Experimental Investigations of AlMg3 Components with Polyurethane and Graphene Oxide Nanosheets Composite Coatings, after Accelerated UV-Aging

The use of graphene (Gr) and its derivates graphene oxide (GO) showed that these materials are good candidates to enhance the properties of polyurethane (PU) coatings, especially the anticorrosion ones since graphene absorbs most of the light and provides hydrophobicity for repelling water. An important aspect of these multifunctional materials is that all these improvements can be realized even at very low filler loadings in the polymer matrix. In this work, an ultrasound cavitation technique was used for the proper dispersion of GO nanosheets (GON) in polyurethane (PU) resin to obtain a composite coating to protect the AlMg3 substrate. The addition of GON considerably improved the physical properties of coatings, as demonstrated by electrochemical impedance spectroscopy (EIS) analysis, promising improved anticorrosion performance after accelerated UV-ageing. Computational methods and Differential Scanning Calorimetry (DSC) measurements showed that GON facilitates the formation of additional bonds and stabilizes the PU structures during the ultraviolet (UV) exposure and aggressive attack of corrosive species. Limiting oxygen index (LOI) data reveal a slow burning behaviour of PU-GON coatings during UV exposure, which is better than PU alone.

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Electrodeposition of NiSn-rGO Composite Coatings from Deep Eutectic Solvents and Their Physicochemical Characterization

Metals ◽

10.3390/met10111455 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1455

Author(s):

Sabrina Patricia Rosoiu ◽

Aida Ghiulnare Pantazi ◽

Aurora Petica ◽

Anca Cojocaru ◽

Stefania Costovici ◽

...

Keyword(s):

Graphene Oxide ◽

Electrochemical Impedance ◽

Composite Coatings ◽

Choline Chloride ◽

Physicochemical Characterization ◽

Metallic Matrix ◽

Deep Eutectic Solvents ◽

Force Microscopy ◽

Atomic Force ◽

Reduced Graphene

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.

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Synthesis of Silane Functionalized Graphene Oxide and Its Application in Anti-Corrosion Waterborne Polyurethane Composite Coatings

Coatings ◽

10.3390/coatings9090587 ◽

2019 ◽

Vol 9 (9) ◽

pp. 587 ◽

Cited By ~ 8

Author(s):

Chao Chen ◽

Shicheng Wei ◽

Bin Xiang ◽

Bo Wang ◽

Yujiang Wang ◽

...

Keyword(s):

Graphene Oxide ◽

Corrosion Rate ◽

Electrochemical Impedance ◽

Composite Coatings ◽

Condensation Reaction ◽

Waterborne Polyurethane ◽

Functionalized Graphene ◽

Functionalized Graphene Oxide ◽

Polyurethane Composite ◽

Modified Graphene Oxide

In this study, novel silane functionalized graphene oxide (PVSQ-GO) composite material is synthesized through the hydrolysis condensation reaction of vinyl triethoxysilane monomers occurred at the surface of graphene oxide. Results obtained from FTIR, Raman, X-ray photoelectronic spectroscopy (XPS), XRD and TGA measurements reveal that polyvinyl sesquisiloxane microspheres adhere to graphene oxide lamellae in the form of chemical bonds. Meanwhile, it is intuitive that abundant polyvinyl sesquisiloxane microspheres stick to the surface of graphene oxide and increase the thickness of the flake. Modified graphene oxide changes from hydrophilicity to hydrophobicity were owing to the existence of polyvinyl sesquisiloxane microspheres on the surface of graphene oxide (GO). PVSQ-GO composite exhibited good dispersion in eco-friendly waterborne polyurethane coating. Electrochemical impedance spectroscopy manifested that the anti-corrosion performance of waterborne polyurethane (WPU) coating embedded at 0.5 wt.% PVSQ-GO composite improved effectively. Tafel curves reveal that 0.5 wt.% PVSQ-GO/WPU coating specimen shows the lowest corrosion rate of 8.95 × 10−5 mm/year when compared with the other coating specimens. The good anti-corrosion abilities of PVSQ-GO composite coating can be interpreted as the good compatibility between PVSQ-GO composite and waterborne polyurethane, however, the intrinsic hydrophobicity of PVSQ-GO composite is beneficial to inhibit the permeation of corrosive medium and thus slows down the corrosion rate.

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Hydrophobic Modification of Graphene Oxide and Its Effect on the Corrosion Resistance of Silicone-Modified Epoxy Resin

Metals ◽

10.3390/met11010089 ◽

2021 ◽

Vol 11 (1) ◽

pp. 89

Author(s):

Wei Yuan ◽

Qian Hu ◽

Jiao Zhang ◽

Feng Huang ◽

Jing Liu

Keyword(s):

Contact Angle ◽

Corrosion Resistance ◽

Graphene Oxide ◽

Physical Properties ◽

Epoxy Resin ◽

Electrochemical Impedance ◽

Salt Spray ◽

X Ray ◽

Modified Graphene Oxide ◽

Modified Epoxy

This study modified graphene oxide (GO) with hydrophilic octadecylamine (ODA) via covalent bonding to improve its dispersion in silicone-modified epoxy resin (SMER) coatings. The structural and physical properties of ODA-GO were characterized by field-emission scanning electron microscopy (FE-SEM), X-ray diffraction analysis (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and contact angle tests. The ODA-GO composite materials were added to SMER coatings by physical mixing. FE-SEM, water absorption, and contact angle tests were used to evaluate the physical properties of the ODA-GO/SMER coatings, while salt spray, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP) methods were used to test the anticorrosive performance of ODA-GO/SMER composite coatings on Q235 steel substrates. It was found that ODA was successfully grafted onto the surfaces of GO. The resulting ODA-GO material exhibited good hydrophobicity and dispersion in SMER coatings. The anticorrosive properties of the ODA-GO/SMER coatings were significantly improved due to the increased interfacial adhesion between the nanosheets and SMER, lengthening of the corrosive solution diffusion path, and increased cathodic peeling resistance. The 1 wt.% ODA-GO/SMER coating provided the best corrosion resistance than SMER coatings with other amounts of ODA-GO (including no addition). After immersion in 3.5 wt.% NaCl solution for 28 days, the low-frequency end impedance value of the 1 wt.% ODA-GO/SMER coating remained high, at 6.2 × 108 Ω·cm2.

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Zn-Co-CeO2 vs. Zn-Co Coatings: Effect of CeO2 Sol in the Enhancement of the Corrosion Performance of Electrodeposited Composite Coatings

Metals ◽

10.3390/met11050704 ◽

2021 ◽

Vol 11 (5) ◽

pp. 704

Author(s):

Marija Riđošić ◽

Nebojša D. Nikolić ◽

Asier Salicio-Paz ◽

Eva García-Lecina ◽

Ljiljana S. Živković ◽

...

Keyword(s):

Corrosion Resistance ◽

Healing Rate ◽

Electrochemical Impedance ◽

Composite Coatings ◽

Self Healing ◽

Kelvin Probe ◽

Artificial Defect ◽

Volta Potential ◽

Superior Corrosion Resistance ◽

The Stability

Electrodeposition and characterization of novel ceria-doped Zn-Co composite coatings was the main goal of this research. Electrodeposited composite coatings were compared to pure Zn-Co coatings obtained under the same conditions. The effect of two ceria sources, powder and home-made sol, on the morphology and corrosion resistance of the composite coatings was determined. During the electrodeposition process the plating solution was successfully agitated in an ultrasound bath. The source of the particles was found to influence the stability and dispersity of plating solutions. The application of ceria sol resulted in an increase of the ceria content in the resulting coating and favored the refinement from cauliflower-like morphology (Zn-Co) to uniform and compact coral-like structure (Zn-Co-CeO2 sol). The corrosion resistance of the composite coatings was enhanced compared to bare Zn-Co as evidenced by electrochemical impedance spectroscopy and scanning Kelvin probe results. Zn-Co doped with ceria particles originating from ceria sol exhibited superior corrosion resistance compared to Zn-Co-CeO2 (powder) coatings. The self-healing rate of artificial defect was calculated based on measured Volta potential difference for which Zn-Co-CeO2 (sol) coatings exhibited a self-healing rate of 73.28% in a chloride-rich environment.

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Polypropylene/Lignin/POSS Nanocomposites: Thermal and Wettability Properties, Application in Water Remediation

Materials ◽

10.3390/ma14143950 ◽

2021 ◽

Vol 14 (14) ◽

pp. 3950

Author(s):

Abeer Alassod ◽

Syed Rashedul Islam ◽

Mina Shahriari Khalaji ◽

Rogers Tusiime ◽

Wanzhen Huang ◽

...

Keyword(s):

Organic Liquid ◽

Contact Angles ◽

Water Remediation ◽

Scanning Calorimetry ◽

Water Contact ◽

Thermally Induced ◽

Dsc Measurements ◽

Infrared Measurement ◽

Oligomeric Silsesquioxane ◽

Tga And Dsc

Compositing is an interesting strategy that has always been employed to introduce or enhance desired functionalities in material systems. In this paper, sponges containing polypropylene, lignin, and octavinyl-polyhedral oligomeric silsesquioxane (OV-POSS) were successfully prepared via an easy and elegant strategy called thermally induced phase separation (TIPS). To fully explore the behaviour of different components of prepared sponges, properties were characterized by a thermogravimetric analyser (TGA), differential scanning calorimetry (DSC), Fourier transform infrared measurement (FTIR), and scanning electron microscopy (SEM). Furthermore, wettability properties toward an organic liquid and oil were investigated. The FTIR analysis confirmed the chemical modification of the components. TGA and DSC measurements revealed thermal stability was much better with an increase in OV-POSS content. OV-POSS modified sponges exhibited ultra-hydrophobicity and high oleophilicity with water contact angles of more than 125°. The SEM revealed that POSS molecules acted as a support for reduced surface roughness. Moreover, OV-POSS-based blend sponges showed higher sorption capacities compared with other blend sponges without OV-POSS. The new blend sponges demonstrated a potential for use as sorbent engineering materials in water remediation.

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High-Tribological-Performance Polymer Nanocomposites: An Approach Based on the Superlubricity State of the Graphene Oxide Agglomerates

Polymers ◽

10.3390/polym13142237 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2237

Author(s):

Eder H. C. Ferreira ◽

Angela Aparecida Vieira ◽

Lúcia Vieira ◽

Guilhermino J. M. Fechine

Keyword(s):

Graphene Oxide ◽

High Viscosity ◽

Tribological Performance ◽

Multilayer Graphene ◽

High Concentration ◽

Scanning Calorimetry ◽

Mechanical Reinforcement ◽

Transmission Electron ◽

Twin Screw ◽

Mechanical Tensile

Here, nanocomposites of high-molecular-weight polyethylene (HMWPE) and HMWPE-UHMWPE (80/20 wt.%) containing a low amount of multilayer graphene oxide (mGO) (≤0.1 wt.%) were produced via twin-screw extrusion to produce materials with a higher tribological performance than UHMWPE. Due to the high viscosity of both polymers, the nanocomposites presented a significant concentration of agglomerates. However, the mechanical (tensile) and tribological (volumetric loss) performances of the nanocomposites were superior to those of UHMWPE. The morphology of the nanocomposites was investigated using differential scanning calorimetry (DSC), microtomography, and transmission electron microscopy (TEM). The explanation for these results is based on the superlubricity phenomenon of mGO agglomerates. It was also shown that the well-exfoliated mGO also contained in the nanocomposite was of fundamental importance as a mechanical reinforcement for the polymer. Even with a high concentration of agglomerates, the nanocomposites displayed tribological properties superior to UHMWPE’s (wear resistance up to 27% higher and friction coefficient up to 57% lower). Therefore, this manuscript brings a new exception to the rule, showing that agglomerates can act in a beneficial way to the mechanical properties of polymers, as long as the superlubricity phenomenon is present in the agglomerates contained in the polymer.

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A Facile and Green Synthesis of a MoO2-Reduced Graphene Oxide Aerogel for Energy Storage Devices

Materials ◽

10.3390/ma13030594 ◽

2020 ◽

Vol 13 (3) ◽

pp. 594 ◽

Cited By ~ 3

Author(s):

Mara Serrapede ◽

Marco Fontana ◽

Arnaud Gigot ◽

Marco Armandi ◽

Glenda Biasotto ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Photoelectron Spectroscopy ◽

Electrochemical Impedance ◽

Chemical Reduction ◽

Low Cost ◽

Xps Analysis ◽

3D Scaffold ◽

Energy Storage Devices ◽

Reduced Graphene

A simple, low cost, and “green” method of hydrothermal synthesis, based on the addition of l-ascorbic acid (l-AA) as a reducing agent, is presented in order to obtain reduced graphene oxide (rGO) and hybrid rGO-MoO2 aerogels for the fabrication of supercapacitors. The resulting high degree of chemical reduction of graphene oxide (GO), confirmed by X-Ray Photoelectron Spectroscopy (XPS) analysis, is shown to produce a better electrical double layer (EDL) capacitance, as shown by cyclic voltammetric (CV) measurements. Moreover, a good reduction yield of the carbonaceous 3D-scaffold seems to be achievable even when the precursor of molybdenum oxide is added to the pristine slurry in order to get the hybrid rGO-MoO2 compound. The pseudocapacitance contribution from the resulting embedded MoO2 microstructures, was then studied by means of CV and electrochemical impedance spectroscopy (EIS). The oxidation state of the molybdenum in the MoO2 particles embedded in the rGO aerogel was deeply studied by means of XPS analysis and valuable information on the electrochemical behavior, according to the involved redox reactions, was obtained. Finally, the increased stability of the aerogels prepared with l-AA, after charge-discharge cycling, was demonstrated and confirmed by means of Field Emission Scanning Electron Microscopy (FESEM) characterization.

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Encapsulation of linseed oil in graphene oxide shells for preparation of self-healing composite coatings

Progress in Organic Coatings ◽

10.1016/j.porgcoat.2019.01.024 ◽

2019 ◽

Vol 129 ◽

pp. 285-291 ◽

Cited By ~ 14

Author(s):

Jing Li ◽

Zhenwei Li ◽

Qingkang Feng ◽

Hanxun Qiu ◽

Guangzhi Yang ◽

...

Keyword(s):

Graphene Oxide ◽

Linseed Oil ◽

Composite Coatings ◽

Self Healing

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Scaling up Studies on PEMFC Using a Modified Serpentine Flow Field Incorporating Porous Sponge Inserts to Observe Water Molecules

Molecules ◽

10.3390/molecules26020286 ◽

2021 ◽

Vol 26 (2) ◽

pp. 286

Author(s):

Muthukumar Marappan ◽

Rengarajan Narayanan ◽

Karthikeyan Manoharan ◽

Magesh Kannan Vijayakrishnan ◽

Karthikeyan Palaniswamy ◽

...

Keyword(s):

Flow Field ◽

Proton Exchange Membrane ◽

Electrochemical Impedance ◽

Scaling Up ◽

Gas Diffusion ◽

Proton Exchange ◽

Experimental Investigations ◽

Serpentine Flow Field ◽

Exchange Membrane ◽

Power Densities

Flooding of the cathode flow channel is a major hindrance in achieving maximum performance from Proton Exchange Membrane Fuel Cells (PEMFC) during the scaling up process. Water accumulated between the interface region of Gas Diffusion Layer (GDL) and rib of the cathode flow field can be removed by the use of Porous Sponge Inserts (PSI) on the ribs. In the present work, the experimental investigations are carried out on PEMFC for the various reaction areas, namely 25, 50 and 100 cm2. Stoichiometry value of 2 is maintained for all experiments to avoid variations in power density obtained due to differences in fuel utilization. The experiments include two flow fields, namely Serpentine Flow Field (SFF) and Modified Serpentine with Staggered provisions of 4 mm PSI (4 mm × 2 mm × 2 mm) Flow Field (MSSFF). The peak power densities obtained on MSSFF are 0.420 W/cm2, 0.298 W/cm2 and 0.232 W/cm2 compared to SFF which yields 0.242 W/cm2, 0.213 W/cm2 and 0.171 W/cm2 for reaction areas of 25, 50 and 100 cm2 respectively. Further, the reliability of experimental results is verified for SFF and MSSFF on 25 cm2 PEMFC by using Electrochemical Impedance Spectroscopy (EIS). The use of 4 mm PSI is found to improve the performance of PEMFC through the better water management.

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Improving the microstructure and mechanical properties of laser cladded Ni-based alloy coatings by changing their composition: A review

REVIEWS ON ADVANCED MATERIALS SCIENCE ◽

10.1515/rams-2020-0027 ◽

2020 ◽

Vol 59 (1) ◽

pp. 340-351

Author(s):

Lin Yinghua ◽

Ping Xuelong ◽

Kuang Jiacai ◽

Deng Yingjun

Keyword(s):

Mechanical Properties ◽

Wear Resistance ◽

Corrosion Resistance ◽

Rare Earth ◽

Composite Coatings ◽

Single Element ◽

Properties Of Coatings ◽

Hard Particles ◽

Microstructure And Mechanical Properties ◽

Nickel Based Alloy

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.

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