scholarly journals Perfect Combination of LBL with Sol–Gel Film to Enhance the Anticorrosion Performance on Al Alloy under Simulated and Accelerated Corrosive Environment

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 111 ◽  
Author(s):  
Xia Zhao ◽  
Shuai Yuan ◽  
Zuquan Jin ◽  
Binbin Zhang ◽  
Nazhen Liu ◽  
...  
Keyword(s):  
Salt Spray ◽  
Sol Gel ◽  
Chloride Ions ◽  
Al Alloy ◽  
Layer By Layer ◽  
Neutral Salt ◽  
Multilayered Coatings ◽  
Multilayered Coating ◽  
Gel Film ◽  
Anticorrosion Performance

Given their outstanding versatile properties, multilayered anticorrosion coatings have drawn great interest from researchers in the academic and engineering fields. However, the application of multilayered coatings is restricted by some limitations such as low interlayer compatibilities, the harsh preparation process, etc. This work introduced a composite film fabricated on a 2A12 aluminum alloy surface, including an anodic oxide film, a sol–gel film, and a layer-by-layer (LBL) self-assembling film from bottom to top. The microstructure and elemental characterization indicated that the finish of the coating with the LBL film resulted in a closely connected multilayered coating with a smoother surface. The anticorrosion performance was systematically evaluated in the simulated corrosive medium and neutral salt spray environment. The integrated coating with the LBL film presented an excellent anticorrosion ability with system impedance over 108 Ω·cm2 and a self-corrosion current density two orders of magnitude lower than that of the other coatings. After the acceleration test in a salt spray environment, the multilayered coatings could still show a good protective performance with almost no cracks and no penetration of chloride ions. It is believed that the as-constructed multilayered coating with high corrosive properties and a fine surface state will have promising applications in the field of anticorrosion engineering.

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%.

Effect of coating composition on the anticorrosion performance of a silane sol–gel layer on mild steel

RSC Advances ◽  
2015 ◽  
Vol 5 (129) ◽  
pp. 106485-106491 ◽  
Author(s):  
A. Foroozan E. ◽  
R. Naderi
Keyword(s):  
Mild Steel ◽  
Electrochemical Impedance ◽  
Steel Substrate ◽  
Sol Gel ◽  
Gel Layer ◽  
Gel Film ◽  
Coating Composition ◽  
Anticorrosion Performance ◽  
Protective Performance ◽  
Mild Steel Substrate

In this study, the effect of coating composition on the protective performance of an eco-friendly silane sol–gel film applied on a mild steel substrate was investigated using electrochemical impedance spectroscopy and surface analysis methods.

scholarly journals Ultrasonic Sensors-Assisted Corrosion Studies on Surface Coated AlSi9Cu3 Alloy Die Castings

Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85
Author(s):  
Yuh-Chung Hu ◽  
Senthil Kumaran Selvaraj ◽  
Manivannan Subramanian ◽  
Kathiravan Srinivasan ◽  
Srinivasan Narayanan
Keyword(s):  
Corrosion Resistance ◽  
Die Casting ◽  
Pure Aluminum ◽  
Salt Spray ◽  
Salt Spray Test ◽  
Al Alloy ◽  
Neutral Salt ◽  
Powder Coatings ◽  
Acrylic Paint ◽  
Epoxy Primer

A novel phenomenon known as Industry X.0 is becoming extremely popular for digitizing and reinventing business organizations through the adaption of rapid and dynamic technological, innovational, and organizational changes for attaining the profitable revenue. This work investigates the die-casted commercially pure aluminum alloyed with 9% silicon and 3% copper (AlSi9Cu3) that is produced through the gravity die casting process. Further, the degradation of surface coating on die-casted AlSi9Cu3 alloy was explored. The acrylic paint electrodeposition (ED) coat, 2-coat polyester without primer and 3-coat polyester with epoxy primer powder coatings were used in this study. Moreover, the 3.5 wt.% of sodium chloride (3.5 wt.% of NaCl) test solution was used for electrochemical and salt spray test and the tools used to assess electrochemical properties were electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and neutral salt spray test (NSS). The microstructure of AlSi9Cu3 after corrosion exposure was investigated; also, the microstructure of coated and uncoated AlSi9Cu3 samples was analyzed by SEM microscopy after corrosion exposure. Besides, the electrochemical studies were also carried out on the Al alloy die casting. It was found that acrylic paint ED coatings exhibited higher corrosion resistance than 2-coat polyester without primer & 3-coat polyester with epoxy primer powder coatings. Acrylic paint ED coating showed higher corrosion resistance in AC and a lower value in DC and 3-coat polyester with epoxy primer powder coating displayed higher corrosion resistance in DC and a lower value in AC.

scholarly journals The Durability of an Organic–Inorganic Sol–Gel Interlayer in Al-GFRP-CFRP Laminates in a Saline Environment

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2362 ◽  
Author(s):  
Barbara Surowska ◽  
Monika Ostapiuk ◽  
Patryk Jakubczak ◽  
Magda Droździel
Keyword(s):  
Aluminum Alloy ◽  
Salt Spray ◽  
Sol Gel ◽  
Exposure Period ◽  
Open Circuit ◽  
Fiber Reinforced Polymers ◽  
Metal Composite ◽  
Neutral Salt ◽  
Fiber Reinforced ◽  
Ambient Temperatures

The aim of the study was to assess the selected properties of a hybrid organic–inorganic silane sol–gel coating (HSG) used in hybrid fiber metal laminates (FML) in a corrosion environment. The HSG coating on the aluminum alloy was produced using 3M™ AC130-2 formulation consisting of 3-glycidoxypropyl-trimethoxysilane (GPTMS) and tetra-n-propoxyzirconium (zirconium(IV) propoxide) (TPOZ). Laminates consisted of aluminum alloy AA2024-T3 sheets, with carbon fiber reinforced polymers (CFRPs) and a glass fiber reinforced metal–composite structure (GFRP). Potentiodynamic and polarization curve and impedance (EIS) tests were carried out on HSG at ambient temperatures after 1 h and 150 h of soaking. Neutral 0.5 M NaCl and 0.8 M NaCl solutions were used for open circuit potential (OCP) and potentiodynamic tests, and 0.5 NaCl was used for the EIS test. A neutral salt spray (NSS) test was applied to laminates with a 12 week exposure period. The results obtained revealed that the HSG coating did not provide sufficient protection against corrosion of the aluminum alloy in direct contact with an aggressive environment but was effective as an interlayer. Local aluminum sheet perforation did not lead to delamination at the metal–composite interface regardless of the type or configuration of the composite. This confirms the durability of HSG used in FMLs.

Influence of Surface Finishing on Corrosion Behaviour of Mg-Al Hydrotalcite Doped Hybrid Sol-Gel Coatings on Al Alloy in Saline Environment

2010 ◽  
Vol 636-637 ◽  
pp. 1004-1010 ◽  
Author(s):  
D. Álvarez ◽  
A. Collazo ◽  
Miguel Hernández ◽  
Xosé R. Nóvoa ◽  
C. Pérez
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Sol Gel ◽  
Barrier Properties ◽  
Dip Coating ◽  
Surface Finishing ◽  
Al Alloy ◽  
Gel Film ◽  
Aa 2024 ◽  
Surface Morphologies

The behaviour of hybrid sol-gel coatings doped with hydrotalcite-like compound applied on AA2024-T3 alloy was investigated in the present work. The hybrid sol-gel coatings were prepared by copolymerization of 3-Glycydoxypropyltrimethoxysilane (GPTMS) and tetra-n-propoxyzirconium (TPOZ). Three different surface finishing on the aluminium alloy AA-2024-T3, grounded, chemical etching and degreased were studied. A sol-gel film with hydrotalcite 5% w/w was deposited by dip coating procedure. The presence of hydrotalcite particles was confirmed by means of X-ray diffraction technique. The different surface morphologies were characterised using mechanical profilometry. The corrosion resistance properties were studied by means of electrochemical impedance spectroscopy and salt fog spray cabinet. The results show higher barrier properties in grounded aluminium substrates.

scholarly journals Design and Multidimensional Screening of Flash-PEO Coatings for Mg in Comparison to Commercial Chromium(VI) Conversion Coating

Metals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 337
Author(s):  
Ewa Wierzbicka ◽  
Marta Mohedano ◽  
Endzhe Matykina ◽  
Raul Arrabal
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Protection ◽  
Electrochemical Impedance ◽  
Salt Spray ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Chromium Vi ◽  
Alkaline Electrolytes ◽  
Az31b Alloy ◽  
Plasma Electrolytic

REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) regulations demand for an expedient discovery of a Cr(VI)-free alternative corrosion protection for light alloys even though the green alternatives might never be as cheap as current harmful technologies. In the present work, flash- plasma electrolytic oxidation coatings (FPEO) with the process duration < 90 s are developed on AZ31B alloy in varied mixtures of silicate-, phosphate-, aluminate-, and fluoride-based alkaline electrolytes implementing current density and voltage limits. The overall evaluation of the coatings’ anticorrosion performance (electrochemical impedance spectroscopy (EIS), neutral salt spray test (NSST), paintability) shows that from nine optimized FPEO recipes, two (based on phosphate, fluoride, and aluminate or silicate mixtures) are found to be an adequate substitute for commercially used Cr(VI)-based conversion coating (CCC). The FPEO coatings with the best corrosion resistance consume a very low amount of energy (~1 kW h m−2 µm−1). It is also found that the lower the energy consumption of the FPEO process, the better the corrosion resistance of the resultant coating. The superb corrosion protection and a solid environmentally friendly outlook of PEO-based corrosion protection technology may facilitate the economic justification for industrial end-users of the current-consuming process as a replacement of the electroless CCC process.

scholarly journals Application of Commercial Surface Pretreatments on the Formation of Cerium Conversion Coating (CeCC) over High-Strength Aluminum Alloys 2024-T3 and 7075-T6

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 930
Author(s):  
Juan Jesús Alba-Galvín ◽  
Leandro González-Rovira ◽  
Francisco Javier Botana ◽  
Maria Lekka ◽  
Francesco Andreatta ◽  
...  
Keyword(s):  
Electrochemical Impedance ◽  
Salt Spray ◽  
Aluminum Matrix ◽  
Optical Emission ◽  
High Strength ◽  
Chemical Conversion ◽  
Conversion Coating ◽  
Neutral Salt ◽  
Corrosion Properties ◽  
Surface Pretreatment

The selection of appropriate surface pretreatments is one of the pending issues for the industrial application of cerium-based chemical conversion coatings (CeCC) as an alternative for toxic chromate conversion coating (CrCC). A two-step surface pretreatment based on commercial products has been successfully used here to obtain CeCC on AA2024-T3 and AA7075-T6. Specimens processed for 1 to 15 min in solutions containing CeCl3 and H2O2 have been studied by scanning electron microscopy coupled with energy-dispersive X-ray analysis (SEM-EDX), glow discharge optical emission spectroscopy (GDOES), potentiodynamic linear polarization (LP), electrochemical impedance spectroscopy (EIS), and neutral salt spray (NSS) tests. SEM-EDX showed that CeCC was firstly observed as deposits, followed by a general coverage of the surface with the formation of cracks where the coating was getting thicker. GDOES confirmed an increase of the CeCC thickness as the deposition proceed, the formation of CeCC over 7075 being faster than over 2024. There was a Ce-rich layer in both alloys and an aluminum oxide/hydroxide layer on 7075 between the upper Ce-rich layer and the aluminum matrix. According to LP and EIS, CeCC in all samples offered cathodic protection and comparable degradation in chloride-containing media. Finally, the NSS test corroborated the anti-corrosion properties of the CeCC obtained after the commercial pretreatments employed.

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
Sign in / Sign up

Export Citation Format

Share Document