40 results on '"H.C. Jiang"'
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2. Effect of interlayer addition on microstructure and mechanical properties of NiTi/stainless steel joint by electron beam welding
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H. Niu, Zhao Modi, Lijian Rong, and H.C. Jiang
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Materials science ,Polymers and Plastics ,Alloy ,02 engineering and technology ,Welding ,Laves phase ,engineering.material ,010402 general chemistry ,01 natural sciences ,law.invention ,Brittleness ,law ,Electron beam welding ,Materials Chemistry ,Composite material ,Mechanical Engineering ,Metals and Alloys ,Fracture mechanics ,021001 nanoscience & nanotechnology ,Microstructure ,0104 chemical sciences ,Intergranular fracture ,Mechanics of Materials ,Ceramics and Composites ,engineering ,0210 nano-technology - Abstract
NiTi/Stainless Steel (SS) sheets have been welded via a vacuum electron beam welding process, with three methods (offsetting electron beam to SS side without interlayer, adding Ni interlayer and adding FeNi interlayer), to promote mechanical properties of the NiTi/SS joints. The joints with different interlayers are all fractured in the weld zone near the NiTi side, which is attributed to the enrichment of intermetallic compounds including Fe2Ti and Ni3Ti. The fracture mechanisms of different joints are strongly dependent on the types of interlayers, and the joints without interlayer, adding Ni interlayer and adding FeNi interlayer exhibit cleavage fracture, intergranular fracture and mixed fracture composed of cleavage and tearing ridge, respectively. Compared with the brittle laves phase Fe2Ti, Ni3Ti phase can exhibit certain plasticity, block the crack propagation and change the direction of crack propagation. The composite structure of Ni3Ti and Fe2Ti will be formed when the FeNi alloy is taken as the interlayer, which provides the joint excellent mechanical properties, with rupture strength of 343 MPa.
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- 2021
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3. Orbitally and galactic cosmic forced abrupt climate events during the last glacial period
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H.C. Jiang, Q.Z. Yin, A. Berger, L.H. Wei, Z.P. Wu, X.T. Wei, and W. Shi
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Archeology ,Global and Planetary Change ,Geology ,Ecology, Evolution, Behavior and Systematics - Published
- 2023
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4. Thermal Stability of Ultrafine Grained CuCrZr Alloy Produced by Continuous Extrusion
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Hui Feng, H.C. Jiang, Desheng Yan, and Lijian Rong
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Materials science ,Annealing (metallurgy) ,Alloy ,Metallurgy ,Recrystallization (metallurgy) ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,010305 fluids & plasmas ,Grain growth ,0103 physical sciences ,engineering ,Grain boundary ,Extrusion ,Dislocation ,0210 nano-technology - Abstract
The Cu-0.36Cr-0.15Zr alloy was prepared by solid solution, continuous extrusion and cold deformation. The microstructural evolution, microhardness and the thermal analysis were examined for the alloy after annealing treatment at different temperatures ranging from 300 oC to 700 oC. Experimental results show that the microstructure of the alloy remains stable after annealed below 500 oC due to the pinning effect of dislocations from the nanoscale precipitates. However, recrystallization and grain growth took place after a 600 oC annealing treatment when the precipitates grew up and lose inhibition of movement of dislocations and grain boundaries. Meanwhile, the higher dislocation density and finer grains introduced by continuous extrusion accelerate the recrystallization process compared with that prepared by the traditional rolling process.
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- 2019
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5. Improving the fatigue strength of A7N01 aluminum alloy by adjusting Si content
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Peng Zhang, H.C. Jiang, Lijian Rong, Zhefeng Zhang, Zheng Liu, Z.J. Zhang, Bing Gong, and Yeliang Wang
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010302 applied physics ,Materials science ,Mechanical Engineering ,Alloy ,technology, industry, and agriculture ,chemistry.chemical_element ,02 engineering and technology ,engineering.material ,equipment and supplies ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Fatigue limit ,chemistry ,Mechanics of Materials ,Aluminium ,0103 physical sciences ,Homogeneity (physics) ,engineering ,General Materials Science ,Grain boundary ,Composite material ,0210 nano-technology ,Si element - Abstract
As high-strength aluminum alloy for traction beam of high-speed rail, the fatigue strength of A7N01 aluminum alloy is particularly critical for its industrial application. In order to improve the fatigue strength of this aluminum alloy, three kinds of A7N01 aluminum alloy with different Si content were selected. The result indicates that, with the increase of Si element content, the fatigue strength is enhanced monotonously and meanwhile the dispersivity of S-N curves is largely reduced. Analyses of microstructure and the error of strength and hardness all indicate that the microstructure homogeneity of the alloy is improved when increasing the Si content, which is proved to be the main reason for the enhanced fatigue strength and reduced fatigue life dispersivity. Besides, it is found that the discontinuous distribution of the grain boundary precipitates due to the increase of Si content also contributes to the improved fatigue property.
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- 2019
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6. Two-stage double peaks ageing and its effect on stress corrosion cracking susceptibility of Al-Zn-Mg alloy
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Lijian Rong, Li Zhaoming, Dong Zhang, Desheng Yan, Yumin Wang, and H.C. Jiang
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010302 applied physics ,Materials science ,Polymers and Plastics ,Mechanical Engineering ,Metallurgy ,Alloy ,Metals and Alloys ,Free zone ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,01 natural sciences ,Lower temperature ,Mechanics of Materials ,Ageing ,0103 physical sciences ,Ultimate tensile strength ,Materials Chemistry ,Ceramics and Composites ,engineering ,Grain boundary ,Stress corrosion cracking ,0210 nano-technology - Abstract
Different artificial two-stage ageing behaviors and their effect on stress corrosion cracking (SCC) susceptibility of Al-Zn-Mg alloy have been investigated. The experimental results show that two hardness peaks present on the second-stage ageing-hardening curve when the first-stage ageing is dealt with comparatively lower temperature than the conventional one. The first peak is caused by dispersive and evenly distributed G.P. zones, while η′ phases and coarsened G.P. zones contribute to the second peak. Tensile strength of experimental alloy raises 9.6% (33.2 MPa) and SCC susceptibility decreases 38.9% by applying the second peak ageing regime instead of conventional T73. Al-Zn-Mg alloy obtains high strength and SCC resistance due to its finely dispersive matrix precipitates (MPts), coarsened and discontinuous grain boundary precipitates (GBPs), as well as the narrow precipitate free zone (PFZ) in the second peak ageing condition.
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- 2018
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7. Effect of minor Sc addition on microstructure and stress corrosion cracking behavior of medium strength Al–Zn–Mg alloy
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H.C. Jiang, Wang Yunli, Desheng Yan, Li Zhaoming, Duo Zhang, and Lijian Rong
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010302 applied physics ,Materials science ,Polymers and Plastics ,Mechanical Engineering ,Metallurgy ,Metals and Alloys ,Recrystallization (metallurgy) ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Microstructure ,01 natural sciences ,Mechanics of Materials ,visual_art ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,Dynamic recrystallization ,Aluminium alloy ,visual_art.visual_art_medium ,Grain boundary ,Stress corrosion cracking ,0210 nano-technology ,Electron backscatter diffraction ,Hydrogen embrittlement - Abstract
Influence of Sc content on microstructure and stress corrosion cracking behavior of medium strength Al–Zn–Mg alloy have been investigated by optical microscopy, scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy and slow strain rate test. The results indicate that the addition of Sc results in the formation of the quaternary coherent Al3(Sc, Zr, Ti) dispersoids during homogenization treatment, which will inhibit the dynamic recrystallization behavior. The number density of Al3(Sc, Zr, Ti) particles increases with the increase of Sc content, and thus the recrystallization fraction of hot-extruded alloy is reduced and the peak strength in two-stage artificial aging sample is enhanced. At the same time, the wide of precipitation free zone is reduced, and the content of Zn and Mg in grain boundary particles and precipitation free zone is increased with the increase of Sc content. In peak-aged state, the 0.06 wt% Sc added alloy shows the better stress corrosion cracking resistance than the Sc-free alloy because of the reduction of recrystallization fraction and the interrupted distribution of grain boundary precipitates along grain boundary. However, the further addition of Sc to 0.11 wt% will result in the deterioration of stress corrosion cracking resistance due to the increase of electrochemical activity of grain boundary particles and precipitation free zone as well as hydrogen embrittlement.
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- 2018
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8. Effect of nitrogen doping on the thermoelectric properties of ITO-In 2 O 3 thin film thermocouples
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W. L. Zhang, Haiqiang Li, Sisi Jiang, H.C. Jiang, and Xiaowei Zhao
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Materials science ,Oxide ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,01 natural sciences ,chemistry.chemical_compound ,X-ray photoelectron spectroscopy ,Sputtering ,0103 physical sciences ,Thermoelectric effect ,Materials Chemistry ,Thin film ,010302 applied physics ,business.industry ,Metals and Alloys ,Surfaces and Interfaces ,021001 nanoscience & nanotechnology ,Microstructure ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Indium tin oxide ,chemistry ,Optoelectronics ,0210 nano-technology ,business ,Indium - Abstract
Nitrogen doped indium oxide (InON) and indium tin oxide (ITON) thin films have been fabricated with reactive sputtering in nitrogen-rich plasmas for high temperature thin film thermocouples (TFTCs). Different content of nitrogen was introduced into InON film electrode in order to improve the thermoelectric properties of the thin film thermocouples. XRD, XPS and SEM were used to reveal the chemistry and microstructure of InON films and high temperature static calibration was used to characterize the thermoelectric properties of InON-ITON TFTCs. The relationship between the thermoelectric properties of TFTC and the microstructures of the films was investigated. TFTCs with high linearity and excellent stability were realized.
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- 2017
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9. Temporal dynamics of microbial community structure and its effect on arsenic mobilization and transformation in Quaternary aquifers of the central Yangtze River Basin
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Y.X. Wang, T.L. Zheng, H.C. Jiang, and Y. Deng
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geography ,geography.geographical_feature_category ,Mobilization ,Earth science ,chemistry.chemical_element ,Aquifer ,Structural basin ,Transformation (genetics) ,Microbial population biology ,chemistry ,Yangtze river ,Quaternary ,Geology ,Arsenic - Published
- 2019
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10. Effect of microbial sulfate reduction on arsenic mobilization in aquifer sediments from the Jianghan Plain, Central Yangtze River Basin
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Y. Deng, H.C. Jiang, J. Gao, and T.I. Zheng
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geography ,chemistry.chemical_compound ,Mobilization ,geography.geographical_feature_category ,chemistry ,Environmental chemistry ,Yangtze river ,Environmental science ,chemistry.chemical_element ,Aquifer ,Structural basin ,Sulfate ,Arsenic - Published
- 2019
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11. Influence of Mn on the negative natural aging effect in 6082 Al alloy
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Z.J. Cui, Yuwei Song, Dongfen Zhang, H.C. Jiang, D.S. Yan, and L.J. Rong
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010302 applied physics ,Microstructural evolution ,Number density ,Materials science ,Mechanical Engineering ,Natural aging ,Alloy ,Analytical chemistry ,02 engineering and technology ,engineering.material ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Microstructure ,01 natural sciences ,Artificial aging ,Mechanics of Materials ,0103 physical sciences ,engineering ,General Materials Science ,0210 nano-technology - Abstract
The microstructural evolution and mechanical properties of the 6082 alloys with different Mn content were systematically investigated to deeply understand the influence of Mn on the negative natural aging (NA) effect. It is found that α-Al(Mn,Fe)Si precipitated during homogenization is larger in size and less in amount in the alloy with lower Mn content, resulting in the less consumption of Si to create a relatively Si-rich environment in the matrix. The true Mg/Si ratio of alloy with higher Mn content is higher so that the alloy possesses a stronger negative natural aging effect. Additionally, four types of aggregates including clusters, GP zones, elongated β'' and β′ are present in the microstructures aged at 175 °C/8 h which is the peak artificial aging (AA) treatment in the two alloys. The number density of β'' and the total number density of the aggregates in alloy with lower Mn content is always higher than that in alloy with higher Mn content at the same heat treatment condition, which lead to the higher hardness and strength.
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- 2020
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12. Variation of nanoparticle fraction and compositions in two-stage double peaks aging precipitation of Al−Zn−Mg alloy
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Dongfen Zhang, H.C. Jiang, Li Zhaoming, Yumin Wang, Yilin Song, and Lijian Rong
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Materials science ,Al−Zn−Mg alloy ,Alloy ,Analytical chemistry ,Nanochemistry ,Nanoparticle ,02 engineering and technology ,Atom probe ,engineering.material ,01 natural sciences ,law.invention ,Fraction ,law ,Phase (matter) ,0103 physical sciences ,lcsh:TA401-492 ,General Materials Science ,High-resolution transmission electron microscopy ,010302 applied physics ,Nano Express ,Precipitation (chemistry) ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Compositions ,Transmission electron microscopy ,Two-stage double peaks aging ,engineering ,lcsh:Materials of engineering and construction. Mechanics of materials ,0210 nano-technology ,Atom probe tomography (APT) - Abstract
Atom probe tomography (APT) coupling high-resolution transmission electron microscopy (HRTEM) was used to analyze the fraction and compositions of different nanoparticles in two-stage double peaks aging process of Al−Zn−Mg alloy. Al content is found to be closely related to the size of nanoparticles and it can be greater than ~ 50.0 at. % in the nanoparticle with the equivalent radius under ~ 3.0 nm. Correspondingly, Al content of the nanoparticle, with the equivalent radius over ~ 5.0 nm, is measured under ~ 40.0 at. %. Evolution from Guinier–Preston (G.P.) zone to η phase is a growing process where Mg and Zn atoms enter the nanoparticle, therefore rejecting Al atoms. G.P. zones can take up a number fraction of ~ 85.0 and ~ 22.7% of nanoparticles in the first and second peak-aged samples, respectively, and even in the over-aged (T73) sample, they can still be found. As aging time increases, fraction of η′ phases monotonically rises to the peak value (~ 54.5%) in the second peak-aged state and then drops, which is significant for the second hardness peak and directly proves their function as the transitional medium. In T73 state, ~ 63.3% nanoparticles compose of η phases, which were measured to still contain ~ 10.2 to ~ 36.4 at. % Al atoms.
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- 2018
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13. Microstructure and Mechanical Properties of a CuCrZr Welding Joint After Continuous Extrusion
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Hui Feng, Desheng Yan, Lijian Rong, and H.C. Jiang
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Materials science ,Polymers and Plastics ,Mechanical Engineering ,Metallurgy ,Alloy ,Metals and Alloys ,Welding joint ,engineering.material ,Microstructure ,Flash welding ,Mechanics of Materials ,Materials Chemistry ,Ceramics and Composites ,engineering ,Dynamic recrystallization ,Grain boundary ,Extrusion ,Composite material ,Deformation (engineering) - Abstract
The effect of continuous extrusion forming (CEF) process on the microstructure and mechanical properties of a CuCrZr welding joint was investigated. The experimental results showed that after the CEF process the grains were refined to submicron-scale through dynamic recrystallization, which improved the mechanical properties of the welding joint as well as the base material. Meanwhile, the micron-scale precipitates aggregated at the grain boundaries in the welding process were broken down to smaller ones and recrystallized grains of several micrometers formed around the precipitates after CEF process, which could alleviate the negative effect induced by the micron-scale precipitates during plastic deforming process. Finer grains and smaller micron-scale precipitates made contributions to improve the properties of a CuCrZr alloy with a welding joint.
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- 2015
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14. Effect of continuous extrusion on the microstructure and mechanical properties of a CuCrZr alloy
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H.C. Jiang, Hui Feng, Desheng Yan, and Lijian Rong
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Materials science ,Mechanical Engineering ,Metallurgy ,Alloy ,Recrystallization (metallurgy) ,engineering.material ,Condensed Matter Physics ,Microstructure ,Grain size ,Mechanics of Materials ,Dynamic recrystallization ,engineering ,General Materials Science ,Extrusion ,Severe plastic deformation ,Strengthening mechanisms of materials - Abstract
A Cu–0.16Cr–0.12Zr alloy with an initial grain size of about 400 μm was extruded by continuous extrusion forming (CEF), where severe plastic deformation and precipitation process occurred. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were employed to examine the microstructure and morphology of the precipitates. Experimental results show that a notable grain size reduction to sub-micron scale is obtained through continuous dynamic recrystallization and precipitates maintain a fine and disperse morphology after the CEF process. These two features are considered as the effective ways to improve the strength and ductility of the CuCrZr alloy after cold deformation and subsequent aging process without a significant decrease of electrical conductivity.
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- 2013
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15. Effect of sputtering pressure on microstructure and magnetic properties of amorphous FeCoSiB films
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Q.Y. Xie, H.C. Jiang, W.L. Zhang, Bo Peng, and W.X. Zhang
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Materials science ,Magnetic domain ,Condensed matter physics ,Coercivity ,Condensed Matter Physics ,Microstructure ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Condensed Matter::Materials Science ,Magnetic anisotropy ,Nuclear magnetic resonance ,Sputtering ,Condensed Matter::Superconductivity ,Materials Chemistry ,Ceramics and Composites ,Magnetic force microscope ,Anisotropy - Abstract
The effects of argon pressure on the microstructure and magnetic properties of the sputtered FeCoSiB amorphous films were investigated. At low deposition pressure the samples show flat and dense surface, while those at higher pressure show columnar growth with rough surface. The formation of the columnar grains results in the perpendicular magnetic anisotropy due to the shape anisotropy. Stripe magnetic domains were observed in the latter samples. Both the magnetic contrast in magnetic force microscope images and the coercivity of FeCoSiB films increase first and then decrease with the increasing of the sputtering pressure. It is suggested that the columnar grains introduce shape anisotropy which plays an important role in tuning the magnetic behaviors of the FeCoSiB films with the sputtering pressure.
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- 2013
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16. Influences of Nitrogen Partial Flux on the Phase Structures and Electrical Properties of Aluminium Doping TaNX Thin Films
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Chaojie Wang, H.C. Jiang, Bin Peng, Wan Li Zhang, and Xu Si
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Materials science ,Mechanical Engineering ,Analytical chemistry ,Flux ,chemistry.chemical_element ,Sputter deposition ,Condensed Matter Physics ,Nitrogen ,chemistry ,Mechanics of Materials ,Electrical resistivity and conductivity ,Sputtering ,Aluminium ,General Materials Science ,Thin film ,Temperature coefficient - Abstract
Aluminium doping TaNx thin films were deposited on Al2O3 ceramic wafers by DC reactive magnetron sputtering. The influences of nitrogen partial flux on the phase structures and the electrical properties of the samples were investigated in detail. The results show that the main phases in the samples are gradually changed from poor nitrogen phases to rich nitrogen phases with the increase of the nitrogen partial flux. The deposition rate of the samples is decreased with the increase of the nitrogen partial flux. With the increase of the nitrogen partial flux, the resistivity and the absolute value of the temperature coefficient of resistance (TCR) of the samples increase slowly at lower nitrogen partial flux, and then increase remarkably at higher nitrogen partial flux. These experimental results can be explained by the presentation of rich nitrogen phases with higher resistivity and absolute value of the TCR when the samples were prepared at higher nitrogen partial flux.
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- 2011
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17. K-Type Thin Film Thermocouples Deposited on Ni-Based Superalloy Substrates
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Xing Zhao Liu, Yanrong Li, H.C. Jiang, Yin-Zhi Chen, Chao Wang, and Wan Li Zhang
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Materials science ,Mechanical Engineering ,Sensitivity coefficient ,Thin film thermocouples ,Analytical chemistry ,Atmospheric temperature range ,Condensed Matter Physics ,Superalloy ,Bond coating ,Mechanics of Materials ,Seebeck coefficient ,Electronic engineering ,General Materials Science ,Tube furnace ,Layer (electronics) - Abstract
NiCr-NiSi K-type thin film thermocouples with multi-layer structure were fabricated on Ni-based superalloy substrates (95 mm×35 mm×2 mm). The multi-layer structure contains NiCrAlY buffer layer (2 μm)/ thermally grown Al2O3 bond coating (200 nm)/ Al2O3 insulating layer (8 μm)/ NiCr-NiSi thin film thermocouples (1 μm)/ Al2O3 protecting layer (500 nm). The samples were statically calibrated in a tube furnace in the temperature range from 170 °C to 610 °C. The results show that the resistance of Al2O3 insulating layer is about 14.6 kΩ at 800 °C and exceeds 100 MΩ at room temperature. The Seebeck coefficient a of the samples is about 34 μV/°C, and the sensitivity coefficient K is greater than 0.8 in the temperature range from 170 °C to 610 °C. The maximal sensitivity coefficient is about 0.97 at 265 °C.
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- 2011
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18. TRANSPORT PROPERTIES OF <font>Ag</font>-DOPED <font>La</font>0.7<font>Ca</font>0.3<font>MnO</font>3 THIN FILMS ON SILICON SUBSTRATE
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W.X. Zhang, H.C. Jiang, W.L. Zhang, X. F. Cao, and Bo Peng
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Materials science ,Silicon ,Annealing (metallurgy) ,Transition temperature ,Doping ,Analytical chemistry ,chemistry.chemical_element ,Statistical and Nonlinear Physics ,Sputter deposition ,Condensed Matter Physics ,chemistry ,Electrical resistivity and conductivity ,Thin film ,Metal–insulator transition - Abstract
Ag -doped La 0.7 Ca 0.3 MnO 3 (LCMO) films were prepared on silicon substrate by RF magnetron sputtering. The dependences of transport properties on annealing temperature were explored. It is shown that the resistivity of the samples decreases and the metal–insulator transition temperature shifts to higher temperature with the increase in annealing temperature. Two metal–insulator transition temperatures are presented in the R – T plots of Ag -doped LCMO films, which can be explained by the Ag 1+ substitution of La 3+ to form La 1-x Ag x MnO 3 compound. Compared with LCMO thin films, Ag -doping can observably improve the TM-I and decrease the resistivity of the samples.
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- 2010
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19. COMPOSITION CONTROL AND ITS ELECTRICAL PROPERTIES OF <font>TaN</font>x THIN FILMS
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H.C. Jiang, Wan Li Zhang, Chunyu Wang, and Xin Si
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Materials science ,Analytical chemistry ,chemistry.chemical_element ,Statistical and Nonlinear Physics ,Cubic crystal system ,Sputter deposition ,Condensed Matter Physics ,Nitrogen ,chemistry ,Sputtering ,Electrical resistivity and conductivity ,Orthorhombic crystal system ,Thin film ,Sheet resistance - Abstract
TaN thin films were deposited on Al 2 O 3 wafers by DC reactive magnetron sputtering. The composition control by nitrogen partial flux in the working gas and the electrical properties of the samples were investigated in detail. The results show that the atomic number ratio of Ta to N in the samples can be adjusted from 4 to 0.88, corresponding to the contents of N in the samples from 20 at.% to 53 at.%, by adjusting the nitrogen partial flux from 2% to 6%. The main phases in the TaN x thin films are hexagonal Ta 2 N , body centered cubic Ta 10 N and face centered cubic TaN at lower N contents (lower than 28 at.%). However, at higher N contents (higher than 28 at.%), orthorhombic Ta 3 N 5 phase gradually precipitates out from the samples, and the hexagonal Ta 2 N phase disappears. When the N contents in the samples are lower than 28 at.%, the sheet resistance and resistivity of TaN x thin films are all low. With further increase of the N contents, the sheet resistance and resistivity of TaN x thin films increase sharply. The sheet resistance and the resistivity of the samples can be adjusted from 17 Ω/sq. to 77 Ω/sq., from 344 μΩ ·cm to 1030 μΩ ·cm by adjusting the nitrogen contents, respectively. When the nitrogen contents in the samples are lower than 28 at.%, the TCR of the samples is less than 50 ppm/°C. With further increase of N contents, the TCR of the samples increases sharply up to a few hundred ppm/°C.
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- 2010
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20. BARIUM HEXAFERRITE THICK FILMS BY HOT PRESS SINTERING
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Ying He, H.C. Jiang, W.L. Zhang, Bo Peng, and W.X. Zhang
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Diffraction ,Magnetic anisotropy ,Materials science ,Remanence ,Film plane ,Sintering ,Ferrite (magnet) ,Statistical and Nonlinear Physics ,Composite material ,Condensed Matter Physics ,Anisotropy ,Porosity - Abstract
BaFe 12 O 19 ferrite thick films were screen-printed and sintered at 1150°C under pressure (hot press sintering). The effects of the hot press sintering on the properties of barium hexaferrite thick films were investigated. The X-ray diffraction pattern shows improvement of the (00l) texture under pressure. The porosity size of the hot press sintering samples decreases obviously and the surface compactness is improved as the pressure is increased. The films are quite anisotropic with magnetic easy axis perpendicular to the film plane. The largest remanence ratio achieved is 0.75 under the highest pressure of 4 MPa.
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- 2010
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21. Effects of argon pressure on magnetic properties and low-field magnetostriction of amorphous TbFe films
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H.C. Jiang, Bo Peng, Wenxu Zhang, and Wan Li Zhang
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Argon ,Materials science ,Condensed matter physics ,Magnetic domain ,Physics::Instrumentation and Detectors ,chemistry.chemical_element ,Magnetostriction ,Coercivity ,Sputter deposition ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Condensed Matter::Materials Science ,Magnetization ,Magnetic anisotropy ,chemistry ,Physics::Plasma Physics ,Physics::Atomic and Molecular Clusters ,Physics::Chemical Physics ,Electrical and Electronic Engineering - Abstract
Amorphous TbFe films were fabricated by DC magnetron sputtering, and the effects of argon pressures on the microstructure, magnetic properties and the low magnetic field magnetostrictions of the samples were explored. It is found that with the increase of argon pressure, the surface smoothness and the compactness of TbFe films are declined. At lower argon pressure, maze magnetic domains exist, and it possesses, hence, stronger perpendicular anisotropy. With the increase in argon pressure, the domain walls become gradually wider and the contrast of domain image appears to be less sharper. It implies that the magnetic anisotropy direction of the films gradually changes from perpendicular to parallel to the film plane with larger argon pressure. In addition, the magnetization is stronger with increase in argon pressure, and reaches its maximum value at 0.6 Pa. After that, the magnetization begins to decrease with further increase in argon pressure. However, the coercivity of the films decreases monotonically with the increase in the argon pressure. At low magnetic fields, the magnetostriction of amorphous TbFe films becomes larger with increase in the argon pressure. After reaching its maximum value at 0.6 Pa, a decrease was observed with further increase in argon pressure.
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- 2010
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22. The effect of Mo additions to high damping Ti–Ni–Nb shape memory alloys
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Shuhu Liu, L.J. Rong, X.Q. Zhao, H.C. Jiang, and Yuntang Chen
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Materials science ,Precipitation (chemistry) ,Mechanical Engineering ,Metallurgy ,Titanium alloy ,Condensed Matter Physics ,Microstructure ,Damping capacity ,Precipitation hardening ,Mechanics of Materials ,Martensite ,Phase (matter) ,Volume fraction ,General Materials Science ,Composite material - Abstract
The effect of Mo addition on the microstructure, phase transformation, mechanical behavior and damping capacity has been investigated. It is found that the Mo addition depresses the solubility of Nb in the TiNi matrix and results in abundant dispersive Nb-rich precipitation. The R-phase transformation is induced in Ti-Ni-9.0 at.%Nb alloys by the substitution of Mo for Ni. The yield strength and rupture strength increase with increasing Mo content due to the precipitation strengthening of Nb-rich particles and the solution strengthening of the Mo, while the elongation remains at a high level. With the increment of Mo content, the damping in the martensitic state and the damping during the phase transformation are enhanced. The increment of the martensite volume fraction and the presence of abundant Nb-rich particles are responsible for the high damping in the martensitic state. The improvement of the damping properties during the phase transformation is related to the volume fraction of the transformed martensite phase per unit time and the contribution of the R-phase transformation. (C) 2009 Elsevier B.V. All rights reserved.
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- 2009
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23. An investigation of the magnetic domains in the stressed amorphous FeCoSiB magnetoelastic films
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Q.Y. Xie, B.K. Shen, W.X. Zhang, Bo Peng, W.L. Zhang, and H.C. Jiang
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Materials science ,Magnetic domain ,business.industry ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Stress (mechanics) ,Condensed Matter::Materials Science ,Optics ,Compressive strength ,Condensed Matter::Superconductivity ,Ultimate tensile strength ,Materials Chemistry ,Ceramics and Composites ,Perpendicular ,Composite material ,Anisotropy ,business - Abstract
The effects of tensile and compressive stress on the magnetic domains of amorphous FeCoSiB films are investigated. It is observed that the unstressed sample consists of irregular domains while the stressed samples show stripe domains. With the increase of the tensile stress, the stripe domain of the stressed films tends to align parallel to the direction of the stress, while with the increase of the compressive stress the stripe domain of the stressed films tends to align perpendicular to the direction of the stress. The magnetic domain and its evolution under the stress are explained by introducing the magnetoelastic anisotropy induced by the stress.
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- 2008
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24. Study on the magnetic domain and anisotropy of FeCoSiB amorphous films fabricated by strained growth method
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H.C. Jiang, Q.Y. Xie, Bo Peng, Yuanxun Li, W.L. Zhang, and W.X. Zhang
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Materials science ,Amorphous metal ,Condensed matter physics ,Magnetic domain ,business.industry ,Condensed Matter Physics ,Magnetic hysteresis ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Stress (mechanics) ,Condensed Matter::Materials Science ,Hysteresis ,Magnetic anisotropy ,Optics ,business ,Anisotropy ,human activities - Abstract
The effect of stress on the magnetic domain and anisotropy of FeCoSiB amorphous films is investigated. It is observed that the unstressed sample consists of irregular domain while the stressed samples show the strip domain. The strip domain of the sample under tensile stress aligns parallel to the direction of the stress while that of the sample under compressive stress aligns perpendicular to it. The variation of the magnetic domain is explained with the magnetoelastic anisotropy induced by the stress, which has been verified by the hysteresis loops, remanences and the anisotropy field. It is also obtained that the stress-induced anisotropy increases with the increase of the stress. The effects of the stress on the magnetic properties of the FeCoSiB films have been discussed.
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- 2007
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25. EFFECTS OF OXYGEN CONTENT ON THE TRANSPORT PROPERTIES OF <font>La</font>0.7<font>Ca</font>0.3<font>MnO</font>3-δ THIN FILMS
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H.C. Jiang, W.L. Zhang, W.X. Zhang, Z. C. Chen, and Bo Peng
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Materials science ,Transition temperature ,Analytical chemistry ,Surfaces and Interfaces ,Atmospheric temperature range ,Sputter deposition ,Condensed Matter Physics ,Nanocrystalline material ,Surfaces, Coatings and Films ,Amorphous solid ,Electrical resistivity and conductivity ,Materials Chemistry ,Metal–insulator transition ,Thin film - Abstract
We report the effects of oxygen content on the transport properties of La 0.7 Ca 0.3 MnO 3-δ thin films grown epitaxially on LaAlO 3 (001) substrates by RF magnetron sputtering. The as-deposited thin films were annealed and treated by oxygen plasma to improve the oxygen content. We observe that the La 0.7 Ca 0.3 MnO 3-δ films annealed at 850°C is highly oriented growth on (001) LAO substrate. However, the XRD patterns of the samples annealed at lower than 850°C show no distinct diffraction peaks. This evidence indicates that the samples annealed at lower than 850°C are still amorphous or nanocrystalline. The La 0.7 Ca 0.3 MnO 3-δ films without oxygen plasma do not suffer insulator to metal transition at the temperature range from 213 to 293 K. But, at the same temperature range, for the 650°C, 750°C, and 850°C annealed samples with oxygen plasma treatment show an insulator to metal transition at 239 K, 239 K, and 257 K, respectively. Moreover, compared to without oxygen plasma treatment, the resistivity of the sample with oxygen plasma treatment is dramatically decreased. These results imply that the insulator to metal transition is strongly determined by the ratio of Mn 4+/ Mn 3+ and the oxygen content of the films. The increases of the ratio of Mn 4+/ Mn 3+ and the oxygen content lead to a higher insulator to metal transition temperature.
- Published
- 2007
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26. Ways to lower transformation temperatures of porous NiTi shape memory alloy fabricated by self-propagating high-temperature synthesis
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Lijian Rong and H.C. Jiang
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Materials science ,Mechanical Engineering ,Metallurgy ,Self-propagating high-temperature synthesis ,Titanium alloy ,Temperature cycling ,Shape-memory alloy ,Condensed Matter Physics ,Differential scanning calorimetry ,Mechanics of Materials ,Nickel titanium ,Pseudoelasticity ,General Materials Science ,Composite material ,Porous medium - Abstract
Self-propagating high-temperature synthesis (SHS) of porous NiTi alloy for hard tissue implants shows shape memory effect and superelasticity due to the B2 B19' transformation. In order to decrease the A(f) temperature to the human body temperature, 310 K, the effects of preheating temperature, thermal cycling and the third element Mo on the transformation temperatures were investigated using differential scanning calorimetry. The experimental results indicate that the preheating temperature has no obvious effect on the transformation temperatures; the transformation temperatures slightly decreased with increasing number of thermal cycles, but the At temperature was still above 310 K within 10 times; the addition of Mo decreased transformation temperatures considerably, and the R-phase transformation was induced during cooling. Transformation temperatures of porous TiNi(Mo) shape memory alloys with appropriate Mo contents fabricated by SHS meet the demands for human-body implants. (c) 2006 Elsevier B.V. All rights reserved.
- Published
- 2006
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27. Effect of hydroxyapatite coating on nickel release of the porous NiTi shape memory alloy fabricated by SHS method
- Author
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H.C. Jiang and L.J. Rong
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Materials science ,Simulated body fluid ,Metallurgy ,technology, industry, and agriculture ,Titanium alloy ,chemistry.chemical_element ,Biomaterial ,Surfaces and Interfaces ,General Chemistry ,Shape-memory alloy ,equipment and supplies ,Condensed Matter Physics ,Surfaces, Coatings and Films ,Nickel ,chemistry ,Nickel titanium ,Materials Chemistry ,Composite material ,Porosity ,Titanium - Abstract
The amount of nickel release from a porous NiTi shape memory alloy (SMA) fabricated by the self-propagating high-temperature synthesis (SHS) method is about two orders of magnitude more than that of a solid NiTi sample with the same nominal surface exposure to simulated body fluid (SBF). A hydroxyapatite coating has been employed to limit the nickel release from porous NiTi samples without blocking the pores. After 32.5% HNO3 and 1.2 M NaOH aqueous solution treatments, and subsequent sample immersion in SBF for 5 days, a uniform hydroxyapatite layer forms, not only on the surface of the porous NiTi alloy, but also on the inside of the pores. This greatly decreases the amount of nickel release from the porous NiTi shape memory alloy. The exceedingly fast nickel releases from the porous NiTi alloy and mechanism of hydroxyapatite layer formation have been discussed in this paper. (c) 2006 Published by Elsevier B.V.
- Published
- 2006
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28. Effects of stress on the magnetic properties of the amorphous magnetic films
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H.C. Jiang, Wenxu Zhang, Wan Li Zhang, S.Q. Yang, and Bo Peng
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Materials science ,Condensed matter physics ,Coercivity ,Condensed Matter Physics ,Magnetic hysteresis ,Condensed Matter::Disordered Systems and Neural Networks ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Condensed Matter::Materials Science ,Hysteresis ,Magnetization ,Remanence ,Condensed Matter::Superconductivity ,Stoner–Wohlfarth model ,Electrical and Electronic Engineering ,Single domain - Abstract
In this paper, a theoretical model has been established to study the contributions of the magnetization rotations to the magnetic properties of stressed amorphous magnetic films. The influences of both magnitude and direction of the applied stress on the magnetic properties have been discussed. The results show that the shapes of the hysteresis loops are significantly dependent on the applied stress. For amorphous magnetic film with positive magnetostriction, the longitudinal tensile stress can increase the coercivity but the remanence seems independent on the stress. Both the coercivity and remanence approach zero while the longitudinal compressive stress is large enough. The observed magnetostrictions of the amorphous magnetic films are influenced markedly by applied stress.
- Published
- 2006
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29. Geometric and Mechanical Considerations for the Design of the Magnetostrictive Thin Film Actuators#
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H.C. Jiang, Bo Peng, J. Q. Liao, W.X. Zhang, and W.L. Zhang
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Cantilever ,Materials science ,business.industry ,Mechanical Engineering ,General Mathematics ,Aerospace Engineering ,Modulus ,Ocean Engineering ,Magnetostriction ,Young's modulus ,Structural engineering ,Substrate (printing) ,Condensed Matter Physics ,Finite element method ,symbols.namesake ,Mechanics of Materials ,Automotive Engineering ,symbols ,Thin film ,Composite material ,business ,Actuator ,Civil and Structural Engineering - Abstract
The driving field of the magnetostrictive thin film actuator should be as small as possible in order to develop miniature devices. The aim of this paper is to reduce the driving field by varying the structural and the material parameters of the substrate of the cantilever in the actuator based on the finite element calculation. The influences of the geometric and the material parameters on the reference driving field have been studied. The results show that the reference driving field is sensitive to the length of the cantilever, the thickness of both the magnetostrictive film and the substrate, and also the Young's modulus of the substrate. The length of the cantilever should be long enough. In order to achieve a small driving field, the thickness of both the magnetostrictive film and the substrate should be carefully designed according to the ratio of the Young's modulus of the substrate to that of the film.
- Published
- 2006
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30. Modeling microwave behaviors of series cantilever MEMS switch
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G.H. Chen, W.X. Zhang, W.L. Zhang, H.C. Jiang, and Bo Peng
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Microelectromechanical systems ,Cantilever ,Materials science ,Series (mathematics) ,Metals and Alloys ,ComputerApplications_COMPUTERSINOTHERSYSTEMS ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Condensed Matter Physics ,Computer Science::Other ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Hardware_GENERAL ,Hardware_INTEGRATEDCIRCUITS ,Electronic engineering ,Electrical and Electronic Engineering ,Instrumentation ,Microwave - Abstract
Simple and effective model is demanded which enables the design and structural optimization of the microwave MEMS switch efficiently. For this purpose the microwave behaviors of series metal cantilever MEMS switch have been modeled by “simple” circuit in this paper. The microwave characteristics have been calculated and compared with the experiment data based on the developed model. The results show that the microwave characteristics of series metal cantilever MEMS switch can be described very well with this model. Based on this model, the influences of the structural parameters of the switch on the microwave characteristics have been discussed extensively.
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- 2006
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31. Magnetization reversal simulation of diamond-shaped NiFe nanofilm elements
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R.J. Tang, Wanli Zhang, H.C. Jiang, Bin Peng, H.W. Zhang, and Wenxu Zhang
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Random access memory ,Materials science ,Condensed matter physics ,Field (physics) ,Magnetization reversal ,Magnetic storage ,Diamond ,Edge (geometry) ,engineering.material ,Electronic, Optical and Magnetic Materials ,law.invention ,Magnetization ,law ,engineering ,Electrical and Electronic Engineering ,Micromagnetics - Abstract
We have studied magnetization reversal behaviors of diamond-shaped NiFe nanofilm elements with different length-to-width ratios (LWRs) between long and short diagonals by micromagnetic simulation. The results show that the reversal process of the diamond-shaped element strongly depends on the LWR. If the LWR is smaller than 2, the reversal starts at the element edge, but it starts from the center of the element with larger LWR. With a bias field and when the LWR is larger than 2, all the elements experience a similar reversal process, which is simple and unique. In addition, the switching field becomes stable and nearly constant. These results suggest that the diamond-shaped NiFe nanofilm element can be potentially used in magnetic random access memory.
- Published
- 2005
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32. Obliquely sputtered TbFe giant magnetostrictive films with in-plane anisotropy
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Wanli Zhang, Bin Peng, H.C. Jiang, S.Q. Yang, and Wenxu Zhang
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Magnetization ,Magnetic anisotropy ,Materials science ,Magnetic domain ,Condensed matter physics ,Sputtering ,Film plane ,Magnetostriction ,Electrical and Electronic Engineering ,Magnetic force microscope ,Sputter deposition ,Electronic, Optical and Magnetic Materials - Abstract
We have found that in-plane magnetostriction characteristics at low fields can be greatly improved by an oblique sputtering technique. We report a study of deposition of in-plane anisotropic TbFe giant magnetostrictive films by dc magnetron oblique sputtering, including the influences of deposition angle on TbFe film magnetic and magnetostrictive performances. The in-plane magnetization of TbFe films at 1600 kA/m is drastically increased with a change of deposition angles from 90/spl deg/ to 15/spl deg/. Magnetic domain structures explored by magnetic force microscopy indicate that the easy magnetization directions of the films can be gradually changed from perpendicular to the film plane at sufficiently shallow deposition angles. The in-plane magnetostrictive coefficients /spl lambda/ at 16 kA/m also can be increased by decreasing the deposition angles from 90/spl deg/ to 15/spl deg/. The significant variation in the in-plane magnetic and magnetostrictive performances can be explained by the decrease of perpendicular anisotropy of TbFe films.
- Published
- 2005
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33. The Influences of Depositing Angles on TbFe Film Magnetic and Magnetostrictive Characteristics
- Author
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Shi Qing Yang, H.C. Jiang, Wan Li Zhang, Bin Peng, and W.X. Zhang
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Materials science ,Magnetic domain ,Condensed matter physics ,Mechanical Engineering ,Metallurgy ,Magnetostriction ,Sputter deposition ,Condensed Matter Physics ,Magnetization ,Mechanics of Materials ,Perpendicular ,External field ,General Materials Science ,Anisotropy ,Saturation (magnetic) - Abstract
In this paper, the influences of depositing angles on TbFe film magnetic and magnetostrictive characteristics were discussed. TbFe films were deposited by DC magnetron sputtering. With the decrease of depositing angles from 900 to 150, TbFe film in-plane magnetization measured at 1600kA.m-1 external field is greatly increased. With the decrease of depositing angles from 900 to 150, the magnetostrictive saturation field is decreased. TbFe film in-plane magnetostriction is improved when depositing angles are changed from 900 to 150. Magnetic domain structures detected by MFM indicates that film easy magnetization direction is gradually changed from perpendicular to parallel with the decrease of depositing angles. The variation of film magnetic and magnetostrictive performances can be explained by the oblique anisotropy associated with columnar grain morphology of the films.
- Published
- 2005
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34. TbFe2/α-Fe Nanocrystalline Exchange Coupling Magnetostrictive Films
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W.X. Zhang, Shi Qing Yang, Bin Peng, Wan Li Zhang, and H.C. Jiang
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Materials science ,Annealing (metallurgy) ,Mechanical Engineering ,Magnetostriction ,Sputter deposition ,Laves phase ,Coercivity ,Condensed Matter Physics ,Nanocrystalline material ,Magnetization ,Nuclear magnetic resonance ,Mechanics of Materials ,General Materials Science ,Crystallite ,Composite material - Abstract
In this paper, the influences of annealing temperature on TbFe magnetostrictive film magnetic and magnetostrictive characteristics were discussed. TbFe films were prepared by RF magnetron sputtering. XRD patterns indicate that polycrystalline films consisting mainly of a-Fe and TbFe2 Laves phase could be obtained through rapid cycle annealing process (RCAP) at higher annealing temperature. Grain sizes could be controlled through varying annealing temperature. From film hysteresis loops measured by VSM, it has been found that the annealing treatment can improve TbFe film in-plane magnetization at 1600 kA.m-1 external field, and decrease in-plane coercivity. Magnetostriction of annealed TbFe films measured by optical cantilever deflectometer is better than as-deposited films at 40 kA.m-1 external magnetic field.
- Published
- 2005
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35. Composition control and its influence to the magnetic properties of TbFex film
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L.W Lin, W.L. Zhang, W.X. Zhang, Bo Peng, S.Q. Yang, and H.C. Jiang
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Materials science ,Argon ,Magnetic domain ,business.industry ,Film plane ,chemistry.chemical_element ,Magnetostriction ,Substrate (electronics) ,Sputter deposition ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Optics ,chemistry ,Magnetic force microscope ,Composite material ,business ,Spontaneous magnetization - Abstract
In this paper, magnetostrictive film of TbFe x is fabricated by DC magnetron sputtering. Influence of the argon pressure to the film composition is studied both experimentally and theoretically. The results show that the argon pressure can change the composition of the film in relatively large range: When the gas pressure is increased from 0.2 to 0.6 Pa , the atomic contents of iron decrease from 69% to 55%. The as-deposited film spontaneous magnetization changes from perpendicular to parallel to the film plane when the iron contents decrease which is indicated by magnetic force microscopy. The studies also suggest that decrease of the plasma temperature and increase of the substrate and target distance can enhance the composition control capability of gas pressure variation.
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- 2004
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36. Simulation of magnetostriction in TbFe2/Fe multilayers
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H.C. Jiang, Bo Peng, W.L. Zhang, W.X. Zhang, and S.Q. Yang
- Subjects
Hysteresis ,Materials science ,Condensed matter physics ,Orientation (geometry) ,Perpendicular ,Magnetostriction ,Condensed Matter Physics ,Layer (electronics) ,Micromagnetics ,Layer thickness ,Electronic, Optical and Magnetic Materials - Abstract
In this paper, micromagnetic simulation is used to study the magnetostrictive and magnetic character of a TbFe 2 /Fe multilayer. The influence of magnetic easy-axis orientation, thickness of the TbFe 2 layer and number of layers of the multilayer are examined in detail. According to our numerical results, some general rules to improve the performances of magnetostrictive multilayers are determined which can be stated as: perpendicular easy-axis orientation of two kinds of sub-layer, proper magnetostrictive layer thickness, and more film layers.
- Published
- 2004
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37. Influence of film thickness on deformation of a free magnetostrictive film-substrate system
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S.Q. Yang, Bo Peng, Wenxu Zhang, and H.C. Jiang
- Subjects
Work (thermodynamics) ,Cantilever ,Materials science ,business.industry ,Magnetostriction ,Substrate (electronics) ,Deformation (meteorology) ,Condensed Matter Physics ,Layer thickness ,Electronic, Optical and Magnetic Materials ,Optics ,Thin film ,Composite material ,Actuator ,business - Abstract
In this paper, the deformation of the cantilever actuator under the influence of the magnetostrictive film thickness has been extensively studied. The prediction is in accordance with the previous work by E. du Tremolet de Lacheisserie, when the film is thin enough. And we find that there exists a maximum of the deformation when the thickness of the film is properly chosen.
- Published
- 2002
- Full Text
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38. Coercivity in stressed amorphous FeCoSiB thin films
- Author
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Bo Peng, W.L. Zhang, W.X. Zhang, and H.C. Jiang
- Subjects
Materials science ,Film plane ,Isotropy ,Coercivity ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Amorphous solid ,Stress (mechanics) ,Magnetic anisotropy ,Compressive strength ,Nuclear magnetic resonance ,Electrical and Electronic Engineering ,Thin film ,Composite material - Abstract
The effect of stress on the magnetic properties of FeCoSiB amorphous films is investigated. It has been observed that the unstressed sample is isotropic in the film plane. The samples under tensile stress show clear easy axis along the stress while the samples under compressive stress show easy axis perpendicular to the stress axis. With increasing of the tensile stress, the coercivity of the films decreases monotonically. The coercivity increases with increase of the compressive stress when the stress is not large and then decreases with further increase of the compressive stress. The variation of the coercivity with stress is understood by taking into account the influences of stress on the rotational and wall displacement magnetization reversal processes.
- Published
- 2010
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39. Comparison on structural systems for Shanghai Jasper Tower
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G. Du, H.C. Jiang, and Q.Q. Guo
- Subjects
Engineering ,business.industry ,Structural system ,Frame (networking) ,Steel structures ,Architecture ,business ,Tower ,Civil engineering - Abstract
Publisher Summary The chapter discusses structural systems of Shanghai Jasper tower. Shanghai Jasper Tower, located in Pu Dong Lujiazui by Huangpu River, consists of a four-storey basement, 46-storey main tower, top-steel frame, and four-storey podium. Its floor area is about 100,000 sq. meters. The total height is 228m and the height of the main structure is 199.8m. It is a multi-functional building for office, commercial, and amusement use. Based on the character of the architecture layout and its height, two kinds of structural systems—mixed structure and steel structure—are presented as alternative schemes. From the experience of similar buildings, both mixed structure and steel structure can be satisfied to the demand of architecture function and structure safety. The chapter studies the dynamic characteristic, displacement, and economic index of the two systems, so that an effective and reasonable structural system can be selected to optimize the design.
- Published
- 2005
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40. FILM THICKNESS INFLUENCES ON THE THERMOELECTRIC PROPERTIES OF <font>NiCr</font>/<font>NiSi</font> THIN FILM THERMOCOUPLES
- Author
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H.C. Jiang, Xing Zhao Liu, Yin-Zhi Chen, Sisi Jiang, and W. L. Zhang
- Subjects
Materials science ,Electromotive force ,Thermocouple ,Annealing (metallurgy) ,Seebeck coefficient ,Thermoelectric effect ,Statistical and Nonlinear Physics ,Sputter deposition ,Composite material ,Nichrome ,Condensed Matter Physics ,Electron beam physical vapor deposition - Abstract
NiCr / NiSi thin film thermocouples (TFTCs) with a multi-layer structure were fabricated on Ni -based superalloy substrates (95 mm × 35 mm × 2 mm) by magnetron sputtering and electron beam evaporation. The five-layer structure is composed of NiCrAlY buffer layer (2 μm), thermally grown Al 2 O 3 bond layer (200 nm), Al 2 O 3 insulating layer (10 μm), NiCr / NiSi TFTCs (1 μm), and Al 2 O 3 protective layer (500 nm). Influences of thermocouple layer thickness on thermoelectric properties were investigated. Seebeck coefficient of the samples with the increase in thermocouple layer thickness from 0.5 μm to 1 μm increased from 27.8 μV/°C to 33.8 μV/°C, but exhibited almost no change with further increase in thermocouple layer thickness from 1 μm to 2 μm. Dependence on temperature of the thermal electromotive force of the samples almost followed standard thermocouple characteristic curves when the thickness of the thermocouple layer was 1 μm and 2 μm. Sensitive coefficient K of the samples increased greatly with the increase in thickness of the thermocouple layer from 0.5 μm to 1 μm, but decreased insignificantly with the increase in thermocouple layer thickness from 1 μm to 2 μm, and continuously decreased with the increase in temperature. The sensitive coefficient and the stability of NiCr / NiSi TFTCs were both improved after annealing at 600°C.
- Published
- 2013
- Full Text
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