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Room-temperature-densified H_(3)BO_(3) microwave dielectric ceramics with ultra-low permittivity and ultra-high Qf value

2016年全国压电和声波理论及器件应用研讨会

作者： Biao LU Zhen-hua TANG Dan-dan LI Ying-bang YAO Bo LIANG Tao TAO Shao-ping LI Sheng-guo LU Guangdong Provincial key laboratory of Functional Soft Condensed Matter School of Materials and Energy Guangdong University of Technology

Background, Motivation and Objective Relaxor ferroelectrics possess a glassy polar phase, in which nanosized polar domains are distributed randomly throughout the volume of the material. Thus, the multiple possible orientations of the polar domains might generate an enhanced ECE according to recent calculation. On the other hand, an antiferroelectric to ferroelectric phase transition will be induced when a large enough electric field is applied. During this process, the reorientation of the two opposite dipoles in a unit cell may lead to a large entropy change. In addition, a significant electrocaloric(ECE) is usually associated with the phase transition. Since antiferroelectrics have more types of phase transition than their ferroelectric counterparts, they are also likely to have higher ECEs. Statement of Contribution/Methods In this study, two PLZT compositions(PbLa(ZrTi)O and PbLa(ZrTi(0.18))O) were designed, fabricated and their ECE are characterized directly, and also compared with Maxwell relation and Landau-Ginzburg-Devonshire phenomenological theory derived results. Results Two compositions of this work show relatively large directly measured ECE values, i.e., the electrocaloric efficiencies(ΔT/ΔE) are 0.43 and 0.40, which are largest ones among published data for ceramics. Also, both ECE data are larger than Maxwell relation derived results, but comparable with LGD theory derived ones for relaxor ferroelectrics, and smaller for antiferroelectrics. Discussion and Conclusions The ECE of the relaxor ferroelectric PbLa(ZrTi)O and antiferroelectric PbLa(ZrTi)O ceramics was calculated using the Maxwell relation and Landau-Ginzburg-Devonshire(LGD) phenomenological theory and measured by a thermometer and electric field controlled by a computer directly. The microstructures and phase compositions of the samples were also investigated and discussed in connection with the ECE results. The relaxor ferroelectric PbLa(ZrTi)O and antiferroelectric PbLa(ZrTi)O ceramics

关键词： (PbLa)(ZrTi)O3 Relaxor ferroelectrics Antiferroelectrics Polarization Electrocaloric effect

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Journal of Materiomics 2020年第2期6卷 233-239页

作者： Wen Bin Hong Lei Li Han Yan Shu Ya Wu Hang Sheng Yang Xiang Ming Chen laboratory of Dielectric Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou310027China

With the rapid development of mobile communication technology towards 5G and 6G,the microwave dielectric materials with ultra-low permittivity and ultra-high Qf value are urgently ***,the excellent microwave dielectric properties are reported in H3BO3 ceramics with the molecular crystal structure,whose permittivity(2.84)and density(1.46 g/cm^(3))are record-low among the low-loss *** ultra-high Qf value of 146,000 GHz(or the ultra-low dielectric loss of 1.03×10^(-4) at 15 GHz)is also ***,the H_(3)BO_(3) ceramics can be densified at room temperature by a simple cold sintering process in a short time of 10 min,and this brings many advantages for the integration with microwave *** large molecule volume originating from the molecular crystal structure and the low dielectric polarizabilities of H^(+) and B^(3+) are responsible for the ultra-low permittivity of H_(3)BO_(3) ceramics,and more microwave dielectric materials with ultra-low permittivity and ultra-high Qf value are expected to be explored in the molecular crystals.

关键词： Boric acid Microwave dielectric ceramics Room-temperature cold sintering Ultra-low permittivity

Effect of sintering temperature on thermoelectric properties of CdO ceramics

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Journal of Advanced ceramics 2015年第3期4卷 226-231页

作者： Xinran ZHANG Huiling LI Jianglong WANG Hebei key Lab of Optic-electronic Information and Materials College of Physics Science and TechnologyHebei UniversityBaoding 071002China

The effect of sintering temperature on thermoelectric properties of CdO ceramics was investigated by solid-state reaction method within the temperature range of 700-1000℃.With the increase of sintering temperature,both the grain size and the carrier concentration of these samples increased,while the Seebeck coefficient *** highest dimensionless figure of merit ZT,0.34,was obtained at 1023 K for the sample sintered at 800℃,suggesting the potential application of CdO ceramics in thermoelectric(TE)devices.

关键词： thermoelectric(TE) CdO ceramics sintering temperature solid-state reaction

Phase diagram and dielectric properties of Pb(In_(1/2)Nb_(1/2))O_(3)-Pb(Mg_(1/3)Nb_(2/3))O_(3)-PbTiO_(3) ceramics

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Journal of Advanced Dielectrics 2015年第2期5卷 67-71页

作者： Dabin Lin Haohua Chen Zhenrong Li Zhuo Xu Electronic Materials Research laboratory key laboratory of Education Ministry/International Center for Dielectric Research Xi'an Jiao Tong University Xi'an 710049P.R.China laboratory of Thin Film Techniques and Optical Test Xi'an Technological University Xi'an 710032P.R.China

xPb(In_(1/2)Nb_(1/2))O_(3)–yPb(Mg_(1/3)Nb_(2/3))O_(3)–zPbTiO_(3)(xPIN–yPMN–zPT)ternary ceramics with morphotropic phase boundary(MPB)composition were synthesized by columbite precursor ***–yPMN–zPT phase diagram was investigated by x-ray diffraction and dielectric *** to the results of dielectric measurements,the Curie temperatures(Tc)and rhombohedral to tetragonal phase transition temperature(T_(r-t))were found to be in the range of 173–212℃and 114–155℃,respectively,indicating that the _(Tr-t) was increased with adding PIN *** the MPB region,the highest T_(r-t)=155℃was found in 0.32PIN–0.38PMN–0.30PT ceramic,that greatly expanded temperature usage range.

关键词： Relaxor ferroelectric dielectric phase diagram.

Optimization of synergistic energy storage density and efficiency for eco-friendly (Na_(0.5)Bi_(0.5))_(0.6)Sr_(0.4)TiO_(3)-based relaxor ferroelectric ceramics

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Journal of Materiomics 2021年第4期7卷 869-878页

作者： Hu Di Pan Zhongbin Wu Lukang Yang Fan Tang Luomeng Zhao Jinghao Shen Yihao Chen Yuyun Li Peng Zhai Jiwei Liu Jinjun School of Materials Science and Chemical Engineering Ningbo UniversityNingboZhejiang315211China Guangxi key laboratory of Chemistry and Engineering of Forest Products Guangxi University for NationalitiesNanning530006China School of Materials Science and Engineering Liaocheng UniversityLiaocheng252059China School of Materials Science&Engineering Tongji University4800 Caoan RoadShanghai201804China

Inspired by increasing demand of advanced pulsed power capacitors,the development of lead-free dielectric ceramic capacitors with high energy storage density and temperature-insensitive performance are extremely ***,the lead-free relaxor ferroelectric ceramics based on(1-x)(Na_(0.5)Bi_(0.5))0.6Sr_(0.4)TiO_(3-x)Sr_(0.7)La_(0.2)ZrO_(3)[abbreviated as(1-x)NBST-xSLZ]are prepared by the solid-state reaction *** large recoverable energy density(Wrec)of 3.45 J/cm^(3) and efficiency(h)of 90.1%are simultaneously realized in 0.86NBST-0.14SLZ ceramic due to increased breakdown ***,both the Wrec and h of 0.86NBST-0.14SLZ ceramic display superior of thermal stability(20e180C),frequency stability(1e1000 Hz),and cycle stability(10^(4))within a satisfactory range of *** addition,the 0.86NBST-0.14SLZ ceramic can also achieve a large current density(CD)of 625 A/cm^(2),an ultrahigh power density(PD)of 50 MW/cm^(3) and a fast discharge rate(t0.90)of 160.8 ns at 160 kV/*** results demonstrate that the 0.86NBST-0.14SLZ ceramic could be a highly competitive and ecofriendly relaxor ferroelectric material for next-generation pulsed power capacitors.

关键词： Lead-free ceramics Energy storage density (Na_(0.5)Bi_(0.5))_(0.6)Sr_(0.4)TiO_(3) Thermal stability Power density

A novel lead-free Na_(0.5)Bi_(0.5)TiO_(3)-based ceramic with superior comprehensive energy storage and discharge properties for dielectric capacitor applications

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Journal of Materiomics 2020年第4期6卷 743-750页

作者： Da Li Ying Lin Qibin Yuan Miao Zhang Liang Ma Haibo Yang Shaanxi key laboratory of Green Preparation and Functionalization for Inorganic Materials School of Materials Science and EngineeringShaanxi University of Science and TechnologyXi’an710021China School of Electronic Information&Artificial Intelligence Shaanxi University of Science and TechnologyXi’an710021China Xianyang Non-metallic Mineral R&D Institute Co. LtdXianyang712021China

Na_(0.5)Bi_(0.5)TiO_(3)(NBT)-based ceramics have been widely used as dielectric materials for energy storage capacitors because of their environmental friendliness and excellent ferroelectric ***,their energy storage performance still needs to be further improved to satisfy the increasing ***,we report a novel 0.90(Na_(0.5)Bi_(0.5))0.7Sr_(0.3)TiO_(3-0.10)Bi(Ni_(0.5)Sn_(0.5))O_(3)(0.90NBST-0.10BNS)ceramic with significantly improved energy density(5.0 J cm3),enhanced recoverable energy density(4.18 J cm^(3))and high energy efficiency(83.64%)through the incorporation of Bi(Ni0.5Sn0.5)O3(BNS),due to the increased breakdown strength and the relaxation ferroelectric(RFE)*** first-order reversal curve(FORC)measurements confirm that the addition of BNS improves RFE properties by breaking the order of long-range *** 0.90NBST-0.10BNS ceramic also possesses an outstanding temperature and frequency stability of energy storage properties in the range of 20C e140C and 1 Hze100 Hz,*** importantly,the discharge properties characterized by a preeminent power density(36.19 MW cm^(3)),transient energy release times(144.2 ns),and high discharge energy density(1.16 J cm3)also synchronously observed in 0.90NBST-0.10BNS *** results show that the 0.90NBST-0.10BNS ceramic with outstanding comprehensive performances is a promising energy storage ceramic candidate for capacitors in high power systems.

关键词： Na_(0.5)Bi_(0.5)TiO_(3) Ferroelectric properties Energy density Temperature stability Power density

Enhanced pyrocatalysis of the pyroelectric BiFeO_(3)/g-C_(3)N_(4) heterostructure for dye decomposition driven by cold–hot temperature alternation

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Journal of Advanced ceramics 2021年第2期10卷 338-346页

作者： Mingzi Chen Yanmin Jia Huamei Li Zheng Wu Tianyin Huang Hongfang Zhang College of Physics and Electronic Information Engineering Zhejiang Normal UniversityJinhua321004China School of Science Xi’an University of Posts and TelecommunicationsXi’an710121China College of Environmental and Chemical Engineering Xi’an Polytechnic UniversityXi’an710048China Jiangsu key laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and Technology and School of Environmental Science and EngineeringSuzhou University of Science and TechnologySuzhou215009China

The BiFeO_(3)/g-C_(3)N_(4) heterostructure,which is fabricated via a simple mixing–calcining method,benefits the significant enhancement of the pyrocatalytic *** the growth of g-C_(3)N_(4) content in the heterostructure pyrocatalysts from 0 to 25%,the decomposition ratio of Rhodamine B(RhB)dye after 18 cold-hot temperature fluctuation(25-65℃)cycles increases at first and then decreases,reaching a maximum value of~94.2%at 10%while that of the pure BiFeO_(3) is~67.7%.The enhanced dye decomposition may be due to the generation of the internal electric field which strengthens the separation of the positive and negative carriers and further accelerates their *** intermediate products in the pyrocatalytic reaction also have been detected and confirmed,which proves the key role of the pyroelectric effect in realizing the dye decomposition using BiFeO_(3)/g-C_(3)N_(4) heterostructure *** pyroelectric BiFeO_(3)/g-C_(3)N_(4) heterostructure shows the potential application in pyrocatalytically degrading dye wastewater.

关键词： pyroelectric material BiFeO_(3) g-C_(3)N_(4) heterostructure pyrocatalysis

Robust,fire-resistant,and thermal-stable SiZrNOC nanofiber membranes with amorphous microstructure for high-temperature thermal superinsulation

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Journal of Advanced ceramics 2023年第1期12卷 36-48页

作者： Xiaoshan ZHANG Nana XU Yonggang JIANG Haiyan LIU Hui XU Cheng HAN Bing WANG Yingde WANG Science and Technology on Advanced Ceramic Fiber and Composites laboratory College of Aerospace Science and EngineeringNational University of Defense TechnologyChangsha 410073China

Ceramic nanofibers with robust mechanical properties,high-temperature resistance,and superior thermal insulation performance are promising thermal insulators used under extreme ***,developing of ceramic fibers with both low solid thermal conductivity(λs)and low infrared radiation thermal conductivity(λr)is still a great ***,according to the Ioffe-Regel limit theory,we report a novel SiZrNOC nanofiber membrane(NFM)with a typically amorphous structure by combining the electrospinning method and high-temperature pyrolysis technique in a NH3 *** prepared SiZrNOC NFM has a high tensile strength(1.98±0.09 MPa),excellent thermal stability(1100℃in air),and superior thermal insulation *** thermal conductivity of SiZrNOC NFM was 0.112 W·m^(−1)·K^(−1) at 1000℃,which is obviously lower than that of the traditional ceramic fiber membranes(>0.2 W·m^(−1)·K^(−1) at 1000℃).In addition,the prepared SiZrNOC NFM-reinforced SiO2 aerogel composites(SiZrNOCf/SiO2 ACs)exhibited ultralow thermal conductivity of 0.044 W·m^(−1)·K^(−1) at 1000℃,which was the lowest value for SiO2-based aerogel composites ever *** superior thermal insulation performance of SiZrNOC NFMs was mainly due to significant decreasing of solid heat conduction and thermal radiation by the fancy amorphous microstructure and high infrared shielding *** work not only provides a promising high-temperature thermal insulator,but also offers a novel route to develop other high-performance thermal insulating materials.

关键词： amorphous microstructure SiZrNOC nanofiber thermal stability thermal insulation

Preparation and 1.06μm Fluorescence Decay of Nd3+-Doped Glass ceramics Containing NaYF4 Nanocrystallites

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Chinese Physics Letters 2019年第8期36卷 51-55页

作者： Xing-Yong Huang Da-Qin Chen Bi-Zhou Shen Hai-Zhi Song Southwest Institute of Technical Physics Chengdu610041 School of Physics and Electronic Engineering Yibin UniversityYibin644007 College of Physics and Energy and Fujian Provincial Key Laboratory of Quantum Manipulation and New EnergyMaterialsFujian Normal UniversityFuzhou350117 ENREACH Education(ChengDu)of Dipont Education Management Group Chengdu617000 Institute of Fundamental and Frontier Sciences University of Electronic Science and Technology of ChinaChengdu610054

Considered to be a candidate for large-size bulk materials used in lasers and other fields,Nd3+-doped glass ceramics containing NaYF4 nanocrystallites are *** x-ray diffraction and transmission electron microscopy,we show that pure cubic NaYF4 is well precipitated in the glass *** obtain the optical property of this material at 1.06 μm,the fluorescence decay of 4F3/2 energy levels is measured and *** is found that the fluorescence lifetime decreases first and then increases with the increasing dopant concentration due to the existing but finally weakening energy *** a result,a long radiation lifetime of about 191-444μs is obtained at 1.06μm in the prepared *** is thus revealed that Nd3+-doped glass ceramic containing NaYF4 nanocrystallites is a potential candidate as a near-infrared laser material.

关键词： Nanocrystallites Preparation Fluorescence