Smart PMMA‑cerium oxide anticorrosive coatings: Effect of ceria content on structure and electrochemical properties

Harb, Samarah Vargas; Rodrigues, Mariana S.; Souza, Thiago Alves de; Trentin, Andressa; Uvida, Mayara Carla; Pochapski, Daniel José; Pulcinelli, Sandra Helena; Santilli, Celso Valentim; Hammer, Peter

doi:10.1016/j.porgcoat.2021.106548

Cited by 5 publications

(3 citation statements)

References 55 publications

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“…This behavior could also be associated with the separation of microphases during the formation of hybrids at higher concentrations of SiO 2 NPs . Similar behavior has been observed for other hybrids …”

Section: Resultssupporting

confidence: 78%

“…The value of D f = 2.1 suggested that the silica NPs interacted with the HSD phase to form more branched and less compacted structures. Similar behavior has been observed for silica NPs in poly(vinyl alcohol) (PVA) matrices and other organic–inorganic hybrids. ,− The presence of a non-adsorbed polymer on the surface of SiO 2 NPs gives rise to depletion of attraction forces that become stronger as the solvent evaporates, leading to aggregation of the NPs at a later stage …”

Section: Resultsmentioning

confidence: 53%

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Effects of Curing Temperature and Silica Content on the Structure and Properties of a Sol–Gel PU-Silica Hybrid Coating for Corrosion Protection

Braz

Pochapski

Pulcinelli

et al. 2023

ACS Appl. Eng. Mater.

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Adjustments of the curing temperature and silica content were used to improve the corrosion protection properties of an organic−inorganic hybrid (OIH) coating based on a polyurethane-silica (SPU) system. Fourier transform infrared and nuclear magnetic resonance ( 13 C and 29 Si NMR) spectroscopy analyses revealed the conversion of urethane groups to secondary amines, with concomitant condensation of Si−R to Si−O−Si, when the curing temperature was increased, while small-angle Xray scattering analysis showed the formation of denser and less branched aggregates of the inorganic framework. The silica content influenced the roughness and thickness of the coatings, with values in the ranges 1.6−9.6 nm and 1.7−6.5 μm, respectively. All the hybrid coatings deposited on steel presented impedance modulus at the lowest frequency (|Z 5 |) above 0.1 GΩ cm 2 throughout the 28 days of analysis. The SPU coating prepared using a TEOS/ APTES ratio of 1 and a curing temperature of 167 °C presented the best performance as a corrosion protection barrier, characterized by predominant capacitive behavior and the invariance of |Z 5 | over 10 GΩ cm 2 .

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Section: Resultssupporting

confidence: 78%

Section: Resultsmentioning

confidence: 53%

Effects of Curing Temperature and Silica Content on the Structure and Properties of a Sol–Gel PU-Silica Hybrid Coating for Corrosion Protection

Braz

Pochapski

Pulcinelli

et al. 2023

ACS Appl. Eng. Mater.

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“…After 21 days of immersion, the corrosion resistance exceeded that of the scratched AA7075 reference by two orders of magnitude. The recovery is also evident from the evolution of the phase angle profile, showing the raise in the time constant at about 10 Hz, which is usually attributed to the formation of a stable passive layer [23,27,28]. The EIS data were fitted using an electrical equivalent circuit (EEC) composed of a solution resistance (R s ) in series with RC elements related to three time constants (Figure 9c).…”

Section: Electrochemical Barrier Propertiesmentioning

confidence: 99%

Green-High-Performance PMMA–Silica–Li Barrier Coatings

Trentin

Chagas

Uvida

et al. 2022

CMD

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Organic-inorganic coatings based on polymethyl methacrylate (PMMA)–silica–lithium are an efficient alternative to protect metals against corrosion. Although the preparation methodology is established and the thin coatings (~10 µm) are highly protective, the use of an environmentally friendly solvent has not yet been addressed. In this work, PMMA–silica coatings were synthesized using 2-propanol as a solvent and deposited on aluminum alloy AA7075, widely used in the aeronautical industry. Different concentrations of lithium carbonate (0–4000 ppm) were incorporated into the hybrid matrix to study the structural and inhibitive effects of Li+ in terms of barrier efficiency of the coatings in contact with saline solution (3.5% NaCl). Structural and morphological characterization by low-angle X-ray scattering, X-ray photoelectron spectroscopy, atomic force microscopy, thermogravimetric analysis, thickness, and adhesion measurements, showed for intermediate lithium content (500–2000 ppm) the formation of a highly polymerized PMMA phase covalently cross-linked by silica nodes, which provide strong adhesion to the aluminum substrate (15 MPa). Electrochemical impedance spectroscopy (EIS) results revealed an excellent barrier property in the GΩ cm2 range and durability of more than two years in a 3.5% NaCl solution. This performance can be attributed to the formation of a highly reticulated phase in the presence of Li, which hinders the permeation of water and ions. Additionally, the self-healing ability of scratched samples was evidenced by EIS assays showing a fast Li-induced formation of insoluble products in damaged areas; thus, constituting an excellent eco-friendly solution for corrosion protection of aerospace components.

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Effect of Nb2O5 coating on the corrosion resistance of the 7050-T7451 aluminium alloy

Ferreira,

Teixeira,

Leite

et al. 2023

emergent mater.

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The aircraft industry has been searching for new materials to be used in their aircrafts, which provide good mechanical and corrosive properties. The 7xxx series aluminium alloys are widely used in structural components. However, these alloys are susceptible to localised corrosion processes when exposed to an aggressive environment, which affect their lifetime and performance. Surface treatment appears as a powerful tool to improve the corrosion resistance of these alloys, since the coating may act as a protective physical barrier. This work aims to present an innovative and applied research for the development of the Nb2O5 thin films on the 7050-T7451 aluminium alloy surface by using the reactive sputtering technique. The open circuit potential, potentiodynamic polarization, electrochemical impedance spectroscopy as well as immersion tests were used to access the corrosion behaviour of the 7050-T7451 aluminium alloy in 0.6 mol L -1 NaCl solution. The morphology of the coated and uncoated specimens was verified by using optical microscopy, AFM and SEM/EDX techniques. Results demonstrated a difference of about 315 mV between the pitting potential (Epitting) and corrosion potential (Ecorr) for the coated material, indicating the positive effect of Nb2O5 thin films on the corrosion resistance of the alloy. In addition, EIS results displayed the reactive sputtering technique was advantageous, since the impedance modulus increased significantly.

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Smart PMMA‑cerium oxide anticorrosive coatings: Effect of ceria content on structure and electrochemical properties

Cited by 5 publications

References 55 publications

Effects of Curing Temperature and Silica Content on the Structure and Properties of a Sol–Gel PU-Silica Hybrid Coating for Corrosion Protection

Effects of Curing Temperature and Silica Content on the Structure and Properties of a Sol–Gel PU-Silica Hybrid Coating for Corrosion Protection

Green-High-Performance PMMA–Silica–Li Barrier Coatings

Effect of Nb2O5 coating on the corrosion resistance of the 7050-T7451 aluminium alloy

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