Her-Yueh Huang
,
Kuang-Hung Tseng
金属学报(英文版)
The effects of the process parameters on the joint quality of TO-Can using resistance projection welding were investigated. A capacitor discharge stored energy welding machine was used for joining caps and headers both coated with nickel SPCC steel. The electrode materials used in this study were brass and W- Cu alloy. Experimental results indicated that the peak current of the W-Cu electrode was higher than that of the brass electrode, irrespective of the operating pressure variation. Increased operating pressure influenced the interfacial heat generation and nugget formation. The nugget area increased rapidly with increasing charging voltage, resulting in expulsions and electrodes getting stuck. An acceptable welding zone was found in the relationship between the charging voltage and the operating pressure. Representative test specimens of the acceptable welding zone satisfactorily passed the helium leak test. The microscopic morphology of the nugget showed a recrystallized fine grain structure resulting in the nugget being harder than with the HAZ.
关键词:
Projection welding
Acta Physico-Chimica Sinica
The electrochemical behaviours of the hydrogen evolution reaction (HER) on electrodes prepared by composite coating of nanocrystalline Ni-Mo alloy particle which was formed by ball milling on nickel base has been studied by steady-state polarization and ac impedance techniques. The microstructure and the particle size of Ni-Mo alloy nanocrystals and the morphology of the composite-coated surface of the electrodes were examined by XRD, TEM and SEM. The mechanism of HER on the composite electrodes has been investigated as well. Results showed that for HER electrocatalytic activity which was enhanced with increasing milling time. The reaction rate of HER on the electrodes was proved to be controlled by electrodesorption. The direct composite coating of highly electroactive particles onto the surface may serve as a new approach to the preparation of electrode materials.
关键词:
Composite coating;Hydrogen evolution reaction;Nanocrystalline;Ni-Mo;alloy;Ball milling
催化学报
The IrO2-Ta2O5 coating electrodes were prepared by thermal decomposition. and supported on TIN films synthesized by multi-arc ion plating. The electrocatalytic properties of coating cathodes for hydrogen evolution reaction (HER) were investigated by cyclic polarization combined with scanning electron microscope, energy dispersive X-ray spectroscopy, and X-ray diffraction. The results showed that there existed TIN substrates on the electrodes and the electrode calcined at 420 degrees C exhibited the best electrocatalytic activity for HER. Electrode potential for hydrogen evolution on coating electrodes was - 0.26 V ( vs SCE). The Tafel slope was - 0. 04 V in the low overpotential region of HER. The structure of oxide electrodes was changed by a multitude of hydrogen atoms adsorbed on the electrode surface in the high overpotential region of HER, which restrained the cathodic reduction reaction of oxygen. These results suggest primarily that it is feasible using TiN as support for the IrO2-Ta2O5 coating cathode.
关键词:
titanium nitride;iridium oxide;tantalum oxide;electrocatalysts;hydrogen evolution reaction;oxide electrodes;iridium oxide;nanoparticles;generation;deposition;activation;oxidation;h2so4;water;iro2
Q. Han
,
J.S. Chen
,
K.R. Liu
金属学报(英文版)
NiSCo catalytic cathodes were obtained by electrodeposition in a typical Watt cellwith addition of NH2 CSNH2 and CoCl2. Using CoCl2 concentration, current density,temperature and pH value as main factors, an orthogonal experiment was designed todetermine the optimum technological conditions according to HER overpotentials. Theoptimum technological conditions were obtained from the minimum HER overpoten-tial -70m V. The corresponding electrochemical parameters (Tafel slope b, exchangecurrent density to) were determined by steady-state polarization curves. The contentof S, Co and its microstructure were measured by EPMA and XRD.
关键词:
NiSCo alloy
,
null
,
null
Acta Physico-Chimica Sinica
The cathodic adsorption beheaviors of thiourea and 4 of its derivatives on iron in hydrochloric acid and sulphuric acid were investigated by polarizations curves. The accordance of the adsorption beheavior of thiourea on iron in sulphuric acid with Temkin isotherm was deduced from hynamics, and the thiourea took part in the reaction of HER, this phenomena is a negative catalytic effect. The adsorption beheavoris of thiourea and its 4 derivatives and iron in hydrochloric acid was found to be in accord with Langmuir isotherm and this conclusion was deduced from thermodynamics, this phenomena is a blocking effect.
关键词:
Thiourea;Derivatives;Iron;Adsorption;Cathodic polarization
许传龙
,
王式民
工程热物理学报
在加压密相气力输送实验装置上获得了不同操作条件下煤粉颗粒静电波动信号,并用Hilbert-Huang变换、功率谱进行分析.结果表明:随着表观速度的增加,静电波动信号主峰值的频率增大;静电波动信号希尔伯特-黄变换(Hilbert-Huang)揭示了气固两相流静电信号的非线性和非平稳特征,随气固两相流颗粒相浓度降低和颗粒及表观速度增加,静电波动信号特征尺度由高尺度(低频)向低尺度(高频)转移.多尺度分析有助于认识气固两相流动形态及其转变规律.
关键词:
颗粒静电
,
静电传感器
,
气-固两相流
,
Hilbert-Huang变换
中国腐蚀与防护学报
N。1Atmospheric Corrosivlty for Steels………………………………………………… .LIANG Caideng HO[I i。-tat（6）Caustic Stress Corrosion Cr。king of Alloy 800 Part 2.The Effect of Thiosul执e……………………………………… KONG De-sheng YANG Wu ZHAO Guo-zheng HUANG De.ltL。ZHANG Yu。。he CHEN She。g-bac（13）SERS slid E16CttOCh6iniC81 Stlldy Of Illhibit1Oli M6ch＆tllsth Of ThlollY68 Oil ITOll ID H....
关键词:
Materials Science and Engineering a-Structural Materials Properties Microstructure and Processing
Monocrystalline copper samples with [001] and [221] orientations were subjected to shock/recovery experiments at 30 and 57 GPa and 90 K. The slip system activity and the microstructural evolution were investigated. Different defect structures, including dislocations, stacking faults, twins, microbands, and recrystallized grains were observed in the specimens. The residual microstructures were dependent on crystalline orientation and pressure. The differences with crystalline orientations are most likely due to different resolved shear stresses on specific crystalline planes. The geometric relationships between the shock propagation direction and crystalline orientation are presented under uniaxial strain. It is shown that the [2 2 11 orientation, by virtue of having fewer highly activated slip systems, exhibits greater concentration of deformation with more intense shear on the primary system. This, in turn leads to greater local temperature rise and full recrystallization, in spite of the thermodynamic residual temperature of similar to 500 K and rapid cooling (within 20 s) to ambient temperature. The profuse observation of microbands is interpreted in terms of the mechanism proposed by Huang and Gray [J.C. Huang, G.T. Gray III, Acta Metallurgica 37 (1989) 3335-3347]. (C) 2009 Elsevier B.V. All rights reserved.
关键词:
Shock compression;Shock loading;Slip bands;Microtwins;Microbands;strain rate history;single-crystals;grain-size;constitutive;description;plastic-deformation;mechanical response;deformed metals;loaded nickel;substructure;recrystallization
