Materials
·
2024
·Vol. 17
·期 23
·5824
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IF 3.1
Guoyu Zhang,Lu Li,Yanxin Nan,Peng Li,Tao Deng,Zhipeng Lei,Yuanyuan Li,Jianhua Zhang
In this work, the effects of different sintering temperatures and TiO2concentrations on the dielectric properties of ZrO2and Nb2O5pre-doped CaCu3Ti4O12(CCTO) ceramics were investigated. These doped ceramics were sintered at temperatures of 1020, 1030, and 1040 °C, exhibiting the lowest dielectric loss of 0.01, which consistently remained below 0.03 across a wide frequency range from 10 to 105Hz. Simultaneously, they maintained a high dielectric constant of more than 3000 and remarkably met the requirements for an X8P capacitor (Δε′ ≤ ±10% at temperature range from −55 to 150 °C). It was clarified that TiO2doping increased grain boundary resistance, leading to the reduced dielectric loss, and elevated the grain boundary activation energy, thereby enhancing the temperature stability. The TiO2-doped CCTO-based ceramics also demonstrated reduced sensitivity to variations in sintering temperature, highlighting their excellent manufacturability. This characteristic holds great promise for the fabrication of CCTO-based ceramics, which usually exhibit poor repetitiveness.
研究领域:
材料科学
·
电子工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2023
·
IF 6.2
Ruifeng Wu,Zhilong Fu,Yafei Liu,Yaxin Wei,Hao Sun,Aimin Chang,Bo Zhang
The entropy engineering strategy has been used for the first time to improve the grain boundary (GB) barrier of CaCu 3 Ti 4 O 12 (CCTO) ceramics, in order to solve its nonlinear problem at around 300 ℃ and expand its application in the field of high-temperature thermistors . To achieve this goal, we prepared (CaBaEuZnSr) 0.2 Cu 3 Ti 4 O 12 (CBEZSCT) high-entropy ceramics, and the GB spontaneous segregation properties were exploited to improve the GB resistance of CBEZSCT ceramics. The results show that the GB activation energy of CBEZSCT high-entropy ceramics (0.87 eV) is higher than that of CCTO ceramics (0.7 eV), which linearizes the resistance temperature curve and extends the application temperature limit from 300° to 750 °C. The proposed method of using a high entropy strategy to tune the GB resistance of CCTO to optimize its performance is highly effective, thus providing a new way of thinking about studying high-performance CCTO materials.
研究领域:
材料科学
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电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2023
·Vol. 34
·期 25
·1-13
·
IF 2.8
Yang Xiao-Yu,Yan Meng-Han,Zhang Ying,Zhang Zhi-Fei,Chen Xue-Shuai,Joshi Mahesh Kumar,Li Zi-Liang,Li Peng,Han Wei-Fang,Fu Peng
In this study, a series of perovskite-phase x LaCoO 3 -(1 − x )CaCu 3 Ti 4 O 12 [ x LC-(1 − x )CCTO, with x = 0.02, 0.04, 0.08, 0.15] negative temperature coefficient (NTC) ceramics were fabricated by a solid-state reaction method. XRD analysis indicated that the ceramics consisted of a body-centered cubic perovskite phase. The grain size of the prepared samples was greatly decreased by introducing LC. The decrease in resistivity of all samples as a function of temperature indicated the presence of NTC effect in all the fabricated x LC-(1 − x )CCTO ceramics. The electrical resistivity ρ 30 decreased within a relatively narrow range of 1.58 × 10 6 − 9.28 × 10 5 Ω cm with increasing LC content, whereas thermistor constant B 30/75 increased within a wide range of 2190–5232 K. Our outcomes confirmed that the combination of ρ 30 and B 30/75 could be adjusted to desired values by incorporating LC. In addition, in situ XPS and complex impedance analysis displayed a conduction mechanism based on electron hopping. Current research provided a feasible example to achieve the suitable coupling of high ρ and low B values for NTC thermistors.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
RARE METALS
·
2025
·
IF 11
Mao Pu,Sun Jie,Feng Hui-Min,Liu Zhi-Yong,Guo Kun,Xie Bing,Wang Ting,He Li-Qiang,Gao Jing-Hui
Copper calcium titanate (CaCu 3 Ti 4 O 12 , CCTO) ceramics with colossal permittivity have gained widespread concern because of their potential application in modern electronic devices with miniaturization and integration. However, the extent of grain and grain boundary contribution to the colossal permittivity of CCTO-based ceramics based on the internal barrier layer capacitor (IBLC) model is still in debate. This affects their electrical performance optimization and real-world applications. In this study, a series of novel lead-free colossal permittivity ceramics, x LiCuNb 3 O 9 –(1– x )CaCu 3 Ti 4 O 12 (LCNO-CCTO), were designed and prepared using a solid-phase reaction approach. The colossal permittivity response mechanism of LCNO-CCTO ceramics was further explored by performing the complex impedance spectrum and analyzing the activation energy from the grain and grain boundary contribution viewpoint. As a result, the LCNO-CCTO ceramics present the cubic perovskite structure with the space groups of \(Im \overline{3}\) . All the LCNO-CCTO ceramics exhibit the significantly enhanced colossal permittivity (10 5 ) response, and the ceramic with x = 0.15 shows the highest permittivity of about 4.64 × 10 5 (20 Hz, room temperature) accompanied by a lower grain resistance of 9.61 Ω and larger grain activation energy of 0.21 eV. The enhanced colossal permittivity response is primarily attributed to the great electrical response inside grains of LCNO-CCTO ceramics, resulting from a smaller grain resistance. Also importantly, the high-frequency dielectric relaxation characteristics are improved by incorporating the LCNO into CCTO ceramics as an ion form. Accordingly, the LCNO-CCTO ceramics show a suppressed high-frequency dielectric loss. These results can provide a thorough knowledge and useful optimization strategy for developing high-performance colossal permittivity materials. Graphical
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Meng-Han Yan,Zhi-Fei Zhang,Hai-Hua Huang,Zi-Liang Li,Peng Li,Ji-Gong Hao,Wei Li,Juan Du,Mahesh Kumar Joshi,Peng Fu
In this work, a series of x Sm 2 O 3 -(1- x ) CaCu 3 Ti 4 O 12 ( x Sm 2 O 3 -(1- x )CCTO, x = 0.00–0.05) negative temperature coefficient (NTC) ceramics were prepared by a solid-state method. The influence of Sm 2 O 3 content on electrical properties was examined using microstructural, band gap, morphological, Direct Current (DC) resistivity, and impedance spectroscopy analysis. The increase in Sm 2 O 3 content resulted in a gradual decrease of the resistivities ( ρ 25 ), thermal constants ( B 25/75 ), activation energies for electrical conduction ( E a ) and activation energies of the relaxation process ( E relax ) from 1.16 × 10 7 Ω cm, 6387 K, 0.5456 eV and 0.5592 eV to 3.43 × 10 5 Ω cm, 4149 K, 0.4088 eV and 0.4115 eV respectively. First-principles calculations revealed a reduction in the band gap by adding Sm 2 O 3 , partially explaining the decrease in electrical resistivity. In-situ XPS analysis elucidated a relationship between conduction mechanism of Sm 2 O 3 -doped CCTO ceramics and electron hopping. Impedance analyses showed that both grains and grain boundaries contributed to the NTC effect of ceramics. The electrical inhomogeneity arose from grains and grain boundaries, while local relaxation was due to the short-range motion of charge carriers.
研究领域:
材料科学
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物理学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2021
·Vol. 32
·期 7
·9324-9331
·
IF 2.478
Hao Wentao,Yu Bo,Xu Panpan,Sun Li,Cao Ensi,Zhang Yongjia
CaCu 3 Ti 4 O 12 (CCTO) is a very promising high dielectric permittivity ceramic, but the larger low-frequency dielectric loss limits its application. According to internal barrier layer capacitance effect, which is commonly accepted to explain the unusual dielectric properties of CCTO ceramic in the kHz frequency range, constructing insulating phase boundaries between CCTO grains is an effective method to reduce the low-frequency dielectric loss. Therefore, (In 0.5 Nb 0.5 ) 0.05 Ti 0.95 O 2 (INTO) ceramic powder, another high dielectric permittivity ceramic with much higher sintering temperature than CCTO, was added to CCTO ceramic powder to prepare CCTO/xINTO multiphase ceramics with the structure of INTO phase separating CCTO phase. The experimental results show that CCTO/xINTO multiphase ceramics with the designed structure have been obtained, and their low-frequency dielectric loss indeed decreases significantly compared with CCTO ceramic, which should be mainly attributed to the insulating INTO phase. The CCTO/INTO ceramic sintered at 1040 °C for 8 h in atmosphere exhibits good overall dielectric properties at room temperature, of which the low-frequency dielectric loss is less than 0.05 and the dielectric permittivity reaches 3000.
研究领域:
材料科学
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电子材料
✓ 已验证
产品关联
DOI
高影响因子
Journal of Asian Ceramic Societies
·
2022
·
IF 2.546
Guang-Tan Miao,Zhen-Jie Wang,Peng Li,Ji-Gong Hao,Wei Li,Juan Du,Wei-Fang Han,Chun-Ming Wang,Guo-Rong Li,Peng Fu
The structure and electrical properties of CaCu3Ti4O12 (CCTO) ceramics doped with xHo2O3 synthesized by solid-phase reaction method were systematically studied. Insights from X-ray diffraction (XRD) measurements indicate the existence of a primary phase of CCTO in all samples. Ho2O3 dopant was found to inhibit grain growth and thus leading to a reduced grain size of ceramics. Moreover, the distribution of resistivity with temperature revealed the manifestation of a negative temperature coefficient (NTC) effect in the samples. More specifically, the resistivity (ρ20) values of obtained ceramics configurations decreased from 8.54 × 106 to 1.76 × 105 Ω cm with increasing Ho2O3 doping content. In addition, thermal constant (B20/75) of all samples was higher than 4000 K. Electrical properties analysis disclosed that electron hopping process is main conduction mechanism within CCTO-based ceramics. In addition, insights from complex impedance spectra revealed the existence of grain boundaries with resistance higher than grains resistance. This effect is strongly connected with the manifestation of electrical relaxation procedures within grain boundaries. Our outcomes verify that both the structural configuration and the electrical performance of the CCTO-based ceramics can be tuned directly and effectively by incorporating Ho2O3 dopant.
研究领域:
材料科学
·
电学
✓ 已验证
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Wentao Hao,Panpan Xu,Peide Han,Mingwen Wang
Reduction of dielectric loss for CCTO ceramics is a prerequisite for their applications. Considering internal barrier layer capacitance effect, improving the capacitance and grain boundary resistance is an effective way to reduce dielectric loss. Therefore, more conductive Ti 3+ and Cu + ions were introduced to grains by adding carbon to ceramic bodies, improving the permittivity of CCTO ceramics. Annealing was performed to increase the grain boundary resistance. The dielectric loss of the CCTO ceramics thus prepared, which maintain a giant permittivity, is significantly reduced. Specifically, the CCTO ceramic with carbon addition, which was sintered at 1080 °C for 8 h and air annealed at 950 °C for 2 h, exhibits a giant permittivity of about 2.50(5)×10 4 and a low dielectric loss of less than 0.050(2) from below 20 Hz to 50 kHz at room temperature. Meanwhile, its dielectric loss at 1–10 kHz is less than 0.050(2) from below room temperature to about 100 °C.
研究领域:
材料科学
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）