Papers by Keyword: Current Density

Abstract: On the copper substrate the DLC films is preparated by plasma elcctrodeposition in methanol aqueous solution. The plating solution composition: alcohol water proportion is 4:1, the additive KCl content is 3g/L and the AlCl3 is trace amounts. The influence of the current density and the electrode spacing to the electrode surface bubble zone thickness, uniformity and stability are discussed in the article. The film surface morphology is observed by scanning electron microscopy (SEM). The thickness of the film D=30, 350, 410 and 380 nm. The deposition rate K=150, 175, 205 and 190 nm/h. The polycrystalline structure of the film can be observed through the X-ray diffraction (XRD) pattern., the characteristic peak of the (111),(200) and (220) crystal plane are observed at 2θ= 43.9°,50.9°and75.3°. The high carbon content is observed by EDX analysis.

Abstract: The high speed jet-electrodepositing equipment was used to prepare Ni-P alloy in substrate of 45 steel. The influences of current density on depositing rate, hardness of deposit and microstructure of Ni-P alloy were studied, and the comparation with that of conventional electroplating were studied. The results show that with the increase of stirring intensity of the electrolyte, the thickness of diffused layer decreases, the critical current density increases, and then the depositing rates increase to 69.82/min. A linear increasing of the depositing rate with the increase of current density is observed, and it refines grain size obviously. Deposit hardness up to 679HV.

Abstract: The paper mainly focused on burr removal of the miniature hole drilled on aluminum plate by electrochemical machining. A mathematical model for the electrochemical deburring of miniature holes (M-ECD) was established based on the finite element analysis to the current density distribution. Both theoretical analysis and experimental study were held on the effects of many factors to the deburring results. The results proved that predictions based on our mathematical model were agreed with the experimental data comparatively.

Abstract: In this study, the effects of interfacial crack on thermal mechanical behavior of solder bump only induced by current for flip-chip package are investigated by numerical analysis. In the numerical model, the properties of solder bump are dependent on temperature. First, the crack length effects on thermal mechanical behavior of solder bump is examined, with the parameters of temperature, von Mises stress, shear stress and plastic strain. Second, the influence of current density is also numerically examined. It is demonstrated that the increasing current density and the crack length will induce more plastic strain in the solder bump. This study may be helpful for the fabricated technique of the die-solder bump-substrate system.

Abstract: Nanostructured porous silicon templates (NPSiT) were prepared by photo-electrochemical anodization of p-type crystalline silicon in HF electrolyte at different etching time. Two set anodisation parameter were observed, anodisation time nd current density applied. For set one, five samples were prepared with etching time varied from 10 to 50 minutes at 20 mA/cm2 of current density. For set two, five samples were prepared with current density varied from 5 to 40 mA/cm2 for 30 minutes. The effects of these anodisation parameter on NPSiT were observed based on nanocrystallite size. These studied was demonstrated by Raman spectroscopy. It was found that NPSiT sample with large pore diameter, which is smaller nanocrystallites size of Si between pore.

Abstract: We present the study of the electrical contact properties of monolayer MoS2/Si in terms of semiconductor heterojunctions theory. It shows that the carrier concentration increases in exponential form with temperature, then gradually arrived to its saturation. Additionally, the energy band structures of monolayer MoS2/n, p-Si heterojunctions have been developed before and after contacting. And the work functions of MoS2 and Si, barrier height of the junctions have been investigated. The barrier height linearly increases with the carrier density in Si. Finally, we simulated the voltage-current property of the monolayer MoS2 /n, p-Si heterojunctions in terms of thermal diffused theory of semiconductor.

Abstract: Sr0.4Ba0.6Nb1.85Ta0.15O6 (SBNT) ceramic was used as a target and SBNT thin films were deposited at room temperature. After deposition, the SBN thin films were annealed in conventional furnace (CFA) and in an oxygen atmosphere for 1h by changing the temperature from 700oC to 900oC. The thicknesses of the SBN thin films were calculated by SEM and they were about 450nm independent on the annealing temperature. From the XRD patterns, the as-deposited SBNT thin films displayed amorphous phase, whereas as CFA-treatment was used, the SBNT thin films displayed smooth surfaces. The grain sizes also increased with increasing CFA-treated temperature. In addition, the remanent polarization and saturation polarization increased and coercive field decreased with increasing CFA-treated temperature. Finally, the lnJ-E1/2 curves of the SBNT thin films was developed to find that the linear variations of leakage current densities correspond either to the Schottky emission mechanism or to the Poole-Frenkel emission mechanism.

Abstract: Lead-silver-cobalt was electrodeposited on the aluminum matrix, which was used as anode for zinc electrowinning. Scanning electron microscopy (SEM), linear sweep voltammetry(LSV), Tafel curve were used to study the effect of different current density on the surface morphology, electrocatalytic activity and corrosion resistance of Al/Pb-Ag-Co anode. The results showed that the Ag content change slightly with the current density change, but the Co content change big with the current density change; the value of a and b oxygen evolution of Pb-Ag-Co composite coating electrode obtained under 1 Adm-2were the smallest, respectively, was 1.436 V, 0.930 V; and the corrosion potential was 0.272 V; surface microstructure was smooth and dense.

Abstract: In this work, we present the results of an investigation into the effectiveness of varying ammonium sulphide (NH4)2S concentrations in the passivation of n-type GaAs. Samples were degreased and immersed in aqueous (NH4)2S solutions of concentrations 22% and 10%for 10 min at 295 K, immediately prior to plasma enhanced atomic layer deposition of LaAlO3. The chemical bonding state of (NH4)2S treated GaAs surface were investigated by X-ray photoelectron spectroscopy (XPS), which indicate that Sulfur passivation can reduce intrerfacial GaAs-oxide formation. Transmission electron microscopy (TEM) was implemented to characterize the interface morphology. Finally, capacitance-voltage (C-V) and leakage current density-voltage (J-V) measurement were used to characterize the electrical properties of LaAlO3 films.

Abstract: The use of Potassium-phosphate baths for the alloy deposition of Nickel–Molybdenum is recently proved equally good as Sodium-citrate baths. The coatings so obtained from Potassium-phosphate baths were examined for atomic weight percentage of Molybdenum. The variation in weight percentage of Molybdenum was obtained by varying different plating parameters like - molar ratio, current density range, and potential range. The observed co-deposited Molybdenum Atomic percentage variation in alloy was investigated for grain size, porosity in structure and surface roughness. The results revel that Molybdenum Atomic percentage in the Nickel–Molybdenum alloy has effect on porosity and surface roughness. It was also found that root mean square value of surface roughness was not only affected by the Molybdenum Atomic percentage but also by potential at relaxation time (TOFF) potential.