Study on Corrosion Resistance of Hydrophobic Coating Prepared on AH32 Steel by Plasma Spraying

KANG Hong-wei, CHEN Dong-xu, WANG Ya-nan, ZHOU Yan-wen, LYU Zhe, GAO Peng

Surface Technology ›› 2020, Vol. 49 ›› Issue (4) : 104-112.

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Surface Technology ›› 2020, Vol. 49 ›› Issue (4) : 104-112. DOI: 10.16490/j.cnki.issn.1001-3660.2020.04.013
Special Topic—Research and Application of Thermal Spraying Technology

Study on Corrosion Resistance of Hydrophobic Coating Prepared on AH32 Steel by Plasma Spraying

  • KANG Hong-wei1, CHEN Dong-xu1, WANG Ya-nan1, ZHOU Yan-wen1, LYU Zhe1, GAO Peng2
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Abstract

The work aims to improve the hydrophobic and corrosion resistance of AH32 marine steel and give the excellent composition of the coating with the best performance. Atmospheric plasma spraying was used to prepare three kinds of coatings with different compositions on the surface of AH32 steel. The contact angles of the coatings were measured by microsyringe with the method of hemisphere. The surface energy of the coatings were calculated using the Qwen-Wendt formula. The surface morphologies of the coatings were observed by the scanning electron microscope. The surface roughnesses of the coatings were measured by surface roughness meter. The corrosion resistances of different coatings were measured by the electrochemical workstation. The corresponding mechanisms of hydrophobic and corrosion of different coatings were also discussed. The results show that the hydrophobic properties of AH32 steel with coatings prepared by plasma spraying were improved significantly. In contrast, the static contact angle of Co-based coating and Ni-based coating with water were more than 130° and both coatings have excellent hydrophobic effect. Moreover, the seawater erosion resistances of AH32 steel with three coatings were improved significantly. The corrosion weight loss of AH32 steel substrate is about 1.68×10-2 g/cm2, and the corrosion weight loss of the Ni-based coating is the smallest, about 4.2×10-3 g/cm2. The polarization curve test results also show that the self-corrosion potential of the three coatings is about 300 mV higher than the substrate, and the corrosion current density is more than one order of magnitude lower than that of the substrate. In addition, the corrosion current density of the Co-based coating is higher than that of the Ni-based coating. Hydroxyl groups produced by Co-based coating corrosion process lead to the decrease of the static contact angle between Co-based coating and water and hydrophobic performance degradation of Co-based coating. Therefore, the plasma spraying Ni-based coating has the excellent hydrophobic, the smallest corrosion rate and the excellent erosion-corrosion resistance. Compared with that of the matrix, the corrosion weight loss of the plasma spraying Ni-based coating was reduced by 1.26×10-2 g/cm2.

Key words

AH32 steel; plasma spraying; hydrophobic coating; corrosion resistance

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KANG Hong-wei, CHEN Dong-xu, WANG Ya-nan, ZHOU Yan-wen, LYU Zhe, GAO Peng. Study on Corrosion Resistance of Hydrophobic Coating Prepared on AH32 Steel by Plasma Spraying[J]. Surface Technology. 2020, 49(4): 104-112

Funding

Supported by the Liaoning Provincial Natural Science Foundation (20180510001), Liaoning University of Science and Technology Talent Program (2018RC03), Liaoning Provincial Department of Education Project (SKLMEA-USTL (201709), SKLMEA-USTLN (201909)) and Innovation Team Project of University of Science and technology Liaoning (2017TD01)
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