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The ceramic capacitors with excellent energy storage properties and wide operating temperature are the main challenges in power system applications. Here, the lead‐free (1‐x)Bi0.5Na0.5TiO3‐xCaTiO3 (abbreviated as BNT‐xCT) ceramics were synthesized through solid‐state reaction method. The introduction of CT reduced the temperature of permittivity peak of BNT ceramic, guaranteeing excellent thermal stability over a wide temperature range of −100 ∼ 136°C. Meanwhile, the long‐range order structure of BNT was destructed by structural distortion, and the relaxor behavior was enhanced after doping CT. Moreover, the direct current breakdown strength was improved from 203 to 455 kV/cm, and the high recoverable energy density (Wrec ∼ 2.74 J/cm3) with high efficiency (η ∼ 91%) was achieved for BNT‐0.25CT ceramic, along with a fast discharge speed (t0.9 ∼ 110 ns) superior cycle stability and thermal stability. Those properties enabled a promising practical prospect of BNT‐CT ceramics. [ABSTRACT FROM AUTHOR]

The effects of LB glass on the sintering behavior, structure, and dielectric properties for the Ba3.75Nd9.5Ti17.5(Cr0.5Nb0.5)0.5O54 (BNTCN) ceramic were investigated. The results showed that the LB glass, as an effective sintering aid, successfully lowered the sintering temperature of BNTCN ceramic by formation of the liquid phase. Furthermore, the change of the structure and decrease in grain size had influences on the electrical conductivity, thermal stability, and microwave dielectric properties for the BNTCN ceramics doped LB glass. Finally, the excellent microwave dielectric properties with εr = 73.4, Q × f = 5277 GHz, and τf = +7.1 ppm/°C were obtained for samples sintered at 950°C when x = 5, indicating the BNTCN ceramic doped with 5 wt% LB glass is a promoting LTCC material. [ABSTRACT FROM AUTHOR]

Gd2Zr3(MoO4)9 is a double trigonal molybdate crystallized in the space group R3¯c. The optimal microwave dielectric properties were achieved via solid‐state reaction at 725°C for Gd2Zr3(MoO4)9 ceramics: εr = 11.17, Q × f = 57 460 GHz, τf = −31.91 ppm/°C. The three‐dimensional framework type structure is formed by mixed MoO4 tetrahedron and ZrO6/GdO9 polyhedron. The analysis based on complex chemical bond theory shows that the Mo–O bonds account for majority contribution to controlling microwave dielectric properties. The MoO4 tetrahedron and ZrO6 octahedron stabilize the crystal structure by strong binding ability. As it was shown by Raman spectroscopy, the Raman‐active vibrations primarily originate from MoO4 tetrahedron, similarly to molybdate analogies. [ABSTRACT FROM AUTHOR]

Structure‐property relationships of Y2MgTiO6, a type of double perovskite materials, were investigated systematically. Rietveld refinement of XRD patterns confirmed that Y2MgTiO6 belongs to the P21/c space group and has a structure analogous to that of monoclinic Dy2MgTiO6. In accordance with the observed number of vibrational bands and group theoretical predictions, O and Y ions at the 4e site dominated the Raman peaks. The IR reflectivity spectrum indicated that the major contributions to the relative permittivity and intrinsic loss were modes lower than 500 cm−1. The measured relative permittivity closely approached the calculated values determined according to P‐V‐L theory, the Clausius‐Mossotti equation and IR fitted results. The larger bond energy for Mg–O bonds than for Ti–O bonds corresponds to a more stable octahedron of [MgO6], as verified by the octahedral distortion. Satisfactory microwave dielectric properties of Y2MgTiO6 ceramics were as follows: εr = 20.4 ± 0.8, Q × f = 42 060 ± 310 GHz, τf = −52 ± 3 ppm/°C, sintered at 1450°C. [ABSTRACT FROM AUTHOR]

In this study, intrinsic dielectric properties of ZnNb2O6 ceramics were investigated using P–V–L chemical bond theory and far‐infrared reflectivity spectra. The largest bond ionicity and bond susceptibility of Nb–O bonds suggest that the dielectric polarizability is mainly determined by Nb–O bonds. Relative permittivity, calculated via P–V–L bond theory, is close to experimental value determined using TE011 mode. The Nb–O bonds are also crucial for the structural stability. According to far‐infrared reflectivity spectra and complex dielectric function analysis, a relatively consistent result between calculated and measured dielectric properties, fit using classical damped oscillator mode, indicate that the B1u mode at 168.87 cm−1 provides majority contribution to the dielectric properties. [ABSTRACT FROM AUTHOR]

(1‐x)Sr0.7Pb0.15Bi0.1TiO3‐xBi4Ti3O12 ((1‐x)SPBT‐xBIT, x = 0‐0.125) bulk ceramics were developed and calcined via the solid‐state method, aimed at the application of pulsed power capacitors. The phase structures, temperature stability, hysteresis loop, and discharge properties were systematically investigated. Considering both the temperature stability and dielectric properties, 0.925SPBT‐0.075BIT bulk ceramics with a capacitance variation satisfying the X7R specification were developed for pulsed power capacitors. The energy storage density was 0.252 J/cm3, and the ceramics showed high temperature stability at 80 kV/cm. The discharge current waveforms of the 0.925SPBT‐0.075BIT ceramics were recorded. A high discharge power density of approximately 1.01 × 108 W/kg with an 8 Ω load resistor and short discharge period of 84 ns were achieved at 50 kV/cm. The good temperature stability properties and high power density show that the 0.925SPBT‐0.075BIT ceramics are well suited for pulsed power capacitors with a wide temperature range. [ABSTRACT FROM AUTHOR]

Abstract: The microwave dielectric ceramic Li9Zr3NbO13 was found and investigated. Prepared via the solid‐state reaction method, the Li9Zr3NbO13 formed as a Li2ZrO3‐type solid solution at 880‐900°C, with monoclinic structure in C2/c space group and Z = 4. Typically, the Li9Zr3NbO13 sintered at 900°C exhibited the excellent microwave dielectric properties of εr = 21.3, Q×f = 43 600 GHz (at 7.4 GHz), τf = 7.3 ppm/°C. [ABSTRACT FROM AUTHOR]

In this paper, the Li2/3(1− x)Sn1/3(1− x)Mg xO (LSM xO) ceramic systems were prepared by solid-state reaction using novel atmosphere-controlled sintering ( x = 0-4/7). Pure Li2SnO3 was observed for x = 0, the Li2Mg3SnO6 and Li2SnO3 coexisted for x = 1/7, and the coexistence of three kinds of phases was detected for x = 1/5 and 1/4, including Li4MgSn2O7 impurity phase. Pure Li2Mg3SnO6-like phase with cubic rock salt structure in Fm-3 m space group was obtained in the range of 1/3-4/7. All samples showed well-dense and smooth microstructures. The microwave dielectric properties highly depended on the phase composition, bond valence, FWHM of Raman spectrum, Raman shift, average grain sizes, and octahedral distortion. The LSM xO ceramics sintered at 1250°C for 5 hours possessed excellent comprehensive properties of εr = 15.43, Q×f = 80 902 GHz and τ f = +5.61 ppm/°C for x = 1/7. Typically, the LSM xO ceramics sintered at 1350°C for 5 hours showed a maximum Q × f of 168 330 GHz for x = 1/2. [ABSTRACT FROM AUTHOR]

This study presents the microwave dielectric properties calculation of (1- x)Ba3.75Nd9.5Cr0.25Nb0.25Ti17.5O54- xNdAlO3 ceramics where x denotes the volume molar fraction. From X-ray diffraction results, the solid solution limit is calculated to be about 0.76, where it forms a single BaNd2Ti4O12 phase in Region I (0≤ x<0.76), and both BaNd2Ti4O12 and NdAlO3 coexist in Region II (0.76≤ x<1). The solid solution limit is confirmed by independently calculating it from the dielectric constant data. There is less than 4% deviation between the measured dielectric constant (ε r) and the one calculated from the Maxwell-Wagner formula. The total quality factor ( Q) remains almost constant in Region I and increases rapidly with the volume molar fraction of NdAlO3 in Region II. The measured Q×f, where f is the resonant frequency, is also consistent with the calculated value in both regions. The temperature coefficient at the resonant frequency is −1.4 ppm/°C, which agrees well with the calculated value of 0 ppm/°C. In addition, we observed a close correlation between the bulk density and the phase evolution. [ABSTRACT FROM AUTHOR]

Abstract: The microwave dielectric ceramic Li9Zr3NbO13 was found and investigated. Prepared via the solid‐state reaction method, the Li9Zr3NbO13 formed as a Li2ZrO3‐type solid solution at 880‐900°C, with monoclinic structure in C2/c space group and Z = 4. Typically, the Li9Zr3NbO13 sintered at 900°C exhibited the excellent microwave dielectric properties of εr = 21.3, Q×f = 43 600 GHz (at 7.4 GHz), τf = 7.3 ppm/°C. [ABSTRACT FROM AUTHOR]