Sintering behavior, phase structure and microwave dielectric properties of CeO2 added CaTiO3-SmAlO3 ceramics prepared by reaction sintering method

Zhou, Shicheng; Luan, Xiaowen; Hu, Sang; Zhou, Xiang; He, Sen; Wang, Xi; Zhang, Hailin; Chen, Xiuli; Zhou, Huanfu

doi:10.1016/j.ceramint.2020.09.231

Cited by 11 publications

(3 citation statements)

References 36 publications

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“…where τ fmix is the temperature coefficient of the resonant frequency of the two-phase composite and V 1 , V 2 and τ f1 , τ f2 are the volume fraction of each phase (here mainly MgSiO 3 and Mg 2 SiO 4 ) and the corresponding τ f value, respectively. On the other hand, the τ f value is also influenced by other factors such as crystal structure, microstructure, and porosity [32]. The final τ f value is determined by a combination of multiple factors.…”

Section: Resultsmentioning

confidence: 99%

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Wang,

Li,

Zhu

et al. 2023

Crystals

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Mg2SiO4 and MgSiO3 ceramics with superior microwave dielectric properties are considered to be promising candidates for 5G applications. However, a slight deviation from the stoichiometric Mg/Si ratio will significantly influence their microwave dielectric properties, which will hinder their practical applications. In this work, the xMgO-SiO2 (x = 1~2) ceramics were synthesized by a solid-state reaction method. The influence of the Mg/Si ratio x on the crystalline phase, microstructure, and microwave dielectric properties was investigated through X-ray diffraction (XRD), a scanning electron microscope (SEM), and the resonant cavity method. The XRD patterns revealed the coexistence of Mg2SiO4 and MgSiO3 within the x range of 1~2, which was further demonstrated by the energy-dispersive X-ray spectra. The SEM images show a typical polycrystalline morphology of ceramics with an inhomogeneous grain size distribution. It is found that the microwave dielectric properties fluctuate at both sides of the x range while those remain relatively stable with minor changes at the intermediate components, indicating an obvious low composition dependence helpful for practical applications. Further, a demonstrator of a microstrip patch antenna for 5G applications using the 1.5MgO-SiO2 ceramic was designed and fabricated, and a return loss of −16.2 dB was demonstrated, which demonstrated the potential applications.

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Section: Resultsmentioning

confidence: 99%

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Wang,

Li,

Zhu

et al. 2023

Crystals

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“…A dielectric filter neutralizes the undesirable characteristics of the two filters and provides a relatively low loss and volume. 4,5 Therefore, to enable microwave electronic equipment to benefit from the advantages of miniaturization, such as excellent stability, portability, and high level of integration, ceramics with low dielectric loss, high dielectric constant, and near-zero resonant-frequency temperature coefficient have become increasingly attractive. [6][7][8] K20 microwave dielectric ceramics, such as 95MCT, Li 2 TiO 3 , and LnNbO 4 (Table 1), are widely used in 5G base stations.…”

Section: Introductionmentioning

confidence: 99%

Microwave dielectric properties of V₂O_5/CeO₂ doped (Mg_0.95Ca_0.05)TiO₃‐MgO and their application to a dielectric filter

Shan,

Lu,

Guo

et al. 2024

Int J Applied Ceramic Tech

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The phase composition, microstructure, sintering characteristics, and microwave dielectric properties of nonstoichiometric MgTiO3‐CaTiO3 ceramics containing an additional 0.2 mol MgO, compositely doped with various amounts of V2O5 and CeO2 additives, were studied. The results revealed that adding an optimum amount of V2O5 and CeO2 could effectively impede second‐phase formation in Mg0.95Ca0.05TiO3‐MgO. High amounts of Mg2+ can react with MgTi2O5 to reduce the content of the secondary phase. The addition facilitated the densification of the microstructure and reduction of sintering temperature. Moreover, the dielectric performances of the material were significantly influenced by V2O5 and CeO2. Mg0.95Ca0.05TiO3‐MgO doped with 0.75 wt% CeO2 exhibited excellent frequency and temperature stabilities. In particular, when co‐doped with 0.5 wt% V2O5 and 0.75 wt% CeO2, Mg0.95Ca0.05TiO3‐MgO exhibited optimum properties after sintering at 1300°C for 2 h; a dielectric constant εr ∼ 19.92 (7 GHz),a Q×f value ∼ 65,236 GHz, and a τf value ∼ −2.03 ppm/°C. This indicates the potential of the material for microwave communication applications. Finally, a dielectric filter with a center frequency of 11.55 GHz was successfully designed and fabricated using a Mg0.95Ca0.05TiO3‐MgO sample co‐doped with 0.5 wt% V2O5 and 0.75 wt% CeO2.The filter exhibited excellent performance with a bandwidth of less than 1.5 is about 40 MHz, the loss at the center frequency point was 0.7 dB, and the 3‐dB bandwidth exceeded 200 MHz, which holds a significant practical value.

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“…Among the varieties of perovskite ferroelectrics of the ABO 3 type, it is worth highlighting ceramics based on calcium (CaTiO 3 ), barium (BaTiO 3 ), and strontium (SrTiO 3 ) titanates, which have a number of unique properties, such as a high dielectric constant, thermal stability, and spontaneous polarization, which makes them the most common materials for use as a basis for microelectronic devices, including the creation of anode materials for solid oxide fuel cells [24][25][26][27]. Moreover, considerable focus has been directed not just toward the techniques for producing these ceramics but also toward exploring strategies for altering them through doping with various compounds (usually Nd 2 O 3 , Nb 2 O 5 , Y 2 O 3 , CeO 2 , La 2 O 3 ), the use of which makes it possible to create ceramics with improved properties, and to enhance their resistance both to external influences and to long-term thermal heating during operation [28][29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

Study of the Effect of Adding Nb2O5 on Calcium Titanate-Based Ferroelectric Ceramics

Zdorovets,

Moldabayeva,

Zhumatayeva

et al. 2023

ChemEngineering

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This paper considers the effect of adding niobium oxide (Nb2O5) to ferroelectric ceramics based on calcium titanate (CaTiO3), and establishes a connection between the observed alterations in strength and dielectric properties and the variation in the Nb2O5 dopant concentration in the ceramics’ composition. The method of mechanochemical solid-phase synthesis was used as the main method for obtaining the ceramics, followed by thermal sintering under specified conditions in order to form a stable phase composition of the ceramics, and to initialize phase transformations in the composition. Based on the assessment of the phase composition of the resulting ceramics, it was determined that a growth in the Nb2O5 dopant concentration beyond 0.10 mol results in the formation of an orthorhombic-phase CaNb2O4 of the Pbcm(57) spatial system, the weight contribution of which grows. A growth in the Nb2O5 additive concentration results in the formation of two-phase ceramics, the formation of which allows for an enhancement in the mechanical strength of ceramics and resistance to external influences. During the study of the dependence of the strength properties on the dopant concentration alteration, a three-stage change in hardness and crack resistance was established, regarding both structural ordering and phase transformations. The measurement of dielectric characteristics showed the direct dependence of dielectric losses and the dielectric constant on the phase composition of ceramics.

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Sintering behavior, phase structure and microwave dielectric properties of CeO2 added CaTiO3-SmAlO3 ceramics prepared by reaction sintering method

Cited by 11 publications

References 36 publications

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Microwave dielectric properties of V₂O_5/CeO₂ doped (Mg_0.95Ca_0.05)TiO₃‐MgO and their application to a dielectric filter

Study of the Effect of Adding Nb2O5 on Calcium Titanate-Based Ferroelectric Ceramics

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Sintering behavior, phase structure and microwave dielectric properties of CeO2 added CaTiO3-SmAlO3 ceramics prepared by reaction sintering method

Cited by 11 publications

References 36 publications

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Crystal Structure and Microwave Dielectric Property of xMgO-SiO2 (x = 1~2) System for 5G Applications

Microwave dielectric properties of V2O5/CeO2 doped (Mg0.95Ca0.05)TiO3‐MgO and their application to a dielectric filter

Study of the Effect of Adding Nb2O5 on Calcium Titanate-Based Ferroelectric Ceramics

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Microwave dielectric properties of V₂O_5/CeO₂ doped (Mg_0.95Ca_0.05)TiO₃‐MgO and their application to a dielectric filter