The protective and adhesion properties of silicone-epoxy hybrid coatings on 2024 Al-alloy with a silane film as pretreatment

“…where "Y 0 " is the CPE constant, "ω" is the angular frequency, "j" is the imaginary number, and "n" is the CPE power. The values of capacitances, C c and C t , were calculated from the following equations [35]:…”

Section: Electrochemical Impedance Spectroscopy (Eis) Analysismentioning

confidence: 99%

“…C c is considered to be related to the water resistance of the coatings and R c represents the total resistance of the electrolyte in the micro pores or capillary channels [30]. R t and C t measure the total number of active sites for electrochemical corrosion reactions at the metal/electrolyte interface, reflecting the development of a double-layer at the metal/electrolyte interface and the progress of the corrosion reaction [35]. Lower C c , C t and higher R c , R t values indicate the better corrosion resistance of the coating.…”

Section: Electrochemical Impedance Spectroscopy (Eis) Analysismentioning

confidence: 99%

Influence of Sealing Treatment on the Corrosion Resistance of PEO Coated Al-Zn-Mg-Cu Alloy in Various Environments

et al. 2019

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In the present work, a coating was prepared on an Al alloy substrate by plasma electrolytic oxidation (PEO). To seal the micro defects in the oxide scale, a siloxane layer was prepared on the PEO coating by sol gel method. The polymer sealant was synthesized from Tetraethoxy silane (TEOS) and methacryloxy propyl trimethoxyl silane (MPTES). The chemical structure of the polymer was studied by Fourier transform infrared spectroscopy (FTIR). The morphologies and microstructure of the PEO coating and siloxane coating were investigated by scanning electron microscopy (SEM). The results showed that siloxane formed a continuous layer on the surface and effectively sealed the micro defects. The corrosion behavior of the coatings in three different corrosion solutions (NaCl, HCl, and NaOH) was examined by electrochemical impedance spectroscopy and potentiodynamic polarization. The corrosion resistance of the sealed coatings was superior to that of the PEO coating because it prevented the penetration of corrosive solutions. The corrosion resistance of the sealed coatings was found to decrease with increasing electrolyte concentration. The work demonstrated that siloxane sealing may greatly enhance the corrosion resistance of Al-based PEO coating in acidic, neutral, and alkaline environments.

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“…Epoxy prepolymers are widely used in coatings and adhesives because of their ease of processing, low shrinkage upon curing, good thermal and mechanical stability, high resistance to solvents, and promising anticorrosive properties . Amine curatives and reactive amidoamines are popular building blocks for matrices in two component epoxy coatings .…”

Section: Introductionmentioning

confidence: 99%

Amidoamine: Synthesis, disparity in cure with epoxy resins between bulk and solvent systems, and structure–property relationships of its epoxy‐based coatings

Pramanik

Early

Wand

et al. 2018

Polymer Engineering & Sci

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Amidoamines are widely used as crosslinkers for epoxy resins in protective coatings on metal substrates; however, their cure chemistry is not well elaborated in the technical literature. During cure, the epoxy–amine and epoxy–amide NH reactions could be accompanied by epoxy–hydroxyl etherification, epoxy–epoxy homopolymerization, and reaction between hydroxyls and amide moiety to form in situ ester and amine. To understand the epoxy–amidoamine cure chemistry and correlate it with coating performance properties, amidoamines of known structure are required. Therefore, amidoamines were synthesized by reacting dimer fatty acids with diethylene triamine. When these amidoamines were cured with epoxy resins, discrepancies were observed between systems cured at ambient and thermal conditions. The presence of solvents were seen to greatly affect the rate of epoxy–amidoamine cure at ambient, and before and after vitrification. Near‐IR and mid‐IR spectroscopy studies indicated that side reactions occurred to some extent during cure. No reaction was noted between the amide NH moiety and the epoxide group below 150°C whereas ester formation was noted above 120°C. Solvent‐based clear epoxy–amidoamine coatings formulated at an epoxy:amine equivalent ratio 1.15 passed basic organic coatings evaluation tests. POLYM. ENG. SCI., 59:E69–E81, 2019. © 2018 Society of Plastics Engineers

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The protective and adhesion properties of silicone-epoxy hybrid coatings on 2024 Al-alloy with a silane film as pretreatment

Cited by 48 publications

References 37 publications

In vitro degradation and cytocompatibility of a silane/Mg(OH) 2 composite coating on AZ31 alloy by spin coating

In vitro degradation and cytocompatibility of a silane/Mg(OH) 2 composite coating on AZ31 alloy by spin coating

Influence of Sealing Treatment on the Corrosion Resistance of PEO Coated Al-Zn-Mg-Cu Alloy in Various Environments

Amidoamine: Synthesis, disparity in cure with epoxy resins between bulk and solvent systems, and structure–property relationships of its epoxy‐based coatings

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