JOURNAL OF ALLOYS AND COMPOUNDS
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2019
·
IF 4.175
Lei Li,Wen Bin Hong,Shuang Yang,Han Yan,Xiang Ming Chen
NaCl ceramics were prepared by cold sintering at room temperature with the water content varying from 0 to 10 wt%. The relative density of the NaCl ceramics first decreases rapidly from 99.3% to 95.0% with increasing the water content from 0 to 3 wt%, and it decreases slowly to 93.4% with further increasing the water content up to 10 wt%. The decrease in relative density is mainly attributed to the volume increase caused by the evaporation of the residual water in NaCl ceramic body. The dielectric constant exhibits the same tendency as the relative density, while the Qf value increases from 27,600 GHz to 49,600 GHz with increasing the water content from 0 to 4 wt%, and it does not change much for higher water content. The improved Qf value is attributed to the improved microstructure homogeneity that benefits from the fast mass transport of the water-activated dissolution-precipitation mechanism. The results clearly show that the water content should be optimized but not determined arbitrarily or empirically to achieve the good combination of high density, microstructure homogeneity and good properties. To avoid the negative effect of the residual water, NaCl ceramics were also cold-sintered at 120 °C, in which both high relative density (98.8–99.6%) and high Qf value (48,100–56,000 GHz) were obtained.
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
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Yunlong Liu,Degui Zhu,Salvatore Grasso,Chunfeng Hu
Dense Ti 3 AlC 2 components with a complex shape were fabricated using gel casting followed by pressure-less sintering. Low viscosity slurry was prepared using an aqueous based acrylamide (AM) monomer with a 50% solid loading. Homogeneous and crack free Ti 3 AlC 2 green bodies were obtained. The sintering temperatures were set at 1500, 1550 and 1600 °C, highest relative density of 93% was achieved at 1550 °C. Surprisingly, samples sintered at 1600 °C resulted in a drop of relative density because of the abnormal grain growth and entrapped porosity. The pressure-less sintered samples had mechanical properties comparable to hot pressed counterparts with Vickers hardness of 3.1 ± 0.2 GPa, fracture toughness of 4.2 ± 0.2 MPa m 1/2 and flexural strength of 302.3 ± 25.0 MPa. Final machining was still required to obtain a net shape components free from surface defects .
研究领域:
材料科学
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陶瓷工程
✓ 已验证
DOI
高影响因子
JOURNAL OF WUHAN UNIVERSITY OF TECHNOLOGY-MATERIALS SCIENCE EDITION
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2021
·Vol. 35
·期 6
·1098-1103
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IF 0.957
Zhai Xiaoyu,Peng Xiang,Ma Yunqian,Liu Ting,Liu Jiaxiang
The effect of particle size on the density and resistivity of ITO green bodies and targets was systematically investigated. The experimental results show that the relative density of ITO green bodies decreases with the increase of ITO particle size. When the particle size is 10.7 nm, the relative density of ITO green bodies rises to the maximum value of 56.6%. The resistivity declines exponentially with the increase of particle size, which satisfies the exponential equation of R = exp(−41.823 × d). When the particle size is 41.6 nm, the resistivity reaches the minimum value of 0.8 Ω·cm. The relative density of ITO target decreases with the increase of particle size. Fine particles can increase the driving force of densification in initial stage. Electron mobility, caused by grain boundary scattering, will increase due to the increase of particle size or the decrease of grain boundary potential. When the particle size is 10.7 nm, the target with compact grain stacking and low porosity shows a maximum relative density of 99.25%, and the resistivity reaches the minimum value of 0.34×10 −3 Ω·cm.
研究领域:
材料科学
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物理学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2018
·
IF 3.306
Qing Li,Xiaofang Zhu,Ying Zhang,Zhigang Zak Fang,Shili Zheng,Pei Sun,Yang Xia,Ping Li,Yang Zhang,Xing Zou
Hydrogen assisted magnesiothermic reduction (HAMR) of TiO 2 is a promising new process developed recently to produce Ti metal with low cost and less energy consumption. This work focuses on the understanding and optimization of the reduction process to control the quality of the reduced product. TiO 2 precursor particles with different relative densities were prepared, and the effects of the relative densities on reduction by Mg in H 2 were studied. The changes of oxygen contents vs. reduction time at various temperatures were investigated. The phase transformations during the reduction were analyzed both theoretically and experimentally. The relationship between the morphology of the reduced products and the relative densities of the TiO 2 precursors was analyzed by SEM characterization and the likely reason for the morphology evolution was discussed.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ELECTRONIC MATERIALS
·
2018
·Vol. 48
·期 1
·374-385
·
IF 1.566
Tong Huanzhe,Wang Nengli,Zou Yuqi,Zhang Zhaoquan,Fan Wugang,Shou Jinxiang,Zhang Xiyan
Yttrium aluminum garnet (Y 3 Al 5 O 12 , YAG) ceramics with a relative density of about 99.5% were fabricated by solid-state reaction and pressureless sintering using commercial α-Al 2 O 3 and Y 2 O 3 powders as raw materials in air. The effect of different sintering additives, e.g. tetraethyl orthosilicate (TEOS), MgO and TEOS + MgO, on the relative density and mechanical properties of the YAG ceramic samples were investigated. When the dopant content of TEOS exceeded 0.5 wt.%, a sudden grain growth appeared, as well as a residual second phase located in triangle grain boundary. MgO was more effective as a sintering additive than silica in promoting the densification of the YAG ceramics. The relative density of the ceramics gradually decreased with the increase of MgO doping content and fixed TEOS content. The mechanical properties of the YAG ceramics fabricated by pressureless sintering in air at 1600–1710°C were tested. The fracture surface morphology of the MgO-doped ceramic samples was mainly transgranular, whereas the TEOS-doped samples were mainly intergranular.
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 POWER SOURCES
·
2015
·
IF 6.217
Biyi Xu,Huanan Duan,Wenhao Xia,Yiping Guo,Hongmei Kang,Hua Li,Hezhou Liu
A multistep sintering schedule is developed to synthesize Li 7 La 3 Zr 2 O 12 (LLZO) doped with 0.2 mol% Al 3+ . The effect of sintering steps on phase, relative density and ionic conductivity of Al-doped LLZO has been evaluated using powder X-Ray diffraction (XRD), scanning electron microscopy (SEM), 27 Al magic spinning nuclear magnetic resonance (NMR) spectroscopy and electrochemical impedance spectroscopy (EIS). The results show that by holding the sample at 900 °C for 6 h, the mixture of tetragonal and cubic garnet phases are obtained; by continuously holding at 1100 °C for 6 h, the tetragonal phase completely transforms into cubic phase; by holding at 1200 °C, the relative density increases without decomposition of the cubic phase. The Al-LLZO pellets after multistep sintering exhibit cubic phase, relative density of 94.25% and ionic conductivity of 4.5 × 10 −4 S cm −1 at room temperature . Based on the observation, a sintering model is proposed and discussed.
研究领域:
材料科学
·
电化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Shucheng Liu,Xiaoqing Chen,Pengcheng Zhang,Quanzhang Wen,Linzhao Ma,Hao Li
A novel low-loss La 5 Sn 4 O 15 ceramic is fabricated via traditional solid-state route. The investigation mainly focused on phase composition, dielectric characteristics and crystalline from 1300 to 1400 °C. The XRD analyses confirmed the La 5 Sn 4 O 15 ceramic is consisted of cubic and hexagonal structure. The effects of relative density on the Q × f and permittivity are also investigated. The satisfactory properties (ε r of 17.4, Q × f of 84,760 GHz and τ f of −19.08 ppm/°C) are obtained at optimum sintering condition (sintered at 1350 °C for 4 h), indicating La 5 Sn 4 O 15 ceramic is a promising ceramic for using in wireless applications region.
研究领域:
材料科学
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电子工程
✓ 已验证
产品关联
DOI
高影响因子
MATERIALS CHEMISTRY AND PHYSICS
·
2022
·
IF 4.778
Tianxiang Ning,Qian Zhang,Piao Liu,Xiangtao Lin,Yinyi Luo,Lidan Liu,Zhiwei Luo,Anxian Lu
In this study, Li 2 O–Ga 2 O 3 -GeO 2 -Gd 2 O 3 (LGGG) glass is doped into Li 7 La 3 Zr 2 O 12 (LLZO) ceramic in proportions of 1, 2, 3, 4, and 5 wt% by a conventional solid-state reaction method. The main crystalline phase that existed in this composite electrolyte is proved to be cubic phase LLZO by XRD patterns. With a dosage of 3 wt% LGGG glass, the composite electrolyte has the highest ionic conductivity of 3.26 × 10 −4 S cm −1 , a maximum relative density of about 96.79%, and minimum activation energy of 0.276 eV at room temperature. This work also verifies that doping the same amount of identified elements into LLZO ceramics in the form of glass can obtain higher ionic conductivity and relative density than in the form of oxides (2.40 × 10 −4 S cm −1 and 92.03%). A symmetric cell composed of this electrolyte reveals a good cycling performance and low overpotential in a total of 230 cycles at a current density of 0.125 mA cm −2 . These results confirm the potential of this LGGG-LLZO composite electrolyte for applicating in new generation all-solid-state lithium-ion batteries.
研究领域:
材料科学
·
能源存储与转换
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Jia Peng Yuan,Nuo Chen,Cheng Chao Hu,Bing Liu,Kai Xin Song
Cold sintering has proven effective in densifying microwave dielectric ceramics , but the resulting properties are significantly influenced by the crystallinity of the raw powder. In this study, lithium fluoride (LiF) raw powder underwent pre-calcination at temperatures ranging from 650 °C to 800 °C for 3 h to enhance grain crystallinity. The calcined powder was then mixed with 10 wt% deionized water and cold-sintered at 150 °C under 900 MPa for 1 h to achieve dense LiF ceramics. XRD results confirmed the preservation of LiF phase composition throughout both processes. Increasing calcination temperature exhibited a positive correlation with enhanced relative density in cold-sintered ceramics, reaching up to 98.6 % at 800 °C. SEM images revealed controlled grain growth with higher calcination temperatures. ε r increased with temperature, corresponding to the variation in relative density. Significantly, Qf value experienced substantial enhancement with increasing calcination temperature, ultimately achieving optimal microwave dielectric properties ( ε r = 8.80, Qf = 33,300 GHz, and τ f = −138 ppm/°C) through cold sintering of LiF powder pre-calcinated at 800 °C.
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
CERAMICS INTERNATIONAL
·
2017
·
IF 2.986
Fei Liang,Jiaxiang Liu
High density and low electrical resistivity ITO targets were prepared by normal pressure sintering in oxygen with Bi 2 O 3 –Nb 2 O 5 addition. The relative density, microstructure and electrical properties of the ITO targets can be adjusted by changing the sintering temperature (1350 °C~1550 °C) and the content of Bi 2 O 3 –Nb 2 O 5 . The results show that the sintering temperature of ITO targets with Bi 2 O 3 –Nb 2 O 5 decreased from 1550 °C to 1450 °C, and the maximum relative density (99.6%) and the lowest electrical resistivity (1.78×10 −4 Ω cm) were reached when the sintering temperature was 1450 °C with 5 wt% Bi 2 O 3 –Nb 2 O 5 . The carrier concentration increased as the increase of the contents of Bi 2 O 3 –Nb 2 O 5 and sintering temperature. The mobility first increased, and then decreased above 1450 °C as the sintering temperature increased.
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
·
2015
·
IF 2.605
Xiaosong Lyu,Lingxia Li,Haocheng Cai,Hao Sun
A new low-loss LiNi 0.5 Ti 0.5 O 2 ceramic was prepared by the conventional solid-state reaction route and its microwave dielectric properties were investigated. Single phase LiNi 0.5 Ti 0.5 O 2 was obtained and it showed rock salt structure. The microstructures of the ceramics were characterized by SEM. The variation trends of dielectric constant and Q × f value were in accordance with variation trends of relative density and the grain morphology. Further, the τ f value was insensitive to sintering temperature . The following typical values ε r ~19.25, Q × f ~51290 GHz, τ f ~−20.1 ppm/°C were obtained for LiNi 0.5 Ti 0.5 O 2 (1275 °C/6 h). The microwave dielectric properties of the ceramic are reported for the first time.
研究领域:
材料科学
·
电子工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Wei Wan,Linjun Cao,Shuang Yin,Junrong Luo,Yeming Zhang,Jiaxu Zhang,Yuejun Ouyang
Zircon (ZrSiO 4 ) ceramics are highly valued in various industries due to their exceptional physical and chemical properties. In the present work, zircon ceramics with high-density and desirable mechanical properties were successfully prepared using an aqueous gelcasting method, involving the use of a low-toxic and water-soluble monomer, N,N -dimethylacrylamide (DMAA), as the binder. A high solid loading and low viscosity zircon slurry was achieved by optimizing the pH and the dosage of the ammonium polyacrylate (PAA-NH 3 ) dispersant. Zircon green bodies fabricated through the gelcasting method exhibited uniform microstructures and relatively high mechanical strength exceeding 11.0 MPa. The impact of solid loading on the density, decomposition, flexural strength , micro-hardness, and microstructure of the final ceramics were carefully studied. Notably, the ceramics, prepared by solidifying the slurry with a 45 vol% solid loading and sintering the green body at 1550 °C for 2 h, exhibited a relative density of 96.3 %, high phase purity, a uniform microstructure, and the highest flexural strength of 407.9 MPa. The results demonstrate that mechanically robust dense zircon ceramics can be effectively prepared using the low-toxic gelcasting method.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）