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
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Xinwei Geng,Yongfeng Xia,Hanqin Liang,Dongxu Yao,Yu-Ping Zeng
Magnéli phases are an important class of transition metal oxides widely utilized in fields such as batteries, electrocatalysis , and photocatalysis . However, there are no reports on the use of Magnéli phases as additives in ceramic sintering. In order to explore the impact of the Magnéli phase as an additive on the sintering process, self-made Magnéli phase Ti 4 O 7 powder was added to the graded mixture of titanium dioxide (TiO 2 ) coarse powder and nanopowder , and sintered under atmospheric conditions in this study. The sintering characteristics, microstructure, and mechanical properties of TiO 2 ceramics with different content of Ti 4 O 7 were characterized. The results revealed that the addition of Ti 4 O 7 contributed to the reduction of the densification temperature of TiO 2 ceramics. Compared to the undoped sample, the addition of 1 wt% Ti 4 O 7 powder significantly improved the flexural strength and Vickers hardness of TiO 2 ceramics by 13.5% and 24.8%. According to the results of thermal analysis, UV–Vis–NIR, and XPS, the mechanism of Ti 4 O 7 in the sintering process of TiO 2 ceramics under atmospheric conditions was systematically discussed. This work not only obtained TiO 2 ceramics with improved performance but also showed the tremendous potential of Magnéli phases in the field of ceramic sintering.
研究领域:
材料科学
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陶瓷
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烧结技术
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机械工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Shuai Yan,Sen Wang,Gaobin Liu,Qi Yuan,Kuoming Song,He Zhao,Xin Li,Rongzheng Shen
Herein, MgO–12 % TiO 2 (w) ceramics with different contents of Bi 2 O 3 –CuO sintering aid were prepared using a solid-state method. The effects of the sintering aid content on the sintering temperature and the dielectric and mechanical properties of the ceramics were studied. The material was characterized using scanning electron microscopy and X-ray diffraction and Precision LCR tester and universal testing machine and Archimedes drainage method. When the Bi 2 O 3 –CuO content was less than 9 wt%, the ceramic sample has higher dielectric properties. When the Bi 2 O 3 –CuO content was greater than 9 wt%, the dielectric properties will deteriorate. This is because Bi 2 O 3 participates in the chemical reaction between MgO and TiO 2 , forming a high dielectric loss Bi 4 Ti 3 O 7 phase. At high temperatures, Cu 2+ can easily change valence to Cu + , promoting oxygen vacancies and increasing dielectric loss in ceramic samples. The introduction of Bi 2 O 3 –CuO produces new MgTiO 3 , Mg 2 TiO 4 , and Bi 4 Ti 3 O 12 phases in the sample structure, resulting in a structure in which the MgO grains in the sample are surrounded by the new phases that appear around them. This structure fills the pores, increases density, enhances mechanical properties. The dielectric properties of the ceramics were the when the sintering temperature was 1050 °C, and the Bi 2 O 3 –CuO content was 3 wt%. The dielectric constant and dielectric loss were 11.19 and 1.17 × 10 −4 , respectively. The bending strength of the ceramic sample increased from 138.72 MPa to 179.64 MPa when the Bi 2 O 3 –CuO content was increased from 3 wt% to 15 wt%. The Bi 2 O 3 –CuO sintering aid enables MgO to be better applied in ceramic substrates.
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
CERAMICS INTERNATIONAL
·
2020
·
IF 3.83
Jingxuan Li,Yu Zeng,Yihang Fang,Nan Chen,Guoping Du,Aisheng Zhang
In this work, a sol-gel method was used to synthesize nanometer-sized rutile (La + Nb) co-doped TiO 2 powders, which were employed to prepare (La + Nb) co-doped TiO 2 ceramics. The average grain size of the (La + Nb) co-doped TiO 2 ceramics was less than 200 nm, which is much smaller than that of conventionally prepared co-doped TiO 2 ceramics generally having micron-sized grains. The effect of the (La + Nb) co-doping concentration on the microstructures and dielectric properties of the obtained ceramics was studied in detail. For a 2% co-doping concentration, it was found that the (La + Nb) co-doped TiO 2 ceramic had dielectric permittivity (εʹ) higher than 2 × 10 4 for frequency up to 1 MHz and the lowest dielectric loss (tanδ) was 0.019 at 1 kHz. The electron hopping and electron-pinned defect-dipole effect was considered as the main reasons for colossal permittivity and low tanδ. This work provides a technique for the synthesis of co-doped TiO 2 nanoparticles and preparation of submicron-grain-sized co-doped TiO 2 ceramics with good dielectric properties.
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 THE EUROPEAN CERAMIC SOCIETY
·
2018
·
IF 3.794
Jinshuang Wang,Junbin Sun,Qiangshan Jing,Bing Liu,Hao Zhang,Yu Yongsheng,Jieyan Yuan,Shujuan Dong,Xin Zhou,Xueqiang Cao
The properties of ZrO 2 co-stabilized by CeO 2 and TiO 2 ceramic bulks were investigated for potential thermal barrier coating (TBC) applications. Results showed that the (Ce 0.15 Ti x )Zr 0.85-x O7 (x = 0.05, 0.10, 0.15) compositions with single tetragonal phase were more stable than the traditional 8YSZ at 1573 K. These compositions also showed a large thermal expansion coefficient (TEC) and a high fracture toughness, which were comparable to those of YSZ. However, the phase stability, fracture toughness and sintering resistance of the CeO 2 -TiO 2 -ZrO 2 system showed a decline tendency with the increase of TiO 2 content. The TEC of the ceramic bulks decreased with increase of TiO 2 content as well because the crystal energy was enhanced with increasing substitution of Zr 4+ by smaller Ti 4+ . The (Ce 0.15 Ti 0.05 )Zr 0.8 O 2 had the best comprehensive properties among the (Ce 0.15 Ti x )Zr 0.85-x O 2 compositions as well as a low thermal conductivity . Therefore, it can be explored as a TBC candidate material for high-temperature applications.
研究领域:
材料科学
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热力学工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Advanced Ceramics
·
2018
·Vol. 7
·期 2
·152-159
·
IF 1.605
Wu Jia-Min,Xiao Huan,Liu Meng-Yue,Chen Ying,Ma Yi-Xin,Cheng Li-Jin,Shi Yu-Sheng
In this paper, in-situ coagulation of 0.9Al 2 O 3 –0.1TiO 2 suspension and microwave dielectric properties of 0.9Al 2 O 3 –0.1TiO 2 ceramics prepared by a novel direct coagulation casting via high valence counter ions (DCC-HVCI) method were proposed. The 0.9Al 2 O 3 –0.1TiO 2 suspension could be coagulated via controlled release of calcium ions from calcium iodate at an elevated temperature. The influence of tri-ammonium citrate (TAC) content, solid loading, and calcium iodate content on the rheological properties of the suspension was investigated. In addition, the influence of coagulation temperature on coagulation time and properties of green bodies was also studied. It was found that the stable 0.9Al 2 O 3 –0.1TiO 2 suspension could be successfully prepared by adding 0.3 wt% TAC and adjusting pH value to 10–12 at room temperature. 0.9Al 2 O 3 –0.1TiO 2 green bodies with uniform microstructures were coagulated by adding 8.0 g/L calcium iodate after treating at 70 °C for 1 h. 0.9Al 2 O 3 –0.1TiO 2 ceramics, sintered at 1500 for 4 h and annealed at 1100°C for 5 h, showed °Cuniform microstructures with density of 3.62±0.02 g/cm 3 . The microwave dielectric properties of 0.9Al 2 O 3 –0.1TiO 2 ceramics prepared by DCC-HVCI method were: ε r = 11.26±0.06, Q × f = 11569±629 GHz, τ
f
= 0.93±0.60 ppm/°C. The DCC-HVCI method is a novel and promising route without binder removal process to prepare complex-shaped microwave dielectric ceramics with uniform microstructures and good microwave dielectric properties.
研究领域:
材料科学
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陶瓷学
✓ 已验证
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2023
·
IF 4.6
Qi Yuan,Yutong Meng,Sen Wang,Gaobin Liu,Qiyao Wang,Kuoming Song,He Zhao,Shuai Yan,Xin Li
The effects of different contents of B 2 O 3 -Bi 2 O 3 on the sintering temperature and dielectric properties of MgO-12%TiO 2 (w) ceramics were investigated. B 2 O 3 -Bi 2 O 3 addition effectively reduced the sintering temperature and improved the dielectric properties of ceramic samples; however, an excessive amount of B 2 O 3 -Bi 2 O 3 led to the deterioration of dielectric properties. This is because Bi 2 O 3 participated in the chemical reaction between MgO and TiO 2 and generated a high-dielectric-loss Bi 2 Ti 2 O 7 phase, resulting in an increased dielectric loss in the ceramic samples. In contrast, B 2 O 3 formed a liquid phase to fill the grain gaps and pores during sintering, improving the densities of the ceramic samples. An appropriate amount of B 2 O 3 -Bi 2 O 3 accelerated the reaction between MgO and TiO 2 and formed ultralow-dielectric-loss phases—MgTiO 3 and Mg 2 TiO 4 , and the dielectric losses of the ceramic samples decreased to an order of 10 −5 .
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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Qun Diao,Yong Zeng,Jimin Chen
With the rapid advancement of 5G communication technology, higher communication frequencies have pushed the development of the Luneburg lens (LL) towards greater integration and miniaturization. In this paper, a novel Zn 2 SiO 4 -TiO 2 (ZST) ceramic Flat Luneburg Lens (FLL) for the K-band is designed and successfully fabricated using vat-photopolymerization (VPP) 3D printing technology. By optimizing the rheological properties of the slurry alongside the photopolymerization and thermal treatment processes, the resulting ZST ceramic exhibits excellent microwave dielectric properties after sintering at 1250 °C: a dielectric constant ( εᵣ ) of 9.6933, a quality factor ( Q×f) reaching 85294 GHz, a frequency temperature coefficient ( τ f ) close to zero (-0.78 ppm/°C), and an extremely low dielectric loss (1.29×10 -4 ). Building upon this high-performance ZST ceramic, a miniaturized FLL with a diameter of 30 mm and a thickness of 4 mm was successfully fabricated via metamaterial structural design. The measured results indicate that the FLL achieved a maximum gain enhancement of 5.5 dBi. This work offers useful insights into the 3D printing manufacturing of high-performance microwave dielectric ceramics and their application in miniaturized and integrated radio frequency devices.
研究领域:
材料科学
·
通信工程
·
电子器件
·
增材制造
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Zhijian Wang,Lanlan Liu,Qifeng Du,RuiTao Tang,Jun Ai,Ying Chen
Ti-related oxide ceramics often exhibit excellent microwave dielectric properties and are widely applied in the microwave communication field. However, their microwave dielectric properties are often influenced by unstable defects, which are caused by the relatively low oxygen partial pressure at high sintering temperatures . In this work, Al 2 O 3 was introduced to improve the defect structures of the 0.85CeO 2 -0.15TiO 2 ceramics. According to the XPS pattern and AC conductivity analysis, Al 2 O 3 doping could stabilize the valence state of Ti but increase the oxygen vacancy concentration. Q × f first increased and then decreased as the Al 2 O 3 content increased. The highest Q × f value of 54361 GHz was obtained for the CTA0.015 sample sintered at 1275 °C, as well as the ε r of 29.41 and τ f of +7.8 ppm/°C. Finally, the CTA0.015 sample was used to prepare a microstrip antenna via the screen-printing process, which exhibited a good temperature-independent resonant frequency and indicated good application prospects.
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
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Lin Li,Jiawei Zhao,Shaohua Luo,Pengyue Xing,Xinglong Teng,Zhenzhu Cao,Guorong Li
Materials with colossal permittivity (CP) have been extensively investigated for their promising applications in energy storage devices. In this work, the composition, microstructure and dielectric properties of (Na 0.25 Ta 0.75 ) x Ti 1–x O 2 (x = 0–0.04) ceramics were systematically investigated. Co-doped TiO 2 ceramics demonstrated giant dielectric constants. The optimized dielectric properties were achieved in (Na 0.25 Ta 0.75 ) 0.02 Ti 0.98 O 2 with high dielectric constant (7.32 × 10 4 ) and low loss (0.034) at 1 kHz. The origin of CP was explored by dielectric, complex impedance spectroscopy and X-ray photoelectron spectroscopy measurements. The giant dielectric constant primarily stems from the electronic pinning defect dipole effect and the internal barrier layer capacitance effect. This finding might shed light on the design of high-performance giant dielectric materials.
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
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Wei Zhou,Minghe Cao,Hongye Wang,Hua Hao,Zhonghua Yao,Hanxing Liu
The miniaturization of electronic components requires materials with colossal permittivity. In this work, titanium-powder-doped TiO 2 ceramics with colossal permittivity and a low dielectric loss over a wide range of frequency and temperature were successfully prepared using a solid-state reaction in an Ar atmosphere. TiO 2 ceramics with 2% Ti powder doping had the highest permittivity (110,000) and the lowest dielectric loss (0.029) at 1 kHz and room temperature. Systematic defect analysis showed that Ti 4+ was successfully reduced to Ti 3+ through doping with Ti metal powder. Further, oxygen vacancies were created in the high-temperature inert atmosphere, which promoted the formation of defect clusters with T i 3 + − V o ″ − T i 3 + as the core. Polarization and local confinement of the defect clusters resulted in the colossal permittivity and low dielectric loss. Therefore, this work provides necessary information and novel ideas for the design of correlated defects in colossal permittivity materials.
研究领域:
材料科学
·
电气工程
·
陶瓷
·
缺陷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2023
·Vol. 57
·期 1
·015301
·
IF 3.4
Xiao Zhang,Zhe Xiong,Bin Tang,Chengtao Yang
The rapid advancement of mobile communications technology is imposing greater demands on electronic components. Microwave dielectric ceramics with a high dielectric constant (r) are crucial for the miniaturization and integration of microwave devices. Herein, The perovskite-structured (Ca0.61Nd0.26)1−x(Li0.5Nd0.5)xTiO3 (0 ⩽ x ⩽ 0.8) microwave dielectric ceramics with high r value were prepared by solid-state reaction method. The results demonstrated that the r value reached its peak at x = 0.6, which was influenced by the bond valence at B-sites. The τf and Q× f values decreased with increasing x value. Doping (Li0.5Nd0.5)2+ at A-sites led to an increase in the full width at half maximum of Raman peaks, indicating higher internal loss. A high dielectric constant and temperature-stable (Ca0.61Nd0.26)0.27(Li0.5Nd0.5)0.73TiO3 ceramic can be sintered with good microwave dielectric properties of r = 129.4, Q× f= 2,787 GHz, and τf = +1.9 ppm/°C.
研究领域:
材料科学
·
电气工程
·
微波技术
·
陶瓷
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）