Study on Ni-P-Nanometer Diamond Composite Electroless Plating for 2A12 Aluminum Alloy

On the basis of electroless Ni-P plating, the technique of electroless Ni-P-nanometer diamond composite plating for 2A12 aluminum alloy was studied. The table of L9 (34) of orthogonal design was adopted in the experiment. The optimal formulation of plating bath for 2A12 aluminum alloy was determined. The effect of bath composition on deposition rate and adhesion strength was studied. The results show that the order of marked factors on deposition rate from large to small is nanometer diamond, sodium acetate, nickel sulfate hexahydrate and sodium hypophosphite in turn, while for adhesion strength is nanometer diamond, sodium acetate, sodium hypophosphite and nickel sulfate hexahydrate. The optimal plating formulation are consisted of nanometer diamond (2g/L), NiSO4•6H2O (30g/L), NaH2PO2•H2O (30g/L) and CH3COONa (15g/L), which is operated at 80~85°C, pH (4.5). The microstructure of coating plated with optimal process is cellular structure, which is homogeneous, compact and good brightness, and its deposition rate is 17.0μm/h.

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Effects of Plating Bath Composition and Operating Condition on Properties of Electroless Coating for High Strength Aluminum Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.179-180.334 ◽

2011 ◽

Vol 179-180 ◽

pp. 334-338 ◽

Cited By ~ 2

Author(s):

Shao Min Qu ◽

Xiao Ting Huang ◽

Gang Yi Cai

Keyword(s):

Aluminum Alloy ◽

Deposition Rate ◽

Sodium Acetate ◽

Ph Value ◽

Nickel Sulfate ◽

High Strength ◽

Operating Conditions ◽

Sodium Hypophosphite ◽

Bath Composition ◽

High Strength Aluminum Alloy

The table of L9 (34) of orthogonal design was adopted in the experiment. The optimal formulation and process conditions of electroless nickel plating on high strength aluminum alloy were determined. The influences of bath composition and operating conditions on the hardness and deposition rate were analyzed and discussed. The experimental results show that the optimal plating formulation were obtained, which were consisted of nickel sulfate hexahydrate(25g/L), sodium hypophosphite(20g/L) and sodium acetate(15g/L). The operating conditions are as follows: 80~85°C, pH value 5.0. The coating structure is more homogenous and compact, and the coating has good brightness. Meanwhile, the hardness is up to 376.8HV, and the deposition rate is 17.2μm/h. The order of effects on hardness is pH value, sodium acetate, sodium hypophosphite and nickel sulfate concentration in turn. The hardness of coating decreased after heat treatment on low temperature. When the temperature exceed 200°C, the hardness increased with temperature rising and reached the peak value at 400°C(565.3HV).

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Improvement on Hardness of 6061 Al Alloy Using an Electroless Ni-P Coating

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.26-28.293 ◽

2010 ◽

Vol 26-28 ◽

pp. 293-296 ◽

Cited By ~ 1

Author(s):

Wen Feng Qin ◽

Jiang Long ◽

Feng Liu

Keyword(s):

Surface Morphology ◽

Sodium Hypophosphite ◽

Al Alloy ◽

Plating Bath ◽

Nodular Structure ◽

P Content ◽

Scanning Electron Microcopy ◽

Alloy Plating ◽

6061 Al Alloy ◽

Electroless Ni

The surface morphology and hardness of electroless Ni–P alloy plating on 6061 aluminum alloys substrate in an alkaline plating bath with sodium hypophosphite as reducing agent were investigated. The effects of bath pH on the plating rate, compositions and surface morphology of theelectroless Ni-P deposits were studied. The results showed the deposition rate of the electroless Ni–P deposits increased with the rise of the bath pH, while the P content decreased. Scanning electron microcopy (SEM) of the deposits showed nodular structure for the deposits. Hardness data of the Ni-P coatings indicated that electroless Ni–P plating could obviously improve the hardness of 6061aluminum alloy.

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Formation and Structural Characterization of Electroless Ni-B-P Ternary Alloy Coatings

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.592-594.385 ◽

2014 ◽

Vol 592-594 ◽

pp. 385-390 ◽

Cited By ~ 2

Author(s):

P.G. Venkatakrishnan ◽

S.S. Mohamed Nazirudeen ◽

T.S.N. Sankara Narayanan

Keyword(s):

Electroless Plating ◽

Morphological Characteristics ◽

Reducing Agents ◽

Sodium Hypophosphite ◽

Electron Microscopic ◽

Plating Bath ◽

Peak Broadening ◽

Chloride Hexahydrate ◽

Electroless Ni

The aim of the present investigation is to study the formation of electroless Ni-B-P alloy coatings and structural and morphological characterization of various coatings with different boron and phosphorous content. An alkaline plating bath with nickel chloride hexahydrate as the source of nickel ions and sodium borohydride and sodium hypophosphite as reducing agents were used for the formation of electroless Ni-B-P alloy coatings. The influence of changes in the concentrations of the reducing agents in the electroless plating bath on the chemical composition, structural and morphological characteristics of the coatings were studied. Scanning electron microscopic studies revealed that the surface morphology of Ni-B-P alloy coatings changed from corn cob-like structure to cauliflower-like structure with increasing borohydride concentration in electroless plating bath, whereas increase in hypophosphite concentration favoured sideway growth, thereby decreased the surface roughness of the Ni-B-P alloy coatings. The peak broadening in the X-Ray Diffraction profiles indicates the large reduction in the crystallite size of the electroless Ni-B-P alloy coatings with increasing boron content in the coating (i.e. for higher borohydride concentration in the plating bath).

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Electroless Ni-P Plating on Mg-7Al Alloy by Chemical Conversion Pretreatment

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.652-654.1908 ◽

2013 ◽

Vol 652-654 ◽

pp. 1908-1911

Author(s):

Su Qiu Jia ◽

Jing Xin Guan ◽

Jing Dong Qiu ◽

Hua Chen ◽

Shu Yan Jia

Keyword(s):

Corrosion Potential ◽

Orthogonal Experiment ◽

Orthogonal Design ◽

Saturated Calomel Electrode ◽

Nickel Sulfate ◽

Electroless Nickel ◽

Chemical Conversion ◽

Electroless Nickel Plating ◽

Nickel Plating ◽

Electroless Ni

Electroless Ni-P plating on Mg-7Al alloy by chemical conversion pretreatment was investigated. Morphology of electroless nickel plating coatings and phase compositions were measured by SEM, EDX and XRD. The optimized bath composition parameters were determined through orthogonal design. The morphology of electroless nickel plating coatings on Mg-7Al alloy exhibits a nodular structure and resembles the surface of a cauliﬂower and the coating is compact and consists of amorphous Ni-P coating. Potentiodynamic polarization curves of the Ni-P coatings in 3.5% NaCl show that the Ni-P coating extensively improves the corrosion resistance of Mg-7Al alloy and the highest corrosion potential reached to -0.54V vs. SCE(saturated calomel electrode). The results of the orthogonal experiment show that Nickel Sulfate of 25 g/L, Sodium Hypopho-sphate of 25 g/L and Citrate 7.5 g/L can be considered as the optimum bath content parameters for electroless Ni–P plating on Mg-7Al alloy and Nickel Sulfate has more effect on corrosion potential than Sodium Hypophosphate and Citrate..

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Effect of Bath Compositions on the Properties of Electroless Ni-Cu-P Alloys on Aluminum

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.117-119.1276 ◽

2011 ◽

Vol 117-119 ◽

pp. 1276-1279 ◽

Cited By ~ 1

Author(s):

Xi Ran Wang ◽

Xin Gang Hu ◽

Wei Yuan Li

Keyword(s):

Corrosion Resistance ◽

Electroless Plating ◽

Sodium Citrate ◽

Nickel Sulfate ◽

Sodium Hypophosphite ◽

Micro Hardness ◽

X Ray ◽

Plating Method ◽

The Matrix ◽

Electroless Ni

In this work, the electroless plating Ni-Cu-P on aluminium is obtained successfully by direct Ni-Cu-P plating method. The effect of bath compositions on the electroless plating rate and the properties of the electroless Ni-Cu-P deposits was studied by orthogonal test. The corrosion resistance, hardness, surface morphology and components of the coating were studied by using electrochemical workstation, digital micro-hardness SEM and EDS. The optimum bath formula obtained is 0.6g/L copper sulfate, 30g/L nickel sulfate, 35g/L sodium citrate, 25 g/L sodium hypophosphite, 20g/L acetic anhydride and right amount of self-made additive. The deposition rate, hardness and corrosion resistance are all good. The adhesion between the deposits and the matrix is better. The deposits is smooth and uniformity, smooth by SEM. The deposit contains Ni 78.90%, Cu 8.65%, P 12.46% by the analyses of energy disperse X-ray.

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The Effect of Complexing Agent on the Surface of Aluminum Alloy Plating Ni-P Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.189-193.332 ◽

2011 ◽

Vol 189-193 ◽

pp. 332-335

Author(s):

Qing Hua Chang ◽

Zhen Zhen Chang ◽

Yu Ting Bai ◽

Xiao Yu Chen ◽

Die Peng

Keyword(s):

Corrosion Resistance ◽

Aluminum Alloy ◽

Deposition Rate ◽

Acid Concentration ◽

Malic Acid ◽

Complexing Agents ◽

Complexing Agent ◽

Coating Uniformity ◽

Alloy Plating ◽

Electroless Ni

In this paper, the effect of different concentrations of complexing agent on the surface of aluminum alloy plating Ni-P alloys is studied. Study the influence of malic acid complexing agents on the electroless Ni-P alloy deposition rate, morphology, corrosion resistance, and determine the optimal complexing agent concentration. The results show that when the malic acid concentration is 24g /L, the deposition rate gets to maximum, and coating uniformity, structure compact and corrosion resistance is best.

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Optimization of the Corrosion Resistance of Electroless Ni–W–P Coatings on Magnesium Alloys by the Response Surface Methodology

Coatings ◽

10.3390/coatings11010018 ◽

2020 ◽

Vol 11 (1) ◽

pp. 18

Author(s):

Bin Liu ◽

Qing Zhang ◽

Yang Li ◽

Yuebo Yang ◽

Tao Zhang ◽

...

Keyword(s):

Response Surface Methodology ◽

Corrosion Resistance ◽

Response Surface ◽

Magnesium Alloys ◽

Sodium Tungstate ◽

Nickel Sulfate ◽

Bath Temperature ◽

Sodium Hypophosphite ◽

Technological Parameters ◽

Electroless Ni

Plating processes greatly affect the corrosion resistance of electroless Ni–W–P coatings on magnesium alloys. In the present research, the corrosion resistance of electroless Ni–W–P alloy-coated AZ91D magnesium alloy was optimized by the response surface methodology. The optimum technological parameters of the plating process were determined by establishing a quadratic regression model, and the influence of these variables and their interactions on the corrosion resistance of the coating was analyzed. The optimum technological parameters of the electroless plating process were nickel sulfate concentration = 20 g/L, sodium tungstate concentration = 15 g/L, sodium hypophosphite concentration = 30 g/L, bath temperature = 60 °C, and bath pH = 9.3. Under these conditions, the coating had the best corrosion resistance. Among the aforementioned five variables, sodium tungstate concentration had the most significant influence on the corrosion resistance of the coating. Different degrees of interactions among the variables greatly affected the corrosion resistance of the coating.

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A New Route for Direct Electroless Ni-P Plating on Magnesium Alloys

VNU Journal of Science Natural Sciences and Technology ◽

10.25073/2588-1140/vnunst.4507 ◽

2017 ◽

Vol 33 (2) ◽

Author(s):

Bùi Xuân Vương

Keyword(s):

Corrosion Resistance ◽

Magnesium Alloys ◽

Substrate Surface ◽

Nickel Sulfate ◽

Plating Bath ◽

High Adhesion ◽

Pickling Solution ◽

Salt Component ◽

Coarse Surface ◽

Electroless Ni

This report describes a new route for direct electroless Ni-P plating on magnesium alloys using nickel sulfate as the main salt component. The surface morphology, chemical composition and corrosion resistance of coatings were determined using SEM, EDX and electrochemical polarization techniques. Ni-P coatings with good corrosion resistance and high adhesion were obtained using this route and improved pretreatments. A mixture of H3PO4 and HNO3 was used as a pickling solution for Mg substrate pretreatment. A coarse surface was produced via the developed pickling procedure. A mechanical occlusive force is believed to exist between the coatings and the substrates. Twice activations, K4P2O7 and NH4HF2 as activation components, respectively, were applied for the pretreatment of magnesium alloy plating. An optimal F/O ratio on the Mg substrate surface was obtained by this pretreatment method. The activation film has insoluble partial fluorides which can depress the active points on substrate surface against the reaction of Mg with Ni2+ and H+ in the plating bath. A highly stable bath with pH 5 buffer was identified. The advantages of the developed process include chromium-free, low fluoride, and high bath stability. It is applicable for the production of motorcycle part plating.

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