Influence of Duty Cycle on Composition and Microstructure of Siliconized Layer Using Pulse Electrodeposition

2010 ◽  
Vol 139-141 ◽  
pp. 666-669 ◽  
Author(s):  
Hai Li Yang ◽  
Yan Li ◽  
Yun Gang Li ◽  
Guo Zhang Tang ◽  
Ning He ◽  
...  
Keyword(s):  
Duty Cycle ◽  
Molten Salts ◽  
Layer Structure ◽  
Silicon Steel ◽  
Average Current Density ◽  
Cross Sectional ◽  
Columnar Grains ◽  
Average Current ◽  
Si Content ◽  
Equiaxed Grains

The siliconized layer was pulse electrodeposited on grain oriented low-silicon steel sheet substrate in KCl-NaCl-NaF-SiO2 molten salts and the influence of duty cycle on the composition and microstructure of the siliconized layer was investigated. The results showed that when the duty cycle was in the range of 10% to 50% at average current density 30mA/cm2, Si content of siliconized layers was similar and the thickness of the layer was did not change much with different duty cycle. Cross sectional observation revealed that the siliconized layers had a two-layer structure. The top layer composed of columnar grains and a transition layer with equiaxed grains was close to the substrate. The layer was unsmooth when the duty cycle was 10%. While the surface appeared smooth and dense and the grains were fine when the duty cycle were 20% and 30%. The layer became more porous as the duty cycle increased to 40% and 50%.

Effect of Current Density on Composition and Microstructure of Si Diffusion Layer by Electrodeposition

2010 ◽  
Vol 295-296 ◽  
pp. 33-37 ◽  
Author(s):  
Hai Li Yang ◽  
Yu Zhu Zhang ◽  
Yun Gang Li ◽  
Guo Zhang Tang ◽  
Kuo Jia
Keyword(s):  
Diffusion Layer ◽  
Current Density ◽  
Layer Structure ◽  
Substrate Surface ◽  
Middle Part ◽  
Cross Sectional ◽  
Diffusion Layers ◽  
Columnar Grains ◽  
Si Content ◽  
Steel Substrates

A Si diffusion layer on grain-oriented low-silicon steel substrates was produced by pulse electrodeposition in KCl-NaCl-NaF-SiO2 molten salt and the effect of current density upon the composition and microstructure of the siliconized layer was investigated. The results showed that by glow discharge spectrometry (GDS), the change of Si content of siliconized layers was similar in the range of 20-60 mA/cm2. Si content in the surface was maximum, and then dropped sharply within the surface layer (< 7 m). The Si content remained nearly constant in the middle part of the siliconized layer. The content of Si near to the substrate decreased relatively slowly. The Si content in the surface and the layer thickness increased with increasing current density. Cross-sectional observations revealed that the Si diffusion layers had a two-layer structure: the top layer composed of columnar grains grown perpendicularly to the substrate surface and a transition layer with equiaxed grains was close to the substrate. In addition, the thickness of the layer was too small when the current density was 20 mA/cm2, while the layer became more porous as the current increased from 40 to 60 mA/cm2 according to SEM observations. The optimum current density for deposition was 30 mA/cm2.

Effect of Cooling Rate and Si Content on Solidification Characteristics of Silicon Steel during Near-Rapid Solidification

2010 ◽  
Vol 146-147 ◽  
pp. 1247-1251
Author(s):  
Lei Wang ◽  
Xian Yong He ◽  
Qin Peng ◽  
Rong Yang ◽  
Qi Jie Zhai
Keyword(s):  
Cooling Rate ◽  
Silicon Content ◽  
Physical Simulation ◽  
Silicon Steel ◽  
Strip Casting ◽  
Contraction Rate ◽  
Linear Contraction ◽  
Si Content ◽  
Equiaxed Grains ◽  
Twin Roll

The solidification characteristics of silicon steel in twin roll strip casting was studied by physical simulation. The experiments were designed to approximate the solidification conditions of twin roll strip casting. The strips with different cooling rate and different silicon content were prepared. The results show that the solidification structures of the strips with different cooling rate and different Si content are composed of columnar and equiaxed grains, and the solidification structures vary significantly. And with the decrease of cooling rate, the linear contraction rate decreases.

Effect of Current Density on Composition and Microstructure of Boronized Layer by Electrodeposition

2011 ◽  
Vol 338 ◽  
pp. 589-593
Author(s):  
Guo Zhang Tang ◽  
Yun Gang Li ◽  
Ning He ◽  
Yu Zhu Zhang ◽  
Hai Li Yang
Keyword(s):  
Glow Discharge ◽  
Current Density ◽  
Molten Salts ◽  
Steel Substrate ◽  
Xrd Analysis ◽  
Silicon Steel ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Compositional Depth Profile

Boronized layer was prepared on silicon steel substrate by pulse electrodeposition in KCl-NaCl-NaF-Na2B4O7 molten salts with different current density. The effect of current density on composition and microstructure of boronized layer was studied. The phase, the cross-sectional morphology and the compositional depth profile of the layer were studied by X-ray diffraction analysis (XRD), optical microscopy (OM) and glow discharge spectrometry (GDS). The presence of FeB on the surface of the boronizied steel was confirmed by XRD analysis. Cross sectional observation revealed that the boronized layer consisted of the outer layer FeB and the sublayer Fe2B. In addition, the low current density produced more proportion of Fe2B and bigger saw-tooth grains.

Electromigration in VlSI Metallization Test Structures Stressed Over a Range Of DC Pulse Conditions and Frequencies up to 133 MHz

1996 ◽  
Vol 428 ◽  
Author(s):  
D. W. Malone ◽  
R. E. Hummel
Keyword(s):  
Duty Cycle ◽  
Enhancement Factor ◽  
Failure Time ◽  
Small Variation ◽  
Average Current Density ◽  
Resistance Change ◽  
Density Prediction ◽  
Pulsed Dc ◽  
Duty Cycles ◽  
Average Current

AbstractElectrical resistance data were gathered from AI(Cu) VLSI metallization test structures during pulsed DC current stressing (15 mA peak) at elevated temperature (200 °C). Duty cycles of 50%, 67%, and 80% were applied at a frequency (repetition rate) of 133 MHz. Also, a duty cycle of 50% was applied at frequencies of 100 KHz, I MHz, and 133 MHz. The resistance-to-starting resistance ratio, R/Ro, was logged over time, and the data were used to extract the median time dependence of the resistance change. This, in effect, reveals the dependence of the median “failure” time on the R/Ro (or ΔR/Ro) criterion. An “enhancement factor” was defined as the ratio of the median “failure” time from a given pulsed test to that from a DC test with the same peak current. A weak dependence of this enhancement factor on R/Ro was found in the range examined. The degree of enhancement corresponds more closely to the average current density prediction than to the on-time prediction, although there is some small variation according to duty cycle and frequency.

Electromigration Reliability of 96.5Sn–3Ag–0.5Cu Flip-Chip Solder Joints With Au/Ni/Cu or Cu Substrate Pad Metallization

2009 ◽  
Vol 131 (2) ◽  
Author(s):  
Yi-Shao Lai ◽  
Ying-Ta Chiu ◽  
Chiu-Wen Lee
Keyword(s):  
Flip Chip ◽  
Solder Joints ◽  
Average Current Density ◽  
Cross Sectional ◽  
Cu Substrate ◽  
Cu Metallization ◽  
Substrate Side ◽  
Current Stressing ◽  
Average Current ◽  
A Current

Designed experiments were conducted in this paper to study the effect of Au/Ni/Cu or Cu substrate pad metallization on the electromigration reliability of 96.5Sn–3Ag–0.5Cu flip-chip solder joints with Ti/Ni(V)/Cu under bump metallurgy (UBM) under a current stressing condition with an average current density of around 5 kA/cm2 at an ambient temperature of 150°C. Cross-sectional observations on current-stressed solder joints indicate that although Cu metallization results in severe voiding compared with Au/Ni/Cu metallization on the substrate side of the solder joint, the dominant failure has been identified as UBM consumption, and test vehicles with Cu metallization exhibit better electromigration reliability than those with Au/Ni/Cu metallization. The stronger durability against current stressing for test vehicles with Cu metallization may attribute to the lower UBM consumption rate due to the continuous Cu diffusion toward UBM as a result of the concentration gradient. The consumption of UBM is faster for test vehicles with Au/Ni/Cu metallization because Cu diffusion from the substrate pad is retarded by the Ni barrier.

Study of the Effect of Frequency in Pulse Electrodeposition on Au-Ni from Cyanide-Citrate Electrolyte by the Aim of Design of Experiment

2011 ◽  
Vol 410 ◽  
pp. 377-381 ◽  
Author(s):  
R. Siavash Moakhar ◽  
I. Imanieh ◽  
Mohammad Ghorbani ◽  
A. Dolati
Keyword(s):  
Current Efficiency ◽  
Design Of Experiment ◽  
Duty Cycle ◽  
Pulse Electrodeposition ◽  
Diffusion Control ◽  
Average Current Density ◽  
Ni Content ◽  
Main Effect ◽  
Citrate Electrolyte ◽  
Average Current

The aim of this paper is to study the influence of frequency in pulse electrodeposition, on the current efficiency, Ni content and surface morphology of deposits from a novel cyanide-citrate electrolyte with 20 mM gold as KAu (CN)2 and 7 mM NiSO4, with the aim of design of experiment by respond surface method (RSM). Frequency was in the range of 1-200 Hz in constant average current density, temperature, and duty cycle of 7 mA/cm2, 59 ◦C and 55% respectively. Composition of the deposits was determined by atomic absorption spectroscopy (AAS). Additionally, deposits were characterized by scanning electron microscopy (SEM), and Energy-dispersive X-ray spectroscopy (EDS). It was shown that from main effect plots, decreasing the level of frequency to 50 Hz resulted in an increase in Ni content of the deposits up to 1.5 %. Additionally, by increasing frequency up to 150 Hz, current efficiency increased to 60%. Besides, by decreasing frequency, grain size decreased. It was also shown that duty cycle and frequency have interaction effect on cathode efficiency. Furthermore, by using cyclic voltammetry techniques, Au-Ni electrodeposition from cyanide-citrate electrolyte has been scrutinized and categorized as a diffusion-control system.

Effects of Process Parameters on the Morphologies and Composition of Pulse Electrodeposition of Nickel-Rich Co-Ni Alloys

2012 ◽  
Vol 602-604 ◽  
pp. 565-569 ◽  
Author(s):  
Ming Ming Yu ◽  
Hong You Li ◽  
Yi Wang
Keyword(s):  
Current Density ◽  
Duty Cycle ◽  
Cobalt Content ◽  
Bath Temperature ◽  
Pulse Frequency ◽  
Pulse Electrodeposition ◽  
Average Current Density ◽  
High Microhardness ◽  
Average Current ◽  
Electrodeposition Of Nickel

Nickel-cobalt alloys have broad application prospect for their excellent properties (i.e. high microhardness, strength, abrasion, corrosion resistance and magnetic properties.etc). Nickel-rich Ni-Co coatings were produced on SUS304 substrates by pulse electrodeposition from sulfamate electrolytes with different average current density, pulse frequency, duty cycle and different bath temperature. It is clearly observed that the content of cobalt in the nickel-rich deposits gradually increases from 4.29 % to 25.47 % as the Co2+/Ni2+ concentration ratio increasing from 0.022 to 0.1(the current density applied was 2 A/dm2,bath temperature 25 °C). The Co content increases from 16.98 % to 25.47 % to 30.06 % when the duty cycle ranged from 20 % to 50 % to 60 %.The Co content seems to hardly change when pulse frequency changed from 500 Hz to 1000 Hz. The cobalt content decreases as the growth of the current density. The formation of good Ni-Co deposits with high cobalt content and smooth morphologies can be obtained by reducing current density, increasing bath temperature and pulse duty cycle.

Microstructure and Crystallographic Texture of Oriented Silicon Steel Produced by TSCR

2010 ◽  
Vol 146-147 ◽  
pp. 705-708
Author(s):  
Yong Mei Yu ◽  
Yun Bo Xu ◽  
Chang Sheng Li ◽  
Guo Dong Wang
Keyword(s):  
Silicon Steel ◽  
Texture Gradient ◽  
Goss Texture ◽  
Thin Slab Casting ◽  
Columnar Grains ◽  
Slab Casting ◽  
Cold Rolled ◽  
Rolled Condition ◽  
Hot Rolled ◽  
Equiaxed Grains

The microstructure and textures of oriented silicon steel produced by Thin Slab Casting and Rolling (TSCR) were studied in laboratory. The fractions of equiaxed grains and columnar grains are close to 35% and 65% respectively in as-quenched ingot after being pulled out from the mould. The equiaxed grains and no texture gradient from surface to center can be observed for the 3-pass hot-rolled strips, and the inhomogeneities of microstructure and texture in thickness are relatively clear for the 7-pass samples. The subsurface texture of the hot-rolled sample contains of e (TD// <110>) fibers. The texture of the cold-rolled samples mainly consists of a (<110>//RD) and g (<111>//ND) fibers, and Goss texture ({110}<001>) disappears. The strong a fiber, weak g fiber and minor {001}<110>can be found in all layers in the cold-rolled condition.

Electromigration Characteristics Under High Frequency Pulsed Current Stressing

1991 ◽  
Vol 225 ◽  
Author(s):  
Thomas Kwok ◽  
R. Kaufman ◽  
B. Davari
Keyword(s):  
Current Density ◽  
Duty Cycle ◽  
High Frequency ◽  
Drastic Change ◽  
Density Model ◽  
Pulsed Current ◽  
Average Current Density ◽  
Remarkable Improvement ◽  
Current Stressing ◽  
Average Current

ABSTRACTElectromigration characteristics of Al lines under pulsed current stressing at frequencies 50–200 MHz were measured. Lifetime was found to depend explicitly on both current on-time and current off period. Lifetime increases with t-off as t50 ∝ (t-off)2.2 and decreases with t-on as t50 ∝ (t-on)−0.7. The data indicate no threshold frequency for drastic change in lifetime. Lifetime was also found to increase with duty cycle as t50 ∝ r−2.7, which is a remarkable improvement over an average current density model.

Effect of Charge Density on Electrokinetic Ions and Fluid Flow Through Polyelectrolyte Coated Nanopore

2017 ◽  
Author(s):  
Subrata Bera ◽  
S. Bhattacharyya
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Charge Density ◽  
Ionic Concentration ◽  
Average Flow Rate ◽  
Average Current Density ◽  
Cross Sectional ◽  
Average Flow ◽  
Average Current ◽  
Flow Through

We have studied the electroosmotic flow (EOF) and its effect through a polyelectrolyte coated conical nanopore. The nanopore wall bears a uniform negative surface charge while charged density of the polyelectrolyte layer (PEL) bears positive charge. The degree of softness in the PEL is mainly affects the hydrodynamic field inside the nanopore while ionic current is not affected significantly by flow field. The characteristic of electrokinetic flow is based on the nonlinear Nernst-Planck equations for the ion transport coupled with the Brinkman extended Navier-Stokes equations for fluid flow and the Poisson equation for induced electric potential. The coupled set of governing non-linear equations for fluid flow and ionic species concentration are solved through a finite volume method on a staggered grid system. A numerical method based on the pressure correction iterative algorithm is adopted to compute the flow field. This study investigated the importance of the bulk concentration of the electrolyte, the geometries of the nanopore and both the thickness and the charged density of PEL on the electrokinetic ion and fluid transport. The ratio of the cross-sectional average flow of the present model with plane cylindrical channel, decreases with the increase of the scaled charge density of PEL for both low and high ionic concentration cases when softness parameter and thickness of PEL are fixed. The average flow rate decreases with the increase of the PEL sealed charge density in both low and high ionic concentration cases for fixed PEL thickness. The increase of nanopore radius increases the cross sectional averaged flow for fixed scaled charged density and PEL thickness. The average flow rate decreases with the increase of the PEL thickness for fixed charged density of PEL. The critical value of scaled charge density of PEL is defined for which there is no flow through the nanopore. The average current density increases with the increase of applied electric field for different charged density of PEL. But there is no different of average current density for different charge density of PEL in high ionic concentration cases.

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