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Materials Science and Engineering

Journal of Electrochemistry

2001

Articles 31 - 49 of 49

Full-Text Articles in Engineering Science and Materials

Atmospheric Corrosion Of Steels In China, Cai-Feng Liang May 2001

Atmospheric Corrosion Of Steels In China, Cai-Feng Liang

Journal of Electrochemistry

Data of eight year atmospheric exposures of 17 steels at 7 sites in China were analyzed.The result showed that the most detrimental pollution is sulfur dioxide and chloride ion for corrosion of carbon steels and low alloy weathering steels.This is in accordance with the common knowledge.The effect of sulfur dioxide is serious in the first few years and becomes weak obviously in the later years.The environment factor of humid hot is much more important in long run than the ordinarily acknowledged humidity,pollution for non weathering steels,although it is not obvious in the beginning.If pollution were existed,a severe corrosion may resulted.As …

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Galvanic Corrosion Of Tin-W Electro-Couple During Tungsten Chemical Mechanical Polishing, Xuan Cheng, Chang-Jian Lin May 2001

Galvanic Corrosion Of Tin-W Electro-Couple During Tungsten Chemical Mechanical Polishing, Xuan Cheng, Chang-Jian Lin

Journal of Electrochemistry

Chemical_mechanical polishing (CMP) is a process whereby mechanical and chemical forces are combined to remove material from a wafer and polish it to a flat surface. Tungsten CMP is an important process to gain the global planarity of silicon wafers with tungsten (W) plugs. Tungsten is actually deposited on a thin adhesive layer of titanium nitride (TiN) on silicon. When close to the final stage of polishing, TiN and W will be simultaneously exposed to the polishing chemistry, forming a galvanic couple. The corrosion of TiN and W couple will result in different polish rate. This work studied the potential …

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Preparation Of Ti-Based Nanocrystalline Tio_2 Film Electrode With High Activity, Dao-Bao Chu, Guang-Xia Shen, Xing-Fu Zhou, Chang-Jian Lin, Hua-Shui Lin May 2001

Preparation Of Ti-Based Nanocrystalline Tio_2 Film Electrode With High Activity, Dao-Bao Chu, Guang-Xia Shen, Xing-Fu Zhou, Chang-Jian Lin, Hua-Shui Lin

Journal of Electrochemistry

The potentiostatic electrosynthesis of Ti(EtO) 4 was studied by anodic dissolution of metal titanium(TA1) in solution of 0.005 mol·L -1 (EtO) 4NBr in the ethanol (AR) in the presence negligible CH 3COCH 2COCH 3.The Ti_based nanocrystalline TiO 2 Film electrode (Ti/nano_TiO 2) was prepared by sol_gel method.By TEM,SEM and XRD,it has been shown that the anatase particle of TiO 2 was 10～35 nm in diameter and the film was 0.5 μm in thickness.The nanocrystalline film was composed of a three_diminsional network of interconnected particles.Reodx behavior and electrocatalytic activities of the Ti/nano_TiO 2 electrode were investigated by cyclic voltammetry (CV) from …

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Properties Of Metallized Poly-O-Toluidide Membrane Modified Electrode, Li-Zong Dai, Yi-Ting Xu, Hui-Huang Wu May 2001

Properties Of Metallized Poly-O-Toluidide Membrane Modified Electrode, Li-Zong Dai, Yi-Ting Xu, Hui-Huang Wu

Journal of Electrochemistry

The platinum particles were electrodeposited on poly(o_toluidide),POT,modified electrode,and the surface configuration and crystal orientation of Pt particles were investigated by SEM and XRD.At the same time the oxidation of isopropanol on platinized POT modified electrode was studied.The results indicate that Pt particles deposite towards preferred_orientation;moreover the increase in polymer electroactivity due to proton doping affects the dimension and graininess of deposited Pt particles.At the metallized polymer electrode the oxidation of isopropanol can occur in POT electroactive potential region,however at the more positive than 0.70 V (SCE) potential where POT loses redox activity the electro_oxidation mainly occurrs on Pt particles.It follows …

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Performance Of A Direct Methanol Fuel Cell, Zhao-Bin Wei, Jian-Guo Liu, Ya-Guang Jiao, Wei-Jiang Zhou, Wen-Zhen Li, Li-Kang Chen, Qin Xin, Bao-Lian Yi May 2001

Performance Of A Direct Methanol Fuel Cell, Zhao-Bin Wei, Jian-Guo Liu, Ya-Guang Jiao, Wei-Jiang Zhou, Wen-Zhen Li, Li-Kang Chen, Qin Xin, Bao-Lian Yi

Journal of Electrochemistry

A direct methanol fuel cell with 9cm 2 active area consists of Pt_Ru/C anode,Pt/C cathode and Nafion 115 membrane.The effect of operating conditions:methanol solution concentration,oxygen pressure and cell temperature on the cell performances was investigated.The results show that performance of single cell was enhanced by increasing oxygen pressure and cell temperature,and a maximum power density 75 mW/cm 2 was obtained in the range of 250_300 mA/cm 2 current density,0.2 MPa oxygen pressure,1.0 mol/L methanol concentration and 75 ℃ cell temperature.When cell operating at room temperature,a relatively low,but a stable performance of cell was also observed.

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Study Of The Oxidation Dynamics Of Ti-Zro_2 Metal-Ceramics, Wen-Chao Li, Li-Dong Teng May 2001

Study Of The Oxidation Dynamics Of Ti-Zro_2 Metal-Ceramics, Wen-Chao Li, Li-Dong Teng

Journal of Electrochemistry

The oxidation dynamics of hot pressed Ti ZrO 2 metal_ceramics with the composition of 50 vol.% Ti and 50 vol.% ZrO 2 has been studied. Thermodynamic analysis shows that Ti could react with O 2 but not with N 2 in the oxidizing process of Ti ZrO 2 composites at 0.1 MPa air. The oxidation dynamic behavior of Ti ZrO 2 composites is analogous to that of pure Ti. The activation energy for the oxygen diffusion in Ti ZrO 2 composites is higher than that in Ti solutions, for the presence of ZrO 2 restrains the oxygen diffusion in Ti …

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Preparation And Properties Of Separator For Lithium-Ion Battery, Xu-Mei Ren, Feng Wu, Chuan Wu, Han-Jun Li, Xue-Jie Huang May 2001

Preparation And Properties Of Separator For Lithium-Ion Battery, Xu-Mei Ren, Feng Wu, Chuan Wu, Han-Jun Li, Xue-Jie Huang

Journal of Electrochemistry

Lithium_ion batteries are well adapted to the new multimedia applications. PP/PE based microporous film is commonly used as separator in commercial lithium ion batteries. Here we report a microporous film which is superior to the commercial available separator. The microporous PVDF polymer separators were prepared by the phase inversion process. The pore size of the separator is  7 μm, and it's porosity is 75%. The membrane in LiPF 6 EC/DEC showed high ionic conductivity (above 10 -3 S/cm at room temperature), and good mechanical properties (10 3 kg/cm 2). The half_cells consisted of Li/PVDF separator/MCMB showed excellent cycling characteristics …

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The Effect Of Calcium On The Properties Of Molybdenum Nitride Electrode, Yun-Gui Zhu, Xue-Liang Li, Dao-Rong Lu, Jian-Bo He, Ji-Huai Xia May 2001

The Effect Of Calcium On The Properties Of Molybdenum Nitride Electrode, Yun-Gui Zhu, Xue-Liang Li, Dao-Rong Lu, Jian-Bo He, Ji-Huai Xia

Journal of Electrochemistry

The effect of calcium on the properties of molybdenum nitride film electrode was studied by using XRD, SEM and cyclic voltammetry. The results show that the specific electric capacity and the voltage operating range of electrode vary with the concentration of additive in the dipping solution. At the optimum concentration of additive in the dipping solution, the specific electric capacity of the electrode is 2.1 times as large as that of the electrode prepared in the dipping solution without additive, and the voltage operating range of electrode is increased by 0.11 V. The active mechanism of calcium on the properties …

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Study On Corrosion Resistance Of Electroless Nickel Composite Coatings, Tsong-Jen Yang, Meng-Feng Jou May 2001

Study On Corrosion Resistance Of Electroless Nickel Composite Coatings, Tsong-Jen Yang, Meng-Feng Jou

Journal of Electrochemistry

The eletroless nickel composite coating was prepared by uniform dispersion of diamond (or PTFE) particles throughout electroless nickel deposition. Corrosion resistance of composite coating in 3.5% NaCl aqueous solution was investigated by electrochemical analysis, dipping test and salt spray test. The results showed that the corrosion resistance of composite coating was inferior to that of electroless nickel coating if small amount of particles was added to the composite coating. Microsturctural analysis by SEM,AES,XRD,and EPMA indicated that the distribution of phosphorus is not homogeneous in the composite coating. The phosphorus_rich region acts as microcathode, however, the phosphorus_lean region acts as microanode.The …

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The Applications Of Confocal Raman Micro-Spectroscopy For Study Of Practical Electrode Materials, Yang Y, Chu W, Nan J M, Chen X G, Lin Z G Feb 2001

The Applications Of Confocal Raman Micro-Spectroscopy For Study Of Practical Electrode Materials, Yang Y, Chu W, Nan J M, Chen X G, Lin Z G

Journal of Electrochemistry

Some recent research work about applications of confocal Raman micro spectroscopy for study of practical electrode materials carried out in our lab has been briefly introduced. The examples include study of electrochemical Li + intercalation process, characterization of surface oxide film on AB 5 type electrodes and passive film and pitting corrosion of Rebar electrodes.

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Synthesis Of Limn_2o_(4-Δ) Cl_Δ Cathode Material By Like-Sol-Gel Methode, Zhao Yong Chen, Yi He, Xing Quan Liu, Zhi-Jie Li, Zuo-Long Yu Feb 2001

Synthesis Of Limn_2o_(4-Δ) Cl_Δ Cathode Material By Like-Sol-Gel Methode, Zhao Yong Chen, Yi He, Xing Quan Liu, Zhi-Jie Li, Zuo-Long Yu

Journal of Electrochemistry

LiMn 2O 4 δ Cl δ was synthesized by like sol gel methode, with calculated LiOH.H 2O, Mn(No 3) 2.6H 2O and LiCl.H 2O, and made electrochemical test with these compounds as positive materials. Result demostrated that LiMn 2O 4 δ Cl δ cathode material has exellent stability and nearly no capacity loss after reaching stability.

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How Can Direct Mthanol Fuel Cell Benefit From Carbonate Media, Lin Zhuang, Yang Wang, Jun Tao Lu Feb 2001

How Can Direct Mthanol Fuel Cell Benefit From Carbonate Media, Lin Zhuang, Yang Wang, Jun Tao Lu

Journal of Electrochemistry

The kinetics of methanol oxidation and oxygen reduction in 0.5 mol/L K 2CO 3 were compared with those in 0.5 mol/L H 2SO 4. Experiments revealed that carbonate media could be more beneficial to direct methanol fuel cell(DMFC).Firstly, both electrode reactions show better performance in the carbonate than in the acid; secondly, materials other than noble metals become possible to be used as the anodic and cathodic catalysts;thirdly, the potential dectease caused by methanol crossover could be depressed by using metal oxide catalysts not stable in acid, such as MnO 2.

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Two-Dimensional Surface Raman Imaging Of A Roughened Iron Electrode In Saline Water, Pei-Gen Cao, Jian Lin Yao, Jun Wei Zheng, Bin Ren, Ren-Ao Gu, Zhong Qun Tian Feb 2001

Two-Dimensional Surface Raman Imaging Of A Roughened Iron Electrode In Saline Water, Pei-Gen Cao, Jian Lin Yao, Jun Wei Zheng, Bin Ren, Ren-Ao Gu, Zhong Qun Tian

Journal of Electrochemistry

The analysis of the composite and distribution of iron oxide due to pit corrosion in saline solutions (3.4% NaCl) is of great importance. Many electrochemical methods, XPS, and other photoelectronic techniques have been applied to this domain. Surface?enhanced Raman scattering (SERS) spectroscopy can provide the vibrational information of surface species with high sensitivity and is very useful in the study of surface chemistry of iron. Notwithstanding, the application of SERS in iron corrosion is hampered for its SERS?inactivity. Efforts have been devoted to extend the use of SERS to the study of iron. Approaches include the deposition of particles or …

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A Study On The Performance Of Matrix Prepared By Tape Cast And Its Molten Carbonate Fuel Cells (Mcfcs), Hua-Xin Lin, Bao Lian Yi, Li Zhou, Chang-Qing He, Lian Ying Kong, En Jun Zhang Feb 2001

A Study On The Performance Of Matrix Prepared By Tape Cast And Its Molten Carbonate Fuel Cells (Mcfcs), Hua-Xin Lin, Bao Lian Yi, Li Zhou, Chang-Qing He, Lian Ying Kong, En Jun Zhang

Journal of Electrochemistry

The matrix prepared with γ LiAlO 2 powder and by tape cast displayed higher ability of preventing from gas cross over and lower ohmic polarization. The voltages of the stack (three cells,122 cm 2) stacked with the matrix were 2.02 and 1.78 V at 200 and 246 mA/cm 2, respectively, and the output power reached 53.4 W. The cell(28 cm 2) voltages were 0.85 and 0.75 V at 200 and 300 mA/cm 2, respectively,and the output power was about 6.6 W. Compensating the shrinkage of matrix in stacking cells promoted the enhancement of the MCFC performance.

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Catalytic Effect Of Cl~- On Electrodeposition Of Binary Zinc Alloys With Iron Group Metals, Ren-He Yin, Zheng Hua Fang, Wei Min Cao, A.Zakaria A.Zakaria, Rong-Ming Zhou Feb 2001

Catalytic Effect Of Cl~- On Electrodeposition Of Binary Zinc Alloys With Iron Group Metals, Ren-He Yin, Zheng Hua Fang, Wei Min Cao, A.Zakaria A.Zakaria, Rong-Ming Zhou

Journal of Electrochemistry

Zinc iron group metal alloys were deposited under coulostatic (10C.cm -2 ) at 40 ℃ chloride baths. The deposited alloys were quantitatively analyzed by Atomic Absorption Spectrometry. The current efficiency, percent content and partial polarization curves were obtained by the results. The morphology of the deposits was observed by means of Scanning Electron Microscopy(SEM). We observe that the electrodeposition of zinc iron group metal alloys is one of the best known examples of anomalous codeposition. We found the catalytic effect of Cl - on the electrodeposition behavior of iron group metal. Overpotential of iron group metal droped abruptly at high …

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Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo Liang Chen Feb 2001

Adsorption And Oxidation Of Ethanol On Nm-Pt/Gc Electrode Ii. Eqcm And In-Situ Ftir Spectroscopic Studies In Acid Media, Guo Liang Chen

Journal of Electrochemistry

The adsorption and oxidation of ethanol on nm?Pt/GC electrode in acid solutions containing 0.1 mol·L -1 H 2SO 4 +0.1 mol·L -1 CH 3CH 2OH was investigated by using cyclic voltammetry , EQCM and in?situ FTIR spectroscopy. The experimental results demonstrated that the oxidation of CH 3CH 2OH is closely relaed to solution acidity and oxygen species on electrode surface; CH 3CH 2OH was oxidized on nm?Pt/GC electrode in acidic media via a dual path reaction mechanism, i.e . CH 3CH 2OH may be oxidized into CO 2 through the dissociative adsorbate (CO) and the reactive intermediates that were determined …

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The Photoelectrochemistry Of Tio_2-Polyaniline Composite Film, Huai Guo Huang, Zhi Xin Zheng, Jin Luo, Hong-Ping Zhang, Ling-Ling Wu, Zhong-Hua Lin Feb 2001

The Photoelectrochemistry Of Tio_2-Polyaniline Composite Film, Huai Guo Huang, Zhi Xin Zheng, Jin Luo, Hong-Ping Zhang, Ling-Ling Wu, Zhong-Hua Lin

Journal of Electrochemistry

A TiO 2 and polyaniline (PANI) composite film was obtained by electrochemical methods. The SEM image of the composite film showed that the PANI film is almost completely covered with TiO 2. The spectra of photocurrent for the TiO 2 PANI composite film , which overlaps the TiO 2 film and PANI film, showed that the composite film is able to have higher conversion efficiency. The spectra of photocurrent for the TiO 2 PANI composite film were different from these of TiO 2 film photosensitized by PANI. The bandgap energy of TiO 2 film on partially oxidized PANI film was …

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Adsorption Behavior Of Co At The Ultrathin Rh And Pt Film Electrodes, Yong Xie, Xiao Qin Li, Bin Ren, Zhong-Qun Tian Feb 2001

Adsorption Behavior Of Co At The Ultrathin Rh And Pt Film Electrodes, Yong Xie, Xiao Qin Li, Bin Ren, Zhong-Qun Tian

Journal of Electrochemistry

Pt group metals have been widely used in catalysis such as hydrogenation of organic compounds and the oxidation of carbon monoxide. The information about CO adsorption on the Pt group surfaces and the influence of other surface species, such as hydrogen and CO 2, will be greatly helpful to elucidate the adsorption behavior of CO on Pt group metal surfaces and get a deeper understanding of catalytic mechanisms of Pt group metals. Surface enhanced Raman spectroscopy (SERS) has been becoming an increasingly important means to characterize the electrochemical metal solution interface over the past two decades. Our laboratory has successfully …

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In Situ Raman Spectroelectrochemical Characterization Of The Prussian Blue/Platinum Modified Electrode, Xiao-Wei Cao, Rong Wang, Gui Hua Wang, Zong Rang Zhang Feb 2001

In Situ Raman Spectroelectrochemical Characterization Of The Prussian Blue/Platinum Modified Electrode, Xiao-Wei Cao, Rong Wang, Gui Hua Wang, Zong Rang Zhang

Journal of Electrochemistry

Prussian Blue is known to be deposited electrochemically on the electrode surface, producing a dense redox active layer. Since the Prussian Blue modified electrode was first reported by Neff in 1978 [1] , different in situ spectroelectrochemical techniques have been widely used to investigate its electrochemical mechanism [2～4] . But no research work related to the in situ Raman spectroscopic studies on it has been reported. In this paper we try to characterize the nature of thin Prussian Blue films on platinum substrates with in situ Raman spectroelectrochemical technique. A Super LABRAM confocal microscopic Raman spectrometer (Dilor) with a He?Ne …

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