused ceramics exhibited a dielectric constant of 2.7 × 104 (1 kHz, at room temperature) associated with a dielectric loss of 0.047. The figure of merit of varistor performance, i.e., nonlinear coefficient ( α = 10.6), of the SnO2 diffused sample is significantly higher than that of ZnO diffused ( α = 7.4) and pristine CCTO ( α = 4.5) ceramics. The dielectric data obtained for both the pristine and ZnO or SnO2 diffused ceramics were rationalized by invoking Cole–Cole analysis. The thermal activation energy was estimated from the temperature-dependent dielectric data besides current (I)–voltage (V) characteristics. Equivalent circuit modeling of the Nyquist plots demonstrated that the inclusion of ZnO and SnO2 layers in CCTO ceramics remarkably improved the grain boundary resistance ( Rgb) by 5-fold and 20-fold, respectively, which resulted in making CCTO a better dielectric. This methodology of fabricating ceramics via interfacial engineering could pave the way for obtaining superior CCTO ceramics associated with exotic functional properties.

show abstract

“…More than 200 grains were measured for each sample. The grains were distinguished after image binarization by the software ImageJ [31]. Subsequently, areas of grains were calculated and the equivalent grain sizes were obtained.…”

Section: Surface Morphology and Phase Compositionmentioning

confidence: 99%

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Xie¹,

Wang

2022

Materials

View full text Add to dashboard Cite

In this paper, evolution of microstructures, electrical properties and defects of the double Schottky barrier during the sintering process were investigated by quenching ZnO varistor ceramics at different sintering stages. It was found that morphology of the samples changed little when the temperature was below 800 °C. Remarkable enhancement of the Schottky barrier height and electrical properties took place in the temperature range between 600 °C and 800 °C. The Bi-rich intergranular layer changed from β phase to α phase. The interfacial relaxation at depletion/intergranular layers became detectable in the samples. Meanwhile, a distinct relaxation loss peak from electron trapping of interface states was observed instead of two dispersed ones. It indicated that the differences among the Schottky barriers in ZnO varistor ceramics became smaller with the process of sintering, which was also supported by the admittance spectra. In addition, oxygen vacancy was found more sensitive to the sintering process than zinc interstitial. The results could provide guidance for fine manipulating the Schottky barrier and its underlying defect structures by optimizing sintering process.

show abstract

Improvement in varistor properties of CaCu3Ti4O12 ceramics by chromium addition

Cited by 36 publications

References 55 publications

Effect of soda lime silica glass doping on ZnO varistor ceramics: dry milling method

Effect of soda lime silica glass doping on ZnO varistor ceramics: dry milling method

Superior dielectric and varistor properties of ZnO or SnO2 diffused calcium copper titanate ceramics

Evolution of Intrinsic and Extrinsic Electron Traps at Grain Boundary during Sintering ZnO Based Varistor Ceramics

Contact Info

Product

Resources

About