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STUDY ON THE STRUCTURE, ELECTRICAL PROPERTIES AND CONDUCTION MECHANISM 0F THE MULTICRYSTAL MULTIPHASE MATERIAL Li_2MO_2-xWxO_6
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作者 崔万秋 沈志其 周德保 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 1990年第2期15-21,共7页
The conductivity of non-crystalline fast ionic conductor for B_2O_3-Li_2O-LiCl-Al_2O_3 system is studiedin this paper. The glass structure of this system is discussed by means of infrared spectrum and X-ray fluorescen... The conductivity of non-crystalline fast ionic conductor for B_2O_3-Li_2O-LiCl-Al_2O_3 system is studiedin this paper. The glass structure of this system is discussed by means of infrared spectrum and X-ray fluorescence analysis, and the effects of LiCl and A1_2O_3 on the conductivity of Li^+ in the system are studied as well. Adding Li_2O to the system gives rise to transfer from [BO_3] triangular units to [BO_4] tetrahedral. When Li_2O content exceeds 30mol%, the main group of the glass is the diborate group with more [BO_4] tetrahedra. The adding of LiCl has no obvious influence on the glass structure, and LiCl is under a state dissociated by network, but with the increase of LiCl, the increase of conductivity is obvious. By adding A1_2O_3, the glass can be formed when the room-temperature is cooling down,the conductivity decreases while the conductive activatory energy increases for the glass. The experiment shows that conductivity in the room-temperature is σ= 6.2×10^(-6)Ω^(-1)cm^(-1), when at 300℃, the σ=6.8×10^(-3)Ω^(-1)cm^(-1). The conductive activatory energy computed is 0.6~1.0eV. 展开更多
关键词 MO MO LI OC STUDY ON THE STRUCTURE electricAL PROPERTIES AND conductION mechanism 0F THE MULTICRYSTAL MULTIPHASE MATERIAL Li2MO2-xWxO6 ESR
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Influence of anisotropy on the electrical conductivity and diffusion coefficient of dry K-feldspar: Implications of the mechanism of conduction
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作者 代立东 胡海英 +2 位作者 李和平 孙文清 蒋建军 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第2期630-639,共10页
The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa i... The electrical conductivities of single-crystal K-feldspar along three different crystallographic directions are investigated by the Solartron-1260 Impedance/Gain-phase analyzer at 873 K–1223 K and 1.0 GPa–3.0 GPa in a frequency range of 10-1 Hz–106 Hz. The measured electrical conductivity along the ⊥ [001] axis direction decreases with increasing pressure, and the activation energy and activation volume of charge carriers are determined to be 1.04 ± 0.06 e V and 2.51 ± 0.19 cm~3/mole, respectively. The electrical conductivity of K-feldspar is highly anisotropic, and its value along the⊥ [001] axis is approximately three times higher than that along the ⊥ [100] axis. At 2.0 GPa, the diffusion coefficient of ionic potassium is obtained from the electrical conductivity data using the Nernst–Einstein equation. The measured electrical conductivity and calculated diffusion coefficient of potassium suggest that the main conduction mechanism is of ionic conduction, therefore the dominant charge carrier is transferred between normal lattice potassium positions and adjacent interstitial sites along the thermally activated electric field. 展开更多
关键词 electrical conductivity and diffusion coefficient K-feldspar anisotropy conduction mechanism
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Fabrication and Microstructure of BN Matrix Composites with Electrical Conductivity 被引量:3
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作者 王为民 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2002年第3期5-7,共3页
BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB 2 ceramic has excellent electric conductivity,high melting points, and corrosio... BN ceramic is an advanced engineering ceramics with excellent thermal shock resistance, good workability and excellent dielectricity.TiB 2 ceramic has excellent electric conductivity,high melting points, and corrosion resistance to molten metal.Therefore,the composite consisting of BN and TiB 2 ceramics is expected to have a combination of above mentioned properties,thereby can be used as self heating crucible.In this paper,hot pressing technology was used to fabricate the high performance BN TiB 2 composite materials.microstructure and electric conducting mechanism were studied,and the relationship between the microstructure and physical property was discussed.The results show that the microstructure of composites has a great influence on the physical property of composites.The BN TiB 2 composites with excellent mechanical strength and stable resistivity can be obtained by optimizing the processing parameter and controlling the microstructure of composites. 展开更多
关键词 BN TiB 2 composites hot pressing sintering MICROSTRUCTURE physical property electric conduct mechanism
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Mechanical, electrical, and thermal expansion properties of carbon nanotube-based silver and silver–palladium alloy composites 被引量:3
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作者 Hemant Pal Vimal Sharma 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2014年第11期1132-1140,共9页
The mechanical, electrical, and thermal expansion properties of carbon nanotube(CNT)-based silver and silver–palladium(10:1, w/w) alloy nanocomposites are reported. To tailor the properties of silver, CNTs were ... The mechanical, electrical, and thermal expansion properties of carbon nanotube(CNT)-based silver and silver–palladium(10:1, w/w) alloy nanocomposites are reported. To tailor the properties of silver, CNTs were incorporated into a silver matrix by a modified molecular level-mixing process. CNTs interact weakly with silver because of their non-reactive nature and lack of mutual solubility. Therefore, palladium was utilized as an alloying element to improve interfacial adhesion. Comparative microstructural characterizations and property evaluations of the nanocomposites were performed. The structural characterizations revealed that decorated type-CNTs were dispersed, embedded, and anchored into the silver matrix. The experimental results indicated that the modification of the silver and silver–palladium nanocomposite with CNT resulted in increases in the hardness and Young's modulus along with concomitant decreases in the electrical conductivity and the coefficient of thermal expansion(CTE). The hardness and Young's modulus of the nanocomposites were increased by 30%?40% whereas the CTE was decreased to 50%-60% of the CTE of silver. The significantly improved CTE and the mechanical properties of the CNT-reinforced silver and silver–palladium nanocomposites are correlated with the intriguing properties of CNTs and with good interfacial adhesion between the CNTs and silver as a result of the fabrication process and the contact action of palladium as an alloying element. 展开更多
关键词 metal matrix composites carbon nanotubes mechanical properties coefficient of thermal expansion electrical conductivity
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A high-strength,ductile Al-0.35Sc-0.2Zr alloy with good electrical conductivity strengthened by coherent nanosized-precipitates 被引量:12
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作者 Renguo Guan Yongfeng Shen +1 位作者 Zhanyong Zhao Xiang Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2017年第3期215-223,共9页
Ductility and electrical conductivity of metallic materials are inversely correlated with their strength,resulting in a difficulty of optimizing all three simultaneously. We design an Al-Sc-Zr-based alloy using semiso... Ductility and electrical conductivity of metallic materials are inversely correlated with their strength,resulting in a difficulty of optimizing all three simultaneously. We design an Al-Sc-Zr-based alloy using semisolid extrusion to yield a good trade-off between strength and ductility along with excellent electrical conductivity. The Al-0.35Sc-0.2Zr wire with a diameter of 3 mm exhibited the best combined properties: a tensile strength of 210 ± 2 MPa, elongation of 7.6% ± 0.5%, and an electrical conductivity of 34.9 ± 0.05 MS/m. The average particle size of nanosized Al3(Sc, Zr) precipitates increased from 6.5 ± 0.5 nm to 25.0 ± 0.5 nm as the aging time increased from 1 h to 96 h at 380 °C, accompanied by the corresponding volume fraction variation from(6.2 ± 0.1) × 10^(-4) to(3.7 ± 0.1) × 10^(-3). As proved by transmission electron microscopy observation, the high strength originates from the effective blockage of dislocation motion by numerous nanosized Al3(Sc, Zr) precipitates whilst both electrical conductivity and ductility remain at a high level due to the coherent precipitates possessing an extremely low electrical resistivity. 展开更多
关键词 Al-0.35Sc-0.2Zr alloy Mechanical properties electrical conductivity Nanosized precipitates
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Aluminum matrix composites reinforced by molybdenum-coated carbon nanotubes 被引量:9
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作者 Jun-hui Nie Cheng-chang Jia Na Shi Ya-feng Zhang Yi Li XianJia 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2011年第6期695-702,共8页
To extend the application of carbon nanotubes (CNTs) and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT (Mo-CNT)... To extend the application of carbon nanotubes (CNTs) and explore novel aluminum matrix composites,CNTs were coated by molybdenum layers using metal organic chemical vapor deposition,and then Mo-coated CNT (Mo-CNT)/Al composites were prepared by the combination processes of powder mixing and spark plasma sintering.The influences of powder mixing and Mo-CNT content on the mechanical properties and electrical conductivity of the composites were investigated.The results show that magnetic stirring is better than mechanical milling for mixing the Mo-CNTs and Al powders.The electrical conductivity of the composites decreases with increasing Mo-CNT content.When the Mo-CNT content is 0.5wt%,the tensile strength and hardness of Mo-CNT/Al reach their maximum values.The tensile strength of 0.5wt% Mo-CNT/Al increases by 29.9%,while the electrical conductivity only decreases by 7.1%,relative to sintered pure Al.The phase analysis of Mo-CNT/Al composites reveals that there is no formation of Al carbide in the composites. 展开更多
关键词 carbon nanotubes aluminum matrix composites molybdenum layer mechanical properties electrical conductivity
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Performance improvement of continuous carbon nanotube fibers by acid treatment 被引量:1
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作者 Qiang Zhang Kewei Li +8 位作者 Qingxia Fan Xiaogang Xia Nan Zhang Zhuojian Xiao Wenbin Zhou Feng Yang Yanchun Wang Huaping Liu Weiya Zhou 《Chinese Physics B》 SCIE EI CAS CSCD 2017年第2期523-528,共6页
Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images an... Continuous CNT fibers have been directly fabricated in a speed of 50 m/h-400 m/h,based on an improved chemical vapor deposition method.As-prepared fibers are further post-treated by acid.According to the SEM images and Raman spectra,the acid treatment results in the compaction and surface modification of the CNTs in fibers,which are beneficial for the electron and load transfer.Compared to the HNO3 treatment,HClSO_3 or H_2SO_4 treatment is more effective for the improvement of the fibers' properties.After HCISO_3 treatment for 2 h,the fibers' strength and electrical conductivity reach up to-2 GPa and-4.3 MS/m,which are promoted by-200%and almost one order of magnitude than those without acid treatment,respectively.The load-bearing status of the CNT fibers are analyzed based on the downshifts of the G' band and the strain transfer factor of the fibers under tension.The results reveal that acid treatment could greatly enhance the load transfer and inter-bundle strength.With the HCISO3 treatment,the strain transfer factor is enhanced from-3.9%to-53.6%. 展开更多
关键词 carbon nanotube fiber electrical conductivity mechanical property performance improvement
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Electronic Transport Properties of La_(2/3)Ca_(1/3)Mn_(0.98)Cu_(0.02)O_3 Sintered at Different Temperature
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作者 胡清华 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2009年第2期300-303,共4页
The sol-gel method was adopted to prepare series of La2/3Cal/3Mn0.98Cu0.02O3 samples sintered at different temperatures, and the structure of samples, high-temperature electrical conductive mechanism and electronic tr... The sol-gel method was adopted to prepare series of La2/3Cal/3Mn0.98Cu0.02O3 samples sintered at different temperatures, and the structure of samples, high-temperature electrical conductive mechanism and electronic transport properties of double-peak resistance were investigated. X-ray diffraction pattern indicates that the samples are in perovskite structures and obey the Vari- able-Rang Hopping Mechanism of p = p 0exp[(T0/T)^1/4] under high temperatures during the electrical conduction. In addition, based on the polycrystalline granular system surface and image, the reasonable explanation was given for the double-peak resistance phemomenon. 展开更多
关键词 SOL-GEL Cu doping electrical conductive mechanism rare earth
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