scholarly journals Influence of Electrodeposition Parameters on Morphology and Polymer Inclusion into Polymer/Zn Composite Coatings

2022 ◽  
Vol 58 (4) ◽  
pp. 138-146
Author(s):  
Alina Crina Muresan ◽  
Lidia Benea

In this study different type of composite coatings was obtained by electrodeposition using zinc as matrix and polymeric particles as disperse phase in zinc sulphate electrolyte. The effects of some electrodeposition parameters on the thickness and morphology of obtained composite coatings were analysed by optical microscopy, Scanning Electron Microscopy (SEM) and Energy-Dispersive X-Ray Spectroscopy (EDX) methods. Polymeric particles inclusion into zinc matrix was correlated with imposed electrodeposition parameters. It was observed that the thickness of the coatings is influenced by electrodeposition parameters. From the morphology of the coatings, it could be concluded that pure zinc has a regular surface with hexagonal crystals, while the composite coatings have fine surface structure. Also, the electrodeposition parameters influence the inclusion of the dispersed phase into metallic matrix that will influence further the different properties of the composite materials.

2011 ◽  
Vol 66-68 ◽  
pp. 1668-1675 ◽  
Author(s):  
Xue Tao Yuan ◽  
Zhi Qiang Hua ◽  
Lei Wang ◽  
Dong Bai Sun ◽  
Song Lin Chen

Composite coatings were prepared using electroless nickel bath containing different concentrations of Al2O3nano-particles. The analyses of coating compositions, carried out by EDS, showed that there is marginal difference between phosphorus contents of NiP and NiP/nano-Al2O3deposits. The structure of the coatings was examined by scanning electron microscopy (SEM), and X-ray diffraction (XRD). It has been found that the co-deposition of nano-Al2O3particles with Ni disturbs the NiP coating’s regular surface structure and increases its surface roughness. DC and AC electrochemical tests were carried out on such coatings in a 3.5wt.% solution of NaCl in order to evaluate their corrosion resistance. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) tests both showed that, the corrosion resistance of NiP-Al2O3coatings firstly increases and then decreases when Al2O3concentration in electroless bath is increasing, but the corrosion resistance of NiP-Al2O3composite coating is better than that of amorphous NiP coating.


2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Violeta Vasilache ◽  
Gheorghe Gutt ◽  
Traian Vasilache

The electrochemical deposition of zinc and combinations with elements of the 8th group of the Periodic System (nickel, cobalt, iron) have good properties for anticorrosive protection, compared with pure zinc. For steel pieces, these films delay apparition and formation of white and red iron oxide. We used solutions with different concentrations of zinc chloride, nickel chloride and potassium chloride. To analyze the results we used the optic microscope and the X-ray diffraction.


Parasitology ◽  
1976 ◽  
Vol 72 (1) ◽  
pp. 75-80 ◽  
Author(s):  
J. Martin ◽  
D. L. Lee

Lambs which were given 60000 infective larvae ofNematodirus battus progressively threw off adult nematodes from day 20 onwards. Large, hexagonal crystals appeared in the intestine of the adult nematode at about this time and caused blockage of the intestinal-rectal or -cloacal junction. Lambs which were given 1000–2000 infective larvae did not throw off the infection, and adult nematodes from lambs which had been infected for up to 74 days did not contain these crystals. Chemical, histo-chemical and X-ray microanalysis tests on the crystals indicated that they are lipoprotein in composition. The crystals arise within the lumen of the nematode and appear to be associated with the development of immunity to this nematode in lambs.


Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2505
Author(s):  
Catalin Panaghie ◽  
Ramona Cimpoeșu ◽  
Bogdan Istrate ◽  
Nicanor Cimpoeșu ◽  
Mihai-Adrian Bernevig ◽  
...  

Zinc biodegradable alloys attracted an increased interest in the last few years in the medical field among Mg and Fe-based materials. Knowing that the Mg element has a strengthening influence on Zn alloys, we analyze the effect of the third element, namely, Y with expected results in mechanical properties improvement. Ternary ZnMgY samples were obtained through induction melting in Argon atmosphere from high purity (Zn, Mg, and Y) materials and MgY (70/30 wt%) master alloys with different percentages of Y and keeping the same percentage of Mg (3 wt%). The corrosion resistance and microhardness of ZnMgY alloys were compared with those of pure Zn and ZnMg binary alloy. Materials were characterized using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), linear and cyclic potentiometry, and immersion tests. All samples present generalized corrosion after immersion and electro-corrosion experiments in Dulbecco solution. The experimental results show an increase in microhardness and indentation Young Modulus following the addition of Y. The formation of YZn12 intermetallic phase elements with a more noble potential than pure Zinc is established. A correlation is obtained between the appearance of new Y phases and aggressive galvanic corrosion.


2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Andrea Angelastro ◽  
Sabina L. Campanelli ◽  
Giuseppe Casalino ◽  
Antonio D. Ludovico

As a surface coating technique, laser cladding (LC) has been developed for improving wear, corrosion, and fatigue properties of mechanical components. The main advantage of this process is the capability of introducing hard particles such as SiC, TiC, and WC as reinforcements in the metallic matrix such as Ni-based alloy, Co-based alloy, and Fe-based alloy to form ceramic-metal composite coatings, which have very high hardness and good wear resistance. In this paper, Ni-based alloy (Colmonoy 227-F) and Tungsten Carbides/Cobalt/Chromium (WC/Co/Cr) composite coatings were fabricated by the multilayer laser cladding technique (MLC). An optimization procedure was implemented to obtain the combination of process parameters that minimizes the porosity and produces good adhesion to a stainless steel substrate. The optimization procedure was worked out with a mathematical model that was supported by an experimental analysis, which studied the shape of the clad track generated by melting coaxially fed powders with a laser. Microstructural and microhardness analysis completed the set of test performed on the coatings.


Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1455
Author(s):  
Sabrina Patricia Rosoiu ◽  
Aida Ghiulnare Pantazi ◽  
Aurora Petica ◽  
Anca Cojocaru ◽  
Stefania Costovici ◽  
...  

The present work describes, for the first time, the electrodeposition of NiSn alloy/reduced graphene oxide composite coatings (NiSn-rGO) obtained under pulse current electrodeposition conditions from deep eutectic solvents (choline chloride: ethylene glycol eutectic mixtures) containing well-dispersed GO nanosheets. The successful incorporation of the carbon-based material into the metallic matrix has been confirmed by Raman spectroscopy and cross-section scanning electron microscopy (SEM). A decrease in the crystallite size of the coating was evidenced when graphene oxide was added to the electrolyte. Additionally, the topography and the electrical properties of the materials were investigated by atomic force microscopy (AFM). The corrosion behavior in 0.5 M NaCl solution was analyzed through potentiodynamic polarization and electrochemical impedance spectroscopy methods for different immersion periods, up to 336 h, showing a slightly better corrosion performance as compared to pure NiSn alloy.


Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 758 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Chen ◽  
...  

Pure Zn and Zn–ERGO composite coatings were prepared by direct current electrodeposition on 304 stainless steel. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and laser Raman spectroscopy (Raman). Results obtained have shown that the concentration of GO sheets in zinc sulfate electrolyte has an important effect on the preferred crystal orientation and the surface morphology of Zn–ERGO composite coatings. A study of the corrosion behavior of the coatings by Tafel polarization and electrochemical impedance spectroscopic (EIS) methods leads to the conclusion that the Zn-1.0 g/L ERGO composite coating possesses the best corrosion resistance compared to the pure Zn coating and other composite coatings in this study.


2020 ◽  
Vol 54 (30) ◽  
pp. 4921-4928
Author(s):  
A Mohamed ◽  
MM Mohammed ◽  
AF Ibrahim ◽  
Omyma A El-Kady

In this study, copper powder was reinforced with different weight percentages of Al2O3 particles (0, 5, 10, and 15 wt.% Al2O3 coated Ag) to produce Cu-Al2O3 composites by mechanical alloying and uniaxial cold pressing/sintering route. Electro-less deposition was used to coat Al2O3 particles with Ag. The microstructure of the consolidated samples was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) elemental mapping. The porosity, microhardness, and wear behavior of the consolidated samples were also investigated as a function of Al2O3 content. The EDX mapping images reveal that the Al2O3 reinforcement particles were homogeneously distributed into the Cu matrix. Microstructural analysis shows that the addition of Al2O3 coated Ag particles improves density of the composites coating. SEM micrographs result shows that slight porosities exist in the composites produced. Furthermore, the average hardness of the composite coatings varies from 72.3 to 187.6 HV as Al2O3 content increases from 0 to 15 wt.%. The wear test results showed that the composite with higher Al2O3 content 15 wt.% showed the best wear resistance.


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