Epoxy Coatings Doped with (3-Aminopropyl)triethoxysilane-Modified Silica Nanoparticles for Anti-Corrosion Protection of Zinc
Abstract
:1. Introduction
2. Materials and Methods
2.1. Materials
2.2. Methods
2.3. Functionalization of the SiO2 Nanoparticles
2.4. Coatings’ Preparation
3. Results and Discussion
3.1. Characterization of the Silica Nanoparticles
3.2. Coatings Characterization
3.2.1. Thickness Measurements
3.2.2. Adhesion Tests
3.2.3. Contact Angle Measurements
3.2.4. Scanning Electron Microscopy (SEM)
3.3. Electrochemical Investigation of the Coatings
4. Conclusions
- The modification of silica NPs with APTES was put in evidence by using FT-IR and TEM. FT-IR spectra confirmed that the APTES molecules attached to the terminal oxygens of SiO2, forming terminal -NH2 groups. The TEM images demonstrated that during the modification with APTES, the particle size decreased by approximately half.
- The composite structure was confirmed via SEM/EDS analysis, which exhibited the presence of SiO2 and its dispersion in the EP matrix.
- The electrochemical measurements performed using the EIS and PDP methods revealed the enhanced protective effect of the composite layers against Zn corrosion and their improved stability. This can be attributed to the NPs filling the pores of the EP, thereby extending the diffusion path of the corrosive medium.
- Although all nanocomposite coatings, regardless of the filler, showed superior characteristics compared to neat EP coatings, modification of the SiO2 NPs with APTES followed by their introduction into the epoxy resin (method I) led to weaker results than the deposits prepared through functionalization of the SiO2 NPs in the epoxy gel before the addition of the hardener (method II).
- The composite EP-SiO2 NP coatings are more suitable as protective layers than plain EP coatings; the first ones are more uniform, more adherent and less hydrophilic than the latter, being at the same time responsible for the better anti-corrosion properties of the coatings.
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Sample | EP | EP-SiO2 | EP-SiO2-APTES (I) | EP-SiO2-APTES (II) |
---|---|---|---|---|
0 min | 70° | 70° | 74° | 83° |
After 30 min | 56° | 58° | 64° | 74° |
Sample | Zn | EP | EP-SiO2 | EP-SiO2-APTES (I) | EP-SiO2-APTES (II) |
---|---|---|---|---|---|
|Z|0.01Hz (kΩ) | 1.67 | 2.14 × 103 | 3.72 × 103 | 5.58 × 103 | 8.95 × 103 |
Sample | Rs | 103 × Qcoat | n | Rcoat | 101 × Qdl | n | Rct | Rp = Rcoat + Rct | 103 × Chi2 |
---|---|---|---|---|---|---|---|---|---|
(kΩ cm2) | (μSsn) | (kΩ cm2) | (μSsn) | (kΩ cm2) | (kΩ cm2) | ||||
Zn | 0.01 | - | - | - | 731.0 | 0.8 | 1.20 | 1.20 | 7.63 |
Zn/EP | 0.39 | 15.80 | 0.8 | 1789 | 0.019 | 0.9 | 428 | 2217 | 3.09 |
Zn/EP-SiO2 | 1.40 | 7.630 | 0.8 | 497 | 2.590 | 0.6 | 2918 | 3415 | 7.15 |
Zn/EP-SiO2-APTES (I) | 1.32 | 0.940 | 0.9 | 1176 | 1.300 | 0.7 | 6042 | 7218 | 6.87 |
Zn/EP-SiO2-APTES (II) | 1.41 | 0.613 | 1 | 1171 | 0.524 | 0.7 | 7014 | 8185 | 9.10 |
Sample | 0 min | 2 h | 1 Day | 2 Day |
---|---|---|---|---|
EP | ||||
|Z|0.01Hz (Ω) | 2.09 × 106 | 1.01 × 105 | 1.99 × 104 | 8.40 × 103 |
EP-SiO2 | ||||
|Z|0.01Hz (Ω) | 2.14 × 106 | 2.86 × 105 | 1.85 × 105 | 6.01 × 104 |
EP-SiO2-APTES (I) | ||||
|Z|0.01Hz (Ω) | 4.58 × 106 | 1.05 × 106 | 2.11 × 105 | 1.90 × 105 |
EP-SiO2-APTES (II) | ||||
|Z|0.01Hz (Ω) | 7.16 × 106 | 2.73 × 106 | 4.80 × 105 | 2.18 × 105 |
Sample | Ecorr (V vs. Ag/AgCl/KClsat) | icorr (µA/cm2) | ba (V/dec) | bc (V/dec) | IE (%) |
---|---|---|---|---|---|
Zn | −1.00 | 37.10 | - | 0.018 | - |
Zn/EP | −0.97 | 3.84 | - | 0.025 | 89 |
Zn/EP-SiO2 | −0.95 | 2.05 | 1.06 | 0.023 | 94 |
Zn/EP-SiO2-APTES (I) | −0.93 | 0.95 | 0.56 | 0.043 | 97 |
Zn/EP-SiO2-APTES (II) | −0.92 | 0.75 | - | 0.058 | 98 |
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Ovari, T.-R.; Toth, T.; Katona, G.; Szabó, G.S.; Muresan, L.M. Epoxy Coatings Doped with (3-Aminopropyl)triethoxysilane-Modified Silica Nanoparticles for Anti-Corrosion Protection of Zinc. Coatings 2023, 13, 1844. https://doi.org/10.3390/coatings13111844
Ovari T-R, Toth T, Katona G, Szabó GS, Muresan LM. Epoxy Coatings Doped with (3-Aminopropyl)triethoxysilane-Modified Silica Nanoparticles for Anti-Corrosion Protection of Zinc. Coatings. 2023; 13(11):1844. https://doi.org/10.3390/coatings13111844
Chicago/Turabian StyleOvari, Tamara-Rita, Timea Toth, Gabriel Katona, Gabriella Stefánia Szabó, and Liana Maria Muresan. 2023. "Epoxy Coatings Doped with (3-Aminopropyl)triethoxysilane-Modified Silica Nanoparticles for Anti-Corrosion Protection of Zinc" Coatings 13, no. 11: 1844. https://doi.org/10.3390/coatings13111844