Sintering behavior and dielectric properties of Bi3+-substituted Nd(Zn0.5Ti0.5)O3 microwave ceramics

The sintering behavior and dielectric properties of Bi[Formula: see text]-substituted Nd(Zn[Formula: see text]Ti[Formula: see text]O3 (abbreviated as NZT) microwave ceramics (Nd[Formula: see text]Bi[Formula: see text])(Zn[Formula: see text]Ti[Formula: see text])O3 [Formula: see text] (abbreviated as NBZT) are investigated. XRD results reveal the formation of single perovskite solid solutions for [Formula: see text] samples. For [Formula: see text] samples, pyrochlore phase begins to segregate from the perovskite phase and its volume fraction increases with [Formula: see text]. B-site Zn[Formula: see text]/Ti[Formula: see text] 1:1 long range order (LRO) is detected by Raman Spectroscopy. The degree of LRO varies as a function of sintering conditions and chemical composition. The microwave dielectric properties of the composition are measured. By substituting Bi[Formula: see text] for Nd[Formula: see text], the temperature coefficient of resonant frequency [Formula: see text] tunes toward zero, however, the microwave quality factor, [Formula: see text] deteriorates. For [Formula: see text], [Formula: see text] reaches a minimum value of [Formula: see text] with relative permittivity of [Formula: see text] and [Formula: see text], respectively. The effect of Bi-doping on the [Formula: see text] value is discussed.

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

10.21203/rs.3.rs-206557/v1 ◽

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.

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

Journal of Advanced Dielectrics ◽

10.1142/s2010135x13200038 ◽

2013 ◽

Vol 03 (04) ◽

pp. 1320003 ◽

Cited By ~ 4

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.

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Temperature compensation effects of TiO2 on Ca[(Li1/3Nb2/3)0.8Sn0.2]O3−δ microwave dielectric ceramic

International Journal of Modern Physics B ◽

10.1142/s0217979217501922 ◽

2017 ◽

Vol 31 (27) ◽

pp. 1750192

Author(s):

Mingzhe Hu ◽

Huanghe Wei ◽

Lihua Xiao ◽

Kesheng Zhang ◽

Yongde Hao

Keyword(s):

Crystal Structure ◽

Dielectric Properties ◽

Perovskite Phase ◽

Microwave Dielectric Properties ◽

Microwave Dielectric Ceramic ◽

Microwave Ceramics ◽

Dielectric Ceramic ◽

Structure Transition ◽

Microwave Dielectric ◽

Dielectric Devices

The crystal structure and dielectric properties of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] microwave ceramics are investigated in the present paper. The crystal structure is probed by XRD patterns and their Rietveld refinement, results show that a single perovskite phase is formed in TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics with the crystal structure belonging to the orthorhombic Pbnm 62 space group. Raman spectra results indicate that the [Formula: see text]-site order–disorder structure transition is a key point to the dielectric loss of TiO2-modified Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramics at microwave frequencies. After properly modified by TiO2, the large negative temperature coefficient of Ca[(Li[Formula: see text]Nb[Formula: see text])[Formula: see text]Sn[Formula: see text]]O[Formula: see text] ceramic can be compensated and the optimal microwave dielectric properties can reach [Formula: see text] = 25.66, [Formula: see text] = 18,894 GHz and TCF = −6.3 ppm/[Formula: see text]C when sintered at 1170[Formula: see text]C for 2.5 h, which manifests itself for potential use in microwave dielectric devices for modern wireless communication.

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