Tribological Properties of Electrodeposited Ni–Co3O4 Nanocomposite Coating on Steel Substrate

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Khalida Akhtar ◽  
Hina Khalid ◽  
Ikram Ul Haq ◽  
Naila Zubair ◽  
Zia Ullah Khan ◽  
...  
Keyword(s):  
Particle Size ◽  
Steel Substrate ◽  
Ammonium Hydroxide ◽  
Chemical Precipitation ◽  
Nanocomposite Coating ◽  
Superior Performance ◽  
Nanocomposite Coatings ◽  
Cobalt Sulfate ◽  
Sem Images ◽  
Coated Surfaces

Uniform nanoparticles of cobalt oxide precursors were prepared by the chemical precipitation in which the headspace vapors of ammonium hydroxide solution of known concentration were allowed to bubble through the aqueous solutions of cobalt sulfate, containing appropriate amount of the nonionic surfactant, octylphenoxy poly ethoxy ethanol. Scanning electron microscope (SEM) images showed that uniformity in particle size was dependent upon the applied precipitation conditions. Extensive optimization was therefore performed for the attainment of uniformity in particle size and shape. The amorphous precursor was transformed into crystalline Co3O4 as confirmed by X-ray diffractometry. These particles, with isoelectric point (IEP) at pH ∼ 8.4, were then employed as reinforcement additive for strengthening the electrodeposited nickel matrix. Effect of various parameters, i.e., stirring rate, applied current density, and temperature, was studied on the amount of the codeposited Co3O4 particles in the nanocomposite coatings (Ni–Co3O4) during the electrodeposition process. pH of the coating mixtures was kept below IEP value of Co3O4 so that the latter particles carried net positive surface charge. The coated surfaces were subjected to various tests, i.e., microhardness, wear/friction, and corrosion. Results revealed that irrespective of the amount of the embedded Co3O4 particles, nanocomposite coatings demonstrated superior performance as compared to pure nickel coatings.

Preparation and characterization of pulsed electrodeposited cobalt–graphene nanocomposite coatings

2019 ◽  
Vol 233 (12) ◽  
pp. 2469-2477 ◽  
Author(s):  
R Raveen ◽  
J Yoganandh ◽  
S SathieshKumar ◽  
N Neelakandeswari
Keyword(s):  
Steel Substrate ◽  
Research Work ◽  
Low Carbon Steel ◽  
Trisodium Citrate ◽  
Nanocomposite Coating ◽  
Industrial Applications ◽  
Nanocomposite Coatings ◽  
Low Carbon ◽  
Mechanical And Tribological Properties ◽  
Graphene Nanocomposite

Cobalt–graphene nanocomposite coatings possess unique mechanical and tribological properties which attract researchers to explore its potential for various industrial applications. This research work presents the investigation on cobalt–graphene nanocomposite coatings, with two different graphene compositions cobalt–graphene (0.15 and 0.45 wt%) prepared by pulsed electrodeposition from aqueous bath involving cobalt chloride, trisodium citrate, and citric acid on low carbon steel substrate. Studies on coating morphology, microhardness, tribological characteristics such as wear and corrosion for the cobalt–graphene nanocomposite coatings were reported. Cobalt–graphene (0.45 wt%) nanocomposite coating which exhibits low wear rate in all load conditions due to the self-lubricating property of graphene and cobalt–graphene (0.15 wt%) nanocomposite coating shows higher corrosion resistance due to its layered cauliflower surface morphology.

Corrosion Resistance of Ag/Zr Nanocomposite Coatings Deposited on Medical Co–Cr Alloy Using Plasma Spraying

2019 ◽  
Vol 11 (11) ◽  
pp. 1589-1594
Author(s):  
Lamei Yan ◽  
Meiling Zhang ◽  
Jiewen Zheng ◽  
Hongyi Song ◽  
Junhui Yin ◽  
...  
Keyword(s):  
Particle Size ◽  
Corrosion Resistance ◽  
Plasma Spraying ◽  
Nanocomposite Coating ◽  
Nanocomposite Materials ◽  
Nanocomposite Coatings ◽  
Medical Applications ◽  
Small Particle Size ◽  
Cobalt Chromium ◽  
Alloy Substrate

This study focuses on the corrosion resistance of Cobalt–Chromium (Co–Cr) alloy coated with Silver/Zirconium (Ag/Zr) nanocomposite coatings, using plasma spraying. The Ag/Zr nanocomposite materials are processed into nanoparticles with a range of diameters from 22 μm to 58 μm, because small particle size increases the adhesion between the anti-corrosion Ag/Zr nanocomposite coating and the Co–Cr alloy substrate, which can prevent oxygen from penetrating into the Co–Cr alloy substrate. The samples of Ag/Zr nanocomposite coating effectively diminished the number of microholes and cracks, as well as preserved the substrate's flexibility. We recommend using the Ag8Zr2 coating for medical applications because it had the highest corrosion resistance of all the samples we tested.

scholarly journals Effects of curing condition and particle size of aggregate on the expansion and microstructure of dolomitic aggregates cured in TMAH solution

2019 ◽  
Vol 6 (4) ◽  
pp. 190044
Author(s):  
Bin Yang ◽  
Xiaoxiao Chen ◽  
Min Deng
Keyword(s):  
Particle Size ◽  
Grain Size ◽  
Ammonium Hydroxide ◽  
Curing Temperature ◽  
Sem Images ◽  
Tg Analysis ◽  
Tetramethyl Ammonium Hydroxide ◽  
Microstructural Studies ◽  
Carbonate Reaction ◽  
Tmah Solution

In this paper, the modified microbars prepared by dolomitic aggregates with three kinds of particle size and self-made cement without K + and Na + were cured in 1 and 2 N tetramethyl ammonium hydroxide (TMAH) solution at 20°C, 60°C and 80°C, respectively. TMAH was used as curing solution to exclude the expansion contribution of alkali–silica reaction. Effects of the concentration of TMAH solution, curing temperature and aggregate grain size on the expansion of dolomitic aggregates were systematically investigated to determine the expansion characteristics only caused by alkali–carbonate reaction (ACR). Expansion of modified microbars cured in TMAH solution was measured. The porosities of original and reacted aggregates were also measured. Microstructural studies were carried out by scanning electron microscopy (SEM) and thermo-gravimetric (TG) analysis. The results showed that the aggregate grain size and curing temperature can influence the expansion of modified microbars significantly. When the modified microbars prepared by aggregates with 2.5–5 mm grain size and cured in 1 N TMAH solution at 80°C, the samples exhibited obvious expansion only caused by ACR, which is beneficial to detect the ACR reactivity of dolomitic rocks exclusively in concrete engineering. Based on the pore structure analysis, there was a slight increase (13%) in porosities of aggregates cured for 140 days at 80°C. Rod-like brucite crystals formed in the process of ACR were also found in TG analysis and SEM images.

scholarly journals Impact of Iron on the Fe–Co–Ni Ternary Nanocomposites Structural and Magnetic Features Obtained via Chemical Precipitation Followed by Reduction Process for Various Magnetically Coupled Devices Applications

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 341
Author(s):  
Tien Hiep Nguyen ◽  
Gopalu Karunakaran ◽  
Yu.V. Konyukhov ◽  
Nguyen Van Minh ◽  
D.Yu. Karpenkov ◽  
...  
Keyword(s):  
Particle Size ◽  
Magnetic Properties ◽  
Reduction Process ◽  
Chemical Precipitation ◽  
Precipitation Method ◽  
Magnetic Characteristics ◽  
Reduction Temperature ◽  
Fe Content ◽  
Magnetic Features ◽  
Co Precipitation

This paper presents the synthesis of Fe–Co–Ni nanocomposites by chemical precipitation, followed by a reduction process. It was found that the influence of the chemical composition and reduction temperature greatly alters the phase formation, its structures, particle size distribution, and magnetic properties of Fe–Co–Ni nanocomposites. The initial hydroxides of Fe–Co–Ni combinations were prepared by the co-precipitation method from nitrate precursors and precipitated using alkali. The reduction process was carried out by hydrogen in the temperature range of 300–500 °C under isothermal conditions. The nanocomposites had metallic and intermetallic phases with different lattice parameter values due to the increase in Fe content. In this paper, we showed that the values of the magnetic parameters of nanocomposites can be controlled in the ranges of MS = 7.6–192.5 Am2/kg, Mr = 0.4–39.7 Am2/kg, Mr/Ms = 0.02–0.32, and HcM = 4.72–60.68 kA/m by regulating the composition and reduction temperature of the Fe–Co–Ni composites. Due to the reduction process, drastic variations in the magnetic features result from the intermetallic and metallic face formation. The variation in magnetic characteristics is guided by the reduction degree, particle size growth, and crystallinity enhancement. Moreover, the reduction of the surface spins fraction of the nanocomposites under their growth induced an increase in the saturation magnetization. This is the first report where the influence of Fe content on the Fe–Co–Ni ternary system phase content and magnetic properties was evaluated. The Fe–Co–Ni ternary nanocomposites obtained by co-precipitation, followed by the hydrogen reduction led to the formation of better magnetic materials for various magnetically coupled device applications.

Antibacterial Activity of Silver-Hydroxyapatite/Titania Nanocomposite Coating on Titanium against Oral Bacteria

2007 ◽  
Vol 330-332 ◽  
pp. 455-458 ◽  
Author(s):  
An Chun Mo ◽  
Wei Xu ◽  
Su Qin Xian ◽  
Yu Bao Li ◽  
Shi Bai
Keyword(s):  
Antibacterial Activity ◽  
Streptococcus Mutans ◽  
Porphyromonas Gingivalis ◽  
Nanocomposite Coating ◽  
Oral Bacteria ◽  
Tio2 Coating ◽  
Prevotella Intermedia ◽  
Anaerobic Incubation ◽  
Coating Method ◽  
Coated Surfaces

This study was focused on evaluating the bactericidal and anti-adhesive efficacy of silver-hydroxyapatite/ titania nanocomposites (nAg-HA/TiO2) coating on titanium against oral bacteria. Porphyromonas gingivalis, Prevotella intermedia and Fusohacterium nucleatum and Streptococcus mutans were used. Antibacterial activity of nAg-HA/TiO2 coating was investigated quantitatively using film applicator coating method and titanium plates incubated with bacteria were prepared for SEM to observe the adherence of oral bacteria. The viability of each type of bacteria on the antibacterial film was suppressed to about 10% after anaerobic incubation for 3 hours. Image of SEM demonstrated that bacteria on sandblasting surfaces were relatively confluent whilst on coated surfaces fewer bacteria were observed. Adherence of bacteria on nAg-HA / TiO2-coated surfaces compared with uncoated surfaces was remarkably decreased.

Preparation of Electrodeposited Ni-CNTs Nanocomposite Coatings with Highly Wear and Corrosion Resistance Properties

2012 ◽  
Vol 548 ◽  
pp. 101-104 ◽  
Author(s):  
W. Shao ◽  
D. Nabb ◽  
N. Renevier ◽  
I. Sherrington ◽  
J.K. Luo
Keyword(s):  
Mechanical Property ◽  
Carbon Nanotubes ◽  
Corrosion Resistance ◽  
Surface Morphology ◽  
Corrosion Property ◽  
Nanocomposite Coatings ◽  
Sem Images ◽  
Wear And Corrosion ◽  
Watts Bath ◽  
Wear And Corrosion Resistance

Ni-carbon nanotubes nanocomposite coatings were obtained from a Watts bath containing uniformly dispersed carbon nanotubes (CNTs). The surface morphology was investigated by the SEM images of coatings. The mechanical property and corrosion resistance of the nanocomposite coatings were investigated. This study revealed these CNTs reinforced Ni nanocoatings have improved mechanical and corrosion property.

scholarly journals Ammoniacal System Mechanisms for Leaching Copper from Converter Slag

Metals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 712
Author(s):  
Alvaro Aracena ◽  
Andrés Valencia ◽  
Oscar Jerez
Keyword(s):  
Particle Size ◽  
Converter Slag ◽  
Research Work ◽  
Ammonium Hydroxide ◽  
Copper Extraction ◽  
Solution Ph ◽  
Intraparticle Diffusion Model ◽  
Electron Microscopy Analysis ◽  
Leaching Solution ◽  
Conversion Stage

In pyrometallurgical processes refining copper, the main source of loss in the conversion stage is from slag. This paper reports on research work treating converter slag containing high percentages of copper (36 wt%) using ammonium hydroxide at room temperature. Variables analyzed are solution pH, agitation, temperature, NH4OH concentration and particle size. Results showed that the hydronium ion resulting from ammonium hydroxide dissociation was the main oxidant of copper compounds in slag, such as CuO, Cu2O and Cu, with the exception of CuFeO2. The particles contain a large amount of microcracks (porosity) in their refractory structure (analyzed by compositional image capture (BSE)). Thus, the diffusion of the leaching solution through the microcracks making contact with the copper oxides would be allowed. Leaching mechanisms were corroborated by X-ray diffraction and scanning electron microscopy analysis. Increasing temperature and NH4OH concentration while decreasing particle size obtained higher copper recoveries, reaching values of 84.8%. Under the same conditions, the main impurity (iron) was minimal (<2%). Solution pH also affected slag leaching. Agitation of the solution positively affected the rate of copper extraction. Leaching kinetics of the leaching solution through the porosity formed in the slag was analyzed under the intraparticle diffusion model. The reaction order was 1.2 with respect to the concentration of ammonium hydroxide and the model was inversely proportional to the square of the particle radius. The activation energy obtained was 42.3 kJ/mol for temperature range 283 to 333 K.

scholarly journals Changes in Structural and Rheological Properties of Guar Gum Particles in Fluidized-Bed Agglomeration: Effect of Sucrose Binder Concentration

Foods ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 73
Author(s):  
Donghyeon Lee ◽  
Byoungseung Yoo
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Guar Gum ◽  
Sucrose Concentration ◽  
Ftir Spectra ◽  
Sem Images ◽  
Low Concentrations ◽  
Binder Concentration ◽  
Bed Agglomeration ◽  
Xrd Patterns

Fluidized-bed agglomeration (FBA) is known to modify the structure and rheology of food powders. In this study, guar gum (GG) powders with various concentrations of sucrose binder (0%, 10%, 20%, or 30%) were subjected to fluidized-bed agglomeration. Subsequently, changes in the characteristics of the GG powders were evaluated by using scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), particle size distribution (PSD) analysis, and rheological and dispersibility measurements. SEM images and FTIR spectra revealed surface morphology changes and structural modification, respectively, in the original GG powder after FBA, although the changes observed in FTIR spectra were only slightly dependent on sucrose concentration at low concentrations (0–20%). XRD patterns confirmed that the crystallinity of the GG powder was affected by FBA, but not greatly so by binder concentration. The PSD results showed that the GG particle size was increased by FBA and there was a clear relationship between sucrose concentration (10–30%) and mean particle size. The rheological behavior and dispersibility of GG (properties that are known to be affected by the structure of a powder) were also influenced by sucrose concentration. To sum up, FBA and the concentration of sucrose binder used can serve as factors for modifying GG powder.

Effect of Powder Properties such as Particle Size, Density and Melt Flow Rate on the Properties of Flame Sprayed PE Coating

2000 ◽  
Author(s):  
E. Rajamäki ◽  
M. Leino ◽  
P. Vuoristo ◽  
P. Järvelä ◽  
T. Mäntylä
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Flow Rate ◽  
Heating Temperature ◽  
Steel Substrate ◽  
Great Influence ◽  
Hot Water ◽  
Melt Flow ◽  
Melt Flow Rate ◽  
Powder Properties

Abstract Three different types of polyethylene powders were flame sprayed onto pre-heated steel substrate previously coated by electrostatic spray system with a thin epoxy primer layer. Properties of the polyethylene (PE) powders, including powder density, particle size and melt flow rate (MFR) were measured in order to study their influence on the mechanical properties of the coating. The spray experiments started with optimization of spraying parameters. The main variables were pre-heating temperature of the substrate, temperature increase during spraying (influenced by the spraying distance), and thickness of the PE coatings. The laboratory tests performed for the coatings were coating characterization by microscopy and mechanical testing. Porosity and thickness of the coatings were determined by optical and stereo microscopy studies from polished cross-sectional samples. Hardness, impact strength, peel strength, and adhesive strength of the coatings were also investigated. Also some hot water sinking and heat cycling tests were performed. As a result from the present studies it can be concluded that powder properties have great influence on the mechanical properties of the final coating.

Colloidal characteristics of gelatin-treated clay: Intercalation, stability, wettability, and rheological properties

2021 ◽  
Vol 29 (9_suppl) ◽  
pp. S1361-S1370
Author(s):  
Xuwu Luo ◽  
Guancheng Jiang ◽  
Xinliang Li ◽  
Lili Yang
Keyword(s):  
Contact Angle ◽  
Particle Size ◽  
Rheological Properties ◽  
Water Contact Angle ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Water Contact ◽  
Ζ Potential ◽  
And Behavior ◽  
Clay Intercalation

In this paper, sodium montmorillonite was modified with gelatin of different concentrations, and various colloidal characteristics of the gelatin-treated clays were measured and analyzed in detail. First, the influence of gelatin on the interlayer space of Mt layers was investigated by X-ray diffraction analysis. Moreover, the aggregation of Mt particles was examined using a combination of electron microscopy and particle size distribution experiments, while the variation of the electrical property of Mt was measured using ζ potential test. Gelatin of different concentrations can increase the particle size of Mt in different degrees. The addition of 4% gelatin could improve the ζ potential of Mt from −30.65 to −15.55 mV. The wettability change of modified Mt induced by the adsorption of gelatin was followed by measurements of water contact angle and observations of the morphology of Mt/gelatin membrane through SEM images. 4% gelatin could improve the water contact angle of Mt to 81.3°. Finally, the rheological properties of Mt/gelatin dispersion including shear viscosity and shear stress were measured using a stress-controlled rheometer. All of the results were consistent by showing that the overall colloidal characteristics and behavior of the gelatin-treated Mt strongly varied depending on the gelatin concentration used in the modification process. These results can provide a deep and comprehensive understanding of the colloidal properties of clay/gelatin systems and give important guidance for the performance design and improvement of Mt/gelatin composite materials. Furthermore, this study can also be expanded the application of gelatin and its composites to other fields.

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