Abstract
The demand for hydrophobic polymer-based protective coatings to impart high corrosion resistance has increased recently. The increase of the hydrophobicity in a hybrid coating is a new challenge, for that reason and in order to protect a metallic surface of oxidant agents, a poly (methyl methacrylate) (PMMA) coating with the addition of a different amount of silicon dioxide (SiO2) was developed. The hybrid coating was applied on a sample of stainless steel AISI 304 by the dip-coating method. The characterization of the coatings was determined by electrochemical impedance spectroscopy and with a scanning electrochemical microscopy. The best coatings were PMMA and PMMA + SiO2 0.01% that exhibits a real impedance in the Nyquist diagram of 760 and 427,800 MΩ⋅cm2, respectively, and the modulus of the real impedance in the Bode diagram present values of 2.2 × 108 and 3.3 × 108 Ω⋅cm2. Moreover, the phase angle presents constant values around 75° to 85° and 85° for the PMMA and PMMA + SiO2 0.01%, respectively. Moreover, the values of the real resistance for the PMMA + SiO2 0.01% coating present values in the order of Mega-ohms despite the coating exhibits an artificial defect in their surface. The contact angle test showed that the hydrophobicity of the hybrid PMMA + SiO2 0.01% coating is higher than that of the pure PMMA coatings. The hybrid PMMA + SiO2 coatings developed in this work are a very interesting and promising area of study in order to develop efficient products to protect metallic surfaces from corrosion phenomenon.
Highlights
Materials used in marine environments are subject to chemical, physical, and biological deterioration that can accelerate the degradation of structural materials
The maximum of the of the improve the barrier effect over the coating but if the amount of 2 increases above 0.01% with real impedance were 2.2 × 10 and 3.3 × 10 Ω·cm for poly(methyl methacrylate) (PMMA) and PMMA + SiO2 0.01%, respectively, respect to PMMA, the of the coating could be theta affected, such as the adherence of the at the frequency value of properties
The results of total impedance, modulus of the real impedance, as well as the shape of the Nyquist and Bode diagrams, show that the addition of nanoparticles of SiO2 into the PMMA matrix improve the barrier effect over the coating but if the amount of SiO2 increases above 0.01% with respect to PMMA, the properties of the coating could be affected, such as the adherence of the coating on the metallic sheet that results from an increment of the porosity over the coating that, in some cases, exposes the metallic substrate to the electrolyte
Summary
Materials used in marine environments are subject to chemical, physical, and biological deterioration that can accelerate the degradation of structural materials. The corrosion behavior is one of the most destructive phenomena for marine structures steel and their alloys, and it is the electrochemical oxidation of the metal [1]. In the presence of chloride anion, the pitting corrosion causes failure in equipment due to the damage, but it only produces a small percentage of weight loss of the structure [2]. The hole begins its formation when there is a defect in a protective film (oxide or organic coating), that results in the formation of an electrochemical cell. This is an autocatalytic process that occurs within the hole. The most viable option is preventing interaction (physical barrier) between the metal substrate (anode) and the dissolution that contains the corrosion agents (electrolyte) [8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
