| XIE Xinyuan,XU Chenkai,DONG Yanhao,ZOU Minmin,ZHANG You.Corrosion Warning Coating of Mg Alloys Based on Boron-doped Carbon Dots and Its Properties[J],54(8):64-73 |
| Corrosion Warning Coating of Mg Alloys Based on Boron-doped Carbon Dots and Its Properties |
| Received:July 01, 2024 Revised:October 12, 2024 |
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| DOI：10.16490/j.cnki.issn.1001-3660.2025.08.005 |
| KeyWord:boron-doped carbon quantum dots Mg alloys micro-arc oxidation sol-gel anti-corrosion corrosion warning |
| Author | Institution |
| XIE Xinyuan |
School of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing , China |
| XU Chenkai |
School of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing , China |
| DONG Yanhao |
School of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing , China |
| ZOU Minmin |
School of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing , China |
| ZHANG You |
School of New Materials and Chemical Engineering, Beijing Institute of Petrochemical Technology, Beijing , China |
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| Abstract: |
| To enhance the corrosion resistance of Mg alloys, achieve effective corrosion warning, extend their service life, and monitor their service status, a Micro-Arc Oxidation-Sol-Gel-Boron-doped Carbon Dots (MAO-SG-BCDs) composite coating with advanced corrosion warning capability was developed on an AZ91D Mg alloy matrix. This was accomplished by incorporating Boron-doped Carbon Dots (BCDs) with high selectivity for Mg2+, ensuring targeted and efficient functionality. The structure, composition, and fluorescence properties of the BCDs, in relation to Mg2+ and the corroded surface of the Mg alloys, were meticulously studied with advanced analytical techniques such as Fourier transform infrared spectroscopy, Raman spectroscopy, and fluorescence spectroscopy. The structure and properties of the composite coating were comprehensively analyzed by X-ray diffraction, scanning electron microscopy, fluorescence microscopy, and electrochemical testing, providing a robust dataset for evaluation. The experimental results demonstrated that after a 7 d immersion in 3.5wt.% NaCl solution, the composite coating embedded with BCDs was denser and more uniform, exhibiting a higher impedance value in the low-frequency region compared to the sample without BCDs. This denser and more uniform structure indicated a more effective barrier against corrosive agents. The high impedance value in the low-frequency region is a crucial indicator of the ability of the coating to resist the ingress of corrosive ions, thereby prolonging the durability of the material in harsh environments. Furthermore, the MAO-SG-BCDs coating showed a significant increase in corrosion potential, and the corrosion current density and corrosion rate were reduced by two orders of magnitude, indicating that the incorporation of BCDs substantially enhanced the corrosion resistance of the coating. As immersion time increased, the surface of the MAO-SG-BCDs coating gradually exhibited blue fluorescence, in stark contrast to the MAO-SG coating sample that did not contain BCDs. This clear and observable response was attributed to the aggregation of BCDs, leading to strong complex formation between Mg2+ and the hydroxyl and phenolic oxygen atoms of the BCDs. This fluorescence provided a reliable method for real-time monitoring and early detection of corrosion, contributing to the development of smart anti-corrosion technologies. The blue fluorescence signal acted as an early warning system, indicating the onset of corrosion before significant material degradation occurred, thus enabling timely maintenance and intervention. XPS testing results indicated that, after 7 d of immersion, signals from BCO2 and BC2O were present in the BCDs-doped sample, confirming that physical adsorption occurred on the MAO layer of the Mg alloys, resulting in the formation of an adsorption film that effectively inhibited the erosion of the corrosive medium. The presence of these signals proved that BCDs were not only uniformly distributed within the coating but also actively engaged in the corrosion prevention process. The XPS spectra provided detailed insights into the chemical states of the elements within the coating, further validating the protective role of BCDs. BCDs function as fluorescent probe materials for corrosion warning in Mg alloys. When incorporated into MAO and sol-gel composite coatings, they significantly enhance the corrosion resistance of AZ91D Mg alloy while simultaneously providing a fluorescent warning response for substrate corrosion. This innovative approach not only improves the protective capabilities of the coating but also allows for real-time monitoring of corrosion processes. The findings of this research offer valuable new perspectives for the development of effective corrosion warning materials and smart anti-corrosion coatings specifically designed for Mg alloys. |
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