| XIAO Yao,HE Xiaoyan,WAN Tao,BAI Xiuqin.Preparation and Corrosion Resistance Analysis of Modified Cerium Oxide/Waterborne Epoxy Composite Coatings[J],53(14):96-105, 189 |
| Preparation and Corrosion Resistance Analysis of Modified Cerium Oxide/Waterborne Epoxy Composite Coatings |
| Received:August 24, 2023 Revised:December 29, 2023 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2024.14.008 |
| KeyWord:cerium oxide polyaniline waterborne epoxy composite coatings corrosion resistance |
| Author | Institution |
| XIAO Yao |
Hubei Longzhong Laboratory, Hubei Xiangyang , China;a.State Key Laboratory of Maritime Technology and Safety, b.School of Transportation and Logistics Engineering, Wuhan University of Technology, Wuhan , China |
| HE Xiaoyan |
Hubei Longzhong Laboratory, Hubei Xiangyang , China;a.State Key Laboratory of Maritime Technology and Safety, b.School of Transportation and Logistics Engineering, Wuhan University of Technology, Wuhan , China |
| WAN Tao |
Hubei Swan Coatings Co., Ltd., Hubei Xiangyang , China |
| BAI Xiuqin |
Hubei Longzhong Laboratory, Hubei Xiangyang , China;a.State Key Laboratory of Maritime Technology and Safety, b.School of Transportation and Logistics Engineering, Wuhan University of Technology, Wuhan , China |
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| Abstract: |
| The work aims to prepare waterborne composite coatings with modified cerium oxide nanoparticles to improve their corrosion resistance. The cerium oxide was modified by the coupling agent γ-Glycidoxypropyltrimethoxysilane (KH560) to obtain the silanized cerium oxide (CeO2-K), and then aniline was polymerized in-situ on the surface of CeO2-K particles to obtain the polyaniline/cerium oxide composite particles, with mass ratios of aniline to cerium oxide of 1∶1, 4∶1, 7∶1, respectively, and were named as PA@CeO2(1∶1), PA@CeO2(4∶1), and PA@CeO2(7∶1). CeO2-K composite waterborne epoxy coatings (CeO2-K/WEP) and PANI@CeO2 composite waterborne epoxy coatings (PA@CeO2(1:1)/WEP, PA@CeO2(4∶1)/WEP and PA@CeO2(7∶1)/WEP) were prepared. The structure and morphology of the modified nanoparticles were characterized by SEM, EDS, and FTIR. The SEM morphology analysis showed that the agglomeration of the CeO2-K particles was attenuated after modification, and the PA@CeO2 composite particles exhibited a 'spherical + fibrous' nanocomposite structure, and polyaniline was grafted and coated on the surface of CeO2-K particles. The EDS and FTIR analysis revealed that KH560 and polyaniline successfully grafted onto cerium oxide nanoparticles. The corrosion resistance of modified cerium oxide/waterborne epoxy composite coatings was investigated from different aspects including SEM morphology analysis from surfaces and cross sections, EDS analysis, and LSCM morphology analysis, scratch test, water absorption test, electrochemical test and neutral salt spray test. SEM and LSCM morphology analysis indicated that the nanocomposite coating exhibited enhanced densification without any discernible voids compared with waterborne epoxy coatings, indicating effective hole-filling by nanoparticles. The densification and impermeability of PA@CeO2(4∶1)/WEP coatings was further confirmed through a water absorption test, revealing its exceptionally low water penetration rate of 1.72%. Additionally, the scratch test results, with a grade of 0, indicated that PA@CeO2 added epoxy waterborne coatings exhibited superior bonding properties with the substrate. After 30 d of immersion, the bode plot of impedance spectrum revealed that PA@CeO2(4∶1)/WEP coatings exhibited the highest impedance modulus at the lowest frequency of 0.01 Hz. Remarkably, this impedance modulus was found to be 2.4 times greater than that of CeO2-K/WEP coatings and two orders of magnitude higher than WEP coatings. The equivalent circuit fitting analysis showed that the coating resistance of PA@CeO2(4∶1)/WEP coatings was consistently higher than that of the other nanocomposite coatings, and could still be stably maintained above 107 Ω.cm2 under long time immersion. The charge transfer resistance of nanocomposite coatings was much higher than that of WEP coatings, roughly 20 times higher than that of WEP coatings. After 336 h of salt spray test, both WEP and CeO2-K/WEP coatings exhibited noticeable corrosion and peeling. The peeling width at scratches of WEP coatings was the largest, and that of CeO2-K/WEP coatings was narrower than that of WEP coatings, which was about 6.5 mm. However, PA@CeO2/WEP coatings demonstrated the narrowest peeling width of 4 mm at the scratch, and the peeling area remained stable without expanding throughout the duration of the experiment. The aforementioned series of experimental results has demonstrated that PA@CeO2/WEP composite coatings exhibit optimal corrosion resistance performance compared with WEP and CeO2-K/WEP coatings. |
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