Next Article in Journal
Top Coating Anti-Erosion Performance Analysis in Wind Turbine Blades Depending on Relative Acoustic Impedance. Part 1: Modelling Approach
Next Article in Special Issue
Microstructure and Properties of Fe-Based Alloy Coating on Gray Cast Iron Fabricated Using Induction Cladding
Previous Article in Journal
Research on Cleaning Mechanism of Anti-Erosion Coating Based on Thermal and Force Effects of Laser Shock
Previous Article in Special Issue
High Temperature Corrosion Behaviors of 20G Steel, Hastelloy C22 Alloy and C22 Laser Coating under Reducing Atmosphere with H2S
Open AccessArticle

Coating Deterioration and Underlying Metal Corrosion Processes in Water-Line Area: Role of DACs

by Zhiwei Chen 1,2, Wei Zhang 1,2,*, Yi Zhan 1,2, Bing Lei 1,2, Tianying Sun 1,2 and Weihua Li 1,2,3,*
1
School of Chemical Engineering and Technology, Sun Yat-sen University, Zhuhai 519082, China
2
Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519082, China
3
Key Laboratory of Marine Environmental Corrosion and Bio-fouling, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China
*
Authors to whom correspondence should be addressed.
Coatings 2020, 10(7), 684; https://doi.org/10.3390/coatings10070684
Received: 1 July 2020 / Revised: 11 July 2020 / Accepted: 13 July 2020 / Published: 16 July 2020
(This article belongs to the Special Issue Corrosion Science and Surface Engineering)
Water-line corrosion is a highly concentrated type of localized corrosion. The conventional single electrode method is limited in its ability to obtain the kinetic information of the corrosion occurrence and development processes. Herein, the coating deterioration and underlying metal corrosion processes in water-line area were studied by a small wire beam electrode to monitor the current density distribution. The distance between each electrode was very small (interval: 0.3 mm), thus facilitating it to approach the practical metal component with a continuous surface. The results showed that cathodic and anodic sites tended to be weak points of the coating at the initial stage. With the continuous degradation of the coating, the cathodic zone tended to occur in the above the anodic zone due to the effect of differential aeration cells (DACs). Subsequently, the cathodic zone expanded to the waterline and the polarity reversed to the anodic zone, causing the coating to peel and blister continuously from the bottom up. When the cathodic zone extended to the gas phase area above the water line, this area became the strongest cathodic zone under the action of the thin liquid film, thus significantly accelerating the corrosion of the base metal at the bottom. The present study aims to achieve an in-depth understanding of coating deterioration and underlying metal corrosion processes in the water-line area, providing a new means of directly visualizing the role of DACs played in water line corrosion. View Full-Text
Keywords: water-line corrosion; wire beam electrode; coating deterioration; metal corrosion water-line corrosion; wire beam electrode; coating deterioration; metal corrosion
Show Figures

Figure 1

MDPI and ACS Style

Chen, Z.; Zhang, W.; Zhan, Y.; Lei, B.; Sun, T.; Li, W. Coating Deterioration and Underlying Metal Corrosion Processes in Water-Line Area: Role of DACs. Coatings 2020, 10, 684.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Search more from Scilit
 
Search
Back to TopTop