Investigations on the properties of composite coatings electro co-deposited on AZ80 Mg alloy using triangular waveform pulse current

2021 ◽  
Author(s):  
Peter Pushpanathan ◽  
Alagumurthi Natarajan ◽  
Pradeep Devaneyan
Keyword(s):  
Magnesium Alloy ◽  
Wear Rate ◽  
Surface Properties ◽  
Current Density ◽  
Duty Cycle ◽  
Pulse Current ◽  
Composite Coatings ◽  
Specific Wear Rate ◽  
Triangular Waveform ◽  
Az80 Magnesium Alloy

Abstract In this research, boron carbide (B4C) and titanium carbide (TiC) nanoparticles were deposited along with Nickel on AZ80 magnesium alloy substrates. Triangular waveform pulse current was used for depositing the coatings on the substrate. The objective of this research is to investigate the microstructural evolution of the coatings in response to the current density, duty cycle and the concentration of reinforcements in the bath. The influence of process parameters were also assessed in terms of the microhardness and specific wear rate. To enhance the surface properties of AZ80 magnesium alloy, a three component layer was successfully applied via electro co-deposition technique for the first time. The magnesium alloy substrates were cleaned and pretreated as per ASTM B480−88. The pretreated samples were coated at three levels of current density viz. 1.5 A/dm2, 2 A/dm2 and 2.5 A/dm2, and the duty cycle was varied between 30%, 40% and 50%. The concentrations of reinforcements in the bath were kept at 0 g/L, 0.5 g/L and 1 g/L. The samples were coated according to Taguchi L9 orthogonal array with two replications. The microstructural studies conducted using scanning electron microscope (SEM) revealed the defects, grain refinement and homogeneous distribution of reinforcements in the Ni matrix. The deposition and orientation of reinforcements in preferred planes were investigated with XRD. Vickers microhardness tests conducted as per ASTM E384-17 revealed that the sample coated with 2.5 A/dm2current density, 30 % duty cycle, 1 g/L B4C and 0.5 g/L TiC produced the coatings with the highest hardness of 412.56 Hv. The results of the pin on disc wear tests conducted according to ASTM G99 were in agreement with the hardness results and the corresponding microstructure. The sample with the maximum microhardness exhibited the minimum specific wear rate of 2.1 E-08 mm3/Nm. The ability of triangular pulse current waveform to deposit hybrid composite coatings on AZ80 magnesium alloy and enhance its surface properties has been confirmed by the results of this research.

scholarly journals Influence of Pulse Current Forward-Reverse Duty Cycle on Structure and Performance of Electroplated W–Cu Composite Coatings

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Yuchao Zhao ◽  
Nan Ye ◽  
Haiou Zhuo ◽  
Chaolong Wei ◽  
Weiwei Zhou ◽  
...  
Keyword(s):  
Composite Coating ◽  
Duty Cycle ◽  
Electrode Materials ◽  
Pulse Current ◽  
Electrical Discharge Machining ◽  
Composite Coatings ◽  
Electrical Contact ◽  
Pulse Plating ◽  
Fusion Welding ◽  
Raw Material

Tungsten-copper (W–Cu) composites are widely used as electrical contact materials, resistance welding, electrical discharge machining (EDM), and plasma electrode materials due to their excellent arc erosion resistance, fusion welding resistance, high strength, and superior hardness. However, the traditional preparation methods pay little attention to the compactness and microstructural uniformity of W–Cu composites. Herein, W–Cu composite coatings are prepared by pulse electroplating using nano-W powder as raw material and the influence of forward-reverse duty cycle of pulse current on the structure and mechanical properties is systematically investigated. Moreover, the densification mechanism of the W–Cu composite coating is analyzed from the viewpoints of forward-pulse plating and reverse-pulse plating. At the current density (J) of 2 A/dm2, frequency (f) of 1500 Hz, forward duty cycle (df) of 40% and reverse duty cycle (dr) of 10%, the W–Cu composite coating rendered a uniform microstructure and compact structure, resulting in a hardness of 127 HV and electrical conductivity of 53.7 MS/m.

Improvement of microstructure and properties of Ni–Al2O3 composite coating via jet electrodeposition

2020 ◽  
Vol 34 (27) ◽  
pp. 2050243
Author(s):  
Hui Fan ◽  
Jie Jiang ◽  
Yangpei Zhao ◽  
Shankui Wang ◽  
Zhijing Li
Keyword(s):  
Wear Rate ◽  
Surface Morphology ◽  
Composite Coating ◽  
Process Parameters ◽  
Current Density ◽  
Composite Coatings ◽  
Coating Structure ◽  
Mechanical And Tribological Properties ◽  
Al2o3 Composite ◽  
Jet Electrodeposition

Ni–Al2O3 composite coatings were prepared with a modified Watt’s bath by using jet electrodeposition method. As the key process parameter, current density and the addition of Al2O3 nanoparticles in electrolyte were studied about the effect on the surface morphology and co-deposition of Al2O3 nanoparticles of composite coating. The mechanical and tribological properties of the composite coating were also tested. The results show that properly increasing the current density and Al2O3 addition can increase the co-deposition of nanoparticles in the coating and promote the formation of a dense and refined coating structure. Using the optimized process parameters of current density (300 A/dm2) and Al2O3 addition (30 g/L), the co-deposition of Al2O3 in the composite coating can reach a maximum of 13.1 at.%. The hardness of the coating reaches the peak at 623 HV. The wear rate of the composite coating is also greatly reduced with optimized parameters.

Influences of Pulse Current Density on the Characteristics of Ni-W-P-CeO2-SiO2 Composite Coatings

2011 ◽  
Vol 418-420 ◽  
pp. 856-860 ◽  
Author(s):  
Rui Dong Xu ◽  
Da Cheng Zhai ◽  
Shuang Li Hu
Keyword(s):  
Chemical Composition ◽  
Current Density ◽  
Pulse Current ◽  
Composite Coatings ◽  
Average Current Density ◽  
Fine Grained ◽  
Fine Grained Structure ◽  
Average Current ◽  
S Deposition ◽  
Microhardness Tester

Square-wave double pulse current was used to electrodeposit Ni-W-P-CeO2-SiO2composite coatings in fine-grained structure on the surface of carbon steel, influences of forward pulse average current density, +Jm, in the range of 5~25A/dm2on characteristics of the composite coatings were researched, and the chemical compositionSubscript texts, deposition rate, microhardness and microstructures were evaluated by EDX, SEM and Microhardness tester. The results show that the uniform composite coatings can be obtained at +Jmof 20A/dm2, which possess higher microhardness of 735Hv. The grains sizes of the composite coatings decrease when +Jmis increased from 5A/dm2to 20A/dm2, while the reappearance of large grains structure at 25A/dm2.

Growth of Tunnels during Aluminum DC Pulse Current Etching

2014 ◽  
Vol 654 ◽  
pp. 24-30
Author(s):  
Dan Lu Liu ◽  
Ren Gui Xiao ◽  
Teng Zou ◽  
Jian Zhong Wang ◽  
Jian Xin Cao ◽  
...  
Keyword(s):  
Current Density ◽  
Duty Cycle ◽  
Growth Velocity ◽  
High Purity ◽  
Pulse Current ◽  
Aluminum Foil ◽  
Experimental Results ◽  
Surface Areas ◽  
High Purity Aluminum ◽  
First Time

High-purity aluminum foil was etched with DC pulse current in acids solutions at first time. Experiments indicated that tunnels morphology was influenced by current density, pulse duty-cycle and frequency of DC pulse current, tunnels began to grow when the current density reached to 0.8A cm-2, and tunnels grew along three directions to form a netlike construction in the surface of aluminum foil, which increased effectually surface areas of aluminum foil. In addition, when aluminum was etched in the solution of 1 N HCl +0.8 N HNO3,tunnels morphology shows that tunnel does not grow continually during DC pulse current etching, so it is a method to study the mechanism of tunnel growth, for example period of tunnel growth, velocity of tunnel growth. The experimental results are discussed according to tunnels morphology.

Preparation and Numerical Simulation of Ni-SiC Composite Coatings Deposited by Electrodeposition

2014 ◽  
Vol 543-547 ◽  
pp. 3707-3710
Author(s):  
Yong Wang ◽  
Lei Zhang
Keyword(s):  
Composite Coating ◽  
Current Density ◽  
Pulse Current ◽  
Composite Coatings ◽  
Maximum Error ◽  
Duty Ratio ◽  
Sic Particles ◽  
Ultrasonic Parameters ◽  
Steel Substrates ◽  
Sic Coatings

In order to investigate and predict effects of preparation parameters on wear mass loss of Ni-SiC composite coatings, Ni coatings and Ni-SiC composite coatings were prepared on steel substrates by electrodeposition process. The results showed that the contents of SiC particles increased with density of pulse current and on-duty ratio of pulse current increasing. The predictive curves of wear mass losses predicted by ANN had the similar shapes with the measured curve, and the maximum error was 9.7%. When the current density was between 30 A/dm2 and 50 A/dm2, the wear losses of Ni coatings and Ni-SiC coatings decreased with the increase of current density. SiC particles in a composite coating electrodeposited by ultrasonic parameters were much greater in number and were dispersed homogeneously in the deposit, and the Ni-SiC composite coating exhibited a dense structure.

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.

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.

ELECTRIDEPOSITION AND WEAR BEHAVIOR OF NANO-STRUCTURED Cr-WC COMPOSITE COATINGS FROM A TRIVALENT CHROMIUM BATH

2012 ◽  
Vol 05 ◽  
pp. 737-743 ◽  
Author(s):  
A. AMADEH ◽  
S. NADALI ◽  
S.M. LARI BAGHAL ◽  
H. MORADI
Keyword(s):  
Wear Resistance ◽  
Current Density ◽  
Duty Cycle ◽  
Wear Behavior ◽  
Composite Coatings ◽  
Sodium Dodecyl ◽  
Trivalent Chromium ◽  
Sodium Saccharin ◽  
Average Size ◽  
Pin On Disk

Electrodeposition of nano-structured Cr - WC had been carried out from a trivalent chromium bath using a square shaped pulse current. The average size of WC particles was 70 nm. The effect of sodium saccharin and sodium dodecyl sulfate (SDS) additives as well as pulse electroplating parameters such as current density, duty cycle and frequency on the amount of incorporated WC particles and morphology of the coatings was investigated. The structure and morphology of the coatings were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. In addition, the hardness and tribological behavior of the coatings were investigated by microhardness and pin on disk methods, respectively. The results showed that although the addition of saccharin and SDS decreased the amount of WC particles in the coating, but reduced the size of WC agglomerates which, in turn, increased the wear resistance of the coatings. Also, the optimum wear resistance was achieved at the current density of 8 A/dm2, duty cycle of 50% and frequency of 10 Hz.

scholarly journals Strategies to Achieve High Strength and Ductility of Pulsed Electrodeposited Nanocrystalline Co-Cu by Tuning the Deposition Parameters

Molecules ◽  
2020 ◽  
Vol 25 (21) ◽  
pp. 5194
Author(s):  
Killang Pratama ◽  
Christian Motz
Keyword(s):  
Tensile Strength ◽  
Current Density ◽  
Duty Cycle ◽  
Pulse Current ◽  
High Strength ◽  
Internal Stresses ◽  
Low Duty Cycle ◽  
Deposition Parameters ◽  
Pulse On Time ◽  
Strength And Ductility

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.

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