Influence of Thermal Treatment on the Electrochemical Properties of Ni+W+Mo+Si Composite Coatings in an Alkaline Solution

2015 ◽  
Vol 228 ◽  
pp. 305-309
Author(s):  
Magdalena Popczyk ◽  
Bożena Łosiewicz ◽  
Eugeniusz Łągiewka ◽  
A. Budniok

The Ni+W+Mo+Si composite coatings were prepared by electrodeposition under the galvanostatic conditions (jdep= -100 mA cm-2) from the nickel bath containing powders of tungsten, molybdenum and silicon. Thermal treatment of the obtained coatings was conducted in argon atmosphere. Chemical composition of the coatings was determined by energy dispersive spectrocopy (EDS). Phase composition investigations were conducted by X-ray diffraction (XRD) method. Studies of electrochemical corrosion resistance were carried out in 5 M KOH solution. On the basis of these investigations it was found that Ni+W+Mo+Si thermally treated coating is more corrosion resistant than Ni+W+Mo+Si as-deposited coating.

2015 ◽  
Vol 228 ◽  
pp. 231-236 ◽  
Author(s):  
Magdalena Popczyk ◽  
B. Łosiewicz ◽  
Eugeniusz Łągiewka ◽  
A. Budniok

The Ni+Mo composite coatings were prepared by electrodeposition under the galvanostatic conditions (jdep= -300 mA cm-2) from the nickel bath containing molybdenum powders of different granulation (3-7 μm, <150 μm, <100 nm). Thermal treatment of the obtained coatings was conducted in the argon atmosphere. The surface morphology of the coatings was studied using a scanning electron microscopy (SEM). Chemical composition of the electrodeposits was determined by X-ray fluorescence spectroscopy (XRF). Phase composition investigations were conducted by X-ray diffraction (XRD) method. Investigations of hydrogen evolution reaction (HER) and electrochemical corrosion resistance were carried out in 5 M KOH solution. It was found that for the Ni+Mo thermally treated coatings the decrease in activity towards the HER was observed. Simultaneously these coatings are more corrosion resistant than Ni+Mo as-deposited coatings. The reasons for the electrochemical properties of these coatings have been discussed.


2015 ◽  
Vol 228 ◽  
pp. 168-171
Author(s):  
Iwona Napłoszek ◽  
Eugeniusz Łągiewka ◽  
A. Budniok ◽  
Magdalena Popczyk ◽  
Grzegorz Dercz ◽  
...  

The Ni+Al+Ti composite coatings were prepared by the electrodeposition under the galvanostatic conditions at the deposition current denisty ofjdep= -225 mA cm-2. Phase composition investigations were conducted by X-ray diffraction (XRD) method. The surface morphology, cross-section and chemical composition of the coatings were examined using a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. Thermal treatment of the obtained composite coatings was conducted in argon atmosphere at the temperature of 800oC for 12 h. It was found that the as-deposited Ni+28at.%Al+25at.%Ti composite coating is a three-phase material (Ni, Al and Ti phases). The thermal treatment caused the chemical reaction in solid state of the heated coating, and a new multi-phase material was formed containing Ni and Al metallic phases as well as NiAl, Ni2Al3, Ni3Al, NiTi, NiTi2and Ni3Ti intermetallic phases. Thus obtained composite coatings may be useful in the applications as materials in the electrochemical processes.


2010 ◽  
Vol 636-637 ◽  
pp. 1042-1046
Author(s):  
Magdalena Popczyk ◽  
Antoni Budniok

Zn-Ni and Zn-Ni-W coatings were prepared by the electrodeposition under the galvanostatic conditions (jdep. = -0.020 A cm-2) from the zinc bath containing additionally ions of nickel (Zn-Ni) and ions of nickel and tungsten (Zn-Ni-W). The Zn-Ni coating after electrodeposition was subjected to outside passivation and in the Zn-Ni-W coating the passive function performs tungsten (inside passivation). The surface morphology of the coatings was studied using a scanning electron microscope (JEOL JSM - 6480). Chemical composition of obtained coatings was determined by the X-ray fluorescence spectroscopy (XRF). Phase composition investigations were conducted by X-ray diffraction method using a Philips diffractometer. Electrochemical corrosion resistance investigations were carried out in the 3% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that Zn-Ni coating is more corrosion resistant than the Zn-Ni-W coating.


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.


2008 ◽  
Vol 587-588 ◽  
pp. 815-819 ◽  
Author(s):  
Magdalena Popczyk ◽  
Antoni Budniok ◽  
Eugeniusz Łągiewka

Ni+W+Si composite coatings were prepared by nickel deposition from a bath containing suspension of tungsten and silicon powders. These coatings were obtained under galvanostatic conditions, at the current density of jdep. = 0.100 A cm-2 and at the temperature of 338 K. A scanning electron microscope was used for surface morphology characterization of the coatings. Chemical composition of the coatings was determined by EDS method and phase composition investigations were conducted by X-ray diffraction. Thermal treatment of obtained coatings was conducted in the air and nitrogen atmosphere. Electrochemical corrosion resistance investigations were carried out in the 5 M KOH, using potentiodynamic method. It was found that Ni+W+Si coatings after thermal treatment in the air are more corrosion resistant in alkaline solution than Ni+W+Si coatings after thermal treatment in the nitrogen atmosphere and as-deposited coatings. The main reason of this is presence of new phases, in particular NiWO4 and SiO2.


2015 ◽  
Vol 228 ◽  
pp. 153-157
Author(s):  
Magdalena Popczyk ◽  
Bożena Łosiewicz

The Ni-W alloy coatings and Ni+W composite deposits were prepared by the electrodeposition under the galvanostatic conditions at the deposition current density ofjdep= -300 mA cm-2. The surface morphology and chemical composition of the coatings were examined using a scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), respectively. Phase composition investigations were conducted by X-ray diffraction (XRD) method. It was found that introduction of tungsten powder into nickel matrix allowed to obtain the Ni+W composite coating with very rough surface as compared with the smooth Ni-W alloy coating. Thus obtained Ni+W porous coating may be useful for the need of hydrogen technologies.


2015 ◽  
Vol 228 ◽  
pp. 163-167
Author(s):  
Magdalena Popczyk ◽  
B. Łosiewicz ◽  
Eugeniusz Łągiewka ◽  
A. Budniok

Electrodeposited Ni-P, Ni-W-P, Ni-P+W and Ni-P+NiO+W coatings were obtained in the galvanostatic conditions at the current density jdep = -200 mA cm-2. A stereoscopic microscope was used for surface characterization of the coatings. The phase composition of the coatings was determined using X-ray diffraction (XRD) method. The chemical composition of the deposits was determined using atomic absorption spectroscopy (AAS). It was found out that the introduction of the tungsten powder in one case, and the nickel oxide and tungsten powder in the other into the electrolytic Ni-P matrix results in obtaining the coatings with a very rough surface. The coatings obtained in this way may be useful while applying them as electrode materials in electrochemistry.


Coatings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 712
Author(s):  
Channagiri Mohankumar Praveen Kumar ◽  
Avinash Lakshmikanthan ◽  
Manjunath Patel Gowdru Chandrashekarappa ◽  
Danil Yurievich Pimenov ◽  
Khaled Giasin

Zinc (Zn) is one of the five most widely consumed metals in the world. Indeed, more than 50% of all the zinc produced is used in zinc-galvanizing processes to protect steel from corrosion. Zn-based coatings have the potential for use as a corrosion-resistant barrier, but their wider use is restricted due to the poor mechanical properties of Zn that are needed to protect steel and other metals from rusting. The addition of other alloying elements such as Ni (Nickle) and WC (Tungsten Carbide) to Zn coating can improve its performance. This study investigates, the corrosion performance of Zn–Ni coating and Zn–Ni–WC composite nanocoatings fabricated on mild steel substrate in an environmentally friendly bath solution. The influence of WC nanoparticles on Zn–Ni deposition was also investigated. The surface morphologies, texture coefficients via XRD (X-ray diffraction), SEM (Scanning Electron Microscopy), and EDS (Energy-dispersive X-ray spectroscopy) were analyzed. The electrochemical test such as polarization curves (PC) and electrochemical impedance spectroscopy (EIS) resulted in a corrosion rate of 0.6948 Å/min for Zn–Ni–WC composite nanocoating, and 1.192 Å/min for Zn–Ni coating. The results showed that the Zn–Ni–WC composite nanocoating reduced the corrosion rate by 41.71% and showed an 8.56% increase in microhardness compared to the hardness of the Zn–Ni coating. These results are augmented to better wettable characteristics of zinc, which developed good interfacial metallurgical adhesion amongst the Ni and WC elements. The results of the novel Zn–Ni–WC nanocomposite coatings achieved a great improvement of mechanical property and corrosion protection to the steel substrate surface.


2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Valentina Krylova ◽  
Mindaugas Andrulevičius

Copper sulfide layers were formed on polyamide PA 6 surface using the sorption-diffusion method. Polymer samples were immersed for 4 and 5 h in 0.15 mol⋅  solutions and acidified with HCl (0.1 mol⋅) at . After washing and drying, the samples were treated with Cu(I) salt solution. The samples were studied by UV/VIS, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) methods. All methods confirmed that on the surface of the polyamide film a layer of copper sulfide was formed. The copper sulfide layers are indirect band-gap semiconductors. The values of are 1.25 and 1.3 eV for 4 h and 5 h sulfured PA 6 respectively. Copper XPS spectra analyses showed Cu(I) bonds only in deeper layers of the formed film, while in sulfur XPS S 2p spectra dominating sulfide bonds were found after cleaning the surface with ions. It has been established by the XRD method that, beside , the layer contains as well. For PA 6 initially sulfured 4 h, grain size forchalcocite, , was  nm and fordjurleite, , it was 54.17 nm. The sheet resistance of the obtained layer varies from 6300 to 102 .


2009 ◽  
Vol 610-613 ◽  
pp. 1150-1154
Author(s):  
Ai Lan Fan ◽  
Cheng Gang Zhi ◽  
Lin Hai Tian ◽  
Lin Qin ◽  
Bin Tang

The Mo surface modified layer on Ti6Al4V alloy was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified Ti6Al4V alloy was investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo modified layer contains Mo coating on subsurface and diffusion layers between the subsurface and substrate. The X- ray diffraction analysis of the Mo modified Ti6Al4V alloy reveals that the outmost surface of the Mo modified Ti6Al4V alloy is composed of pure Mo. The electrochemical corrosion performance of the Mo modified Ti6Al4V alloy in 25°C Hank’s solution was investigated and compared with that of Ti6Al4V alloy. Results indicate that the self-corroding electric potential and the corrosion-rate of the Mo modified Ti6Al4V alloy are higher than that of Ti6Al4V alloy in 25°C Hank’s solution.


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