scholarly journals Sintering Characteristic, Structure, Microwave Dielectric Properties and Compatibility with Ag of Novel 3MgO-B2O3-xwt% Ba(CuB2)O5-ywt% H3BO3 Ceramics

2021 ◽  
Author(s):  
Haiquan WANG ◽  
Shixuan LI ◽  
Kangguo WANG ◽  
Xi WANG ◽  
Hailin ZHANG ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Microwave Properties ◽  
Potential Candidate ◽  
Optimum Temperature ◽  
Microwave Ceramics ◽  
Characteristic Structure ◽  
Microwave Dielectric ◽  
Diffraction Peaks ◽  
Two Phases

Abstract In this study, 3MgO-B2O3-xwt%BCB-ywt%H3BO3 (2 ≤ x ≤ 8, 0 ≤ y ≤ 20) ceramics were sintered at the optimum temperature to form Mg3B2O6 and MgO phases. The effects of H3BO3 and BCB on product characteristics, phase transition, microstructure, and microwave properties of 3Mg-B2O3 ceramics were investigated. The intensities of diffraction peaks of two phases varied with changing the x and y values. After sintering at 950 °C, the ceramics with x = 6 and y = 15 achieved excellent microwave properties with a εr of 6.72, Q × f of 83205 GHz, and τf of −65.05 ppm/℃. Besides, the ceramic with x = 8 and y = 5 sintered at 925 ℃ also achieved good microwave dielectric properties with a εr of 6.64, Q × f of 78173 GHz, and τf of −57.27 ppm/℃. The sintering temperatures of above both ceramics are well lower than the melting point of Ag, showing promising applications in low temperature cofired ceramic devices. In particular, these two ceramics can be used as potential candidate materials for microwave ceramics for 5G technology, provided that τf can be further optimized.

Effects of zinc substitution on the dielectric properties of Ca5Nb4TiO17 microwave ceramics

2013 ◽  
Vol 03 (04) ◽  
pp. 1320003 ◽  
Author(s):  
Chunchun Li ◽  
Xiaoyong Wei ◽  
Haixue Yan ◽  
Michael J. Reece
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Behavior ◽  
Potential Candidate ◽  
Strongly Correlated ◽  
Microwave Ceramics ◽  
Microwave Dielectric ◽  
Method Effects

Ca 5-x Zn x Nb 4 TiO 17 ceramics with 0 ≤ x ≤ 0.4 were prepared through a solid-state reaction method. Effects of zinc substitution on sintering behavior and microwave dielectric properties of Ca 5 Nb 4 TiO 17 ceramics were investigated. The sintering temperature was significantly lowered from 1480°C for pure Ca 5 Nb 4 TiO 17 to 1260°C for x = 0.4. The microwave dielectric properties are strongly correlated with the composition. It is worth noting that the temperature coefficient of resonant frequency (τf) displays a tendency toward positive value, ranging from −126.4 ppm/°C to −8.6 ppm/°C. A temperature stable microwave ceramic with dielectric constant of 52 and Q × f value of 9937 GHz is achieved at x = 0.4 and is a potential candidate for application as cores in dielectrically loaded antennas.

Mechanism of Quality Factor Compensation by Nb2O5 Addition for Dielectric Properties of Low-T Sintered ZST Microwave Ceramics

2000 ◽  
Vol 658 ◽  
Author(s):  
Yong H. Park ◽  
Moo Y. Shin ◽  
Hyung H. Kim ◽  
Kyung H. Ko
Keyword(s):  
Dielectric Properties ◽  
Grain Boundaries ◽  
Quality Factor ◽  
Microwave Dielectric Properties ◽  
Microwave Ceramics ◽  
Microwave Dielectric ◽  
Post Annealing ◽  
X Band ◽  
Second Phases ◽  
Nb Addition

ABSTRACTIt has been known that some additives such as Nb2O5 are efficient quality factor compensators to potential additives for low-T sintering of (Zr0.8Sn0.2)TiO4such asZnO. The compensation mechanism of Nb2O5was analyzed in the light of its effects on the Zn incorporation in grains. ZST ceramics were prepared by conventional mixed oxide method and their microwave dielectric properties including quality factor, permittivity and temperature coefficient frequency (TCF) were measured at X-band. After sintering at 1350 and 1400oC, samples were post-annealed at 900∼1100oC. It was found that as Nb2O5 was added, the quality factor of 6 mol % ZnO-ZST specimens increased from 24000 to 44000 without any sacrificing of other dielectric properties such as permittivity and TCF. According to TEM and XRD, Nb addition tends to enhance Zn diffusion toward grain boundaries while Nb moved in the opposite direction. Due to the fact that no second phases were formed, it was assumed that the redistribution of Zn and Nb could play a major role in the enhancement mechanism of quality factor. Post-annealing can also be a secondary booster for the quality factor of ZST. After annealing at 900∼1100oC, the quality factor of a specimen with additives, increased again up to 48000 due to further decrease of oxygen vacancies resulting from further out-diffusion of Zn toward grain boundaries and incorporation of Nb into the grain.

Microwave Dielectric Properties of Elastomers Containing Particulate Metal Fillers

1990 ◽  
Vol 189 ◽  
Author(s):  
Barry G.M. Helme
Keyword(s):  
Dielectric Properties ◽  
Metal Particle ◽  
Microwave Dielectric Properties ◽  
Skin Depth ◽  
High Conductivity ◽  
Microwave Properties ◽  
Thick Sample ◽  
Microwave Dielectric ◽  
Particulate Metal ◽  
Filler Particles

ABSTRACTElastomers have been manufactured containing varying concentrations of particles of Ag/Al, Ag/Cu, Ag/Ni, Ag/glass (G3), Ni/graphite, Ni, and Ag. Their dielectric and microwave properties have been measured between 0.4 GHz and 40 GHz and at temperatures between ambient and 100°C. The filler particles are small relative to the microwave wavelength but larger than the skin depth. Sheets of these elastomers of up to 2 mm thickness gave been subjected to cyclical stretching of up to 40% elongation and up to 10° cycles. The microwave properties have been measured as a function of numbers of stretching cycles and composition of elastomer. Some correlations were found between the composition, the microwave properties and the number of stretch cycles completed.It was found in general that repeated stretching degraded the initially high conductivity of the loaded elastomers. This effect was also revealed by the increase in microwave transmissivity through the sheets, and a decrease in reflectivity. Formulations of elastomer-metal particle mix have recently been produced which have a microwave transmissivity more Phan 80 dB below the incident signal, for a 2 mm thick sample, even after 106 stretching cycles of 20% elongation. This property is of great value for the use of the elastomer as a reflective microwave shield.

Studies on Structural, Microwave Dielectric Properties, and Low-Temperature Sintering of 1.52Li2O-0.36Nb2O5-1.34TiO2 Ceramic

2012 ◽  
Vol 512-515 ◽  
pp. 1226-1230
Author(s):  
Qun Zeng ◽  
Yong Heng Zhou
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
Low Temperature Sintering ◽  
Dielectric Ceramic ◽  
Microwave Dielectric ◽  
M Phase ◽  
Two Phases

The structure, microwave dielectric properties and low-temperature sintering of a new Li2O-Nb2O5-TiO2 system ceramic with the Li2O: Nb2O5: TiO2 mole ratio of 1.52: 0.36: 1.34 have been investigated in this study. The 1.52Li2O-0.36Nb2O5-1.34TiO2 (LNT) ceramic is composed of two phases, the “M-Phase” and Li2TiO3 solid solution (Li2TiO3ss) phase. This new microwave dielectric ceramic has low intrinsic sintering temperature ( ~ 1100 oC ) and good microwave dielectric properties of middle permittivity (εr ~38.6), high Q×f value up to 7712 GHz, and near zero τf value (~ 4.64 ppm/oC). In addition, the sintering temperature of the LNT ceramics could be lowered down effectively from 1100 oC to 900 oC by adding 1 wt.% B2O3. Good microwave dielectric properties of εr = 42.5, Q*f =6819 GHz and τf = 2.7 ppm/oC could be obtained at 900 oC, which indicate the ceramics would be promising candidates for low-temperature co-fired ceramics (LTCC) applications.

Influences of MnCO3 Doping on Processing Parameters and Dielectric Properties of ZnNb2O6 Microwave Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 23-26
Author(s):  
J. Luo ◽  
Z.Y. Pang ◽  
Y.S. Lin ◽  
Zhao Xian Xiong
Keyword(s):  
Dielectric Properties ◽  
Ceramic Body ◽  
Microwave Dielectric Properties ◽  
Microwave Frequency ◽  
Solid State Reaction Method ◽  
Processing Parameters ◽  
Microwave Ceramics ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Ceramic Microstructure

MnCO3 was added into ZnNb2O6 ceramics to obtain excellent microwave dielectric properties. The samples were prepared by conventional solid-state reaction method. The effects of the amount of MnCO3 on sintering temperatures, ceramic densities and contraction were systematically investigated. The crystalline structure of ceramic body was analyzed by XRD. The ceramic microstructure was observed by SEM. The dielectric properties of ZnNb2O6 ceramics were measured by a vector network analyzer at microwave frequency, which showed: er = 22.65, Q×f = 36700 GHz (loaded value) and tf = -40 ppm/°C.

Preparation and Microwave Dielectric Properties of xBaZn2Ti4O11-(1-x)BaNd2Ti4O12 Ceramics

2017 ◽  
Vol 726 ◽  
pp. 210-214
Author(s):  
Xu Wang ◽  
Ren Li Fu ◽  
Yue Xu ◽  
Yang Yang ◽  
Jun De Cai ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Phase System ◽  
Microwave Ceramics ◽  
Two Phase ◽  
Microwave Dielectric ◽  
X Band ◽  
High Dielectric

xBaZn2Ti4O11–(1-x)BaNd2Ti4O12 (x = 0.18–0.30) ceramics were prepared by solid-state reaction method and their microwave dielectric properties were investigated with the purpose of finding a microwave ceramics with high dielectric constant (εr), high quality factor (Q×f ) and zero temperature coefficient of resonant frequency (τf).The two phase system BaZn2Ti4O11–BaNd2Ti4O12 affected the unit cell volume and the microstructure, the microwave dielectric properties (εr, Q×f, τf). As increasing x from 0.18 to 0.30, the main phase composition was BaNd2Ti4O12. Therefore, the εr decreased from 64.9 to 60.3 and the Q×f values raised from 11,350GHz to 13,210GHz, and the τf values decreased from 7ppm/° to -5ppm/°.The 0.22BaZn2Ti4O11–0.78BaNd2Ti4O12 ceramics sintered at 1250°C for 4 h displayed the best dielectric constant εr,Q×f and τf, as 63.9, 12380 GHz and-0.1 ppm/° respectively.

Microwave Dielectric Properties of MgNb2O6 Ceramics Prepared via High Energy Ball Milling Method

2013 ◽  
Vol 631-632 ◽  
pp. 499-503
Author(s):  
Zhi Fen Fu ◽  
Jian Li Ma ◽  
Peng Liu ◽  
Yong Xin Tang
Keyword(s):  
Dielectric Properties ◽  
Ball Milling ◽  
Microwave Dielectric Properties ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Potential Candidate ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Milling Method ◽  
Energy Ball

The effects of high-energy ball milling and subsequent calcinations on the mixture of MgO and Nb2O5 are investigated. It is found that the pure MgNb2O6 phase can be synthesized at 800 °C for 5 h by using high-energy ball milling method. MgNb2O6 ceramics were prepared at 1220 °C by using calcined powders of milled 15 h, which is lower 100 °C than that required by using the conventional solid state reaction method. The microwave dielectric properties of MgNb2O6 ceramic with εr = 19.7 and Qf = 29 044 GHz were obtained by the High-energy ball milling method, which made it a potential candidate for application.

Effect of V2O5 and ZnO Additives on the Sintering Temperature and Microwave Dielectric Properties of Ca[(Li1/3Nb2/3) 0.8Ti 0.2]O3-δ Ceramics

2011 ◽  
Vol 239-242 ◽  
pp. 77-80 ◽  
Author(s):  
Ji Hong Liao ◽  
Ying Dai ◽  
Ren Zhou Yang ◽  
Wen Chen
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Solid State Reaction Method ◽  
Sintering Behavior ◽  
Conventional Solid State Reaction ◽  
Microwave Dielectric ◽  
Diffraction Peaks ◽  
Dielectric Ceramics ◽  
The Relationship

Low-temperature sintered Ca[(Li1/3Nb2/3)0.8Ti0.2]O3-δ (CLNT) microwave dielectric ceramics with V2O5 and ZnO additives were prepared by the conventional solid state reaction method. The sintering behavior and microwave dielectric properties of CLNT ceramics were investigated. The main diffraction peaks of all the specimens sintered at the temperature under 1150◦C split due to the coexistence of the non-stoichiometric phase and stoichiometric phase, which all possess CaTiO3-type perovskite structures. ZnO and V2O5 combined additives lowered the sintering temperature of CLNT ceramics from 1150◦C to 1090◦C. and the Qf values were improved from 18,210 GHz to 20,740 GHz. The CLNT ceramics with 4 wt% ZnO addition sintered at 1090◦C showed good microwave dielectric properties with εr ~39.7, Qf ~20,740 GHz, τf ~8.6 ppm/◦C. The relationship between dielectric properties and the sintering behavior was also discussed.

scholarly journals Effect of B2O3 On the Microstructure and Microwave Dielectric Properties of Ba(Mg1/3Nb2/3)O3 Ceramics

2021 ◽  
Author(s):  
Sen Peng ◽  
Wenxiang Yao ◽  
Wenfei Zeng ◽  
Jianming Xu
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Secondary Phase ◽  
Positive Influence ◽  
Sem Analysis ◽  
Sintering Behavior ◽  
Microwave Ceramics ◽  
Dense Microstructure ◽  
Microwave Dielectric ◽  
Scanning Electron

Abstract The influences of different doping contents of additive B2O3 on the sintering behavior, microstructure and microwave properties of Ba(Mg1/3Nb2/3)O3 (BMN) microwave ceramics were studied. The main phase in the sintered ceramics was crystallized as Ba(Mg1/3Nb2/3)O3 (BMN). Ba2B2O5 as secondary phase was observed with x ≥ 10. Scanning electron microscopy (SEM) analysis revealed that the photograph of optimally nonstoichiometric ceramics sintered at 900 ℃ for 5 h displayed a dense microstructure. The dielectric properties and microstructures of BMN ceramics were very sensitive to the nonstoichiometry. The addition of B2O3 had a positive influence on the Q×f value, for example the sample with x = 7 showed the highest Q×f value of 89800 GHz. Finally, excellent microwave dielectric properties (εr = 31.6, Q×f = 89,800 GHz and τf = 3.6 ppm/℃) were achieved for the sample with x = 7 sintered at 900 ℃ for 5 h.

Sign in / Sign up

Export Citation Format

Share Document