CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Liang Shi,Xueying Wang,Rui Peng,Yongcheng Lu,Cheng Liu,Dainan Zhang,Huaiwu Zhang
A series of Mn 2+ -doped Mg 1-x Mn x Ta 2 O 6 (x = 0.02, 0.04, 0.06, 0.08, 0.10, 0.12) ceramics were synthesized by solid-state reaction method. The influence of introducing Mn–O bonds as a partial replacement for Mg–O bonds on the lattice and microwave dielectric properties was systematically investigated. XRD and Rietveld refinement confirm that Mn 2+ occupies the 2a Wyckoff position and forms a pure trirutile phase. Moreover, based on the chemical bond theory, the dielectric constant is mainly affected by the ionicity of the Ta–O bond. The lattice and dielectric properties remain relatively stable with Mn 2+ doping below 0.1, but excessive Mn 2+ doping leads to pronounced distortion of the lattice, which is not beneficial for lattice stability and microwave dielectric properties. Introducing an appropriate amount of Mn–O bonds with high bond dissociation energy facilitates MgO6 octahedron stability, which improves the thermal stability of the lattice. Accordingly, the microwave dielectric properties for 0.06 Mn 2+ -doped MgTa 2 O 6 ceramics were determined: ε r = 28, Q × f = 105,000 GHz (at 7.5 GHz), τ f = 19.5 ppm/ ° C.
研究领域:
材料科学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Liang Shi,Xueying Wang,Rui Peng,Gang Wang,Cheng Liu,Xiaolei Shi,Dainan Zhang,Huaiwu Zhang
Ni 2+ modified MgTa 2 O 6 ceramics with a trirutile phase and space group P4 2 /mnm were obtained. The correlations between crystallographic characteristics and microwave dielectric performance of MgTa 2 O 6 ceramics were systematically studied based on the chemistry bond theory (PVL theory) for the first time. The results indicate that the introduction of Ni 2+ causes a change in polarizability and the Mg–O bond ionicity, which contributes to the variation of dielectric constant. Moreover, the lattice energy, and packing fraction, full width at half maximum of the Raman peak of Ta–O bond, as the quantitative characterization of crystallographic parameters, regulate the dielectric loss of MgTa 2 O 6 ceramics in GHz frequency band. In addition, the study of sintering behavior shows that the densification and micromorphology are the crucial factors affecting the microwave dielectric performance. Typically, Ni 2+ doping on the A-site of MgTa 2 O 6 can effectively promote the Q × f values to 173,000 GHz (at 7.43 GHz), which ensures its applicability in 5G communication technology.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Haotian Liu,Liang Shi,Cheng Liu,Dainan Zhang,Kui Liu,Huaiwu Zhang
Ion substitution engineering is an effective procedure in refining the crystal structure and performance for the microwave dielectric ceramics . In this study, MgTa 2 O 6- x F 2 x ( x = 0.1, 0.2, 0.3, 0.4, 0.5, 0.6) ceramics were synthesized using the conventional solid-phase reaction method. The effects of F − substitution for O 2− in MgTa 2 O 6 matrix were systematically investigated. The correlations between the crystal structure and the microwave dielectric properties were analyzed. The solution of F − into the oxygen sites was confirmed by the XRD and Raman spectra. The introduction of F − improved the morphology as well as the stability of the crystal structure significantly, which successfully depressed the electromagnetic wave loss through the bulk and enhanced the quality factor ( Q × f ) by nearly 50%, reaching up to 179,000 GHz (7.15 GHz) in the sample of x = 0.4 at the sintering temperature of 1425 °C.
研究领域:
材料科学
·
电子材料
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2024
·Vol. 108
·期 2
·e20232
·
IF 3.5
Yang Gao,Junjie Chen,Weishuang Fang,Haiyi Peng,Tianyi Xie,Haishen Ren,Xiaogang Yao,Huixing Lin
Mg 1/3 A1 1/3 A2 1/3 Ta 2 O 6 ceramics (where A1 and A2 represent Co, Ni, or Zn) were prepared using the solid-phase reaction route. The results of X-ray diffraction and Raman tests showed that (Co 1/2 Ni 1/2 ) 2+ , (Co 1/ 2 Zn 1/2 ) 2+ , and (Ni 1/2 Zn 1/2 ) 2+ ions replaced Mg 2+ ions in the lattice of MgTa 2 O 6 , resulting in the formation of a pure tri-rutile structure. All three complex ions could significantly reduce the sintering temperature of the ceramics (by 150°C–200°C) and could broaden the sintering window. The large deviation (48.8%–69.2%) between the porosity corrected relative permittivity ε r-corr. and the theoretical relative permittivity ε r-theo. might be due to the overestimation of the ionic polarizability of Ta 5+ by Shannon. (Co 1/2 Ni 1/2 ) 2+ has the most significant effect of increasing the bond energy of ceramic A–O bonds, reducing the τ f value from 51 to 36 ppm/°C. In addition, the mechanisms affecting their dielectric properties are discussed based on bond ionicity ( f i ), full width at half maximum (FWHM) of Raman peak, and bond energy ( E ). Mg 1/3 Co 1/3 Ni 1/3 Ta 2 O 6 ceramic sintered at 1350°C have the most excellent microwave dielectric properties: ε r = 26.8, Q × f = 86,000 GHz, and τ f = 36 ppm/°C.
研究领域:
材料科学
·
电子材料
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）