Microwave dielectric properties of oriented BaLa4Ti4O15 ceramics fabricated by templated grain growth

2004 ◽  
Vol 833 ◽  
Author(s):  
Yuko Fukami ◽  
Kensuke Wada ◽  
Ken-ichi Kakimoto
Keyword(s):  
Dielectric Properties ◽  
Grain Growth ◽  
Microwave Dielectric Properties ◽  
Molten Salt Synthesis ◽  
X Ray Diffraction ◽  
Templated Grain Growth ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Growth Method ◽  
Large Anisotropy

ABSTRACTDense and highly textured BaLa4Ti4O15 (BLT) ceramics was fabricated by templated grain growth method. Plate-like BLT particles prepared via a molten salt synthesis using NaCl flux were mixed with B LT powders obtained by the conventional solid state method. X-ray diffraction and scanning electron microscope studies of the textured ceramics showed plate-like BLT grains aligned parallel to the casting direction. Large anisotropy was found in the dielectric properties.

scholarly journals Effects of (Mg1/3Sb2/3)4+ Substitution on the Structure and Microwave Dielectric Properties of Ce2Zr3x(Mg1/3Sb2/3)3-3x(MoO4)9 Ceramics

2020 ◽  
Author(s):  
Zhou Xu ◽  
Sun Jiajia ◽  
Zhang Ningkang ◽  
Sun Huazhang ◽  
Tao Wenhong ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Far Infrared ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Refinement Method ◽  
Traditional Solid State Method

Abstract Ce2[Zr1-x(Mg1/3Sb2/3)x]3(MoO4)9 (0.02≤x≤0.10) ceramics were prepared well through the traditional solid-state method. A single phase, belonging to the space group of R-3c, was detected by using X-ray diffraction at sintering temperatures ranging from 700 to 850 °C. The crystallization micro-structural of specimens was examined by applying Scanning electron microscopy. The structural refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bonds parameters and microwave dielectric properties were calculated and analyzed by P-V-L theory. Ce2[Zr0.94(Mg1/3Sb2/3)0.06]3(MoO4)9 ceramics with excellent dielectric properties: εr = 10.37, Q×f = 71748 GHz and τf = −13.6 ppm/°C sintered at 725 °C for 6 hours.

scholarly journals Effects of (Mg1/3Sb2/3)4+ substitution on the structure and microwave dielectric properties of Ce2Zr3(Mg1/3Sb2/3)3-3(MoO4)9 ceramics

2021 ◽  
Author(s):  
Zhou Xu ◽  
Liu Lintao ◽  
Sun Jiajia ◽  
Zhang Ningkang ◽  
Sun Huazhang ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Microwave Dielectric Properties ◽  
Far Infrared ◽  
Structural Refinement ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Refinement Method ◽  
Traditional Solid State Method

Abstract Ce 2 [Zr 1-x (Mg 1/3 Sb 2/3 ) x ] 3 (MoO 4 ) 9 (0.02≤x≤0.10) ceramics were prepared well through the traditional solid-state method. A single phase, belonging to the space group of R-3c, was detected by using X-ray diffraction at sintering temperatures ranging from 700 to 850 °C. The crystallization micro-structural of specimens was examined by applying Scanning electron microscopy. The structural refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bonds parameters and microwave dielectric properties were calculated and analyzed by P-V-L theory. Ce 2 [Zr 0.94 (Mg 1/3 Sb 2/3 ) 0.06 ] 3 (MoO 4 ) 9 ceramics with excellent dielectric properties: ε r = 10.37, Q×f = 71748 GHz and τ f = −13.6 ppm/°C sintered at 725 °C for 6 hours.

Tuning the Microwave Dielectric Properties of Nd0.96Yb0.04(Mg0.5Sn0.5)O3 by Introducing Ca0.8Sr0.2TiO3

2015 ◽  
Vol 1119 ◽  
pp. 451-455
Author(s):  
Yih Chien Chen ◽  
Chih Hung Li ◽  
Hua Xian Liu ◽  
Jing Yu Fu
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Ceramic System ◽  
Solid State Method ◽  
X Ray ◽  
Microwave Dielectric ◽  
Conventional Solid State Method ◽  
Diffraction Patterns

The influence of sintering temperature on the microwave dielectric properties and microstructure of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system were investigated with a view to their application in microwave devices. The (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic systems were prepared using the conventional solid-state method. The X-ray diffraction patterns of the (1-y)Nd0.96Yb0.04(Mg0.5Sn0.5)O3-yCa0.8Sr0.2TiO3 ceramic system shifted to higher angle as y increased. A dielectric constant of 38.2, a quality factor (Q×f) of 53,500 GHz, and a temperature coefficient of resonant frequency of-3 ppm/°Cwere obtained when the 0.4 Nd0.96Yb0.04(Mg0.5Sn0.5)O3–0.6Ca0.8Sr0.2TiO3 ceramic system was sintered at 1600 °C for 4h.

scholarly journals Effects of (Mg1/3Sb2/3)4+ substitution on the structure and microwave dielectric properties of Ce2Zr3(MoO4)9 ceramics

2021 ◽  
Author(s):  
Xu Zhou ◽  
Lintao Liu ◽  
Jiajia Sun ◽  
Ningkang Zhang ◽  
Huazhang Sun ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Single Phase ◽  
Structure Refinement ◽  
Microwave Dielectric Properties ◽  
Far Infrared ◽  
X Ray Diffraction ◽  
Solid State Method ◽  
Microwave Dielectric ◽  
Refinement Method ◽  
Traditional Solid State Method

AbstractCe2[Zr1−x(Mg1/3Sb2/3)x]3(MoO4)9 (0.02 ⩽ x ⩽ 0.10) ceramics were prepared by the traditional solid-state method. A single phase, belonging to the space group of $$R⩈erline 3 c$$ R 3 ¯ c , was detected by using X-ray diffraction at the sintering temperatures ranging from 700 to 850 °C. The microstructures of samples were examined by applying scanning electron microscopy (SEM). The crystal structure refinement of these samples was investigated in detail by performing the Rietveld refinement method. The intrinsic properties were calculated and explored via far-infrared reflectivity spectroscopy. The correlations between the chemical bond parameters and microwave dielectric properties were calculated and analyzed by Phillips-van Vechten-Levine (P-V-L) theory. Ce2[Zr0.94(Mg1/3Sb2/3)0.06]3(MoO4)9 ceramics with excellent dielectric properties were sintered at 725 °C for 6 h (εr = 10.37, Q×f = 71,748 GHz, and τf = −13.6 ppm/°C, εr is the dielectric constant, Q×f is the quality factor, and τf is the temperature coefficient of resonant frequency).

scholarly journals Sintering behaviour and microwave dielectric properties of MgO-2B2O3-xwt%BaCu(B2O5)-ywt%H3BO3 ceramics

2021 ◽  
Author(s):  
Haiquan Wang ◽  
Shixuan Li ◽  
Kangguo Wang ◽  
Xiuli Chen ◽  
Huanfu Zhou
Keyword(s):  
Dielectric Properties ◽  
Bulk Density ◽  
Single Phase ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
X Ray Diffraction ◽  
Microwave Dielectrics ◽  
X Ray ◽  
Microwave Dielectric ◽  
Sintering Behaviour

AbstractThis study investigates the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 series ceramics synthesised by solid-state reaction. According to the X-ray diffraction and microstructural analyses, the as-prepared MgO-2B2O3 ceramics possess a single-phase structure with a rod-like morphology. The effects of different quantities of H3BO3 and BaCu(B2O5) (BCB) on the bulk density, sintering behaviour, and microwave dielectric properties of the MgO-2B2O3 ceramics were investigated. Accordingly, the optimal sintering temperature was obtained by adding 30 wt% H3BO3 and 8 wt% BCB. We also reduced the sintering temperature to 825 °C. Furthermore, the addition of 40 wt% H3BO3 and 4 wt% BCB increased the quality factor, permittivity, and temperature coefficient of resonance frequency of MgO-2B2O3 to 44,306 GHz (at 15 GHz), 5.1, and −32 ppm/°C, respectively. These properties make MgO-2B2O3 a viable low-temperature co-fired ceramic with broad applications in microwave dielectrics.

scholarly journals Structure, Defects and Microwave Dielectric Properties of Al-doped and Al/Nd Co-doped Ba4Nd9.33Ti18O54 Ceramics

2021 ◽  
Author(s):  
Weijia Guo ◽  
Zhiyu Ma ◽  
Yu Luo ◽  
Yugu Chen ◽  
Zhenxing Yue ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Resonant Frequency ◽  
Microwave Dielectric Properties ◽  
Relative Dielectric Constant ◽  
Doping Amount ◽  
Solid State Method ◽  
Depolarization Current ◽  
Structure Defects ◽  
Microwave Dielectric ◽  
Co Doped

Abstract Ba4Nd9.33Ti18-zAl4z/3O54 (BNT-A, 0 ≤ z ≤ 2) and Ba4Nd9.33+z/3Ti18-zAlzO54 (BNT-AN, 0 ≤ z ≤ 2) ceramics were prepared by solid state method, and the effects of the two doping methods on microwave dielectric properties were compared. As the doping amount z increased, the relative dielectric constant (εr) and the temperature coefficient of resonant frequency (τf) values of the ceramics decreased, and the quality factor (Q, usually expressed by Q×f, where f is the resonant frequency) of the ceramics obviously increased when z ≤ 1.5. With the same z value, the εr and Q×f values of Al/Nd co-doped ceramics are both higher than those of Al-doped ceramics. Rietveld refinement, Raman spectroscopy and thermally stimulated depolarization current (TSDC) technique were applied to clarify the relationship among the structure, defects and microwave dielectric properties. It is shown that the Q×f values of those ceramics were closely related to the strength of the A-site cation vibration and the concentration of oxygen vacancies (B). Excellent microwave dielectric properties of εr = 72.2, Q×f = 16480 GHz, and τf = +14.3 ppm/℃ were achieved in BNT-AN ceramics with z = 1.25.

HIGH THERMAL STABILITY OF MICROWAVE DIELECTRIC PROPERTIES OF CaTi1-x(Nb1/2Fe1/2)xO3 CERAMICS

2011 ◽  
Vol 01 (04) ◽  
pp. 417-427 ◽  
Author(s):  
A. D. S. BRUNO COSTA ◽  
M. C. ROMEU ◽  
R. C. S. COSTA ◽  
T. S. M. FERNANDES ◽  
F. W. DE O. AMARANTE ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Solid Solutions ◽  
Microwave Dielectric Properties ◽  
Titanium Content ◽  
Milling Process ◽  
Solid State Method ◽  
Small Shift ◽  
X Ray ◽  
Microwave Dielectric

This paper presents a study of the structure and microwave properties of [Formula: see text] substituted into the Ti 4+ site of calcium titanate ceramics. The structural and dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, was done. The microwave dielectric properties of solid solutions in CaTi 1-x( Nb 1/2 Fe 1/2)x O 3, (CNFTOX with x = 0.1 to x = 1) is discussed. The modified CaTiO3 (CTO) ceramics were prepared by a new procedure in the solid-state method. A study of the variations of the ball-milling process was done. The calcinations were done at 900°C for 3 and 5 h respectively, and the sintering at 1100°C, for 3 h. The structural property studies of the ceramics were investigated by X-ray diffraction (XRD) and Raman spectroscopy. The X-ray analysis showed that all samples have an orthorhombic structure. The refinement analysis of all samples were also duly performed and discussed. The nine scattering bands centered at 183, 227, 247, 288, 338, 470, 490 and 805 cm-1 were observed. Several peaks presented a small shift as a function of the x value. All Raman spectra in the studied samples showed a small band at 805 cm-1, which is a function of the x value. The dielectric permittivity and loss at microwave frequencies (MW) were investigated. For both calcination treatments (900°C for 3 and 5 h), the dielectric permittivity decreased with a decrease of the titanium content. Dielectric permittivity values in the range of 20 to 80 were obtained. It was also observed that a higher number of balls in the milling process contribute to the increase of the εr values. The CNFTO has an excellent microwave property at x = 0.6, with a temperature coefficient of resonant frequency (τf) near zero (τf = 2.8 ppm/°C).

scholarly journals Influence of B2O3 doping on synthesis of MgTiO3 ceramics from recycled magnesia-hercynite materials

2021 ◽  
Vol 8 (12) ◽  
pp. 125901
Author(s):  
Xiaodong Jia ◽  
Shuo Mao ◽  
Lin Tian ◽  
Shujiang Chen ◽  
Guohua Li ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Raw Materials ◽  
Microwave Dielectric Properties ◽  
Synthesis Rate ◽  
Cement Kiln ◽  
X Ray Diffraction ◽  
Optimum Amount ◽  
X Ray ◽  
Microwave Dielectric ◽  
Microstructural Studies

Abstract Herein, magnesium metatitanate (MgTiO3) ceramics were synthesised using recycled magnesia-hercynite (MH) bricks as the raw materials to achieve solid waste reusing of cement kiln refractories. The recycled MH materials were mixed with anatase TiO2 to investigate the effect of addition of doped B2O3 during the synthesis of MgTiO3 ceramics at 1400 °C. Phase compositions and microstructural studies were performed using x-ray diffraction (XRD) and scanning electron microscope (SEM), respectively. In addition, energy-dispersive spectroscopy (EDS) was conducted and the dielectric properties of the samples were studied. Results show that the addition of B2O3 can promote sintering, improve shrinkage, promote densification, stabilise MgTiO3 lattice, and inhibit the formation of MgTiO3. In addition, the presence of appropriate amount of B2O3 can accelerate the material diffusion and result in grain growth through the formation of intercrystalline liquid phase. Results also suggest that an increase in dielectric constant results in a decrease in dielectric loss. It was concluded that 2 wt% was the optimum amount of B2O3 required to obtain the most favourable synthesis rate of MgTiO3 (98.2%). The samples exhibited a maximum density of 3.69 g·cm−3 and excellent microwave dielectric properties at ε r = 18.28 and tanδ = 0.086.

scholarly journals Structural, optical and microwave dielectric properties of Ba(Ti1−xSnx)4O9, 0 ≤ x ≤ 0.7 ceramics

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Asad Ali ◽  
Sarir Uddin ◽  
Madan Lal ◽  
Abid Zaman ◽  
Zafar Iqbal ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Orthorhombic Symmetry ◽  
X Ray Diffraction ◽  
Low Dielectric ◽  
Microwave Dielectric ◽  
Ceramic Samples ◽  
Red Color ◽  
High Dielectric ◽  
Quality Factor Q

AbstractSn-doped BaTi4O9 (BT4) dielectric ceramics were prepared by a mixed oxide route. Preliminary X-ray diffraction (XRD) structural study shows that the ceramic samples have orthorhombic symmetry with space group (Pnmm). Scanning electron microscopy (SEM) shows that the grain size of the samples decreases with an increase in Sn4+ content. The presence of the metal oxide efficient group was revealed by Fourier transform infrared (FTIR) spectroscopy. The photoluminescence spectra of the ceramic samples reported red color ~ 603, 604, 606.5 and 605 nm with excitation energy ~ 2.06, 2.05, 2.04 and 2.05 eV for Sn4+ content with x = 0.0, 0.3, 0.5, and 0.7, respectively. The microwave dielectric properties of these ceramic samples were investigated by an impedance analyzer. The excellent microwave dielectric properties i.e. high dielectric constant (εr = 57.29), high-quality factor (Qf = 11,852), or low-dielectric loss (3.007) has been observed.

scholarly journals Phase, microstructure and microwave dielectric properties of Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics

2015 ◽  
Vol 33 (1) ◽  
pp. 95-99 ◽  
Author(s):  
Abdul Manan ◽  
Dil Nawaz Khan ◽  
Atta Ullah ◽  
Arbab Safeer Ahmad
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Scanning Electron

AbstractMg0:95Ni0:05Ti0:98Zr0:02O3 ceramics was prepared via conventional solid-state mixed-oxide route. The phase, microstructure and microwave dielectric properties of the sintered samples were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and a vector network analyzer. The microstructure comprised of circular and elongated plate-like grains. The semi quantitative analysis (EDS) of the circular and elongated grains revealed the existence of Mg0:95Ni0:05T2O5 as a secondary phase along with the parent Mg0:95Ni0:05Ti0:98Zr0:02O3 phase, which was consistent with the XRD findings. In the present study, εr ~17.1, Qufo~195855 ± 2550 GHz and τf ~ -46 ppm/K was achieved for the synthesized Mg0:95Ni0:05Ti0:98Zr0:02O3 ceramics sintered at 1325 °C for 4 h.

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