To see the other types of publications on this topic, follow the link: Ba(Ti,Ce)O3.
Dissertations / Theses on the topic 'Ba(Ti,Ce)O3'
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 41 dissertations / theses for your research on the topic 'Ba(Ti,Ce)O3.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.
1
Amoroso, Danila. "Étude ab-initio de solutions solides piézoélectriques (Ba,Ca)TiO3-Ba(Ti,Zr)O3." Thesis, Bordeaux, 2018. http://www.theses.fr/2018BORD0163/document.
Full textAbstract:
Les piézoélectriques à haute performance sont des composants clés pour les dispositifs agiles. Il a été démontré récemment que les solutions solides (Ba,Ca)(Ti,Zr)O3 (BCTZ) présentent des propriétés électromécaniques prometteuses. Cependant, les mécanismes microscopiques conduisant à de telles caractéristiques restent à éclaircir, et les investigations théoriques de BCTZ demeurent très limitées à ce jour. En conséquence, cette thèse propose d’étudier les propriétés de différentes compositions de solutions solides (Ba,Ca)TiO3-Ba(Ti,Zr)O3 au moyen de calculs de premiers principes, en mettant l’accent sur la dynamiquedu réseau et sur la compétition entre différentes phases ferroélectriques. Nous nous intéressons d’abord aux quatre composés parents BaTiO3, CaTiO3, BaZrO3 et CaZrO3, afin de comparer leurs propriétés et leurs différentes tendances à la ferroélectricité. Ensuite, le coeur de notre étude est une caractérisation systématique des systèmes binaires (Ba,Ca)TiO3 et Ba(Ti,Zr)O3 en utilisant à la fois l’approximation du cristal virtuel (VCA) et des calculs directs sur supercellules.Lorsqu’on passe continument de BaTiO3 à CaTiO3 dans (Ba,Ca)TiO3, la caractéristique principale est une transformation progressive de la ferroélectricité de type B en type A en raison d’effets stériques, lesquels déterminent en grande partie le comportement du système. En particulier, pour les petites concentrations en calcium, nous avons mis en évidence que laferroélectricité guidée par le site B est globalement affaiblie, conduisant à la disparition de la barrière d’énergie entre différents états polaires et à une polarisation quasi-isotrope. Une amélioration considérable de la réponse piézoélectrique résulte de ces caractéristiques. En passant de BaTiO3 à BaZrO3 dans Ba(Ti,Zr)O3, en revanche, le comportement est dominé parles mouvements coopératifs Zr-Ti et l’électrostatique locale. En particulier, la phase R3m est stabilisée significativement pour les faibles concentrations en zirconium. Sous l’effet d’une augmentation de la concentration en zirconium, le système montre une tendance à la réduction de la distorsion polaire; néanmoins, la ferroélectricité peut être préservée localement dans les régionsriches en titane. Grâce à un modèle électrostatique basé sur un super-réseau BaZrO3/mBaTiO3, nous avons également découvert une activation polaire inattendue pour Zr, en fonction d’un ordre atomique spécifique. Un facteur microscopique expliquant la réponse piézoélectrique exaltée dans BCTZ, pour de faibles concentrations en Ca et Zr, peut donc résider dans l’interaction entre la ferroélectricité affaiblie induite par Ti et la ferroélectricité émergente induite par Ca, interaction produisant une anisotropie minimale pour la polarisation. En outre, notre étude comparative révèle que la physique microscopique spécifique de ces solutions solides limite sévèrement l’applicabilité de l’approximation du cristal virtuel (VCA) à ces systèmesHigh-performance piezoelectrics are key components of various smart devicesand, recently, it has been discovered that (Ba,Ca)(Ti,Zr)O3 (BCTZ) solid solutions show appealingelectromechanical properties. Nevertheless, the microscopic mechanisms leading to suchfeatures are still unclear and theoretical investigations of BCTZ remain very limited. Accordingly,this thesis analyzes the properties of various compositions of (Ba,Ca)TiO3-Ba(Ti,Zr)O3solid solutions by means of first-principles calculations, with a focus on the lattice dynamicsand the competition between different ferroelectric phases. We first analyze the four parentcompounds BaTiO3, CaTiO3, BaZrO3 and CaZrO3 in order to compare their properties andtheir different tendency towards ferroelectricity. Then, the core of our study is a systematiccharacterization of the binary systems (Ba,Ca)TiO3 and Ba(Ti,Zr)O3 within both the virtualcrystal approximation (VCA) and direct supercell calculations. When going from BaTiO3 toCaTiO3 in (Ba,Ca)TiO3, the main feature is a gradual transformation from B-type to A-typeferroelectricity due to steric effects that largely determine the behavior of the system. In particular,for low Ca-concentration we found out an overall weakened B-driven ferroelectricitythat produces the vanishing of the energy barrier between different polar states and resultsin a quasi-isotropic polarization. A sizable enhancement of the piezoelectric response resultsfrom these features. When going from BaTiO3 to BaZrO3 in Ba(Ti,Zr)O3, in contrast, thebehavior is dominated by cooperative Zr-Ti motions and the local electrostatics. In particular,low Zr-concentration produces the further stabilization of the R3m-phase. Then, the systemshows the tendency to globally reduce the polar distortion with increasing Zr-concentration.Nevertheless, ferroelectricity can be locally preserved in Ti-rich regions. We also found out anunexpected polar activation of Zr as a function of specific atomic ordering explained via a basicelectrostatic model based on BaZrO3/mBaTiO3 superlattice. A microscopic factor behind theenhanced piezoelectric response in BCTZ, at low concentration of Ca and Zr, can thus be theinterplay between weakened Ti-driven and emerging Ca-driven ferroelectricity, which producesminimal anisotropy for the polarization. In addition, our comparative study reveals that thespecific microscopic physics of these solid solutions sets severe limits to the applicability of thevirtual crystal approximation (VCA) for these systems
2
Kuvatov, Azamat. "Polungs- und Biegeverhalten von Ba(Ti, Sn)O3-Keramiken mit einem Funktionsgradienten." [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975671650.
Full text
3
CONFALONIERI, GIORGIA. "LOCAL DISORDER IN THE STRUCTURE OF BA(TI,CE)O3 PEROVSKITE BY MEANS OF POWDER DIFFRACTION AND TOTAL SCATTERING. EFFECT OF TEMPERATURE, DOPING CONCENTRATION AND GRAIN SIZE." Doctoral thesis, Università degli Studi di Milano, 2017. http://hdl.handle.net/2434/478906.
Full textAbstract:
Nowadays BaTiO3 is considered as one of the most relevant environmental-friend ferroelectric and, thank to the chemical substitutions at the Ba2+ and/or Ti4+ sites, its properties are usually tailor to meet a big variety of devices and performance requirements. A classical example is the solid solution BaTi1-xMIVxO3, where M could be Sn, Zr, Hf, Ce etc., whose ferroelectric behavior shows an almost continuous variation with composition. The study of these compounds is then essential to improve their characteristics and make their suitable in more applications. Considering that their properties are deeply linked to the structure and especially to structural defects, average and local structural analyses are essential to better understand the origins of different polar behaviours and to have a real control on these materials. Despite this need, only BaTi1-xZrxO3 (BTZ) system, which is one of the most popular dielectrics used in multilayer ceramic capacitors, has been investigated in some detail. Although the similarity to BTZ suggests that BaTi1-xCexO3 (BTC) may be promising as lead free actuator materials, studies on this solid solution are almost limited. Thus in this research the BTC solid solution has been structurally investigated in order to provide knowledge lacks. Different ceramic samples with different doping amounts and different polar behaviours (from normal ferroelecric to relaxor via diffuse phase transition) have been investigated at different temperatures. In addition, taking into account the current tendency in miniaturized devices required in microelectronics, also chemical equivalent nano powders have been considered to explore not only doping effects, but also that of size. Pair Distribution Function (PDF) with different type of approaches (as carbox, biphasic and so on) has been employed coupled with TEM analysis and Raman spectroscopy. A complete description of that BaTi1-xCexO3 materials is given underlining links between polar behaviours, temperature, doping and size effects.
4
Bijalwan, Vijay. "Studie syntéz a přípravy bezolovnaté keramiky (Ba,Ca)(Ti,Zr)O3 v závislosti na struktuře a výsledných vlastností." Doctoral thesis, Vysoké učení technické v Brně. CEITEC VUT, 2018. http://www.nusl.cz/ntk/nusl-390293.
Full textAbstract:
V poslední době je snahou nahradit klasickou komerční olovnatou piezoelektrickou keramiku bezolovnatou, z důvodu zvýšeného zájmu o ochranu životního prostředí a zdraví. Různé typy materiálů již byly navrženy, jako například (K, Na) NbO3 (KNN), (Bi, Na) TiO3 (BNT), (Bi, Na) TiO3 – BaTiO3 (BNT-BT), ale jejich piezoelektrické vlastnosti zatím nedosáhly takových hodnot jako u olovnatý chkeramik (např. olovnatý titanát olova ((Pb Zr)TiO3). Nejvíce se olovnatým materiálů blíží bezolovnatý systém na bázi (1-x)Ba(Zr0.2Ti0.8)O3-x(Ba0.7Ca0.3)TiO3 nebo (Ba, Ca) (Zr, Ti) O3 ((1-x)BZT-xBCT, BCZT) a to díky vysokým piezoelektrickým a dielektrickým parametrům. Nevýhodou tohoto prostředku je jeho velmi vysoká teplota slinování (1520 ° C) za účelem dosažení vysokých piezoelektrických vlastností (např. Piezoelektrické konstanty d33 > 600 pC / N). Tato práce se zabývá bezolovnatou keramikou na bázi BCZT, její výrobou a vylepšením piezoelektrických vlastností dopováním CeO2. Přidáním CeO2 (y wt.%) do (Ba0.85Ca0.15) (Zr0.1Ti0.9) O3 se výrazně snížila slinovací teplota a došlo ke zhutnění při 1350°C. U této kompozice se Curieova teplota pohybovala kolem TC~105°C a velikost zrn byla v rozmezí ~ 10-13 m. Fázový přechod z romboedrické struktury na tetragonální (R-T) byl zjištěn pomocí rentgenové spektroskopie u y = 0 - 0.1 wt.%, což koreluje s výsledky Ramanovy spektrální analýzy. Mikrostrukturní a strukturní charakteristiky byly detailně studovány v korelaci s dielektrickými, feroelektrickými a piezoelektrickými vlastnostmi. Nejlepší funkční vlastnosti byly dosaženy pro keramiku BCZT – 0.07 wt.% CeO2. Tato keramika vykazovala piezoelektrický nábojový koeficient d33 = 507±20pC/N, elektromechanický planární koeficient kp = 51.8 %, dielektrickou konstantu r = 4091±100, ztrátový činitel tan = 0.02, remanentní polarizaci Pr = 13.58C/cm2, intenzitu koercitivního pole EC = 2.13kV/cm při normovaném napětí, d33* nebo Smax/Emax = 840pm/V. Dvoustupňovou kalcinační technikou bylo docíleno homogenního růstu zrn s vysokou relativní hustotou (~ 99% teoretické hustoty). Tato kompozice BCZT- CeO2 vykazovala stálé feroelektrické, dielektrické a piezoelektrické vlastností i při velikosti zrn 10 µm. Bezolovnatá piezoelektrická keramika (Ba0.85Ca0.15-y Cey) (Zr0.1Ti0.9) O3 (BCCeZT) byla dále dopována CeO2 s cílem substituce Ce4+ v místě A krystalické mřížky. Posunutí rentgenových vrcholů k vyšším úhlům naznačuje kontrakce mřížky, což by mohlo způsobit obsazení iontů ceru v místech A této soustavy. Bylo zjištěno, že velikost zrn kolem 10 - 12 m je významná pro vysokou piezoaktivitu bezolovnaté BCCeZT keramiky. Nejvyšší piezoelektrické vlastnosti tato keramika vykazovala při y;Ce = 0.00135 a slinovaná na teplotě 1350°C/4h, kdy piezoelektrické parametry byly d33 = 501±10 pC/N, kp = 38.5±1.92 %, Pr = 12.19 C/cm2, TC = 108.1 °C a s maximální deformací S do 0.14 %. Pro další studium substituce v místě A, byly vyrobeny keramické materiály (Ba1-x-y Cax Cey) (Zr0.1 Ti0.9) O3 (x:Ca = 0.05, 0.10, 0.15, 0.20 a y;Ce = 0.00135). Opět se ukázalo, že pokud byla velikost zrn ~13um, tak keramika vykazovala vysoké piezoelektrické vlastnosti (d33 = 457pC/N) pro x = 0.15 % kalcinované na teplotě 1425 °C. Když se se velikost zrn zvýšila nad 16 um, piezoelektrický nábojový koeficient d33 klesl na 200 pC/N. Rentgenová analýza ukázala změnu fázové struktury z rombické na tetragonální při zvýšení obsahu vápníku.
5
Медведев, Д. А. "Высокотемпературные протонные электролиты на основе Ba(Ce,Zr)O3 со структурой перовскита: стратегии синтеза, оптимизация свойств и особенности применения : диссертация на соискание ученой степени доктора химических наук : 02.00.05." Thesis, б. и, 2019. http://hdl.handle.net/10995/76290.
Full text
6
Медведев, Д. А. "Высокотемпературные протонные электролиты на основе Ba(Ce,Zr)O3 со структурой перовскита: стратегии синтеза, оптимизация свойств и особенности применения : автореферат диссертации на соискание ученой степени доктора химических наук : 02.00.05." Thesis, б. и, 2019. http://hdl.handle.net/10995/76279.
Full text
7
Hayn, Silke [Verfasser], Karsten [Akademischer Betreuer] Albe, Jürgen [Akademischer Betreuer] Rödel, Hans-Joachim [Akademischer Betreuer] Kleebe, and Gerd [Akademischer Betreuer] Buntkowsky. "First-principles calculations on the structural and thermodynamic stability of (Na1/2Bi1/2,Ba)TiO3 and Pb(Zr,Ti)O3 / Silke Hayn. Betreuer: Karsten Albe ; Jürgen Rödel ; Hans-Joachim Kleebe ; Gerd Buntkowsky." Darmstadt : Universitäts- und Landesbibliothek Darmstadt, 2013. http://d-nb.info/1108093310/34.
Full text
8
Ho, CHI PANG, and 何志鵬. "Synthesis and Characterization of Hexagonal (Ba,Sr)(Ti,Ga)O3." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/59041800190273672028.
Full textAbstract:
碩士中國文化大學
材料科學與奈米科技研究所
98
The (Ba,Sr)(Ti,Ga)O3 samples are synthesized by the solid state method in air and the parent components BaTi1-xGaxO3 (ABO3) are substituted Ba for Sr (x=0.1, 0.2 and Sr: 1%~9%) in this work. The structure of samples are changed from hexagonal to mixed phases then tetragonal through the A-site substituting process, which is consistent with the thermodynamic prediction on literature. The all samples can form the pure hexagonal structure when the Sr-concentration is lower than 2%, and the mixed phase region is decreasing with Sr-doping level increasing. In the higher Sr-doping region, the structures of samples are tetragonal only. The hexagonal structure of (Ba,Sr)(Ti,Ga)O3 samples are increasing with the sintering temperature increasing in the lower Sr-doping region, but the tetragonal structure is dominant in the higher Sr-doping region. This is consistent with the result of room temperature Raman spectrum measurements. Because the Raman spectrum is reported that the tetragonal modes of BaTiO3 will go away and the intensity of hexagonal modes of BaTiO3 systems are increasing with sintering temperature increasing. During the substituting proceeding, because the ion-radius of Sr2+ is smaller than Ba2+, the volume of unit cell of (Ba,Sr)(Ti,Ga)O3 samples are decreasing with the Sr-concentration increasing. Although the atomic weight of Sr is lighter than Ba, but the density of samples aren’t also decreasing with Sr-doping level increasing, because the hexagonal phase is a metastable structure on thermodynamic, which is due to tetragonal phase replacing hexagonal phase in higher doping region at room temperature. The microwave property measurement are showed that because the main phase of samples will change from hexagonal to tetragonal with the Sr-doping level increasing, which is due to the Qxf value and K value of samples are dramatic dropping with Sr-concentration increasing. It means that if the samples are included the tetragonal structure, whose Qxf value and K value are hugely decreasing, so it also proofs that the hexagonal BaTiO3 material has very good microwave property and a large potential for application.
9
Wen-An, Lan. "A Study of Ferroelectric Ba(Zr,Ti)O3 Thin Film Varactors." 2006. http://www.cetd.com.tw/ec/thesisdetail.aspx?etdun=U0016-1303200709284817.
Full text
10
Lan, Wen-An, and 藍文安. "A Study of Ferroelectric Ba(Zr,Ti)O3 Thin Film Varactors." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/54262041506247480797.
Full textAbstract:
博士國立清華大學
材料科學工程學系
94
The dielectric constant of ferroelectric material, Ba(Zr,Ti)O3, (BZT) changes with external dc biasing voltage. Based on this tunable characteristic, it is useful to fabricate the varactors, tunable filters and phase shifter devices. In this research, two kinds of ferroelectric varactors were investigated, i.e. structures made with parallel and coplanar electrodes, and the study includes three topics: (1) the influences of bottom electrodes in parallel structure, (2) the influences of interfacial layer in the ferroelectric varactors fabricated on high-resistivity silicon (HR-Si), (3) the influences of high-k and low loss buffered layer and annealing condition in the ferroelectric varactors fabricated on high-resistivity silicon. In the first topic, three kinds of bottom electrode with different thickness were studied; including Pt, LaNiO3/Pt and LaNiO3/Au/Pt. Increasing the Pt thickness reduces effectively the total loss and raises the figure-of-merit (FOM) value. The conductive oxide, LaNiO3 (LNO) layer, enhances the textured crystallinity and increases the breakdown voltage, resulting in higher tunability of capacitance and FOM value. In the second topic, the BZT films deposited on HR-Si with or without tetraethylorthosilane (TEOS) SiO2 as buffer layer were studied. The influences of electrical characteristics were measured by impedance and network analyzer at high and microwave frequencies, respectively. The results at high frequency show that the tunability of coplanar varactors results from the depletion and accumulation of carriers in Si, which can be modeled by two back-to-back MOS capacitors in series connection. At microwave frequencies, positive tunability, i.e. [C(V)-C(0)]/C(0) > 0, was observed and can be explained by an equivalent circuit in relation to the formation of positively-charged defects at the interfacial layer and the modulation of carrier accumulation at the interface in Si. In the third topic, the Ta2O5 and (Ta2O5)1-x(TiO2)x layers were used to investigate the influences of high-k and low loss buffer layer. The results show that the thicker buffer layer and lower dielectric constant result in lower tunability. Moreover, the reduction of Ta5+ and formation of oxygen vacancies induce the change of carrier distribution at interface in Si, giving rise to different tunability at microwave frequencies. The positively-charged defects in the interfacial layer attract the electrons accumulated on the surface of silicon which screen the microwave from penetrating into the HR-Si, and affect the capacitive effect of HR-Si in series connection to the varactor. In addition, annealing in O2 annihilates the oxygen vacancies and oxidize the cations of BZT films causing the reduction of carrier accumulation and tunability. Annealing in N2 increases the oxygen vacancies and the reduction of cations in BZT films causing the raise of charged defects and injected carriers giving rise to hystersis behavior.
11
Chen, Chung-Yung, and 陳仲苑. "Prepared Ba(Ti,Sn)O3 thin film on Si by magnetron R.F.sputter." Thesis, 1997. http://ndltd.ncl.edu.tw/handle/57126328927476319514.
Full text
12
Chi-LinWu and 吳其霖. "Microstructure analysis on (Ba,Ca)(Ti,Zr)O3 base MLCC by constrained sintering." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/12405171940377064174.
Full textAbstract:
碩士國立成功大學
電機工程學系專班
98
Based on BCTZ by MLCC BME process, to add constraint layers inside on the samples to control the shrinkage. Besides, apply rapid sintering concept to resist inner electrode shrinkage during sintering. Depending on this concept, expect to get good continuity of inner electrode. According to results, constraint layers added can be useful to control grain growth of BCTZ. At the same time, rapid sintering performs good continuity of inner electrode and repression of grain growth.
13
Chen, Chung I., and 陳仲宜. "Study of Preparation And Properties of Ba(Ti,Zr)O3 High Dielectric Thin Film." Thesis, 1998. http://ndltd.ncl.edu.tw/handle/01922457963392027063.
Full textAbstract:
碩士國立成功大學
材料科學(工程)學系
86
In this study, Ba(Ti ,Zr)O3 thin film were prepared by R.F. magnetron sputtering onto N-type (100) Si substrate.The film were deposited at low temperature. Composition, crystallization, microstructure and electrical properties of thin film are characterized as function of components of target, R.F. power, ambient pressure and the partial pressure of O2 .Experimental results shows that deposition rate and crystallization of thin film were increased with optimum sputtering parameters. The higher substrate temperature led to better crystallization. The permittivity increased with the Zr content of thin film, substrate temperature and R.F. power, and the maximum value is 282.The relaxor behavior of BZT thin film became dominant with increasing the Zr content of thin film.The I-V curve shows that leakage current was effectively improved by increasing the Zr content . Paraelectric phase was determined by the hysteresis curve. In conclusion, BZT thin film can be applied to memory device.
14
Wang, Chia-Jung, and 王嘉榮. "Fabrication and Characteristics of (Ba,Sr)(Ti,Zr)O3 High Dielectric Constant Thin Films." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/82762875707635956947.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
91
ABSTRACT In this study, the reactive rf magnetron sputtering was used to deposit (Ba,Sr)(Ti,Zr)O3 (BSTZ) thin films on Pt/SiO2/Si substrate. The optimal sputtering parameters were found to be RF power of 160W、sputtering pressure of 10 mTorr、substrate temperature of 580°C and oxygen concentration (O2/O2+Ar) of 40%. The physical characteristics of BSTZ thin films deposited on Pt/SiO2/Si substrate with different sputtering parameters were obtained by the analyses of XRD, SEM and AFM. The characteristics and dielectric constant of thin films were discussed. The electrical properties of BSTZ thin films using HP4194A and HP4156C semiconductor parameters analyzer were estimated through the measurement of leakage current on MIM structure. The dependences of dielectric constants on applied voltage、frequency and temperature were discussed. From the experimental results, it reveals that the dielectric constant with optimal sputtering parameters was about 191, and the leakage current of thin film was about 3x10-8 A/cm2 when the applied electrical field of thin film was at 0.1 MV/cm. Besides, the Curie temperature (Tc) of BSTZ thin film was confirmed to be about 20°C and the dielectric constants of BSTZ thin films exhibited little change under different temperature(0~80°C) and frequency (~1MHz). * student ** advisor
15
Kuvatov, Azamat [Verfasser]. "Polungs- und Biegeverhalten von Ba(Ti,Sn)O3-Keramiken mit einem Funktionsgradienten / von Azamat Kuvatov." 2005. http://d-nb.info/975671650/34.
Full text
16
ZHOU, YU-SHANG, and 周玉商. "The investigation of (Ba, Sr)(Ti, Sn)O3 as a boundary layer insulating ceramuic capacitor." Thesis, 1986. http://ndltd.ncl.edu.tw/handle/63889221200216594883.
Full text
17
Yang, Cheng-Fu, and 楊證富. "Properties of Low Sintering Temperature (Ba,Sr)(Ti,Zr)O3 Based Ceramics and Related Devices." Thesis, 1993. http://ndltd.ncl.edu.tw/handle/39811175502091021929.
Full textAbstract:
博士國立成功大學
電機工程研究所
81
In this dissertation, four succeeding main topic are studied. The first topic is tried to lower the temperature required to densify the (Ba0.8Sr0.2)(Ti0.9Zr0.1)O3 ( BSTZ ) with studying its dielectric properties at different amount of CuO added and different calcining temperature. For 1050oC calcination, the calcined powder contains BaTiO3, SrTiO3 and some raw materials such as ZrO2 and BaCO3. With sintering, some residual raw materials form unknown phase and/or low-dielectric-constant compounds with CuO, causing the liquid phase effect of CuO to disappear. For 1170oC calcination, the calcined powder compl- etely forms ABO phases containing (Ba,Sr)TiO3 and BaZrO3. The sintering temperature for densification of ceramics is lowered, and the firing characteristics critically depend on the amount of CuO added and the sintering temperature. In the second topic, by using the results in topic one, in order to lower the temperature required to densify (Ba1-xSrx) (Ti1-yZry)O3( BSTZ-series ) and Ba(Ti1-xZrx)O3 ( BTZ-series ) and to avoid the formation of a low dielectric constant phase, copper oxide is added as liquid-phase propmoter after BSTZ- series and BTZ-series are calcined. The puepose of this study was to form a (Ba1-xSrx)(Ti1-yZry)O3 composition which had maximum permittivity at about 25oC. However, for different amounts of CuO added, the dielectric constant increases with increasing amount of CuO at lowering sintering temperature ( below ∼ 1100oC ). When a higher sintering temperature is used ( above ∼ 1200oC ), the dielectric constant reaches a maximum at ∼ 1wt%-CuO-added ceramics, and decreases slightly on further additon of CuO.
18
Chen-ChingChu and 朱振慶. "Development of non-core-shell (Ba,Ca)(Ti,Zr)O3 base MLCC with Ni electrodes." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/48941195489073008372.
Full textAbstract:
碩士國立成功大學
電機工程學系專班
98
Based on BCTZ by MLCC BME process, using BaTiO3 as constraining layers, to add constraining layers on the samples to control grain growth, and then to get the good dielectric constant and TCC. Besides, apply rapid sintering concept to resist inner electrode shrinkage during sintering. Depending on this concept, expect to get good continuity of inner electrode to gain higher capacitance. According to results, containing layers added can be useful to control grain growth of BCTZ. At the same time, rapid sintering performs good continuity of inner electrode and good outliner of sample by constraining sintering.
19
林奐汝. "The Effect of Bottom Electrode on Ferroelectric Thin Films Ba(Zr,Ti)O3 as Microwave Varactors." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/43508829725598829166.
Full text
20
Hsin-IHo and 何欣宜. "Microstructure and dielectric properties of (Ba,Ca)(Ti,Zr)O3 system prepared by two-step sintering." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/72888855607150373630.
Full text
21
Yan-FuChiu and 邱彥富. "A study on low firing (Ba, Ca) (Ti, Zr) O3 dielectric cofired with Cu inner electrode." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/82550464829942827117.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
101
In this paper, the high dielectric constant and the high density of (Ba,Ca)(Ti,Zr)O3(BCTZ) ceramic using the sintering aid for co-firing with copper electrode was investigated. The SiO2 and Li2CO3 were used to reduce the sintering temperature below 1050℃ for 2hr in the reducing atmosphere due to the promote liquid-phase sintering. The additional amount of SiO2 and Li2CO3 have been optimized to achieve optimum dielectric characteristics and uniform grain size distribution. However, it was found that the excess amount of Li2CO3 resulted from the secondary phase, which led to the dielectric constant and insulation resistance of the BCTZ were decreased and the dielectric loss of BCTZ was increased. It was demonstrated that the secondary phase (Ba1.55Ca0.45Si1O4) was examined by High-Resolution Transmission Electron Microscopy and energy-dispersive spectrometry (HRTEM-EDS). The high dielectric constant up to 9700, dielectric loss of 23×10-4 and high insulation resistance up to 5×1010 of (Ba,Ca)(Ti,Zr)O3 of the specimen were sintered at 1050℃ for 2hr with copper electrode in the reducing atmosphere.
22
Tsung-YuHsieh and 謝宗諭. "Microstructure, crystal structure, and dielectric property of (Ba,Ca)(Ti,Zr)O3 system synthesized with excess Ba2+." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/33358823103285178187.
Full textAbstract:
碩士國立成功大學
資源工程學系碩博士班
98
Due to the great performance of dielectric property, barium titanate was widely used in great number of high-K capacitor products, such as passive devices, multilayer ceramic capacitors, and thermistors. To make electric device reach the EIA’s industrial standard (X7R, Z5U, Y5V, etc), it’s necessary to add dopants into BaTiO3 proceeding ion exchanging or dopant to adjust the dielectric and temperature property. Single phase Ba0.95Ca0.05Ti0.88Zr0.12 (BCTZ) was obtained in this study by Ca2+ and Zr4+ doped into BaTiO3-based material, and (Ba,Ca)(Ti,Zr,Ca)O3 (BCTZC) was reacted of BCTZ system with excess of 0.04 and 0.06 mole of barium carbonate. In the study, we analyzed the material, structure and property analysis of both composition to realize the crystal structure and dielectric property’s affect when Ba2+ was occupied in Ti site. As the result, single phase of BCTZ and BCTZC powder could be obtained under the calcined condition of 1200℃/4 h. The crystal structure of both was tetragonal phase which was analysed by XRD, Raman, and TEM diffraction pattern. Compared with BCTZ of XRD patterns, as the more amount of BaCO3 was added, d-spacing was raised by the observation of the lower angle of all the crystal planes. According to cell parameter calculation, a and c axis were increased after Ca2+ entered the Ti site, enlarged the volume of an unit cell and decreased the theory density. After sintering under the condition of 1240℃/6 h and 1280℃/6 h, BCTZ and BCTZC sintered bulk’s relative density was 97%, 85% - 95%. The average grain size was about 4, 6 – 8 μm. Dielectric constant of BCTZ was about 2400 under 1 kHz condition and grain growth was observed at higher temperature with lower dielectric constant. BCTZC sintered bulk with 0.04 mole BaCO3 was nearby 4200 and rarely affect by the grain size, added with 0.06 mole BaCO3 was 6000 and decreased with lager grain. With Ca2+ occupied into Ti site after excess BaCO3 were added, curie temperature was lower when there was more BaCO3 doped and also the raise of dielectric constant at room temperature had been proved
23
Rodrigues, Ana Sofia Freire. "Síntese, caraterização e aplicações ambientais de óxidos metálicos mistos do tipo perovesquite (La,Ba)(Fe,Ti)O3." Doctoral thesis, 2021. http://hdl.handle.net/10400.6/12048.
Full textAbstract:
O principal objetivo deste trabalho consistiu em preparar óxidos metálicos de
perovesquites do tipo (La,Ba)(Fe,Ti)O3, caracterizá-los e utilizá-los como fotoânodos em
aplicações ambientais, nomeadamente fotocatálise, eletrocatálise e/ou
fotoeletrocatálise, na degradação dos poluentes modelo AO7 e Diclofenac.
Foram preparados 44 pós perovesquíticos da família LaxBa1-xFeyTi1-yO3, com 0≤x,y≤1,
utilizando dois métodos de preparação, o cerâmico e o de polimerização de complexos,
e diferentes condições de calcinação. Estes pós foram caracterizados estrutural e
morfologicamente e foram determinadas algumas outras propriedades, como
composição química e energia de Band Gap. Foi dada especial ênfase às perovesquites
com índices (0,0), (0,1), (1,0) e (1,1), tendo-se verificado que BaTiO3 cristaliza no
sistema cúbico, BaFeO3 exibe diferentes estruturas, predominantes consoante o método
de síntese, sendo hexagonal quando sintetizada pelo método cerâmico e cúbica quando
o método de preparação é o de polimerização de complexos, LaFeO3 cristaliza no
sistema ortorrômbico e La2Ti2O7 no sistema monoclínico .
Em relação às outras amostras preparadas, verificou-se que grande parte das amostras
não corresponde a fases puras. Pode, ainda, concluir-se que a introdução de elementos
na estrutura perovesquítica e/ou a substituição de elementos leva a modificações
estruturais na perovesquite, sendo que as estruturas predominantes nos diferentes
elementos preparados mostram uma relação com (x,y) que é a seguinte: (x≤0.6, y≤0.3)
cúbica; (x≥0.8, y=0) monoclínica; (x≥0.6, y≥0.8 e x≥0.8, y≥0.6) ortorrômbica; (x≤0.1,
y≥0.4) hexagonal; para y=1 e 0.2≤x≤0.6, tetragonal. Em relação à caracterização
morfológica, embora haja algumas diferenças na morfologia das amostras preparadas,
não foram identificados padrões de relevo.
A maior parte dos pós preparados apresenta energias de Band Gap na zona do
ultravioleta, com valores superiores 3.2 eV. De um modo geral, verifica-se que diminui
com a introdução simultânea de La e Fe. Contudo, a perovesquite que apresenta menor
energia de Band Gap é a BaFeO3.
A maioria das perovesquites testadas em fotocatálise com luz UV conduziram a
remoções superiores às obtidas na fotólise. Contudo, em relação às perovesquites
testadas em fotocatálise com luz visível, apenas a perovesquite La0.1Ba0.9Fe0.2Ti0.8O3 mostrou atividade catalítica com luz visível superior à apresentada na presença de
radiação UV. Nos ensaios com perovesquite imobilizada sobre substrato de TiO2NTs,
os melhores resultados também foram obtidos na presença de radiação UV.
Algumas perovesquites também foram testadas num Reactor LED, com radiação UV de
365 nm para a fotodegradação de diclofenac em soluções aquosas e numa amostra de
água engarrafada. Os melhores resultados foram obtidos com a perovesquite BaTiO3,
preparada pelo método cerâmico, que é, de entre as perovesquites testadas, a que
apresenta uma energia de Band Gap mais próxima da energia da radiação utilizada.
Alguns destes ensaios foram também realizados com adição de persulfato, o que
conduziu a um aumento da velocidade de degradação do diclofenac.
Nos ensaios de fotocatálise realizados com luz solar foi possível perceber que, em
condições idênticas de luminosidade e temperatura, as perovesquites BaTiO3,
preparada pelo método de polimerização de complexos, e BaFeO3, preparada pelo
método cerâmico, degradaram com eficácia soluções aquosas de AO7 e também dos
seus metabolitos, aminonaftol e ácido sulfanílico. Contudo, as perovesquites com
substituições nas posições A e/ou B que foram testadas em fotocatálise com luz solar
manifestaram resultados inferiores à fotólise, possivelmente porque a introdução dos
pós em suspensão levou, nesses casos, a uma absorção dos fotões pelos pós, sem que
ocorresse ativação das suas propriedades catalíticas.
Em suma, o principal objetivo deste trabalho foi alcançado, pois foi possível o
desenvolvimento de materiais foto-ativos não-poluentes e de baixo custo, apropriados
para a degradação de compostos orgânicos em processos amigos do ambiente.The main objective of this work was to prepare metal oxides of perovskites of the type (La,Ba)(Fe,Ti)O3, characterize them and use them as photo-anodes in environmental applications, namely photocatalysis, electrocatalysis and/or photoelectrocatalysis, for the degradation of the model pollutants AO7 and Diclofenac. In this work, 44 perovskitic powders of the LaxBa1-xFeyTi1-yO3 family were prepared, with 0≤x, y≤1, using two preparation methods, the ceramic and the complex polymerization, and different calcination conditions. These powders were characterized structurally and morphologically, and some other properties were determined, such as chemical composition and band-gap energy. Special emphasis was given to perovskites with indices (0.0), (0.1), (1.0) and (1.1), with BaTiO3 crystallizing in the cubic system, BaFeO3 exhibiting different structures, depending on the synthesis method, being hexagonal predominant when synthesized by the ceramic method and cubic when the method of preparation is the complex polymerization, LaFeO3 crystallizes in the orthorhombic system and La2Ti2O7 in the monoclinic system. Regarding the other samples, it was found that most of the samples do not correspond to pure phases. It can also be concluded that the introduction of elements in the perovskitic structure and/or the substitution of elements leads to structural changes in perovskite, with the predominant structures in the different prepared elements showing a relationship with (x, y) which is the following: (x≤0.6, y≤0.3) cubic; (x≥0.8, y = 0) monoclinic; (x≥0.6, y≥0.8 and x≥0.8, y≥0.6) orthorhombic; (x≤0.1, y≥0.4) hexagonal; for y = 1 and 0.2≤x≤0.6, tetragonal. Regarding the morphological characterization, although there are some differences in the morphology of the prepared samples, no relevant patterns were identified. Most of the prepared powders present band-gap energies in the ultraviolet zone, with values above 3.2 eV. In general, there is a decrease with the simultaneous introduction of La and Fe. However, the perovskite that presents lower band-gap energy is BaFeO3. Most of the perovskites tested in photocatalysis with UV light LED to removals higher than those obtained in photolysis. However, for the perovskites tested in photocatalysis with visible light, only the perovskite La0.1Ba0.9Fe0.2Ti0.8O3 showed catalytic activity with visible light superior to that presented in the presence of UV radiation. In tests with the perovskites immobilized on a TiO2NTs substrate, the best results were also obtained in the presence of UV radiation. Some perovskites were also tested in a LED Reactor, with 365 nm UV radiation, for the photodegradation of diclofenac in aqueous solutions and in bottled water. The best results were obtained with the BaTiO3 perovskite, prepared by the ceramic method, which is, among the tested perovskites, the one presenting the band-gap energy closest to the energy of the radiation utilized. Some of these tests were also carried out with the addition of persulfate, which led to an increase in the rate of diclofenac degradation. In the photocatalysis tests carried out with sunlight it was possible to observe that, under identical conditions of luminosity and temperature, the perovskites BaTiO3, prepared by the complex polymerization method, and BaFeO3, prepared by the ceramic method, effectively degraded aqueous solutions of AO7 and also its metabolites, aminonaftol and sulfanilic acid. However, perovskites A and or B substituted that were tested in photocatalysis with sunlight showed inferior results to photolysis, possibly because the introduction of suspended powders, in these cases, led to an absorption of the photons by the powders, without activation of its catalytic properties. Thus, the main objective of this work was achieved, as it was possible to develop nonpolluting and low-cost photo-active materials, suitable for the degradation of organic compounds in environmentally friendly processes.
24
Yu-JuKao and 高育儒. "Hydroxyl Defect-Dielectric Property Relations in Reoxidation of Acceptor-Doped (Ba,Ca)(Ti,Zr)O3 Bulk Ceramics." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/95841854108990606915.
Full textAbstract:
博士國立成功大學
資源工程學系
104
Dielectric property and degradation behavior of acceptor (Sc or Y)-doped (Ba,Ca)(Ti,Zr)O3 ceramics sintered in moist reducing atmosphere and subsequently re-oxidized in dry or wet atmospheres was contrasted. In moist firing atmosphere, water vapor was found to react with oxygen vacancies, forming positively charged hydroxyl defects on regular oxygen sites in the crystal lattice. Proton hopping is considered to raise the ionic conductivity significantly. Therefore, hydroxyl defects in turn influence the grain conduction. Hydroxyl defects are also considered to be responsible for alternations of the dielectric maximum at the Curie point. On the other hand, the degradation behavior critically depends on the water vapor incorporation, the time to degradation systematically decreased with the incorporation of hydroxyl defects. The electrical conductivity was investigated by means of impedance spectroscopy (IS) to determine properties, such as grain and grain boundary conductivity, grain boundary potential barrier height, and space charge layer thickness. Furthermore, transmission electron microscopy (TEM) and electron energy loss spectroscopy (EELS) were applied to consider microstructure, microchemistry, and oxygen stoichiometry changes.
25
邱信雄. "(Ba,Sr)(Ti,Zr)O3介電材料之物性及電性探討." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/95248014812397780903.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
87
Abstract Barium titanate has a high dielectric constant and is used extensively for electronic applications.These include multilayer capacitors, positive temperature coefficient of resistance thermistors, piezoelectrics for ultrasonics, and a variety of electro-optic devices. The experiment is to study the best composition and structure of the dielectric characteristics in the BaTiO3-BaZrO3-SrTiO3 system ( BSZT system ). Different samples are prepared by conventional solid-state reaction,and then have been investigated by X-ray diffractometry, SEM , TEM ,and dielectric measurements. The sample of higher sintering temperature shows higher dielectric constant with Curie temperature shifted slightly to lower temperature. The decrease of Tc by substitution of Zr4+ for Ti4+ is more effective than that of Sr2+for Ba2+. Whereas, when the total content of Zr and Sr is higher than 20% mole, the lowered and broaden dielectric constant peak is attributed to the diffused phase-transition (DPT) which is caused by coexisting ferroelectric and paraelectric phases. In the effect of grain size, the dielectric constant around its Curie temperature increases with increasing grain size. When the amount of BaZrO3 or SrTiO3 increases in BSZT system, the crystal structure will be transformed from a tetragonal to cubic phase. The high dielectric constant property with diffuse-phase transition of the BSZT ceramics yields to a good candidate of dielectric application.
26
Wen-ChinLiu and 劉文欽. "Development of non-core-shell (Ba,Ca)(Ti,Zr)O3 base MLCC with Mn-Si-O glass." Thesis, 2010. http://ndltd.ncl.edu.tw/handle/45935699169191624116.
Full textAbstract:
碩士國立成功大學
電機工程學系碩博士班
98
The (Ba,Ca)(Ti,Zr)O3 was used as the primary dielectric material in this study. And the Mn-Si-O glass was applied in the BCTZ system as a sintering aids to prepare multilayer ceramic capacitor by BME process. The Yttrium/Silicon doped BaTiO3 material was applied as the constraining layer to inhibit the XY direction shrinkage and grain growth of BCTZ dielectrics while sintering. Then the constrained BCTZ will have smaller mean grain size after sintering process. The fast sintering technology was applied in this study also. It could reduce the internal stress caused by sintering shrinkage between base metal electrode and ceramic dielectric. The electrode continuity will become better and the capacitance will be increased. The experimental result shows that the constraining construction could inhibit the shrinkage and grain growth of BCTZ dielectrics indeed. The mean grain size could be inhibited around 0.6um after 1260 oC sintering process, the dielectric constant, dissipation factor and temperature dependence characters of capacitor will be affected.
27
吳平宏. "Low Sintering Temperature Behavior and Dielectric Properties of (Ba,Ca)(Ti,Zr,Mn)O3 in a Reducing Atmosphere." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/72818965619427188708.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
87
(Ba,Ca)(Ti,Zr,Mn)O3 would possess high dielectric constant. Because of the utilization of the base metals such as Ni and Cu, the multilayer capacitor must be sintered in a reducing environment and at lower temperature to reduce the stress of interface. The purposes of this study were to evaluate the effect of flux additive of MST on the sintering behavior and the dielectric properties in the different atmospheres. It was found that the reducing environment could enhance the sintering rate. It prevents the formation of the liquid phase and delays the diffusion of calcium ions into barium titanate. But it will be dedensified owing to the pore growth. The sintering temperature could be lowered to 1100℃ when more than 2% MST were added . The more MST was added, the more uniform the grains were but the more the pore growth was. Reducing atmosphere would enhance dielectric constant, in which Mn+3 would become Mn+2 and the Curie temperature would shift from 65℃ to 30℃. Higher sintering temperature would develop more oxygen vacancies which in turn would lower resistance and enhance dielectric loss. Mn would diffuse in BCTZM when MST was added, which would reduce dielectric loss and dielectric constant and make Curie temperature shift to lower temperatures. For preparing MnSiO3 and MnTiO3, the mixture of MnO2 and SiO2 was calcined in air to form MnMn6SiO12 first. At 1200℃, it melted and did not form MnSiO3 completely. However, when it was calcined at 1100℃ for 8 hours in the reducing atmosphere, more pure MnSiO3 could be obtained. MnTiO3 could be synthesized at 1250℃ for 4 hours in a reducing atmosphere. MST calcined in different atmospheres would possess different colors, which might be due to the different oxidation states of Mn.
28
Gaik, Teoh Lay, and 張莉毓. "Effect of the oxide conductive buffer layer on the electrical characteristics of Ba(Ti , Sn)O3 thin films." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/91227681832156889799.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
87
RF magnetron sputtering deposition of Ba(Ti,Sn)O3 ferroelectric thin film on Pt electrode was studied. La2CuO4 was used as a conductive buffer layer for the deposition of Ba(Ti,Sn)O3 thin films. Properties of the films including crystallization, microstructure and electrical properties were investigated. La2CuO4 is a metallic oxide having a perovskite structure as that of Ba(Ti,Sn)O3 ferroelectric materials. After post-deposition annealing, it was found that a polycrystalline film of La2CuO4 having a resistivity of 0.7 mΩ-cm could be prepared by RF magnetron sputtering. The results reveal the effect of the La2CuO4 buffer layer on promoting the crystallization of perovskite phase of the Ba(Ti,Sn)O3 films. The dielectric constant of 250 was obtained by deposition on the La2CuO4-buffered substrates at temperature 500℃. The leakage current problem of Ba(Ti,Sn)O3 thin film have been improved by the inserting La2CuO4 buffer layer. The hysteresis loop shows the ferroelectricity of the thin film. The La2CuO4-buffered substrates have higher value of the remanent polarization and lower value of the coercive field. At high deposition temperature, the atoms of La and Cu were diffused in the dielectric layer.
29
Chang, Sheng-Hao, and 張盛皓. "Microwave Characteristics of (Ba,Ca)(Ti,Zr)O3 Thin Films Deposited by RF Magnetron Sputtering for High Quality Capacitances." Thesis, 2007. http://ndltd.ncl.edu.tw/handle/93931946405061866489.
Full text
30
劉恒睿. "The Study of Ba(Zr,Ti)O3 Thin Films Deposited on LaNiO3 electrode by RF Magnetron Sputtering for microwave varactors." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/18601718609582075905.
Full text
31
Lai, Ga-Pon, and 賴家鵬. "Effect of Dy2O3 addition on the dielectric properties of (Ba,Ca)(Ti,Zr,Mn)O3 sintered at a reduced atmosphere." Thesis, 2003. http://ndltd.ncl.edu.tw/handle/04510553811087154284.
Full textAbstract:
碩士國立成功大學
資源工程學系碩博士班
91
In the previous studies, the addition of Mn or Ca in the BME MLCC was used to prevent the occurrence of semiconducting and the deterioration of insulation resistance. However, the addition of anti-redaction additives would generate oxygen vacancies that would lead to low insulation resistance and poor life stability under high electric filed. Generally, Dy and Nb were doped in BaTiO3 to improve the life stability of BME MLCCs during HALT. The raw materials (Ba0.96011Ca0.03988)(Ti0.82089Zr0.17911) O3（BCTZ）were doped with MnO and Nb2O5 to adjust Ba/Ti = 1. The samples then were added different amount of Dy2O3 and sintered at 1320℃ for 2 h in a reducing atmospheres. This investigation was to elucidate the effects of different addition of Dy2O3 in (Ba,Ca)(Ti,Zr) O3 on the microstructure and electricity properties. At Dy concentration x = 0.001, Dy occupied B-site and resulted in increasing lattice constant. In this condition, Ti-rich phase Ba6Ti17O40 formed produced and lead to liquid phase sintering and grain growth. Therefore, the insulation resistance deteriorated due to the presence of Ti-rich phase Ba6Ti17O40 and the decrease of the volume fraction of grain boundary. Experimental results reveal the ofεmax increased with increasing grain size. At the doping level of 0.003 mol% to 0.01 mol%, Dy substituted A-site of the BCTZ and resulted in semiconducting at room temperature. During the temperature rose, Dy2Ti2O7 was formed, which suppressed grain growth due to the pinning effect. Some of the Ca ions were forced to occupy the B site, which act as acceptors and lead to increasement of lattice constant. Simultaneously, the formation of oxygen vacancies that can trap more free electrons and slow down the decrease of the insulation resistance. For sample with Doping 0.015 mol%, the lattice constant and insulation resistance become to decreased compared with 0.01mol% doped sample. It indicated that the occupational sites of some Dy ions changed from A site to B site and, correspondingly the amounts Ca ions in B-site decreased.
32
Shy, Hsiou-Jeng, and 施修正. "The Study of Ba(Zr,Ti)O3 Thin Film Deposited on LaNiO3 Electrode by rf Magnetron Sputtering for DRAMs Applications." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/94023991690212175947.
Full text
33
Lin, Chia-Wei, and 林家煒. "The effect of SiO2 on the sintering behavior and dielectric properties of (Ba,Ca)(Ti,Zr)O3 in reducing atmospheres." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/57145003804198078136.
Full textAbstract:
碩士國立屏東科技大學
材料工程所
96
Sintering behavior in reducing the atmospheres, it will produce semiconductor and drop in the insulating resistance with ceramics. Add Calcium or Manganese, inhibit and resist this situation to produce semiconductor. The additive will produce oxygen vacancy while sintering under reducing the atmosphere. Enable the electricity degradation of the component, and the reliability is reduced. Therefore, we usually improve the question by adding some dopant. In the article, we try to understand in reducing atmospheres the effect of SiO2 on the sintering behavior and dielectric properties of BCTZ. For example, phase structure, dielectric properties, macrostructure etc. In addition, we use which X-ray powder diffraction, SEM and TEM analyze second phase, phase compositions and macrostructure. 0.3 mol% SiO2, add it in BCTZ ceramics powder, the density of trying one frits to reach the dense result in the liquid phase, improving dielectric properties. We observed obvious second phase from grain size above 3 mol% SiO2 after Sintering behavior in reducing the atmospheres. In addition, we prove that second phase had existence Si-rich by SEM-EDS. By creating synthetic phase, BaTiSiO5, we can get some results. BaTiSiO5 will make the insulating resistance drop, produced the semiconductor. Making use of analyzing physical and dielectric properties after sintering behavior, Effect of analyze structure in the physical and dielectric properties form SEM macrostructure.
34
Hayn, Silke. "First-principles calculations on the structural and thermodynamic stability of (Na1/2Bi1/2,Ba)TiO3 and Pb(Zr,Ti)O3." Phd thesis, 2013. http://tuprints.ulb.tu-darmstadt.de/3634/7/HaynAkzeptiertElektronisch.pdf.
Full textAbstract:
Piezoelectric materials couple polarization Pα and mechanical strain εβδ [1]. The technologically most used piezoelectric material system is the ferroelectric PbZr1− xTixO3 (PZT) [2,3]. Due to the toxicity of lead oxide, and to obtain properties beyond the range of PZT [2], such as a higher temperature of depolarization, larger Young’s modulus or higher cohesive stress, current research on ferroelectric materials devotes large resources to the identification of new lead-free materials [3].
The aim of this thesis is to improve the understanding of lead-free ferroelectric perovskite materials and eventually to guide the search for new ferroelectric materials. This is done by analyzing the structure and thermodynamic stability of different ferroelectric perovskite materials, focusing on PZT as reference and (Na1/2Bi1/2TiO3)1− x-(BaTiO3)x (BNT-BT). Ferroelectricity is an intrinsic material property that occurs only in materials with certain crystal structures [1]. Therefore, atomistic simulations are an appropriate tool to analyze ferroelectric materials. In this thesis the structure and thermodynamic stability of different ferroelectric perovskites are analyzed based on density functional theory (DFT) calculations.
As a first step chemical ordering and its influence on relaxation is analyzed. Chapter 3 shows that although chemical ordering is preferred in thermodynamic equilibrium for PZT, the driving force is too small to overcome diffusion barriers in bulk materials. In Chapter 4 a combination of DFT calculation and high resolution transmission electron microscopy (HRTEM) is used to analyze the cation distribution in BNT-BT. Finally, the solid solution BNT-BT is modeled according to the atomic distribution found in Chapter 4, and cation displacement is used as a measure of ferroelectricity. It is found, that the instabilities of the cation sites are a bilinear function of lattice parameter and composition. Also traits of the region showing improved ferroelectric properties are identified.
35
黃聆惠. "High Frequency and Microwave Frequency Characteristics of Ba(Zr,Ti)O3 Thin Films deposited by RF Magnetron Sputtering for MFIS varactors." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/62843695901261478405.
Full text
36
Wei-HsiangChao and 趙偉翔. "The Study of MnO2-Doped (Ba,Ca)(Ti,Sn,Hf)O3 Lead-Free Ceramics and Their Applications on the Piezoelectric Ultrasonic Motors." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/tt9ug8.
Full textAbstract:
碩士國立成功大學
電機工程學系
105
In this study, the development of lead-free (Ba,Ca)(Ti,Sn)O3 (BCTS) piezoelectric ceramics are carried out by conventional solid state reaction method. Firstly, we search the optimum boundary for (Ba1-xCax)(Ti1-ySny)O3 (x = 0.02-0.04, y = 0.04-0.06), we obtain (Ba0.97Ca0.03)(Ti0.96Sn0.04) has the greater TC = 97 oC, superior d33 = 415 pC/N and then using double-stages to modify our material. First stage, substituting Hf for Sn in the (Ba0.97Ca0.03)(Ti0.96Sn0.04-zHfz)O3 (BCTS0.04-zHz), revealing relatively higher TC = 113 oC and excellent piezoelectric properties kp = 49 %、kt = 45.7 %, Qm = 122.4 and d33 = 313 pC/N with z = 0.035, the most important thing is to improve the change rate of resonant frequency with increasing temperature. Second stage, dopig sintering aid a mole% MnO2 in the (Ba0.97Ca0.03)(Ti0.96Sn0.005Hf0.035)O3 (BCTSH–a Mn), revealing TC = 113 oC and kp = 36.4 %, kt = 36.0% and d33 = 230 pC/N with a = 2, the most noticeable thing is to refine grain size 22.59 μm efficiently and increase Qm = 340.8 obviously. Based on the material properties of ceramics above, the lead-free ceramics BCTSH+2Mn piezoelectric ceramics with high d33 and Qm values are choosen for fabrication of ultrasonic motor and investigate mechanism between d33, Qm and motor’s output characteristics, the output characteristics of lead-free piezoelectric motor : left-pull velocity = 3.21 mm/s、right-pull velocity = 3.39 mm/s、up-pull velocity = 2.56 mm/s and force 〉 2N. Eventually, our lead-free piezoelectric motor can pull 0.5 ml commercial insulin syringes successfully.
37
Chang, Chia-Hao, and 張家豪. "The Influences of Thermal Annealing and Oxygen Plasma Treatment on the Characteristics of High Dielectric Coefficient (Ba, Sr)(Ti, Zr)O3 Thin Films." Thesis, 2004. http://ndltd.ncl.edu.tw/handle/32495658390127546527.
Full textAbstract:
碩士國立中山大學
電機工程學系研究所
92
In this thesis, the reactive rf magnetron sputtering was used to deposit (Ba,Sr)(Ti,Zr)O3 (BSTZ) thin films on Pt/Ti/SiO2/Si substrate with the optimal parameters. The post-treatments of rapid thermal annealing (RTA), conventional thermal annealing (CTA), O2 plasma, N2 plasma, and N2O plasma respectively were used to promote the dielectric characteristics. The physical characteristics of BSTZ thin films were obtained by the analyses of XRD, SEM, and AFM. The influences of post-treatments on thin films were discussed. The electrical properties of BSTZ thin films were estimated through the measurement of leakage current on MIM structure with HP4194A and HP4156C semiconductor parameters analyzer. Also, the dependences of dielectric constants on applied voltage were discussed. After annealing treatments, the dielectric constants were increased and the leakage currents were decreased respectively. But with the higher annealing temperature of CTA, the larger leakage currents were obtained. In the different atmosphere of plasma treatments, the leakage currents were decreased obviously. The dielectric constant was about 295 after O2 plasma treatment of 6 minutes succeeded with RTA at 600℃ for 2 minutes； it reveals that the leakage current was about 1.38x10-9 A/cm2 under the applied electrical field of 0.1 MV/cm. Therefore, to combine the annealing and plasma treatments properly could increase the dielectric characteristics effectively.
38
Cheng, Ya-Fang, and 鄭雅芳. "Crystal Structrue and Dielectric Properties of Ba-Ti-O Compounds and Structure-Microwave Dielectric Property Relations in Ba1-xCax(Mg1/3Nb2/3)O3 Ceramics." Thesis, 2005. http://ndltd.ncl.edu.tw/handle/79340371063952285112.
Full textAbstract:
碩士國立成功大學
資源工程學系碩博士班
93
In the microwave ceramic material, we focus on two types of dielectric systems and discuss their structures and properties, respectively. (1)Complex perovskite structure of Ba1-xCax(Mg1/3Nb2/3)O3 system: As far as we're concerned, the microstructure and crystal structure considerably influence the dielectric properties of BCMN system. In view of crystal structure, the dielectric constant is associated with the distorted octahedra in the unit cell, the lower degree of distorted octahedra, the more free space for ions displacement which will result in the increasing dielectric constant. Besides, Ca2+ could be an effective dopant for the ordering degree. The quality factor of ratio 1:2 perovskite ceramics which is very sensitive to the B-site cation ordering could be improved as the degree of order increases. Nevertheless, the second phase and low relative density of sintered bulk would both decrease quality factor. The unit cell parameters decreased due to the contents of Ca2+ increased promote the τf increased. (2)Ti-O and Ba-Ti-O system: The stable phase of Ti-rich of Ba-Ti-O compounds, such as BaTiO3, Ba6Ti17O40, Ba4Ti13O9, BaTi4O9, and Ba2Ti9O20 are more useful in microwave ceramic material. According to variation of Ti/O ratio, we found out the relationship between connected types of Ti-O octahedra and their dielectric properties. With the increasing of Ti/O ratio , more octahedra connected to each other. When this happened, the center of cation ion has higher potential energy to deviate from the center, then the distorted octahedra formed. So with the Ti/O ratio increased, The type of shared octahdera tends to transform from perovskite-like structure to rutile-like structure. Besides, with Ba/Ti ratio decreased, fewer Ba2+ ions with more octahedra connection cause the displacement of Ba ions and form octahedral tilt in the meantime due to more free space around. The displacement of center ion in octahedra and tilted octahedra also causes octahedral distortion and results in polarization which gives better dielectric properties.
39
Lin, Ting-I., and 林庭逸. "The Study Li2CO3-Doped (Ba,Ca)(Ti,Sn,Hf)O3+MnO2 of Lead-Free Ceramic Using Tape Casting Method and Their Applications as Piezoelectric Pumps." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/eevd84.
Full text
40
蔡承琪. "以射頻磁控濺鍍法製備(Ba,Sr)(Ti,Sn)O3晶片電容薄膜及其特性之探討." Thesis, 1999. http://ndltd.ncl.edu.tw/handle/61856920499326998913.
Full textAbstract:
碩士國立成功大學
材料科學及工程學系
87
ABSTRACT In this study, ferroelectric thin film (Ba , Sr)(Ti ,Sn)O3 deposited onto n-type (100) Si substrate form target in composition of BaTiO3 , SrTiO3,and BaSnO3 mixed and sintered by R.F. magnetron sputtering method .The thin film may be characterized in term of amount of SrTiO3 , growth temperature , R.F. power , ambient pressure and partial pressure of O2 ,etc . Experimental results shows that deposition rate and crystallization of thin film increass with increasing R.F. power and the ambient pressure and partial pressure of O2 .The crystallization of thin film is advantaded predomi-nantly with increasing the preheated temperature of substrate . The dielectric permittivity increases with increasing the added amount of Sr and the temperature of substrate . The maximum value of permittivity is 225 at 30 mol% Sr under 5×10-3 torr working pressure , O2/Ar rate is 1/1 , 175W R.F. power and the temperature of substrate 500℃ .The leakage cur-rent of thin film improved with increasing the rate of O2/Ar . And the leakage current of thin film is 5∼8×10-7 A/cm2 when the ratio of O2/Ar is 1/1 .The hysteresis curve shows that the retained polarization of thin film increasing the amount of Sr . The parameters that compositions , temperature of substrate , R.F.power , working pressure and partial pressure of O2 etc are contralled effectively , and (Ba , Sr)(Ti ,Sn)O3 thin film can be appliced to DRAM of dielectric materi-
41
Mashkina, Elena [Verfasser]. "Structures, ionic conductivity and atomic diffusion in A(Ti1-xFex)O3-δ-derived [A(Ti-1-x-Fe-x)O-3-delta-derived] perovskites (A=Ca, Sr, Ba) / vorgelegt von Mashkina Elena." 2005. http://d-nb.info/976893657/34.
Full text