Abstract
Pre-hydrolysed/condensed tetraethyl orthosilicate (TEOS) was added to a solution of methyl methacrylate (MMA) and 3-methacryloxypropyltrimethoxysilane (MAPTMS), and then copolymerised for various times to study the influence of the latter on the structure of hybrid sol-gel coatings as corrosion protection of aluminium alloy 7075-T6. The reactions taking place during preparation were characterised using real-time Fourier transform infrared spectroscopy, dynamic light scattering and gel permeation chromatography. The solution characteristics were evaluated, using viscosimetry, followed by measurements of thermal stability determined by thermogravimetric analysis. The optimal temperature for the condensation reaction was determined with the help of high-pressure differential scanning calorimetry. Once deposited on 7075-T6 substrates, the coatings were evaluated using a field emission scanning electron microscope coupled to an energy dispersive spectrometer to determine surface morphology, topography, composition and coating thickness. Corrosion properties were tested in dilute Harrison’s solution (3.5 g/L (NH4)2SO4 and 0.5 g/L NaCl) using electrochemical impedance spectroscopy. The copolymerization of MMA and MAPTMS over 4 h was optimal for obtaining 1.4 µm thick coating with superior barrier protection against corrosion attack (|Z10 mHz| ~ 1 GΩ cm2) during three months of exposure to the corrosive medium.
Highlights
Aluminium alloy (AA) 7075-T6, with Zn, Mg and Cu as major alloying elements, has excellent physical properties [1], such as low density and high strength
Considering the great potential of poly(methyl methacrylate) for various applications, we focused on the characterisation of each step of the synthesis to obtain high-yield copolymerization during well-controlled preparation
Hydrolysis and Condensation of tetraethyl orthosilicate (TEOS) Studied by Fourier transform infrared (FTIR) and dynamic light scattering (DLS)
Summary
Aluminium alloy (AA) 7075-T6, with Zn, Mg and Cu as major alloying elements, has excellent physical properties [1], such as low density and high strength It is often used in the aircraft industry as fuselage skin and wing spars [2]. The state-of-the-art in corrosion protection in the aerospace industry is comprised of a multi-layer system consisting of pre-treatment, primer and topcoat [13]. These components should exhibit proper functionality, presumably active corrosion protection that is able to prolong the lifespan of the device, part or construction made of aluminium alloys [14,15,16].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
