JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2021
·Vol. 32
·期 7
·9324-9331
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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
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2020
·
IF 4.65
Wentao Hao,Yupeng Wang,Shuai Yang,Bo Yu,Jiangpeng Zhao,Haitao Huang,Panpan Xu,Li Sun,Ensi Cao,Yongjia Zhang
The dielectric-permittivity ( ε′ ) of (In 0.5 Nb 0.5 ) x Ti 1-x O 12 (INTO) ceramics exceeds 10 4 at room temperature, but the large low-frequency dielectric loss ( tanδ ) limits their applications. Origin of the giant ε′ phenomenon in kHz frequency range is still controversial. However, based on the experimental results, an internal barrier layer capacitance (IBLC) effect seems to be the most plausible mechanism. According to IBLC effect, constructing insulating phase boundaries in INTO ceramics is an effective way to reduce their low-frequency tanδ . Therefore, INTO-based ceramics with ZrO 2 phase boundaries were prepared by solid-state reaction, and their crystalline structures, microstructures, dielectrical properties and complex impedances were analyzed systematically. The results show that the tanδ of our INTO-based ceramics decreased from 0.11 to 0.024 at 1 kHz by ZrO 2 adding and annealing in atmosphere, because of the resistance of ZrO 2 phase boundaries increasing.
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
MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Panpan Xu,Yupeng Wang,Wentao Hao,Li Sun,Ensi Cao,Yongjia Zhang
(In 0.5 Nb 0.5 ) x Ti 1-x O 12 (INTO) ceramics exhibit the unusual dielectric properties of giant dielectric constant and good stabilities, but their low-frequency dielectric loss is relatively large, and the sintering temperature is too high, which are very disadvantageous for practical applications. According to internal barrier layer capacitance effect, which seems to be the most plausible mechanism of the unusual dielectric properties , constructing insulating phase boundaries in INTO ceramics is an effective way to reduce their low-frequency dielectric loss. In this paper, SiO 2 was added to INTO ceramics, because, on the one hand, the insulating phase boundaries could be constructed by SiO 2 , on the other hand, SiO 2 could play the role of sintering agent to reduce the sintering temperature. Therefore, the SiO 2 /INTO ceramics were prepared by solid-state reaction, and their crystalline structures, microstructures, and electrical properties were analyzed. Compared to previous reports, the low-frequency dielectric loss of SiO 2 /INTO ceramics after annealing, which were sintered at a lower temperature of 1300 °C for a shorter time of 5 h, decreases substantially. The reason was discussed.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2021
·
IF 3.995
Panpan Xu,Yupeng Wang,Wentao Hao,Li Sun,Ensi Cao,Yongjia Zhang
TiO 2 ceramics co-doped with In and Nb exhibit unusual large dielectric-permittivity phenomena, but their sintering temperature is essentially higher than 1400 °C and the holding time is usually longer than 5 h, which is very uneconomical for industrial production and practical applications. Therefore, to maintain the relatively good dielectric properties of In and Nb co-doped TiO 2 ceramics and reduce the sintering temperature to about 1300 °C, B 2 O 3 , was added as a sintering aid to prepare B 2 O 3 /(In 0.5 Nb 0.5 ) 0.05 Ti 0.95 O 2 ceramics in this paper. The crystalline structures, microstructures, and electrical properties were investigated and discussed. The results showed that the sintering temperature of B 2 O 3 /(In 0.5 Nb 0.5 ) 0.05 Ti 0.95 O 2 ceramics indeed prominently decreased, but their dielectric loss was relatively large, possibly caused by the pores left following B 2 O 3 volatilization.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Wentao Hao,Panpan Xu,Li Sun,Ensi Cao
Co-doped TiO 2 ceramics exhibit great potential as high-performance giant dielectric materials. However, their excessively high sintering temperature renders them unsuitable for economical industrial production. The giant permittivity of these ceramics is closely correlated with the concentration of Ti 3+ ions present. Adding a sintering aid to the ceramics is an effective method to reduce the sintering temperature. CuO, a common sintering aid, not only reduces the sintering temperature but also potentially enhances the Ti 3+ ions concentration through the multivalence of Cu element, further optimizing their giant dielectric properties. Therefore, the effects of CuO addition on the sintering condition, microstructure, and dielectric properties of In and Nb co-doped TiO 2 ceramics were investigated. The results indicate that CuO effectively lowers the sintering temperature of the ceramics. However, the presence of a large number of Cu + ions inhibits the formation of Ti 3+ ions, resulting in the disappearance of their giant dielectric properties. Upon annealing at 1150 °C for 2 h in air, the Ti 3+ ions concentration significantly increases in the ceramics, consequently restoring their giant dielectric properties. Additionally, a new dielectric relaxation appears around 100 kHz, likely arising from the conductivity difference between the shallow layers and cores of grains induced by annealing. Furthermore, annealing enhances the grain boundary resistance, thereby reducing the low-frequency dielectric loss of the ceramics.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS AND CHEMISTRY OF SOLIDS
·
2024
·
IF 4.3
Panpan Xu,Congli Guo,Wentao Hao,Li Sun,Ensi Cao
The internal barrier layer capacitance effect substantially contributes to the colossal permittivity in In and Nb co-doped TiO 2 (INTO) ceramics. Therefore, enhancing grain boundary density and ceramic compactness can efficaciously reduce their low-frequency dielectric loss . In this investigation, Bi 2 O 3 addition was utilized to aid sintering and refine grains for INTO ceramics. The results reveal that Bi-doped INTO ceramics, in contrast to their undoped counterparts, exhibit a more refined and compact grain structure with a significant increase in the quantity of grain boundaries. Moreover, a noticeable reduction in low-frequency dielectric loss from above 0.1 to below 0.05 and enhanced frequency stability of permittivity from below 10 Hz to approximately 10 kHz were observed, along with a decrease in the sintering temperature to 1300 °C. In comparison to undoped INTO ceramics, Bi doping also enhances the withstand voltage capability by a factor of 1.5–4 for Bi-doped INTO ceramics. However, as the sintering temperature of Bi-doped INTO ceramics increases and the grain size enlarges, their breakdown voltage gradually decreases, but the non-linear coefficient of current-voltage characteristics progressively increases. Analysis of complex impedance spectra confirms that the increased grain boundary density and resistance in Bi-doped INTO ceramics is the primary factor for the enhanced dielectric properties and withstand voltage capability.
研究领域:
材料科学
·
电子工程
✓ 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）