scholarly journals Zn-Cr Alloy Coatings: Electrodeposition and Properties

2021 ◽  
Vol 51 (1) ◽  
pp. 29-42
Author(s):  
Ewa Osuchowska ◽  
Zofia Buczko ◽  
Klaudia Olkowicz

Abstract The electrodeposition process of Zn-Cr alloy coatings under the conditions of direct and pulsed current is discussed. The Cr content in the obtained alloy coatings, the current efficiency of the process, surface morphology, structure and wettability as a function of deposition parameters, such as current density, were determined. The Zn-Cr alloy coatings of good quality contained up to 20 wt.% Cr (for direct current) and up to 9 wt.% Cr (for pulse current). All the obtained coatings had a structure typical of zinc coatings (h.c.p.) and had a hydrophobic character. The morphology of the coatings changed significantly under the influence of changes in deposition conditions.

2018 ◽  
Vol 23 (2) ◽  
pp. 3-10
Author(s):  
Ewa Osuchowska ◽  
Zofia Buczko ◽  
Klaudia Olkowicz

In the present work, the electrodeposition process of Zn-Cr alloy coatings under the conditions of direct and pulse current was discussed. Changes in the Cr content in the obtained alloy coatings, current efficiency of the process, surface morphology, structure and microhardness as a function of chromium(III) concentration in the bath to deposition, current density (direct and pulse) and solution mixing were determined. Surface morphology, structure and hardness of the obtained coatings were investigated. The Zn-Cr alloy coatings of good quality contained up to 0.25 %Cr (for direct current) and up to 9% Cr (for pulse current). The tested Zn-Cr alloy coatings obtained under pulse current conditions showed higher microhardness than the Zn-Cr coatings obtained under direct current conditions and than zinc coatings.


2020 ◽  
Vol 301 ◽  
pp. 12-17
Author(s):  
Nurul Hanida Abd Wahab ◽  
Alhan Farhanah Abd Rahim ◽  
Ainorkhilah Mahmood ◽  
Noorezal Atfyinna Mohammed Napiah ◽  
Rosfariza Radzali ◽  
...  

A set of n-type porous silicon (PS) layers were fabricated by photoelectrochemical etching using direct current (DC) and pulse current (PC) techniques. The study aims to compare the effect of different resistivity (5 Ω and 10 Ω) on the formation of the PS structure. The samples were etched in a solution of HF:C2H6O with a composition ratio of 1:4. The etching process were done for 30 minutes with the current density of J = 10 mA/cm2. In the time of PC etching process, the current was supplied through a pulse generator with 14 ms cycle time (T) which the on time (Ton) set to 10 ms and pause time (Toff) set to 4 ms respectively. The samples were then being characterized in terms of surface morphology by using FESEM, AFM and XRD. Through the FESEM results, it can be seen that sample with 10 Ω resistivity which using PC form a more homogeneous structure of pores as compared to other samples.


2015 ◽  
Vol 827 ◽  
pp. 332-337
Author(s):  
Asep Ridwan Setiawan ◽  
Marsetio Noorprajuda ◽  
Aditianto Ramelan ◽  
Rochim Suratman

In the present work, Zn-ZrO2 nanocomposite coatings were deposited on the copper substrate through DC and pulse electrodeposition technique with low current density (10 mA/cm2). The effect addition of ZrO2 nanoparticles and pulse current were studied. The surface morphology, microhardness and erosion resistance of Zn-ZrO2 nanocomposite coating were evaluated. The result shows that, with the addition of ZrO2 particles, the surface morphology of Zn-ZrO2 nanocomposite coating was smoother. Phase identification by XRD confirm that Zn layer had been sucessfully deposited. The presence of ZrO2 nanoparticles was not detected. Compared to DC, pulsed current electrodeposition technique showed higher cathodic efficiency, better microhardness and good erosion resistance.


2012 ◽  
Vol 66 (5) ◽  
pp. 749-757 ◽  
Author(s):  
Jelena Bajat ◽  
Miodrag Maksimovic ◽  
Milorad Tomic ◽  
Miomir Pavlovic

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).


2008 ◽  
Vol 22 (18n19) ◽  
pp. 3005-3012 ◽  
Author(s):  
MOHSEN SAREMI ◽  
MARYAM ABOUIE ◽  
R. VAGHAR

This paper reports our recent studies on nanocrystalline layer of copper produced using pulse plating method. The grain size of the copper layer was about 60 nm. Electrochemical and physical Properties of the nanocrystalline surface were investigated using Potentiostatic scanning and Impedance measurements. Microcrystalline copper deposits were also produced by direct current electrodeposition processes and compared with pulse plated ones. Effects of deposition parameters, such as the peak Density, frequency, current-on time and current-off time of the pulse current (PC), on the grain size were investigated for the purpose of process optimization. It was demonstrated that the nanocrystalline film was markedly superior to regularly grained film made by direct current (DC) plating; the nanocrystalline deposit shows higher electrochemical stability and lower electrical resistance.


1998 ◽  
Vol 515 ◽  
Author(s):  
Wenzhen Sun ◽  
Douglas G. Ivey

ABSTRACTAu-Sn eutectic solder is widely used in optoelectronic packaging. Electroplating of Au-Sn alloys is attracting increasing research interest because of its lower cost and potential to minimize voiding in bonding layers. The challenge in developing a non-cyanide Au-Sn electroplating bath lies in bath stability and deposit composition control. In this paper a relatively stable electroplating bath is developed based on a chloride solution using citrate as a buffering agent. Direct current plating and pulse current plating are performed and compared. The effects of Au and Sn concentrations in the bath, current density, and ON time on deposit composition and microstructures are also studied.


2014 ◽  
Vol 922 ◽  
pp. 237-241
Author(s):  
Yudai Hanaoka ◽  
Satoshi Ono ◽  
Isao Matsui ◽  
Yorinobu Takigawa ◽  
Tokuteru Uesugi ◽  
...  

Electrodeposition for Al from a dimethylsulfone (DMSO2) bath was consecutively performed, applying two types of current waveforms such as direct current and pulsed current, to investigate the effect of a current type on the preparatory electrodeposition (pre-electrodeposition) process. Electrodeposited Al from a DMSO2bath has a nanograined structure and high strength. However, the electrodeposits showed no plastic deformability due to the large amount of sulfur and chlorine which were incorporated into the electrodeposits as sulfide and chloride. Therefore, we obtained high purity Al from a DMSO2bath using pre-electrodeposition process, which could decrease sulfur and chlorine contents without using additives. The sulfur and chlorine contents of electrodeposits, obtained from a DMSO2bath applying both types current, both decreased to approximately 0.1 at.%. This result indicated that the waveforms made no difference in pre-electrodeposition process.


Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5194
Author(s):  
Killang Pratama ◽  
Christian Motz

Strategies to improve tensile strength and ductility of pulsed electrodeposited nanocrystalline Co-Cu were investigated. Parameters of deposition, which are pulse current density, duty cycle, and pulse-on time were adjusted to produce nanocrystalline Co-Cu deposits with different microstructures and morphologies. The most significant improvement of strength and ductility was observed at nanocrystalline Co-Cu deposited, at a low duty cycle (10%) and a low pulse-on time (0.3 ms), with a high pulse current density (1000 A/m2). Enhancement of ductility of nanocrystalline Co-Cu was also obtained through annealing at 200 °C, while annealing at 300 °C leads to strengthening of materials with reduction of ductility. In the as deposited state, tensile strength and ductility of nanocrystalline Co-Cu is strongly influenced by several factors such as concentration of Cu, grain size, and processing flaws (e.g., crystal growth border, porosity, and internal stresses), which can be controlled by adjusting the parameters of deposition. In addition, the presence of various microstructural features (e.g., spinodal and phase decomposition), as well as recovery processes induced by annealing treatments, also have a significant contribution to the tensile strength and ductility.


2013 ◽  
Vol 579-580 ◽  
pp. 138-143
Author(s):  
Yang Yang Xu ◽  
Yu Jun Xue ◽  
Ji Shun Li ◽  
Yi Liu ◽  
Fang Yang

Ni-ZrO2-CeO2 nanocomposites were prepared by double-pulse current in an ultrasonic field. The effect of average current density, duty ratio and frequency of double-pulse current on nanoparticles content of Ni-ZrO2-CeO2 nanocomposites was studied. Meanwhile, surface morphology and microhardness of nanocomposites were analyzed. The results show that, with the positive average current density, positive duty ratio and positive frequency increased, the nanoparticles contents increased at first and then decreased. On the contrary, it reduced while reverse average current density, reverse duty ratio and reverse frequency were increasing. Compared with Ni-ZrO2-CeO2 prepared by direct current and monopulse current, grain of Ni-ZrO2-CeO2 nanocomposite prepared by double-pulse current is finer, the microhardness is also higher.


2011 ◽  
Vol 1308 ◽  
Author(s):  
Linfei Liu ◽  
Yijie Li ◽  
Huaran Liu ◽  
Xiaokun Song ◽  
Dan Hong ◽  
...  

ABSTRACTIn order to deposit YBCO coated conductor with high critical current densities on rolling assisted biaxially textured Ni-W tapes, this paper has systematically studied the influence of deposition conditions on the orientation, in-plane texture and surface morphology of buffers and superconducting layers. It was found that the crystalline alignment and the in-plane texture of cerium oxide cap-layers were well improved by optimizing deposition parameters. The full width at half maximum of phi-scan x-ray diffraction peaks were reduced from original values of 7-8 degrees to 5-6 degrees. A high critical current density of 4.6×106 A/cm2 has been achieved on optimized buffer layers. This value is comparable with the critical current density of YBCO thin films deposited on single crystalline substrates.


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