JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2022
·Vol. 33
·期 15
·11625-11631
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IF 2.779
Xing Zhuo,Weng Juhai,Ma Chi
A series of Ga 3+ -doped Zn 2 GeO 4 willemite ceramics, in a general formula Zn 2+0.5 x Ge 1− x Ga x O 4 (0.1 ≤ x ≤ 0.4), were prepared and the influence of Ga 3+ doping on the phase composition, structure, microstructure, and microwave dielectric properties were studied. XRD, SEM, and Raman analysis evidence that by moderate gallium substitution in the nominal Zn 2 GeO 4 , the unfavorable ZnO phase was suppressed, while a low-loss ZnGa 2 O 4 phase was induced. With increasing doping content, the ZnGa 2 O 4 phase increases in phase percentage and becomes dominant (~ 69%) after x = 0.3. Due to the mixture rule, both relative permittivity and quality factor were improved, which is related to the superior dielectric properties of ZnGa 2 O 4 compared to Zn 2 GeO 4 . The microwave dielectric properties show a remarkable dependence on the composition. Sintered at 1230 °C, a combination of dielectric performances with ε r ~ 9.4, Q × f ~ 97,000 GHz, and τ f ~ − 30.7 ppm/°C was accessed in the x = 0.4 composition.
研究领域:
材料科学
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电子工程
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DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
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2023
·
IF 5.7
Xiaoyu Li,Naichao Chen,Jin Cheng,Xianqiang Chen,Biao Guo,Fei Jin,Hong Wang
The Li 2 MoO 4 -MoO 3 ceramic system can be densely sintered at ultralow temperatures (< 500 °C). However, the phase composition of the Li 2 MoO 4 -MoO 3 system at a molar ratio of 1:1 has always been controversial. In this study, the traditional solid-state method was used to synthesize Li 4 Mo 5 O 17 (400 °C, 10 h) and Li 2 Mo 2 O 7 (350–400 °C, 4 h). Li 2 Mo 2 O 7 is an intermediate phase that can be converted to Li 4 Mo 5 O 17 at higher temperatures. The Li 4 Mo 5 O 17 ceramic could be sintered and densified at only 490 °C in air, exhibiting a relative density of 95.6% and excellent dielectric properties , including ε ′= 12.79 and tan δ = 0.0004 at 1 GHz. Such an ultralow sintering temperature and dielectric loss indicate that the Li 4 Mo 5 O 17 ceramic is a good candidate for high-frequency capacitance applications.
研究领域:
材料科学
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电子材料
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DOI
高影响因子
JOURNAL OF ELECTROCERAMICS
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2023
·Vol. 51
·期 1
·51-58
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IF 1.7
Zhang Yu,Ma Jianli,Li Chang,Chen Chen,She Yubin
The reaction sintering, without calcination and following re-grinding, has been paid increasing attention. Non - stoichiometric Li 2 Mg 3 Sn 1 − x O 6 ( x = 0.00, 0.02, 0.04, 0.06, 0.08, 0.10) ceramics were successfully gained through reaction sintering process in the study, and its phase composition, morphology and dielectric characteristics were studied. This XRD patterns of Li 2 Mg 3 Sn 1 − x O 6 samples prepared after sintering at 1,305 ℃ for 6 h indicates that green bodies are mainly composed of Li 2 Mg 3 SnO 6 phase, accompanied by the second phase of Mg 2 SnO 4 . A host of pores, elliptic - like grains and wrinkle - like grains were visibly observed from the SEM images of Li 2 Mg 3 Sn 1 − x O 6 ceramics, which is because of the severe volatilization of Li elements at high temperature. The apparent density, relative permittivity, quality factor and temperature coefficient of resonant frequency of samples will be devastate owing to porous morphology and Mg 2 SnO 4 phase to a large extent. Finally, when x = 0.08, Li 2 Mg 3 Sn 0.92 O 6 ceramics have optimal dielectric performances: ε r = 9.133, Q×f = 55,429 GHz, τ f = -36.1 ppm/℃.
研究领域:
材料科学
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陶瓷工程
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DOI
高影响因子
JOURNAL OF NUCLEAR MATERIALS
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2020
·
IF 2.485
Yi Ding,Zhengdi Jiang,Tianheng Xiong,Zimei Bai,Dandan Zhao,Hui Dan,Tao Duan
Zircon is important ceramic used widely due to its excellent properties, in particular for nuclear waste immobilization . However, it is difficult to obtain mono-phase zircon with high yield, usually result in double-phase ZrO 2 /ZrSiO 4 ceramics. Herein, Ce-doped double-phase 0.2Zr 1- x Ce x O 2 /Zr 1- y Ce y SiO 4 (0 ≤ x + y ≤ 1) ceramics were fabricated and their phase and microstructure evolution were studied. The results demonstrated that Ce content has great influence on the phase composition and microstructure. The ceramics with 0 ≤ x + y < 0.1 are tetragonal-ZrSiO 4 , monoclinic-ZrO 2 and tetragonal-ZrO 2 phases, with 0.1 ≤ x + y ≤ 0.3 are tetragonal-ZrSiO 4 , monoclinic-ZrO 2 , tetragonal-ZrO 2 and cubic-ZrO 2 phases, with 0.3 < x + y ≤ 0.6 are tetragonal-ZrSiO 4 , tetragonal-ZrO 2 and cubic-ZrO 2 phases, and with 0.6 < x + y ≤ 1 are cubic-ZrO 2 and Ce 2 Si 2 O 7 phases. With increasing Ce-doping content, the ZrSiO 4 retained the tetragonal phase, while ZrO 2 transformed from monoclinic to stable cubic phase. Furthermore, lattice parameters , grain size and compactness increased with increasing Ce content.
研究领域:
材料科学
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核废物处理
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DOI
高影响因子
CATALYSIS COMMUNICATIONS
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2014
·
IF 3.32
Fuhai Yu,Yanjie Wang,Hailian Tang,Yanjie Zhang,Changzi Jin,Xin Liu,Mingrun Li,Junhu Wang
The synergic effect of cation doping and phase composition for the further improvement of the photocatalytic activity of TiO 2 under visible light is reported for the first time. Fe 3 + and Sn 4 + co-doped TiO 2 with optimized phase composition were synthesized through a simple soft-chemical solution method. The visible-light-driven photocatalytic activity of Fe 3 + and Sn 4 + co-doped TiO 2 was 5 times of that of Evonik P25 TiO 2 using degradation of methylene blue as model reaction. The synthesized photocatalysts were characterized by powder X-ray diffraction, UV–Vis diffuse reflectance spectroscopy, X-ray photoelectron spectroscopy, 119 Sn Mössbauer spectroscopy, and X-ray absorption fine structure spectroscopy. It is indicated that Sn 4 + doping can facilitate the phase transition from anatase to rutile. The different ratios of anatase and rutile can be achieved by tuning the amount of Sn 4 + doped into the lattice. Furthermore, the doping of Sn 4 + into TiO 2 lattice can stabilize the phase composition when Fe 3 + is co-doped. In the Fe 3 + and Sn 4 + co-doped TiO 2 , Sn 4 + is mainly used to tune and stabilize the phase composition of TiO 2 and Fe 3 + acts as a doping cation to narrow the band gap of TiO 2 . Both band gap and phase composition of TiO 2 can be tuned effectively by the simultaneous introduction of Fe 3 + and Sn 4 + . The synergic effect of optimized phase composition (anatase/rutile = 25/75) and narrowed band gap should be the two main reasons for the promoted photocatalytic activity of TiO 2 under visible light.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2018
·Vol. 101
·期 11
·4870-4875
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IF 2.956
Wei-Ming Guo,Li-Xiang Wu,Jun-Jie Yu,Ling-Yong Zeng,Shi-Kuan Sun,Jing-Xi Li,Shang-Hua Wu,Hua-Tay Lin,Cheng-Yong Wang
Based on the previous work on Si 3 N 4 –ZrB 2 [Wu et al. J Eur Ceram Soc ;2017,37:4217], the influence of ZrB 2 addition on the phase and microstructure evolution of Si 3 N 4 –ZrB 2 composites was emphatically investigated, and the mechanical properties were compared with pure Si 3 N 4 ceramics. It was revealed that the ratio of β- to (α+β)-Si 3 N 4 significantly increased from 14.3% in pure Si 3 N 4 ceramics to 39.8% in Si 3 N 4 with 15 vol% ZrB 2 addition, indicating that the introduction of ZrB 2 promoted α- to β-Si 3 N 4 phase transformation. As a consequence, the microstructure of the composite showed the bimodal distribution, containing both elongated and equiaxed Si 3 N 4 grains. For the pure Si 3 N 4 , Vickers hardness, fracture toughness and flexural strength was 22.8 GPa, 7.6 MPa m 1/2 , and 334.5 MPa, respectively. In contrast, the composite of Si 3 N 4 –30 vol% ZrB 2 simultaneously possessed an excellent combination of mechanical properties: 19.5 GPa in hardness, 9.8 MPa m 1/2 in toughness and 702.0 MPa in strength. Present study suggested that Si 3 N 4 -based ceramics with high hardness, high toughness, and high strength could be obtained by the combination of appropriate ZrB 2 content and low hot-pressing temperature.
研究领域:
材料科学
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陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Energy Storage
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2022
·
IF 8.907
Huan Liu,Ziyue Wang,Jiyang Xie,Changjin Guo,Wanbiao Hu
Poly(vinylidene fluoride) (PVDF) is a basic polymer that has been extensively used in flexible electronics, with the properties differing in terms of multiple phases, e.g. α , β , and γ . As generally involved, processing induced phase variations have not yet been identified clearly, which furthermore often embarrasses the attributions and contributions in the properties and mechanisms. To this end, the phase compositions and evolutions in pure PVDF films are systematically tuned and explored by annealing and quenching processing. The annealed PVDF exhibits a predominant γ -phase, while α -phase is dominated in quenched PVDF. Upon the induced different phase compositions, the optimally processed PVDF films similarly exhibit an ultrahigh dielectric energy storage density e.g. 19.66 J cm −3 for annealed and 21.73 J cm −3 for quenched PVDF film, respectively, but only the former maintains a simultaneously high discharge efficiency of 65 %. With showing excellent energy storage performance, the processed especially the annealed PVDF film could compare to many existing high-performance dielectric energy storage systems . This work thus not only uncovers the phase evolutions as well as their impacts on the properties in PVDF system, but also demonstrates firstly a high energy storage performance in pure PVDF.
研究领域:
材料科学
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能源存储
✓ 已验证
产品关联
DOI
高影响因子
METALLURGICAL AND MATERIALS TRANSACTIONS A-PHYSICAL METALLURGY AND MATERIALS SCIENCE
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2018
·Vol. 49
·期 8
·3683-3691
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IF 1.887
Cai Xiaoping,Liu Yanan,Wang Xiaohong,Jiao Xinyang,Wang Jianzhong,Akhtar Farid,Feng Peizhong
Open-cell Fe-Al intermetallic foams were successfully prepared by a simple and energy-saving thermal explosion (TE) process. The effects of the Fe/Al molar ratio (Fe-(40–50) at. pct Al) and thermal treatment temperature on the TE temperature profile, phase composition, pore characteristics, and oxidation resistance of the prepared foams were investigated. The results showed that the Al content significantly influenced the ignition ( T ig ) and combustion ( T c ) temperatures of the TE process; in particular, as the Al content decreased, T ig increased gradually from 623 °C to 636 °C and T c decreased from 1059 °C to 981 °C. FeAl was identified as the dominant phase in the thermally treated foams. The Fe-Al intermetallic foams displayed an open porosity of 60 vol pct, with pores connected with each other to form an open pore structure. The formation of the pores was attributed to the expansion of interparticle pores in the pressed body during the TE reaction. X-ray photoelectron spectroscopy analysis of the Fe-50Al foam showed that the Al 2p and O 1s binding energies were 74.5 eV and at 531.4 eV, respectively. The formation of a surface alumina layer in the early stages of the oxidation process resulted in the parabolic oxidation rate law, and the Fe-50Al foams exhibited an excellent resistance to oxidation at 650 °C in air. These results suggest that the synthesized Fe-Al foams represent promising materials for applications involving an oxidizing environment and high temperatures.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ruichong Chen,Hao Guo,Zhangyi Huang,Haomin Wang,Jianqi Qi,Mao Zhou,Wei Feng,Tiecheng Lu
Li 4 Si 1–x Ti x O 4 ceramic solid solution was considered as a promising tritium breeding material for fusion reactor blanket. In this work, the effects of the sintering atmosphere on the phase composition, microstructure, and mechanical properties of Li 4 Si 0.7 Ti 0.3 O 4 ceramic pebbles were investigated for the first time, aiming to explore the optimal sintering atmosphere for this solid solution. The results show that compared with air and argon atmosphere, the negative pressure of vacuum atmosphere was more favorable for Ti to enter the Li 4 SiO 4 crystal structure as a substitute for Si atom to form a solid solution. More importantly, sintering in argon-vacuum atmosphere can ensure the formation of solid solution while fully exerting the liquid phase sintering effect. The crushing load of the Li 4 Si 0.7 Ti 0.3 O 4 ceramic pebbles sintered at 800 °C in argon-vacuum atmosphere reaches 30.3 ± 3.2 N. In general, the appropriate sintering atmosphere was of great significance for obtaining Li 4 Si 0.7 Ti 0.3 O 4 solid solution to meet the performance requirements of tritium breeding blanket.
研究领域:
材料科学
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核能工程
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产品关联
DOI
高影响因子
International Journal of Applied Ceramic Technology
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2022
·Vol. 20
·期 2
·747-753
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IF 2.328
Shen Zhenguang,Xiaohui Zhao,Muzhang Huang,Yi Han,Wei Pan
Fabrication of transparent or pore-free oxide ceramics usually requires sintering in a vacuum or reducing atmosphere. In the present paper, a near-infrared transparent Dy 2 Zr 2 O 7 ceramic was prepared by ordinary pressureless sintering under the air atmosphere, with a controlled pre-calcining of raw powders process. The key point of the process is to control the content of the phases by pre-calcination of the starting mixture of ZrO 2 and Dy 2 O 3 powders. The influence of pre-calcining temperature on the content of phases, the particle sizes, on the sinterability of the mixture of Dy 2 O 3 and ZrO 2 powders has been investigated. It was found that when the pre-calcination was conducted at 1200°C for 2 h, the powder contains 4 mol% Dy 2 Zr 2 O 7 , 18 mol% m-ZrO 2 , 30 mol% Dy 2 O 3 , and about 50 mol% t/c-ZrO 2 which is beneficial for the sintering of pore-free Dy 2 Zr 2 O 7 ceramics. The mechanism is discussed in the paper. The transparency of the sintered Dy 2 Zr 2 O 7 ceramic was measured, and their transmittance is about 63% at 1450 nm and 73% at 1900 nm. This work provides a simple and convenient way to prepare the near-infrared transparency ceramic without special sintering facilities.
研究领域:
材料科学
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光学工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Wenjie Yang,Chao Han,Yuehua Li,Huizhu Zhou,Shan Liu,Ling Wang,Zhangxing He,Lei Dai
BaHf 0.8 Ln 0.2 O 3-δ doped with rare earth elements with different ionic radii (Ln = Yb , Y, Dy and Gd) as candidate materials for solid oxide fuel cells and H 2 separation membrane have been prepared. Their phase composition , sinterability , chemical stability and conductivity were studied systematically. The rare earth elements are successfully incorporated into the main phase crystal lattice of barium hafnate to generate a single perovskite phase. The relative density of all samples sintered at 1600 °C reaches above 90%, and Y-doped BaHfO 3 has the highest relative density (94.7%) and the biggest grain size (about 1 μm) among all samples. The conductivities of the samples firstly increase and then decrease with the increase of the doped ion radius. Among all samples the conductivity of BaHf 0.8 Y 0.2 O 3-δ is the highest and reaches 6.02 × 10 −3 S cm −1 in wet air at 700 °C, which is attributed to the good sinterability and suitable crystal structure (tolerance factor and free volume). All samples also show excellent chemical stability in the test atmospheres, including saturated H 2 O steam, pure H 2 and CO 2 , 200 ppm H 2 S/Ar and boiling water. The Pt/BaHf 0.8 Y 0.2 O 3-δ electrolyte/Pt single cell was fabricated with a 530 μm-thick disk and its electrochemical properties were tested. The peak power density reaches 10.21 mW cm −2 at 700 °C, which is comparable to similar fuel cells reported. These results suggest that BaHf 0.8 Y 0.2 O 3-δ is a promising electrolyte candidate for proton-conducting fuel cells.
研究领域:
材料科学
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能源工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yingjun Liu,Jianjun Sha,Cheng Su,Jixiang Dai,Yufei Zu
Sintering additive of ZrSi 2 is beneficial to low-temperature densification of ZrB 2 -based ultra-high temperature ceramics (UHTCs), nevertheless, residual ZrSi 2 would severely reduce the high-temperature strength of UHTCs. In the current work, to achieve low-temperature preparation of ZrB 2 -based UHTCs with good high-temperature strength, active carbon (C) was added into ZrB 2 –ZrSi 2 ceramics to convert the sintering additive into refractory phases of SiC/ZrC. C-doped ZrB 2 –ZrSi 2 powders were hot-pressed at different temperatures to investigate the phase composition, microstructure and densification behavior. TG-DSC, XRD and SEM results indicated that ZrSi 2 was almost entirely converted into SiC and ZrC at 1600 °C for 2h, meanwhile, a fully-dense C-doped ZrB 2 –ZrSi 2 ceramic was obtained at such sintering conditions. In addition, the high-temperature (1800 °C) strength of C-doped ZrB 2 –ZrSi 2 ceramic was 390 ± 21 MPa, which was much higher than that of the C-undoped one. The excellent high-temperature mechanical properties could be attributed to the transformation of low-melting-point phases into refractory phases.
研究领域:
材料科学
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陶瓷工程
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）