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Photoluminescence and electrical properties of Eu^3＋-doped Na0.5Bi4.5Ti4O15-based ferroelectrics under blue light excitation

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Frontiers of Materials Science 2016年第1期10卷 31-37页

作者： Xing-an JIANG Xiang-ping JIANG Chao CHEN NaTU Yun-jing CHEN Ban-chao ZHANG Jiangxi Key Laboratory of Advanced ceramic Materials Department of Materials Science and Engineering Jingdezhen Ceramic Institute Jingdezhen 333001 China

Na0.5Bi4.5-xEuxTi4O15 （NBT-xEu^3＋） ceramics with x= 0, 0.05, 0.10, 0.15, 0.20, 0.25, 0.30 and 0.40 were prepared by conventional ceramics processing. NBT-0.25Eu^3＋ ceramics show the strongest red and orange emissions corresponding to the 5D0 → 7F2 （617 nm） and 5D0→ 7F1 （596 nm） transitions, respectively. The strongest excitation band around 465 nm matches well with the emission wavelength of commercial InGaN-based blue LED chip, indicating that Eu^3＋-doped NBT ceramics may be used as potential environmental friendly red-orange phosphor for W-LEDs application. As an inherent ferroelectric and piezoelectric material, the electrical properties of this potentially multifunctional electro-optical material have been also studied. The introduction of Eu^3＋ distinctly increased the Curie temperature （Tc） of NBT-xEu^3＋ ceramics from 640℃ to 711℃ as x ranges from 0 to 0.40. For higher temperature applications, the electrical conductivity was also investigated. The conduction of charge carriers in hightemperature range originates from the conducting electrons from the ionization of oxygen vacancies. High Tc and low tanδ makes Eu^3＋-doped NBT ceramic also suitable for high temperature piezoelectric sensor applications and electro-optical integration.

关键词： Aurivillius bismuth layered structure photoluminescence electricalproperties multifunctional materials

Effects of Cr2O3 doping on the microstructure and electrical properties of （Ba,Ca）（Zr,Ti）O3 lead-free ceramics

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Frontiers of Materials Science 2016年第2期10卷 203-210页

作者： Xiang XlA Xiangping JIANG Chao CHEN Xingan JIANG Na TU Yunjing CHEN Jiangxi Key Laboratory of Advanced ceramic Materials School of Materials Science and Engineering Jingdezhen Ceramic Institute Jingdezhen 333001 China

Lead-free ceramics （Ba0.85Ca0.15）（Zr0.1Ti0.9）O3-x wt,%Cr2O3 （BCZT-xCr） were prepared via the conventional solid-state reaction method. The microstructure and electrical properties of BCZT-xCr samples were systematically studied. XRD and Raman results showed that all samples possessed a single phased perovskite structure and were close to the morphotropic phase boundary （MPB）. With the increase of the Cr content, the rhombohedral-tetragonal phase transition temperature （TR-T） increases slightly, and the Curie temperature （Tc） shifts towards the low temperature side. XPS analysis reveals that Cr3. and Cr5＊ ions co-existed in Cr-doped BCZT ceramics, indicating the different impact on the electrical properties from Cr ions as ＂acceptor＂ or ＂donor＂. For the x = 0.1 sample, relative high piezoelectric constants d33 （-316 pC/N） as well as high Qm （-554） and low tan6 （-0.8%） were obtained. In addition, the AC conductivity was also investigated. Hopping charge was considered as the main conduction mechanism at low temperature. As the temperature increases, small polarons and oxygen vacancies conduction played important roles.

关键词： lead-free ceramics electrical properties BCZT XPS analysis

Photoluminescence and electrical properties of Er3＋-dopedNa0.5Bi4.5Ti4O15-Bi4Ti3O12 inter-growth ferroelectric ceramics

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Frontiers of Materials Science 2017年第1期11卷 51-58页

作者： Yalin JIANG Xiangping JIANG Chao CHEN Yunjing CHEN Xingan JIANG Na TU Jiangxi Key Laboratory of Advanced ceramic Materials Department of Material Science and Engineering Jingdezhen Ceramic Institute Jingdezhen 333001 China

Upconversion （UC） and electrical properties of Na0.5Bi8.5-xErxTi7O27 （NBT-BIT-xEr, 0.00≤x≤0.25） ceramics were studied. Structural analysis revealed that a single inter-growth structured phase exists in all samples and the Er3＋ ion substituting for Bi3＋ at the A-site increases the orthorhombic distortion. Under the 980 nm laser excitation, two characteristic green emission bands and one red emission band were situated at 527, 548 and 670 nm, corresponding to the transitions 2H11/2 → 4I15/2, 4S3/2 → 4I15/2 and 4F9/2 → 4I15/2, respectively. The optimal photoluminescence （PL） were found in the NBT-BIT-0.20Er sample, and the emission color transforms from green to yellowish green. Temperature dependence of fluorescence intensity ratio （FIR） for NBT-BIT-0.20Er was measured ranging from 290 to 440 K and its maximum sensitivity was calculated to be about 0.0020 K-1 at 290 K. Dielectric measurements indicated that Tc slightly increased simultaneously with the decrease of tanS. Therefore, this ceramic has potential applications for high-temperature multifunctional devices.

关键词： inter-growth structure photoluminescence (PL) electrical properties multifunctional materials

Photocatalytic properties of CaTi_(2)O_(5)via a facile additive-free aqueous strategy with different pH values

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Rare Metals 2021年第7期40卷 1746-1752页

作者： Wei-Xia Dong Qi-Fu Bao X-YGu Hui-Juan Shen Peng-Yan Liu Department of Material Science and Engineering Jingdezhen Ceramic InstituteJingdezhen 333001China

CaTi_(2)O_(5)was selectively prepared by a solvothermal process without template and *** phase of the as-prepared samples was determined by X-ray diffraction(XRD).The microstructure was characterized by scanning electron microscopy(SEM)and transmission electron microscopy(TEM).Results found that pH values had a crucial effect on the crystal phase and shape evolution of the ***_(2)O_(5)sample prepared at pH of 5.2 shows high efficient light harvesting,large surface area and ***,CaTi_(2)O_(5)shuttle-like sample shows good photocatalytic activity against methyl orange due to its longer and thinner shuttle-like morphology and high crystallinity,enhanced light harvesting and large surface *** photocatalytic rate of CaTi_(2)O_(5)shuttle-like structure reaches 0.1988 min-1 for 25-min methyl orange degradation under the ultraviolet light irradiation and displays an excellent photostability with a degradation efficiency of 0.1952 min^(-1)after four cycles.

关键词： pH CaTi_(2)O_(5) Solvothermal method Photocatalytic properties

Pressureless sintering of ZrC with variable stoichiometry

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Journal of Advanced ceramics 2017年第2期6卷 165-175页

作者： Katrin SCH(O)NFELD Hans-Peter MARTIN Alexander MICHAELIS Fraunhofer institute for ceramic Technologies and Systems IKTS Dresden Germany

This paper presents the experiments on the synthesis of zirconium carbide (ZrC) using carbothermal reduction of zirconia (ZrO2).The ratio of ZrO2∶C is used to adapt ZrCxOy with x＜ 1 or ZrC + *** modification of ZrCxOy and the total carbon amount allows the use of pressureless sintering method in combination with sintering temperatures ≤ 2000 ℃.Fully densified ZrC products are *** relevant details of ZrC formation are investigated by X-ray diffraction (XRD).The sintered products are characterized by XRD,field emission scanning electron microscopy (FESEM),as well as mechanical and electrical *** and FESEM investigations show that ZrCxOy is formed during the manufacturing *** grain size and additional zirconia or carbon are related to the ZrO2∶C ratio of the starting powder *** strength up to 300 MPa,Young's modulus up to 400 GPa,fracture toughness up to 4.1 MPa·m1/2,and electrical resistance at room temperature around 10-4 Ω.cm are reached by the pressureless sintered ZrC.

关键词： zirconium carbide (ZrC) carbothermal reduction sintering mechanical properties electrical properties

High performance Aurivillius type Na_(0.5)Bi_(4.5)Ti_(4)O_(15) piezoelectric ceramics with neodymium and cerium modification

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Journal of Advanced ceramics 2015年第1期4卷 54-60页

作者： Xiang-Ping JIANG Xiao-Long FU Chao CHEN Na TU Ming-Zhu XU Xiao-Hong LI Hong SHAO Yun-Jing CHEN Department of Material Science and Engineering Jiangxi Key Laboratory of Advanced Ceramic MaterialsJingdezhen Ceramic InstituteJingdezhen 333001JiangxiChina

Bismuth layer-structured ferroelectric ceramics of Na0.5Bi4.5-x(Nd_(0.5)Ce_(0.5)))xTi4O15(NBT-x,0.0≤x≤0.4)were synthesized by a traditional solid-state *** effect of(Nd,Ce)substitution for A-site on the microstructure and electrical properties of Na_(0.5)Bi_(4.5)Ti_(4)O_(15)(NBT)-based piezoelectric ceramics was investigated.X-ray diffraction(XRD)analysis revealed that the(Nd,Ce)-modified NBT ceramics have a pure four-layer Aurivillius type *** piezoelectric properties of NBT ceramics were significantly improved by the modification of neodymium and *** Curie temperature TC gradually decreased from 638℃to 618℃with increasing the(Nd,Ce)*** piezoelectric constant d33,mechanical quality factor Qm,dielectric loss tanδand Curie temperature TC of the Na0.5Bi4.3(Nd_(0.5)Ce_(0.5)))0.2Ti4O15 ceramic were found to be 28 pC/N,3239,0.0032 and 630℃,*** annealing studies indicated that the(Nd,Ce)-modified NBT ceramics possess stable piezoelectric properties,demonstrating that the Na0.5Bi4.3(Nd_(0.5)Ce_(0.5)))0.2Ti4O15 ceramic is a promising candidate for high temperature applications.

关键词： lead-free Na_(0.5)Bi_(4.5)Ti_(4)O_(15)(NBT)ceramics piezoelectric properties

Ferrimagnetic ceramic adsorbents for cleanup of H_2S from exhaust gases

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China Particuology 2007年第1期5卷 156-161页

作者： Bernd Halbedel Apostolos Kontogeorgakos institute of Materials Science Glass and Ceramic Technology Group Technische Universitt Ilmenau P.O. Box 10 05 65 D-98684 Ilmenau Germany NCSR "Demokritos" Institute of Materials Science 15310 Aghia Paraskevi Attiki Greece

Adsorbents that exhibit magnetic properties in addition to other required process-relevant characteristics open up new perspectives for the dry reduction and/or elimination of HES and other sulfur compounds from exhaust gases. These adsorbents eliminate the sulfur compounds from exhaust gases by virtue of their coatings and their magnetic property which makes it possible the use of magnetically assisted and stabilized fluidization in an externally applied magnetic field. In the present paper, the feasibility of the sorptive function of porous ceramic ferrimagnetic beads is ensured by sol-gel coating of zinc oxide without the formation of Zn-Fe-oxides and without considerable decrease of available pore volume. The results of material characterization by SEM, Auger electron spectroscopy, X-ray and mercury-porosity measurements and the loading capacity of a HES/N2 model gas are presented and discussed. The resulting HES loading of the functionalized adsorbent beads is more than 10 times larger than that of the starting material. @ 2007 Chinese Society of Particuolo^v and institute of Process Engineering, Chinese Academy of Sciences. Published by Elsevier B.V.

关键词： Adsorption Adsorbents Ferrites Magnetic materials Magnetic properties Sol-gel Zinc oxide

A review:(Bi,Na)TiO_(3)(BNT)-based energy storage ceramics

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Journal of Materiomics 2024年第1期10卷 86-123页

作者： Wen Zhu Zong-Yang Shen Wei Deng Kai Li Wenqin Luo Fusheng Song Xiaojun Zeng Zhumei Wang Yueming Li Advanced ceramic Materials Research institute China National Light Industry Key Laboratory of Functional Ceramic MaterialsEnergy Storage and Conversion Ceramic Materials Engineering Laboratory of Jiangxi ProvinceSchool of Materials Science and EngineeringJingdezhen Ceramic UniversityJingdezhen333403China

Facing the increasingly serious energy and environmental problems,the research and development of new energy storage technology and environment-friendly energy storage materials are *** a typical lead-free ferroelectric with excellent dielectric properties,(Bi,Na)TiO_(3)(BNT)is supposed to be the most potential and competitive environment-friendly ceramic material and has become a research hotspot for dielectric energy storage in recent *** paper first briefly introduces the basic physical principles and energy storage performance evaluation parameters of dielectric energy storage materials,then summarizes the critical research systems and related progress of BNT-based lead-free energy storage materials(bulk ceramics,films and multilayer ceramics)from the aspects of ions doping modification and multi-component composite optimization,and finally looks forward to the improvement direction and energy storage application prospect of BNT-based lead-free relaxor ferroelectric materials.

关键词： Dielectrics Relaxor ferroelectrics Energy storage ceramics Sodium bismuth titanate Lead free

Influences of Co-Doping Cation on Properties of PWO∶F- Scintillating Crystal

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Journal of Rare Earths 2006年第Z1期24卷 169-171页

作者： Zhang Mingrong Zhang Chunsheng Fan Yuhong Ge Yuncheng Crystal Laboratory Beijing Glass Research Institute Beijing 100062 China Crystal Laboratory Beijing Glass Research Institute Beijing 100062 China Crystal Laboratory Beijing Glass Research Institute Beijing 100062 China Crystal Laboratory Beijing Glass Research Institute Beijing 100062 China

Whereas the light yield of PWO crystal can be significantly improved by doping with either of F- and Sb3+, effects of heavily co-doping with by F-+Sb3+, F-+Ca2+, and F-+Ca2++Sb3+, respectively, on the properties of PWO scintillation crystals, including optical transmission, luminescence and light yield were studied. The result indicates that co-doping with three dopants, F-+Ca2++Sb3+, is a more effective measure than doping with single dopant F- for the improvement of scintillation properties of PWO crystals, including light yield.

关键词： lead tungstate scintillation crystal light yield doping