Dielectric breakdown of BaO–B2O3–ZnO–[(BaZr0.2Ti0.80)O3]0.85 [(Ba0.70Ca0.30)TiO3]0.15 glass-ceramic composites (original) (raw)
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Dielectric behavior of lanthanum added barium strontium titanate borosilicate glass ceramics
Barium strontium titanate borosilicate glasses were prepared by melt-quench method and subsequent crystallization by regulated heat treatment process. The dielectric behavior of investigated glass ceramic samples shows a diffuse phase transition. The double relaxation was observed in one of the glass ceramic samples due to crystallographic transition from orthorhombic to tetragonal and tetragonal to cubic structure with change in temperature. The peak values of dielectric constant and dielectric loss of this glass ceramic sample was found to be 48,289 and 0.01, respectively, at frequency 20 Hz. Lanthanum oxide served the purpose of nucleating agent for crystallization of glass ceramics and hence, enhances the value of dielectric constant. Such glass ceramics may be used in making capacitors for high energy storage purpose.
Dielectric behavior of perovskite glass ceramics
The recent developments of energy storage devices are concerned with larger energy storage ability, low loss and good temperature stability. It has a great technological importance in engineering science. The dielectric materials like ceramics and glass ceramics have great interest in electronic ceramic industry due to above concern. The ceramic dielectrics are used as a capacitive element in electronic circuits. The perovskite glass ceramics have very high dielectric constant and low dielectric loss. The high dielectric constant in glass ceramics is attributed to space charge polarization. In order to produce glass ceramics of high dielectric constant, barium titanate glass ceramics is the first discovered ferroelectric perovskite. In this review article, we are summarizing the dielectric behavior of perovskite glass ceramics such as BaTiO3, SrTiO3, PbTiO3, (Ba,Sr)TiO3 and (Pb,Sr)TiO3.
Microstructural and dielectric behaviour of glass ceramics in the system PbO-BaO-TiO2-B2O3-SiO2
Bulletin of Materials Science, 1986
Glasses in the system PbO-BaO-TiO2-BzO3-SiO2 with and without PzO5 as nucleant have been prepared. The glass samples were ceramized based on DTA studies. The ferroelectric phase crystallizing out has been found to be BaTiO3 from XRD. The optical and scanning electron micrographs show the presence of BaTiO3 as major phase. In these glass ceramic samples, dielectric constant and dissipation factor are approximately constant with temperature and frequency upto the glass transition temperature T~ and thereafter increase sharply with temperature and finally level off. The addition of P20~ as nucleant and molar ratio of (PbO + BaO) to TiO2 has marked influence on the dielectric behaviour and composition of ferroelcetric phase crystallizing out.
Microwave dielectric properties of glass–ceramic composites for low temperature co-firable ceramics
Materials Chemistry and Physics, 2003
The densification behavior and the microwave dielectric properties of RBS–(MgCa)TiO3 (R: MgO, CaO, SrO or BaO, B: B2O3 and S: SiO2) glass–ceramic composite materials were systemically examined. The BaBS glass materials possess highest dielectric constant (K) and quality factor (Q) among the RBS glass materials and the BaBS–(Mg,Ca)TiO3 composites materials also exhibited largest K- and Q-value among the RBS–(Mg,Ca)TiO3 glass–ceramic composite materials. Comparison on the measured K-(Q-) values from the calculated K-(Q-) composition lines implies that the formation of additional crystalline phase other than (Mg,Ca)TiO3 materials markedly modifies the Q-value, but is insignificantly altering the K-value for the composite materials.
Journal of the European …, 2004
Vitrification and crystallization properties of glasses of the system BaO-TiO 2 -PbO-Al 2 O 3 (B 2 O 3 ) were investigated. The fields of vitrification based on ternary diagrams of BaTiO 3 -PbTiO 3 -(TiO 2 +Al 2 O 3 +B 2 O 3 ) with varied contents of Al 2 O 3 (10, 13, 16 mol.%) and B 2 O 3 (3, 15 mol.%) were identified. The glass compositions obtained had relatively low melting temperature (%1450 C). These stable glasses could be thermally treated to produce glass-ceramics characterized by fine-crystalline structures and regulated permittivity associated to the contents of ferroelectric phases. The phase composition of such glass-ceramics included different Pb x Ba 1-x TiO 3 solid solutions depending on the starting chemical composition. Permittivity of the obtained materials (f=800 kHz, T=25 C) varied from 20 to 680 relatively to the time of crystallization. #
High Dielectric Constant Polymer Ceramic Composites
MRS Proceedings, 1999
A new polymer-ceramic composite, using the newly developed relaxor ferroelectric polymer that has a high room temperature dielectric constant as the matrix, is reported. Different kinds of ceramic powders were studied and homogeneous composite thin films (20μm) were fabricated. It was observed that the increase of the dielectric constant of the composites with the ceramic content could be described quite well by the expression developed by Yamada et al., when the ceramic content is below 60% by volume. The experimental data shows that the relative dielectric constant of composites using PMN-PT powders can reach more than 250 with weak temperature dependence (i.e., the dielectric constant changes little in a broad temperature range). In addition to high permittivity, the composite prepared in clean environment also has high breakdown field strength (120MV/m), which yields an energy storage density more than 14J/cm3. The dielectric behavior of the composite at various frequencies was ...
Dielectric Properties of La2O3 Doped Composite (PbxSr1−x)TiO3 Borosilicate Glass Ceramic
Journal of Ceramics, 2013
Ferroelectric (PbxSr1−x)TiO3 (PST) perovskite phase has been crystallized in borosilicate glassy matrix with a suitable choice of composition and heat treatment schedule. La2O3 is a donor dopant for PST and can make it semiconducting. Dispersion of semiconducting perovskite phase in insulating glassy matrix in glass-ceramic samples may lead to the formation of space charge polarization around crystal-glass interface, leading to a high value of effective dielectric constant, εr. Therefore, with the aim of the developing glass ceramics with high dielectric constant, glasses in the system 64[(PbxSr1−x)O·TiO2]-25[2SiO2·B2O3]-5[K2O]-5[BaO]-1[La2O3] have been prepared (0.5≤x≤1). It is found that the addition of La2O3 strongly affected the crystallization and dielectric behavior of glass-ceramic with PST perovskite phase. All glass ceramic samples show a diffuse broad Curie peak in their εr versus T plots. Curie peak temperature, Tc, depends on compositions of the glass-ceramic samples as ...