scholarly journals Effect of Current Density on Electrodeposition of Nickel-Organic Microcapsules Composite Coatings

2014 ◽  
Vol 16 (4) ◽  
Author(s):  
O. Kholkin ◽  
A. Kurbatov ◽  
Gary W. Beall ◽  
T. Djenizian ◽  
A.K. Galeyeva ◽  
...  

<p>A formation of protective composite coatings based on nickel and organic substance of inert nature, containing a corrosion inhibitor, encapsulated in a polymer shell, was studied. The microcapsules were synthesized in an aqueous-organic emulsion using the method of formation of shell of the modified gelatine on the surface of microdroplets. Composite coatings were obtained by electrochemical codeposition of nickel matrix and microcapsules, suspended in the electrolyte. Changes of surface morphology, microhardness and corrosive properties of coatings with respect to changes of deposition parameters of coatings were investigated.  The distribution of particle sizes in coatings depending on the current density was studied. It was shown that an increase in the mass fraction of the microcapsules in the coating leads to an increase in its corrosion resistance.</p>

Author(s):  
Simona BOICIUC ◽  
◽  
◽  

The undertaken research which is described in this paper aims at the corrosion behaviour of composite coatings in nickel matrix using as dispersed phase technical alumina with dimensions of 5 μm and their characterization from a microstructural point of view. The corrosion resistance in the saline fog of the coatings is influenced by the microstructure, the stresses developed in the layer and the roughness.


2020 ◽  
Vol 59 (1) ◽  
pp. 340-351
Author(s):  
Lin Yinghua ◽  
Ping Xuelong ◽  
Kuang Jiacai ◽  
Deng Yingjun

AbstractNi-based alloy coatings prepared by laser cladding has high bonding strength, excellent wear resistance and corrosion resistance. The mechanical properties of coatings can be further improved by changing the composition of alloy powders. This paper reviewed the improved microstructure and mechanical properties of Ni-based composite coatings by hard particles, single element and rare earth elements. The problems that need to be solved for the particle-reinforced nickel-based alloy coatings are pointed out. The prospects of the research are also discussed.


2010 ◽  
Vol 150-151 ◽  
pp. 1546-1550 ◽  
Author(s):  
Xiang Zhu He ◽  
Xiao Wei Zhang ◽  
Xin Li Zhou ◽  
Zhi Hong Fu

This paper presented the composite coatings of nickel with graphite particle on the aluminum substrate using a nickel sulfamate bath. Effects of graphite particle concentration on the surface morphologies of the composite coatings were investigated. The inclusion of graphite particle into metal deposits was dependent on many process parameters, including particle concentration, current density, pH and temperature. Results of SEM and XRD demonstrated that graphite particle had successfully deposited on that nickel matrix; besides, the surface morphology of coatings obtained from sulfamate bath containing 2g/L graphite particle dispersed more uniformly than the ones with higher concentration.


2013 ◽  
Vol 765 ◽  
pp. 663-667
Author(s):  
Marek Nowak ◽  
Mieczysław Opyrchał ◽  
Sonia Boczkal ◽  
Janusz Żelechowski

Composite Ni/Al2O3 coatings were electrochemically deposited from a Watts bath modified with the organic additions of dioctyl sulphosuccinate sodium salt C20H37NaO7S–(DSS) and 2,3-dihydroxy-1,2 benzisothiazol-3-one 1,1-dioxide C7H5NO3–(LSA). The effect of different amount (50 and 100 g/l) of Al2O3 powder and organic additions on microstructure, microhardness, corrosion resistance and tribological properties was investigated. The coatings were examined by optical microscopy, scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) techniques. The electrochemical behaviour of the coatings in corrosive solutions (1 M NaCl and 1 M Na2SO4) was investigated by potentiodynamic polarisation. The tribological properties were investigated by the Taber abrasive wear test, a standard test often applied in industrial practice. The results show that Al2O3 particles are uniformly distributed in the composite coatings compared with coatings without organic additions. The addition of organic compounds also reduced the size of the forming nickel crystallites and improved the tribological and corrosion properties of coatings containing the dispersed hard particles of Al2O3 added in an amount of 50 g/l and the addition of organic LSA and DSS compounds.


2014 ◽  
Vol 633-634 ◽  
pp. 787-790
Author(s):  
Lin Wang ◽  
Jin Lin Lu ◽  
Cheng Wei Li ◽  
Shu Mei Kang

In order to improve the corrosion resistance of Ni-nanoZrO2 composite coatings. By orthogonal test method,the process for composite electroplating of Ni-ZrO2 was optimized involved current density、bath temperature、the ZrO2 particle concentration. Corrosion resistance and the hardness were tested, microstructure was observed with a scanning electron microscope. The optimized technological conditions are:current density i4A/dm2,bath temperature 45°C, nanoZrO2 addition 7g/L. In this optimum process condition, corrosion current density is 6.186×10-6 A/cm2, corrosion resistance is good, and its hardness is much better than pure nickel plating, also a flat morphology and compact microstructure Ni-ZrO2 nanocomposite coating is get.


Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 616
Author(s):  
Zhaoyang Song ◽  
Hongwen Zhang ◽  
Xiuqing Fu ◽  
Jinran Lin ◽  
Moqi Shen ◽  
...  

The objective of this study was to improve the surface properties, hardness, wear resistance and electrochemical corrosion resistance of #45 steel. To this end, Ni–P–ZrO2–CeO2 composite coatings were prepared on the surface of #45 steel using the jet-electrodeposition technique by varying the current density from 20 to 60 A/dm2. The effect of current density on the performance of the composite coatings was evaluated. Scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD) were applied to explore the surface topography, elemental composition, hardness and electrochemical corrosion resistance of the composite coatings. The results showed that with the increase in the current density, the hardness, wear resistance, and electrochemical corrosion resistance tends to increase first and then decrease. At a current density of 40 A/dm2, the hardness reached a maximum of 688.9 HV0.1, the corrosion current reached a minimum of 8.2501 × 10−5 A·cm−2, and the corrosion potential reached a maximum of −0.45957 V. At these values, the performance of the composite coatings was optimal.


Coatings ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 346
Author(s):  
Rouhollah Mousavi ◽  
Flavio Deflorian ◽  
Mohammad Ebrahim Bahrololoom

Ni–Mo/Al composite coatings were obtained by electrodeposition from a Ni–Mo plating bath containing suspended Al particles. The factors including temperature, current density, and stirring rate affecting coating composition, wear, roughness, and morphology have been studied. It was found that properties such as hardness, roughness, wear, and the Al particle content showed parabolic behavior when changing each parameter. That means that there is a critical value for the mentioned parameters at which the properties of coatings become maximal.


2014 ◽  
Vol 61 (4) ◽  
pp. 205-214 ◽  
Author(s):  
Mohsen Salehi Doolabi ◽  
Sayed Khatiboleslam Sadrnezhaad ◽  
Davood Salehi Doolabi

Purpose – The main aim of this study was to improve current efficiency and to obtain thicker coatings via aluminum oxide (Al2O3) addition to the chromium (Cr) (III) bath. Design/methodology/approach – Pure Cr and nanocomposite Cr–Al2O3 coatings were electrodeposited from Cr (III) bath onto cathode copper substrates by conventional method. Dependence of current efficiency to current density, Al2O3 content and particle size were investigated. Findings – Current efficiency increased with Al2O3 amount and decreased with Al2O3 particle size. Maximum current efficiency was achieved at 25 A/dm2 for pure Cr and 30 A/dm2 for composite coatings. Al2O3 bath content, current density and stirring rate increased the coating Al2O3 weight per cent significantly. Addition of Al3+ bath composition inhibited nanoparticle agglomeration, increasing film homogeneity. Cr–Al2O3 nanocomposites showed higher microhardness and better corrosion resistance than pure Cr layer. Originality/value – Cr (III) is not as toxic and as carcinogenic as Cr (VI) which is widely used for Cr electroplating these days. Low current efficiency and poor product quality are, however, major drawbacks of the former. This paper describes significant improvements obtainable by addition of Al2O3 nanoparticles to the Cr (III) bath for increasing the microhardness, the corrosion resistance and the current efficiency of the deposition.


2008 ◽  
Vol 41-42 ◽  
pp. 385-388
Author(s):  
Xiao Yun Zhu ◽  
Zhong Cheng Guo

Process and properties of pulse electrodeposited RE-Ni-W-P-SiC composite coatings were studied. The results show that the deposited rate by pulse current is larger than that by direct current; the deposited coatings by pulse current are better than that by direct current in corrosion resistance and microhardness. And the corrosion resistance of the coatings with pulse current is better than that of stainless steel (1Cr18Ni9Ti). The duty ratio and the pulse frequency in the process of electrodeposition have a large influence on the deposition rate, the composition and the properties of coatings. SEM measurement shows that the crystals with pulse current are smaller and the surface is smoother than that by direct current. It is beneficial to make crystalline grain finer by mixing rare earth.


2020 ◽  
Author(s):  
Renjie Ji ◽  
Hui Jin ◽  
Yonghong Liu ◽  
Tiancong Dong ◽  
Fan Zhang ◽  
...  

Abstract This paper reports a phenomenon that the grain orientation gradually evolves to (220) with the deposition current density increasing when preparing nanoparticles reinforced nickel-based composite coatings by jet electrodeposition (JED). During the preparation of Ni-SiC composite coatings, the deposition current density increases from 180 A/dm2 to 220 A/dm2, and TC(220) gradually increases from 41.4% to 97.7% correspondingly.The Ni-SiC composite coating with highly preferred (220) orientation has superior corrosion resistance and adhesion force. With the increase of TC(220), the surface roughness is reduced from Ra1.210 μm to Ra0.119 μm, the self-corrosion potential increases from -0.747 V to -0.477 V, the corrosion current density decreases from 54.52 μA·cm2 to 2.76 μA·cm2, the diameter of corrosion pits that after 10 days of immersion in 3.5 wt% NaCl solution decreases from 3.3~22.2 μm to 153~260 nm, and the adhesion of the coating is increased from 20.5 N to 61.6 N.The research results can provide theoretical and technical support for the preparation of new composite coatings with high efficiency, low cost, high adhesion and strong corrosion resistance.


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