scholarly journals The Study of Graphene Oxide on the Regulations and Controls of the Sol-Gel Film Structure and Its Performance

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Yan Gao ◽  
Yadong Fan ◽  
Junxi Zhang ◽  
Xuanxuan Liu ◽  
Ning Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Film Formation ◽  
Sol Gel ◽  
Corrosion Current ◽  
Film Structure ◽  
Regulation Mechanism ◽  
Coating Films ◽  
Gel Film ◽  
Diffusion Paths ◽  
Protection Capability

A facile strategy to boost anticorrosion potency of graphene oxide/silica hybrid sol-gel coating is developed through fully exploiting the capabilities of graphene oxide (GO). Together with a barrier to corrosives and crack inhibitor, GO was further explored herein as a regulator to regulate the gelation process and provide robust coating films with stratified microstructures and ultimately extended diffusion paths. The sol-gel coating with stratified microstructure achieved on AA5052 aluminum alloy surface afforded greatly enhanced corrosion protection capability as assessed by electrochemical measurements and immersion tests. The corrosion current density of the sample of a hybrid GO sol-gel film was about 30 times less than that of sample of pure sol-gel film sample. The regulation mechanism of GO during the film formation process and the anticorrosive protection properties of the film were discussed.

Effect of Sol-Gel Film on the Corrosion Resistance of Low Carbon Steel Plate

2020 ◽  
Vol 984 ◽  
pp. 43-50
Author(s):  
Hua Yuan Zhang ◽  
Can Wang ◽  
Bing Xue ◽  
Jing Luo
Keyword(s):  
Corrosion Resistance ◽  
Carbon Steel ◽  
Steel Plate ◽  
Salt Spray ◽  
Sol Gel ◽  
Low Carbon Steel ◽  
Corrosion Current ◽  
Neutral Salt ◽  
Low Carbon ◽  
Gel Film

To improve the corrosion resistance on Q235 low carbon steel, in this paper, tetraethyl orthosilicate (TEOS), N-dodecyl trimethoxysilane and γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560) were used to make organic-inorganic hybrid sol-gel film. Cross cut test adhesion method, neutral salt spray test, electrochemical test and film protective efficiency were taken to value the corrosion resistance property. The corrosion topography was studied by optical microscope. In addition, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) curves and equivalent electric circuit fitting were used to analyze the corrosion mechanism. The cross cut adhesion of sol-gel film can reach 1 class and the protection class can attain 5 class after 72 hours neutral salt spray test. According to the potentiodynamic polarization curve analysis, the corrosion potential of sol-gel film coating sample after 0.5 hours immersion was -0.46 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.74×10-7 A·cm-2. The corrosion potential of bare Q235 low carbon steel plate after 0.5 hours immersion was -0.78 V (vs. SCE) on the 0.1 Hz, and its corrosion current density was 4.75×10-6 A·cm-2. The impedance value on 0.1 Hz (|Z|0.1Hz) (1.27×106 Ω·cm2) of sol-gel film coating sample was more than three orders of magnitude higher than the value of the low carbon steel plate. Even dipping in 3.5 wt. % NaCl for 72 hours, the |Z|0.1Hz value of sol-gel coating sample was still one order of magnitude higher than the low carbon steel plate with 0.5 hours immersion. Sol-gel film with excellent adhesion can significantly improve the corrosion resistance of low carbon steel plate. Sol-gel film can increase the protection efficiency of low carbon steel plate by 90%.

Alumina Sol-Gel Films and Alodine Films on Al 2024 Alloy

2011 ◽  
Vol 356-360 ◽  
pp. 364-367
Author(s):  
Qi Zhou ◽  
Xuan Xiao ◽  
Da Li Zhao ◽  
En Jun Song
Keyword(s):  
Corrosion Resistance ◽  
Aluminium Alloy ◽  
Electrochemical Impedance ◽  
Sol Gel ◽  
Film Surface ◽  
Corrosion Current ◽  
Promising Alternative ◽  
Gel Film ◽  
Alumina Sol ◽  
Sol Gel Films

Development of the sol-gel films for painting pretreatment of aluminium alloy is to replace bichromate conversion films such as Alodine. Corrosion resistance of Alodine film and sol-gel film were evaluated through potentiodynamic polarization curves, electrochemical impedance spectroscopy, salt spraying and acidic dropping solution. Sol-gel film is almost the same as Alodine film at the film surface density, salt spraying resistance and adhesion with painting coating. Changing color times of dropping solution on sol-gel film is shorter than Alodine film. But the corrosion current of sol-gel film is lower than Alodine and the impedance value is higher than Alodine in 35g/L NaCl solution. Mechanism of corrosion resistance of alumina sol-gel film is that the cathode reaction and anodic reactions are restrained by sol-gel film in the Cl- corrosive medium. The EIS of sol-gel film consisted of only a single capacitive arc with one time constant. Sol-gel coating can prevent or delay the corrosive solution from infiltrating the substrate for its better isolation function, thus protecting 2024 aluminium alloy from corrosion. Sol-gel films can improve corrosion resistance of aluminum alloy and have the same adhesion as Alodine film. It will be a promising alternative pretreatment for aluminum alloys prior to painting.

Corrosion protection of AA2024-T3 by sol-gel film modified with graphene oxide

2017 ◽  
Vol 725 ◽  
pp. 84-95 ◽  
Author(s):  
Bing Xue ◽  
Mei Yu ◽  
Jianjun Liu ◽  
Jianhua Liu ◽  
Songmei Li ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Corrosion Protection ◽  
Sol Gel ◽  
Gel Film

Sol-gel preparation of TiO2 ceramic coating films from aqueous solutions of titanium sulfate (IV) containing polyvinylpyrrolidone

2003 ◽  
Vol 18 (2) ◽  
pp. 466-474 ◽  
Author(s):  
Tomoko Kishimoto ◽  
Hiromitsu Kozuka
Keyword(s):  
Refractive Index ◽  
Aqueous Solutions ◽  
Ceramic Coating ◽  
Film Formation ◽  
Sol Gel ◽  
Alcoholic Solution ◽  
Coating Films ◽  
Average Deviation ◽  
Arithmetic Average ◽  
Titanium Sulfate

TiO2 ceramic coating films were deposited on silica glass substrates by the sol- gel method using aqueous solutions of Ti(SO4)2 containing polyvinylpyrrolidone (PVP) as the coating solutions. Unless PVP was added to the solution, the wettability of the substrate was poor, leading to failure in gel film formation. When PVP was added to the solution, on the other hand, homogeneous gel films could be deposited on the substrate, which could be converted to crack- free, transparent TiO2 ceramic thin films about 0.1 μm in thickness. The TiO2 films thus obtained had refractive index, porosity, and surface roughness Ra (the arithmetic average deviation of the assessed profile) of 2.68, 2.1%, and 0.94 nm, respectively. For comparison, a TiO2 film was also prepared from an alcoholic solution of Ti(OC3H7i)4, showing refractive index, porosity, and Ra of 2.65, 3.0%, and 0.98 nm, respectively. These values indicate that the TiO2 films prepared from the Ti(SO4)2 aqueous solutions containing PVP are as smooth and dense as those prepared from conventional alkoxide solutions. The solutions were found to be stable in viscosity for more than five months at room temperature in sealed containers. Thermal analysis, infrared absorption spectra measurement, and x- ray diffraction analysis indicated that the gel films are converted to ceramic films on firing via (i) vaporization of H2O; (ii) decomposition of H2SO4 and/or vaporization of H2SO4 · H2O; (iii) decomposition of SO42− coordinating Ti atoms and oxidation and decomposition of PVP, the latter of which leads to formation of residual carbons; (iv) oxidation of the carbonaceous residues; and (v) crystallization of the titania phase. During the gel- to- ceramic film conversion, the thickness decreased by 90%.

scholarly journals Sol-Gel Film Formation by Dip Coating

1990 ◽  
Vol 180 ◽  
Author(s):  
Alan J. Hurd ◽  
C. Jeffrey Brinker
Keyword(s):  
Film Formation ◽  
Sol Gel ◽  
Dip Coating ◽  
Point Of View ◽  
Inverse Form ◽  
Capillary Phenomena ◽  
Gel Film ◽  
Capillary Collapse ◽  
Field Singularity ◽  
Film Profile

ABSTRACTThe physical aspects of sol-gel film formation are discussed, including the steady state film profile during dip coating, evaporation, and capillary phenomena. It is argued that, since the evaporation rate increases singularly near a sharp boundary (analogous to an electric field singularity near a sharp conductor), the film profile near the drying line falls off precipitously, following the inverse form of the evaporation singularity. Finally, the large tensile pressures in the solvent during the final stage of drying of a porous film are discussed from the point of view of controlling the degree of capillary collapse.

A recycling strategy of ion beam removal and recoating of sol-gel film on fused silica surface

Optik ◽  
2021 ◽  
pp. 167259
Author(s):  
Wenfeng Sun ◽  
Xia Xiang ◽  
Bo Li ◽  
Xiang Dong ◽  
Xiaolong Jiang ◽  
...  
Keyword(s):  
Silica Surface ◽  
Ion Beam ◽  
Sol Gel ◽  
Fused Silica ◽  
Gel Film

scholarly journals High-Performance Graphene Coating on Titanium Bipolar Plates in Fuel Cells via Cathodic Electrophoretic Deposition

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 437
Author(s):  
Yi Liu ◽  
Luofu Min ◽  
Wen Zhang ◽  
Yuxin Wang
Keyword(s):  
Graphene Oxide ◽  
Fuel Cells ◽  
Electrophoretic Deposition ◽  
High Performance ◽  
Proton Exchange Membrane ◽  
Corrosion Current ◽  
Proton Exchange ◽  
Bipolar Plates ◽  
Modified Graphene Oxide ◽  
Bare Titanium

In this article, we proposed a facile method to electrophoretically deposit a highly conductive and corrosion-resistant graphene layer on metal bipolar plates (BPs) while avoiding the oxidation of the metal substrate during the electrophoretic deposition (EPD). p-Phenylenediamine (PPD) was first grafted onto negatively charged graphene oxide (GO) to obtain modified graphene oxide (MGO) while bearing positive charges. Then, MGO dispersed in ethanol was coated on titanium plates via cathodic EPD under a constant voltage, followed by reducing the deposited MGO with H2 at 400 °C, gaining a titanium plate coated with reduced MGO (RMGO@Ti). Under the simulated environment of proton exchange membrane fuel cells (PEMFCs), RMGO@Ti presents a corrosion current of < 10−6 A·cm−2, approximately two orders of magnitude lower than that of bare titanium. Furthermore, the interfacial contact resistance (ICR) of RMGO@Ti is as low as 4 mΩ·cm2, which is about one-thirtieth that of bare titanium. Therefore, RMGO@Ti appears very promising for use as BP in PEMFCs.

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