Article
Engineering, Electrical & Electronic
Fengchao Peng, Xin Liao, Yong Pu, Dachuan Zhu
Summary: The appropriate doping of Sb2O3 can promote grain coarsening in TiO2 varistor ceramics, but excessive doping inhibits grain growth. The sintering process oxidizes Sb3+ ions to Sb5+ ions, releasing free electrons and decreasing resistivity, leading to a continuous decline in breakdown voltage with increasing Sb2O3 doping content. The relative dielectric constant and nonlinear coefficient initially increase with Sb2O3 doping, reaching maximum values at 0.2 mol% before decreasing, but dielectric loss is negatively affected and the ratio of Sb3+/Sb5+ should be controlled for optimal performance.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2021)
Article
Materials Science, Ceramics
Yuechan Song, Peng Liu, Wenwen Wu, Quan Zhou
Summary: Al0.15Nb0.15Ti0.7O2 ceramics were synthesized via strong magnetic field alignment at 6 T and sintered under a nitrogen atmosphere. A ceramic prepared at 6 T by polishing it along the direction parallel to the magnetic field (parallel-6 T) with a brick-layered microstructure shows a colossal permittivity of ?r ?8.2 ? 104 and a low dielectric loss of tan ? ?0.019 at 1 kHz, with impedance spectroscopy suggesting that the colossal permittivity is attributed to internal barrier layer capacitor effects. XRD results indicate that approximately 90 % of the grains are aligned along the magnetic field with a tilt angle less than 10?. The average width and length of the grains for parallel-6 T ceramics are 4.1 ?m and 9.4 ?m. Compared to non-magnetically treated Al0.15Nb0.15Ti0.7O2 ceramics, the high grain boundary resistance (1.6 ? 108 ? cm) of the parallel-6 T ceramic can be responsible for this low dielectric loss.
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
(2021)
Article
Materials Science, Ceramics
Lin Zhou, Mingjia Jiang, Yaqiong Sun, Dong Yang, Jinhua Xu, Zhanhui Peng, Di Wu, Lingling Wei, Pengfei Liang, Xiaolian Chao, Zupei Yang
Summary: In this study, various (Cu0.5W0.5)xTi1-xO2 (CWTOx) ceramics were fabricated by a traditional solid reaction method, showing a high permittivity (epsilon r>104), low dielectric loss (tan delta < 0.1), and good temperature stability within a broad frequency/temperature range for CWTO0.015 ceramic, which meets the application requirement of X8R. Abnormal dielectric relaxation phenomena at low and high temperature regions were explained by interface polarization and ionization of oxygen vacancies, respectively, and the CP performance of CWTOx ceramics was predominantly influenced by the interface barrier layer capacitance effect according to complex impedance, XPS, and EPR results. This finding is expected to promote the further development and application of CP materials.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Ceramics
Xu Guo, Jingrui Kang, Rui Gu, Honglei Hao, Yi Tang, Li Jin, Xiaoyong Wei
Summary: In this work, Ti1-x(Tm0.5Nb0.5)xO2 (TTNOx) ceramics were prepared via the solid state method, and low dielectric loss and colossal permittivity were achieved through defect regulation. This study has important implications for the application of colossal permittivity ceramic materials.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
Xiao-gang Zhao, Lin Chen, Xiang-yu Zhang, Peng Liu, Chun-Long Xu, Zhao-Yang Hou, Zhen Wang, Feng-Long Wang, Jin-Guo Wang, Gang Shi
Summary: Al3+ and Nb5+ co-doped rutile TiO2 ceramic samples were prepared by solid state reaction, showing colossal permittivity with abnormal multiple dielectric relaxation properties. The high dielectric constant is attributed to thermal activation of electrons, polaron hopping polarization, and interfacial polarization.
JOURNAL OF ALLOYS AND COMPOUNDS
(2021)
Article
Materials Science, Multidisciplinary
Yang Yu, Yu Zhao, Yu-Long Qiao, Yu Feng, Wei-Li Li, Wei-Dong Fei
Summary: A strategy to enhance the voltage stability of co-doped TiO2 ceramics has been proposed, resulting in the successful design and synthesis of high-performance CP materials (Ta +Al + La) co-doped TiO2, which exhibit colossal permittivity, excellent temperature stability, and outstanding dc bias stability. The results and mechanisms provide a feasible route to design high-performance CP materials via defect engineering.
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
(2021)
Article
Materials Science, Ceramics
Wei Zhou, Minghe Cao, Hongye Wang, Hua Hao, Zhonghua Yao, Hanxing Liu
Summary: In this study, TiO2 ceramics doped with titanium powder were prepared using a solid-state reaction in an Ar atmosphere, exhibiting colossal permittivity and low dielectric loss over a wide frequency and temperature range. The addition of titanium metal powder successfully reduced Ti4+ to Ti3+, while the high-temperature inert atmosphere created oxygen vacancies and promoted the formation of defect clusters with Ti3+- V-o - Ti3+ as the core. The polarization and local confinement of the defect clusters resulted in the colossal permittivity and low dielectric loss. This work provides important insights and new ideas for the design of correlated defects in colossal permittivity materials.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Zhi Jiang, Mengyang Shi, Zhentao Wang, Juan Liu, Lei Zhang, Yongtao Jiu, Bin Tang, Dong Xu
Summary: In this study, (Ca, Sb)-co-doped TiO2 ceramics were prepared and systematically investigated for their structure, properties, and mechanism. The optimal dielectric performance was observed when the doping amount was x=4%, providing critical insights for the development of new TiO2-based giant dielectric ceramics.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Chemistry, Physical
Jiangtao Fan, Zhen Long, Haitao Zhou, Gang He, Zhanggui Hu
Summary: (Tm+Nb) co-doped TiO2 ceramics were prepared and their phase, microstructure, and dielectric properties were investigated. The ceramics with a co-doping concentration of 0.01 exhibited ultralow dielectric loss and colossal permittivity, showing excellent temperature and frequency stability in a certain range. The dielectric properties of the ceramics were influenced by several factors.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
Ku Noor Dhaniah Ku Muhsen, Rozana Aina Maulat Osman, Mohd Sobri Idris
Summary: This study investigates the dielectric behavior and microstructural analysis of (Nb, La) co-doped TiO2 ceramic. The presence of secondary phase LaNbTiO6 affects the properties of the ceramic, and different materials and sintering temperatures lead to different results.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Ceramics
Jiangtao Fan, Yimeng Chen, Zhen Long, Gang He, Zhanggui Hu
Summary: This study successfully achieved a giant dielectric constant and high energy storage density by doping TiO2 ceramics with SiO2 nanoparticles. Notably, the HTTO - 5 wt% SiO2 composite ceramic exhibited low dielectric loss and ultrahigh permittivity at 1 kHz. Additionally, the ceramic showed excellent energy storage properties with high breakdown field strength and energy storage density.
CERAMICS INTERNATIONAL
(2022)
Article
Engineering, Electrical & Electronic
Tianyu Li, Wei Guo, Aiwen Xie, Cong Zhou, Dong Xu, Ruzhong Zuo
Summary: This study investigated the effect of sintering temperature on the microstructure and electrical properties of ZnO-based varistor ceramics. The results showed that higher sintering temperature led to larger grain size and increased oxygen vacancies, which degraded the varistor properties. Excellent varistor properties were observed in the ceramics sintered at 850℃.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2023)
Article
Chemistry, Physical
Jiangtao Fan, Yimeng Chen, Zhen Long, Liping Tong, Gang He, Zhanggui Hu
Summary: In this work, Tm + Ta co-doped TiO2 ceramics with ultrahigh permittivity and very low loss were prepared using a solid-state reaction method. The high dielectric constant and low dielectric loss were attributed to the electron pinned defect dipole response formed by the coupling of Ti3+ and oxygen vacancies. The impedance analysis and frequency dependent dielectric constant under a DC bias suggested that the internal barrier layer capacitance response and electrode response also contribute significantly to the dielectric constant.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Biochemistry & Molecular Biology
Noppakorn Thanamoon, Narong Chanlek, Pornjuk Srepusharawoot, Ekaphan Swatsitang, Prasit Thongbai
Summary: A novel giant dielectric (GD) oxide with extremely large dielectric permittivity and low loss tangent was reported in this study, attributed to the synthesis of Lu3+/Nb5+ co-doped TiO2 (LuNTO) ceramic with appropriate co-dopant concentration. The remarkable dielectric properties of LuNTO ceramics were due to their inhomogeneous microstructure, composed of semiconducting grains, ultra-high-resistance grain boundaries, and secondary microwave phase particles. The enhancement of grain boundary properties was identified as key to improving the overall dielectric properties of GD oxides.
Article
Materials Science, Multidisciplinary
Zhentao Wang, Liang Zhang, Juan Liu, Zhi Jiang, Lei Zhang, Yongtao Jiu, Bin Tang, Dong Xu
Summary: With the continuous development of electronic technology, the application of colossal permittivity materials is becoming more and more important. In this study, (Sr1/3Sb2/3)( x )Ti1-x O2 (SSTO) colossal permittivity ceramics were successfully prepared and their properties were analyzed. The results showed that SSTO with a doping amount of 2% exhibited the best dielectric performance.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2022)
Article
Materials Science, Multidisciplinary
Songhua Si, Zichao Ding, Ruzhong Zuo, Lei Zhang, Huawei Sun, Bing Cui, Dong Xu
Summary: This study optimized the performance of NiCrSiCuSn boron-free brazing filler metal by adding Hf element, improving the bonding strength and wear resistance with diamond, and reducing the thermal damage and graphitization of diamond.
DIAMOND AND RELATED MATERIALS
(2022)
Article
Engineering, Electrical & Electronic
Zhentao Wang, Pai Peng, Liang Zhang, Nan Wang, Bin Tang, Bing Cui, Juan Liu, Dong Xu
Summary: Flash-sintering was used to fabricate (In + Ta) co-doped TiO2 colossal dielectric ceramics, resulting in significantly reduced processing time and sintering temperature, as well as improved grain size and microstructure uniformity compared to conventional sintering. Flash-sintered samples exhibited similar electrical properties to conventionally sintered ones, with the best dielectric properties observed at 550 V/cm electric field.
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
(2022)
Article
Materials Science, Multidisciplinary
Hailing Li, Ji Chen, Bing Cui, Yucan Fu, Dan Zhao, Yujia Li, Dong Xu
Summary: The addition of Ga to Cu-Sn-Ti fillers has shown to significantly improve the mechanical properties and microstructure, resulting in increased shear strength and decreased melting point. However, a Ga content exceeding 2% has been found to decrease the shear strength of the filler metals.
PHYSICA STATUS SOLIDI A-APPLICATIONS AND MATERIALS SCIENCE
(2022)
Article
Engineering, Electrical & Electronic
Ming Jiang, Mengyang Shi, Jiamao Li, Juan Liu, Lei Zhang, Jian Qin, Yongtao Jiu, Bin Tang, Dong Xu
Summary: This study examines the effects of MnO2 on ZnO-Bi2O3-based varistors prepared using flash sintering technique. The results show that MnO2 doping significantly reduces the onset temperature and improves the electrical performance of the varistors. Among the samples, the one with 0.5 mol% MnO2 doping exhibits the highest improvement in terms of nonlinear coefficient, leakage current, threshold voltage, and dielectric constant.
MICROELECTRONICS INTERNATIONAL
(2022)
Article
Metallurgy & Metallurgical Engineering
Bing Cui, Peipei Yan, Weixing Zhao, Ruzhong Zuo, Lei Zhang, Zhan Cheng, Yongtao Jiu, Jian Qin, Yucan Fu, Dong Xu
Summary: The aim of this paper is to propose a method of improving the interfacial characteristics and wear resistance of brazed diamond by incorporating Ge element into a Cu-based composite filler. The results showed that the addition of 1 wt% Ge led to defect-free morphology and high diamond protrusion in the brazed diamond joints, increased interfacial layer thickness, and removal amount of ground tiles. Moreover, the drop rate and uneven wear rate of diamond were decreased by 12.5% and 25%, respectively.
WELDING IN THE WORLD
(2022)
Article
Materials Science, Multidisciplinary
Zexing Wang, Jiamao Li, Yunfeng Guo, Dong Xu
Summary: Nanocrystalline Nd[(Zn0.925Co0.075)(1/2)Ti-1/2]O-3 (NZCT75) powders were successfully synthesized using glycine-nitrate combustion method, showing improved microwave dielectric properties with a reduction of synthesis temperature by 600 degrees Celsius for pure phase NZCT75. Despite the presence of a large amount of pores with inhomogeneous distribution in size and shape due to rapid combustion reaction, the TEM study revealed an average particle size of around 31.9 nm for the calcined powder.
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
(2022)
Article
Materials Science, Multidisciplinary
Fengting Cao, Zequan He, Tiegang Wang, Guangyao Gao, Qixiang Fan, Yanmei Liu, Jubo Peng, Shanshan Cai, Dong Xu, Jiantao Tao
Summary: The synergistic inhibition effect of sodium phytate and benzotriazole on 20SiMn steel in seawater was studied. They form a protective bilayer film, with benzotriazole acting through chemisorption and sodium phytate through physisorption. The combination of the two shows a better inhibition efficiency.
CORROSION ENGINEERING SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Ceramics
Zhentao Wang, Tianyu Li, Jiamao Li, Feiwen Zhao, Ruzhong Zuo, Lei Zhang, Zhan Cheng, Dong Xu
Summary: (Al, Nb) co-doped TiO2 colossal dielectric ceramics were prepared using conventional sintering, flash sintering, and two-step flash sintering methods. The flash sintering and two-step flash sintering reduced processing temperature by 20% and sintering time by 30 times compared to conventional sintering. The two-step flash sintering samples with finer grain size exhibited higher permittivity. The TSFS ceramic sample sintered at 1080 degrees C showed the best overall performance with a dielectric constant of 1.4 x 105, dielectric loss of 0.57 at 1 kHz, and a nonlinear coefficient of 5.8. The excellent dielectric properties were attributed to the internal barrier layer capacitance model.
CERAMICS INTERNATIONAL
(2023)
Article
Materials Science, Multidisciplinary
Bing Cui, Pengbo Wang, Weixing Zhao, Zichao Ding, Ruzhong Zuo, Lei Zhang, Yongtao Jiu, Zhan Cheng, Jian Qin, Yucan Fu, Dong Xu
Summary: In order to improve the wear resistance and solve the thermal damage of brazed diamond, a new boron-free filler alloy Ni-Cr-Si-Cu-Sn with Zr was proposed. The microstructure of the filler alloy and the morphology of interface carbides were observed. The graphitization of brazed diamond was analyzed by Raman spectroscopy. The hardness and grinding properties of brazed diamond were measured. The results show that the composite alloy has smaller grain size, better morphology of brazed diamond, reduced graphitization and thermal damage of diamond. The addition of Zr in the alloy improved the interfacial hardness and grinding performance of diamond sample, and the uniform carbide connection ensured the high strength control of the composite alloy on the diamond.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Zhentao Wang, Haisheng Zheng, Lei Zhang, Zhan Cheng, Feiwen Zhao, Ruzhong Zuo, Tianyu Li, Dong Xu
Summary: In this study, (M0.5Ta0.5)(0.05)Ti0.95O2 (M=Al, Ga, In) ceramic materials were successfully prepared by Flash Sintering (FS) under an electric field of 550 V cm(-1) at 1200 degrees C for 18 min. The influences of different ionic radius on flash sintering behavior, crystal structure, microstructure and dielectric properties of TiO2-based colossal permittivity (CP) ceramics were systematically investigated. FS can reduce the sintering temperature by 200 degrees C and shorten the sintering time by more than 12 times. The results show that all flash sintering samples were pure rutile TiO2 structure.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Shuaishuai Feng, Tian Jin, Banglun Wang, Zhan Cheng, Chunxia Zhang, Sujuan Zhong, Dong Xu
Summary: The aim of this study is to improve the mechanical properties of diamond tools by brazing diamonds with a modified Ni-Cr filler alloy to achieve the reduction of thermal damage. Rare earth Pr doping into Ni-Cr filler alloy is brazed at 1080 degrees C under vacuum and tested for organization and properties. The results show that the doping of Pr refines the grain size and carbide, improves the bonding strength of the diamond, and reduces the thermal damage.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Materials Science, Multidisciplinary
Liang Zhang, Shuaishuai Feng, Nan Wang, Jiamao Li, Hailing Li, Dong Xu
Summary: In this study, (Sr + Sb) co-doped TiO2 colossal dielectric ceramics were successfully fabricated using flash sintering technology under an electric field of 500 V cm(-1). The flash sintering parameters, phase structure, and electrical properties of the ceramics were analyzed. Compared to conventional sintering methods, the flash sintering process reduced the sintering temperature by approximately 200 degrees C and the sintering time by 90% (18 min, 1150 degrees C). The co-doped TiO2 ceramics showed excellent dielectric properties (epsilon' > 10(4)). The successful preparation of co-doped rutile TiO2 dielectric ceramics expands the application range of flash sintering technology and holds great research significance.
ECS JOURNAL OF SOLID STATE SCIENCE AND TECHNOLOGY
(2023)
Article
Materials Science, Multidisciplinary
Nan Wang, Tian Jin, Huawei Sun, Sujuan Zhong, Guodong Wen, Zhongfang Yan, Dong Xu
Summary: In this study, the properties of Ni-based filler alloy were improved by adding rare earth Sm and brazing at a temperature of 1080°C. Tests were conducted on the filler alloy and brazed joints using electron microscopy (SEM), energy spectroscopy (EDS), and X-ray diffractometry (XRD). The results showed that the addition of rare earth Sm refined the grain of the filler alloy, increased its hardness, and reduced the thermal damage of the diamond after welding.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2023)
Article
Materials Science, Multidisciplinary
Yizhi Du, Lina Hu, Liting Dong, Shuming Du, Dong Xu
Summary: This study aims to solve the icing problem of wind turbine blades in low-temperature environments and improve the power generation efficiency of wind turbines. Modified TiO2 particles, butyl acetate solvent, polyaspartic acid ester polyurea (PAE polyurea), and Crestron N75 curing agent were mixed and sprayed on the epoxy resin board surface. The results showed that the mechanical stability and anti-icing performance of the coating were optimal when the ratio of modified TiO2 particles to PAE polyurea was 1.5. This study provides a simple method to prepare a robust superhydrophobic coating and promotes the application of superhydrophobic coatings in the field of passive anti-icing of wind turbine blades.
Article
Chemistry, Physical
Qing Ni, Yu Li, Zongchao Zhu, Zhexiang Yu, Dong Xu, Xiaoming Hua, Yi Zhen, Lin Ge, Lei Bi
Summary: The authors present a stable anode design for high-efficiency electrolysis at high current densities, integrating a nano La0.6Sr0.4CoO3-δ (LSC) catalyst network with robust microchannels. This controlled structured electrode allows rapid gas diffusion, provides sufficient active sites, and ensures firm anode-electrolyte interface adhesion, resulting in highly stable and efficient electrolysis. The as-prepared cell structure exhibits an extremely low polarization resistance of 0.010Ωcm² and demonstrates high durability at large current densities for over 100 hours at 800°C. The findings suggest the potential application of this design in high-efficiency energy conversion systems.
JOURNAL OF MATERIALS CHEMISTRY A
(2023)
