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 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 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.

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 ceramics

1997 ◽  
Vol 12 (2) ◽  
pp. 518-525 ◽  
Author(s):  
In-Tae Kim ◽  
Yoon-Ho Kim ◽  
Su Jin Chung
Keyword(s):  
Dielectric Properties ◽  
Microwave Dielectric Properties ◽  
Nucleation And Growth ◽  
Annealing Process ◽  
Network Analyzer ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Transmission Electron ◽  
Rich Liquid

Ordering and microwave dielectric properties of Ba(Ni1/3Nb2/3)O3 have been investigated using x-ray diffraction, transmission electron microscopy, energy-dispersive spectroscopy, and a network analyzer. Samples sintered at 1400 °C for 2 h were disordered and showed the presence of Nb-rich liquid phase at grain boundary junctions. Degree of ordering increased with following annealing at 1300 °C. Growth of the ordered region during the annealing process was discussed in terms of nucleation and growth. A long-range order parameter was calculated using structure factor. Measurements of microwave dielectric properties showed that permittivity and temperature coefficient of resonant frequency decreased with ordering, and quality factor increased with ordering. The correlation between microwave dielectric properties and ordering was discussed in terms of covalency of bonding, inhomogeneous charge distribution, and defects concentration.

A new low-loss microwave dielectric ceramic for low temperature cofired ceramic applications

2010 ◽  
Vol 25 (7) ◽  
pp. 1235-1238 ◽  
Author(s):  
Huanfu Zhou ◽  
Xiuli Chen ◽  
Liang Fang ◽  
Dongjin Chu ◽  
Hong Wang
Keyword(s):  
Dielectric Properties ◽  
Low Temperature ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Microwave Dielectric Ceramic ◽  
X Ray Diffraction ◽  
Low Loss ◽  
Dielectric Ceramic ◽  
X Ray ◽  
Microwave Dielectric

A new low sintering temperature microwave dielectric ceramic, Li2ZnTi3O8, was investigated. X-ray diffraction data show that Li2ZnTi3O8 has a cubic structure [P4332(212)] with lattice parameters a = 8.37506 Å, V = 587.44 Å3, and Z = 4 when the sintering temperature is 1050 °C. The Li2ZnTi3O8 ceramic exhibits good microwave dielectric properties with εr about 26.2, Q×f value about 62,000 GHz, and τf about −15 ppm/°C. The addition of BaCu(B2O5) can effectively lower the sintering temperature from 1050 to 900 °C without degrading the microwave dielectric properties. Compatibility with Ag electrode indicates this material can be applied to low temperature cofired ceramic devices.

scholarly journals TAILORING THE MICROWAVE DIELECTRIC PROPERTIES OF ALKALINE EARTH GEHLENITE TYPE CERAMIC

2013 ◽  
Vol 22 ◽  
pp. 173-178 ◽  
Author(s):  
B. ARUN ◽  
K. M. MANU ◽  
M. T. SEBASTIAN
Keyword(s):  
Dielectric Properties ◽  
Alkaline Earth ◽  
Microwave Dielectric Properties ◽  
Partial Substitution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isovalent Substitution ◽  
Microwave Dielectric ◽  
Low Permittivity ◽  
Zinc Borosilicate

The effect of glass fluxing and isovalent substitution on the microwave dielectric properties of low permittivity Sr 2 Al 2 SiO 7 (SAS) ceramic has been investigated. X – ray diffraction pattern of all the compositions indicate the formation of tetragonal Gehlenite type ceramics with space group [Formula: see text] (no. 113). The addition of small amounts of lithium magnesium zinc borosilicate (LMZBS) glass to Sr 2 Al 2 SiO 7 ceramic enhanced the densification. Glass fluxing also improved the quality factor and relative permittivity. A small partial substitution of Al 3+ and Si 4+ by Ga 3+ and Ge 4+ was found to degrade the dielectric properties of SAS ceramic. The composition Sr 2 Al 2 SiO 7 + 1 wt. % LMZBS glass showed the best dielectric properties with εr = 7.3, Qu×f = 36000 GHz and τf = −23.0 ppm/°C.

Sintering Temperature Influence on Microwave Dielectric Properties of TiO2-ZrO2 Ceramics

2010 ◽  
Vol 660-661 ◽  
pp. 646-651
Author(s):  
José Vitor C. Souza ◽  
Pedro José Castro ◽  
Maria do Carmo de Andrade Nono ◽  
Sergio Luiz Mineiro
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Dielectric Constants ◽  
Dielectric Resonators ◽  
Temperature Influence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Dielectric Ceramics

Dielectric ceramics have been widely investigated and used for microwave applications such as resonators and filters. The present study deals with the influence of sintering temperature on microwave dielectric properties of TiO2 ceramics with 10, 20, and 30 wt% ZrO2. Three compositions have been developed through mixing procedures and then tested for each sintering temperature: 1500 and 1400 °C. X-ray diffraction and scanning electron microscopy are carried out aiming to explain the ceramic behavior of each sample. The dielectric constants of different ceramics for both temperatures varied from 85.4 to 62.6, while their quality factor due to dielectric losses varied from 3110 to 1630. The Q decrease is attributed to the non uniform grain growth and to the obtained crystalline phases. The best microwave parameters were obtained for the ceramics sintered at 1400 °C, which can be applied in microwave circuits as dielectric resonators.

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.

Microstructure and Microwave Dielectric Properties of Ba5(Nb1-xTax)4O15 (x = 0 ~ 0.5) Ceramics

2007 ◽  
Vol 280-283 ◽  
pp. 9-12 ◽  
Author(s):  
Fei Zhao ◽  
Zhen Xing Yue ◽  
Ying Chun Zhang ◽  
Zhi Lun Gui ◽  
Long Tu Li
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Large Range ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Relative Content ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Scanning Electron

The Ba5(Nb1-xTax)4O15 (x=0~0.5) solid-solution ceramics with hexagonal perovskite structure were prepared by solid-state oxide route. The phases and structure of the sintered ceramics were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The influences of composition and sintering temperature on the bulk density, microstructure and microwave dielectric properties were also investigated. As the value of x increased from 0 to 0.5, the Q×f value increases from 36,049 to 49,493 GHz (at ~9GHz), whereas the dielectric constant (εr) decreases from 39.21 to 33.03 and the temperature coefficient of resonant frequency (τf ) decreases from 78.6 to 19.4 ppm/oC. The results indicate that the microwave dielectric properties of Ba5(Nb1-xTax)4O15 ceramics can be easily modified in a large range by changing the relative content of Ta to Nb.

Effect of Li0.8Ca0.2F1.2 on Sintering and Microwave Dielectric Properties of (Mg0.95Zn0.05)(Ti0.8Sn0.2)O4 Ceramics

2013 ◽  
Vol 538 ◽  
pp. 266-269
Author(s):  
Guo Guang Yao ◽  
Hong Ma ◽  
Xiu Lao Tian
Keyword(s):  
Crystal Structure ◽  
Dielectric Properties ◽  
Liquid Phase ◽  
Microwave Dielectric Properties ◽  
Liquid Phase Sintering ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric

The effects of Li0.8Ca0.2F1.2 doped on the sinterability, phase constitutions and microwave dielectric properties of (Mg0.95Zn0.05)2(Ti0.8Sn0.2)O4 (MZTS) ceramics were investigated. The crystal structure was analyzed using X-ray diffraction. With 3.0 wt% Li0.8Ca0.2F1.2 addition, the densification sintering of MZTS ceramics was significantly lowed from 1325 oC to 1150 oC due to the liquid phase sintering. Secondary phases CaTiO3 and MgO were formed by reaction between MZTS and CaF2. 3.0wt% Li0.8Ca0.2F1.2-doped MZTS ceramics at 1150 oC for 5 h exhibited dielectric properties: εr=13.4, Qxf=46 672.3 GHz (at 9.3 GHz).

Sinterability and Microwave Dielectric Properties of Li2CO3-V2O5 Added Mg4Nb2O9-CaTiO3 Composite Ceramics

2010 ◽  
Vol 663-665 ◽  
pp. 1196-1199
Author(s):  
Cui Jin Pei ◽  
Guo Guang Yao ◽  
Hong Ma ◽  
Xiu Lao Tian
Keyword(s):  
Dielectric Properties ◽  
Sintering Temperature ◽  
Microwave Dielectric Properties ◽  
Composite Ceramics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Microwave Dielectric ◽  
Microscopy Techniques ◽  
Co Doped ◽  
Scanning Electron

The effects of Li2CO3-V2O5 (LV) co-doped on the sinterability, phase compositions and microwave dielectric properties of Mg4Nb2O9-CaTiO3 composite ceramics have been investigated. The phase compositions and microstructure were analyzed using X-ray diffraction, energy dispersive X-ray analysis and scanning electron microscopy techniques. The densification sintering temperature is lowed from 1275oC to 1200oC with an amount LV addition. For the specimen with 1.5 wt% LV addition sintered at 1200oC for 5 h exhibited dielectric properties: εr=23, Q·f=24 000 GHz (at 7.7GHz ), τf =1.0 ppm/oC. These properties were correlated with the formation of non-stoichiometric compound Mg4(Nb1-xTix)2O9-δ.

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