A Study of the Microstructure and Properties of Electroformed Ni-P Model Insert

2007 ◽  
Vol 364-366 ◽  
pp. 232-236 ◽  
Author(s):  
Shih Tsung Ke ◽  
Jeou Long Lee ◽  
Yih Min Yeh ◽  
Shuo Jen Lee ◽  
Ming Der Ger
Keyword(s):  
Internal Stress ◽  
Current Density ◽  
Duty Cycle ◽  
Pulse Current ◽  
Pulse Frequency ◽  
Cathodic Current ◽  
Peak Current Density ◽  
Peak Current ◽  
Ultrafine Grained ◽  
Nanostructure Material

In this study, a Ni-P alloy electroforming nanostructure material with low surface roughness and low internal stress was developed by using a pulse current. Square-wave cathodic current modulation was employed to electrodeposit ultrafine-grained Ni-P films from an additivefree Sulfamate nickel bath. The effect of various factors, such as peak current density, duty cycle and pulse frequency on the roughness and internal stress were investigated. Pulse current significantly influences the microstructure of Ni-P alloys. The internal stress and roughness of Ni-P alloys increased as peak current density increased, but the internal stress of Ni-P alloys decreased as duty cycle decreased.

THE EFFECT OF PREPARED PARAMETERS ON THE MICROSTRUCTURE OF ELECTRODEPOSITED NANOCRYSTALLINE NICKEL COATING

2004 ◽  
Vol 11 (04n05) ◽  
pp. 433-442 ◽  
Author(s):  
C. Y. DAI ◽  
Y. PAN ◽  
S. JIANG ◽  
Y. C. ZHOU
Keyword(s):  
Grain Size ◽  
Surface Morphology ◽  
Current Density ◽  
Crystal Orientation ◽  
Nickel Coating ◽  
Pulse Frequency ◽  
Lattice Parameter ◽  
Nanocrystalline Nickel ◽  
Peak Current Density ◽  
Peak Current

The nanocrystalline nickel coating was synthesized by pulse-jet electrodeposition from modified Watts bath. Pulse and jet plating was employed to increase the deposition current density, decrease diffusion layer, increase the nucleation rate and in this case the prepared method would result in fine-grained deposits. Transmission and scanning electron microscopy and X-ray diffraction (XRD) were used to study the microstructure, the surface morphology, the crystal preferred orientation and the variety of the lattice parameter respectively. The influence of pulse parameters, namely peak current density, the duty cycle and pulse frequency on the grain size, surface morphology, crystal orientation and microstructure was studied. The results showed that with increasing peak current density, the deposit grain size was found to decrease markedly in other parameters at constant. However, in our experiment it was found that the grain size increased slightly with increasing pulse frequency. For higher peak current density, the surface morphology was smoother. The crystal orientation progressively changed from an almost random distribution to a strong (111) texture. This means that the peak current density was the dominated parameter to effect the microstructure of electrodeposited nanocrystalline nickel coating. In addition, the lattice parameter for the deposited nickel is calculated from XRD and it is found that the calculated value is less than the lattice parameter for the perfect nickel single crystal. This phenomenon is explained by the crystal lattice mismatch.

Experimental Research on Electroforming Nano-ZrO2 Reinforced Cu-Matrix Composite Aided by Pulse Power

2018 ◽  
Vol 764 ◽  
pp. 95-105
Author(s):  
Zhong Wen Sima ◽  
Zhi Yong Li ◽  
Hong Bin Cui ◽  
Hun Guo
Keyword(s):  
Surface Morphology ◽  
Matrix Composite ◽  
Current Density ◽  
Duty Cycle ◽  
Pulse Frequency ◽  
Cathodic Current Density ◽  
Ultrasonic Power ◽  
Cathodic Current ◽  
Maximum Content ◽  
Cycle Pulse

Prepared the nanoZrO2 reinforced Cu-matrix composite by pulse electroforming. The effects of the content of nanoZrO2 particle in the casting solution, average cathodic current density, duty cycle, pulse frequency and ultrasonic power on the content of nanoZrO2 in the electroforming Cu-matrix composite have been studied. The microhardness and surface morphology of Cu-ZrO2 composite were analyzed. The experimental results demonstrate that the maximum content of nanoZrO2 in the electroforming Cu-ZrO2 composite is 2.94%, microhardness is 492 HV, which is significantly improved compared with pulse pure copper’s 337 HV, when the content of nanoZrO2 is 40 g/L, average cathodic current density is 4A/dm2, duty cycle is 0.2 , pulse frequency is 1100 Hz and ultrasonic power is 20w .The surface of composite prepared by pulse electroforming is more smooth, organization is denser, grain is finer and agglomeration of nanoZrO2 particles is fewer compared with Direct-current electroforming nanoZrO2 reinforced Cu-ZrO2 composite.

MORPHOLOGICAL STUDY OF PULSE CURRENT ELECTRODEPOSITED Zn-Fe ALLOY

2008 ◽  
Vol 22 (18n19) ◽  
pp. 3023-3030 ◽  
Author(s):  
D. MOHAMMADYANI ◽  
M. HEYDARZADEH SOHI
Keyword(s):  
Corrosion Resistance ◽  
Current Density ◽  
Duty Cycle ◽  
Morphological Study ◽  
Pulse Current ◽  
The Other ◽  
Peak Current Density ◽  
Pure Zinc ◽  
Alkaline Bath ◽  
Fe Alloys

Zn - Fe alloy electroplated coatings have attracted industrial interest because of their significantly higher corrosion resistance in comparison to pure zinc deposits. In this study pulse currents was applied for electrodeposition of Zn - Fe alloys, using alkaline bath. SEM studies confirmed that pulse electrodeposits are quite dense and smooth. It was also shown that increasing of peak current density (PCD) and duty cycle in pulse electrodeposition coarsen the structure and increase irregularity of the surface. Increasing of the frequency, on the other hand, results in the formation of finer structure.

THE INFLUENCE OF PULSE PARAMETERS ON THE MICROSTRUCTURE OF IRON ELECTRODEPOSITS

2010 ◽  
Vol 09 (04) ◽  
pp. 365-370
Author(s):  
VAHID AFSHARI ◽  
CHANGIZ DEHGHANIAN
Keyword(s):  
Current Density ◽  
Crystal Orientation ◽  
Crystal Size ◽  
Progressive Increase ◽  
Cathodic Current ◽  
Peak Current Density ◽  
Peak Current ◽  
Pulse On Time ◽  
Pulse Off Time ◽  
Off Time

Square-wave cathodic current modulation was used to electrodeposit fine-grained iron from citric acid bath. The effect of pulse on-time, off-time, peak current density, and total plating time on the grain size, surface morphology, and crystal orientation was determined. X-ray diffraction analysis and modified Williamson–Hall relation were used to determine the average grains size of the coatings. The experimental results showed that an increase in peak current density resulted in considerable refinement in crystal size of the deposits. An increase in the pulse off-time at constant on-time and peak current density resulted in a progressive increase in crystal size. However, the crystal orientation remained unaffected with increasing off-time. The design of the pulse deposition parameters is described in terms of the transport limitations through the diffusion layer and electrochemical interface stability.

scholarly journals The study of Zn–Co alloy coatings electrochemically deposited by pulse current

2012 ◽  
Vol 66 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Jelena Bajat ◽  
Miodrag Maksimovic ◽  
Milorad Tomic ◽  
Miomir Pavlovic
Keyword(s):  
Surface Roughness ◽  
Current Efficiency ◽  
Direct Current ◽  
Current Density ◽  
Pulse Current ◽  
Pulse Plating ◽  
Cathodic Current ◽  
Average Current Density ◽  
Corrosion Stability ◽  
Average Current

The electrochemical deposition by pulse current of Zn-Co alloy coatings on steel was examined, with the aim to find out whether pulse plating could produce alloys that could offer a better corrosion protection. The influence of on-time and the average current density on the cathodic current efficiency, coating morphology, surface roughness and corrosion stability in 3% NaCl was examined. At the same Ton/Toff ratio the current efficiency was insignificantly smaller for deposition at higher average current density. It was shown that, depending on the on-time, pulse plating could produce more homogenous alloy coatings with finer morphology, as compared to deposits obtained by direct current. The surface roughness was the greatest for Zn-Co alloy coatings deposited with direct current, as compared with alloy coatings deposited with pulse current, for both examined average current densities. It was also shown that Zn-Co alloy coatings deposited by pulse current could increase the corrosion stability of Zn-Co alloy coatings on steel. Namely, alloy coatings deposited with pulse current showed higher corrosion stability, as compared with alloy coatings deposited with direct current, for almost all examined cathodic times, Ton. Alloy coatings deposited at higher average current density showed greater corrosion stability as compared with coatings deposited by pulse current at smaller average current density. It was shown that deposits obtained with pulse current and cathodic time of 10 ms had the poorest corrosion stability, for both investigated average deposition current density. Among all investigated alloy coatings the highest corrosion stability was obtained for Zn-Co alloy coatings deposited with pulsed current at higher average current density (jav = 4 A dm-2).

Microstructure Evolution of As-Cast Nickel Aluminum Bronze under Electropulsing

2020 ◽  
Vol 861 ◽  
pp. 28-34
Author(s):  
Jie Fang ◽  
Guo Lin Song ◽  
Wei Liu ◽  
Qiu Lin Li
Keyword(s):  
Microstructure Evolution ◽  
Current Density ◽  
Phase Region ◽  
Aluminum Bronze ◽  
Nickel Aluminum ◽  
Peak Current Density ◽  
Peak Current ◽  
Β Phase ◽  
Nickel Aluminum Bronze ◽  
Electropulsing Treatment

In this work, the microstructure evolution of as-cast NAB under different electropulsing parameters were studied. The microstructure of the electropulsing treatment (EPT) sample was characterized by mircohardness test and optical microscopy. The results show that compared with heat treatment, when the peak current density reaches 5.84×108A/m2 (no significant change in the structure when the peak current density is lower), the β' phase region undergo phase transition in a shorter time. When the peak current density reaches 7.25×108A/m2, the sample is significantly affected by the Joule heating effect, and the κⅢ and κⅣ phases are successively dissolved to form Widmanstätten α structure. As the β' phase increases and the Widmanstätten α structure forms, the hardness value of the microstructure increases by 80%.

Sign in / Sign up

Export Citation Format

Share Document