Electrochemical characterization and stress corrosion cracking of E690 high strength steel in wet-dry cyclic marine environments

Wang

2020

Materials & Corrosion

The drawbacks of artificial fabrication methods of superhydrophobic surface including multistep operations, time-consuming and fluorine-containing chemicals employment lead to inefficient preparation, severe environmental pollution, and safety concerns, restricting the large-scale manufacturing and promising applications. Herein, a fluorine-free stearic acid-based one-pot hydrothermal strategy was employed to simultaneously achieve surface roughness and low surface energy, transforming the surface wettability from hydrophilicity to superhydrophobicity. The as-fabricated superhydrophobic 5083 Al alloy surface exhibits excellent water-droplet bouncing, ultralow surface adhesion force, and repeatable self-cleaning ability. The electrochemical impedance spectroscopy results reveal that the impedance modulus value |Z| 0.01 Hz was remarkably improved, demonstrating a high-efficiency corrosion resistance. We believe that the one-pot fluorine-free hydrothermal-fabricated superhydrophobic surface can be considered as an efficient barrier against corrosive environments, and being beneficial for the functional applications of metallic materials.

Section: Resultsmentioning

confidence: 99%

One‐pot fluorine‐free superhydrophobic surface towards corrosion resistance and water droplet bouncing

Wang

2020

Materials & Corrosion

“…Through the effects of the alloying elements on the PRF, the corrosion resistance of alloy compositions on the long-term corrosion behavior of carbon steels in seawater can be explored. Alloy elements of carbon steels are commonly enriched in rust layers (Hao et al , 2018). The rust layer and microenvironment on metal surfaces faces complex seawater environment.…”

Section: Resultsmentioning

confidence: 99%

An electrochemical method based on OCP fluctuations for anti-corrosion alloy composition optimization

Chen

Chen

et al. 2018

ACMM

Purpose An electrochemical method based on the open circuit potential (OCP) fluctuations was put forward. It can be used to optimize the alloy compositions for improving the corrosion resistance of rust layer. Design/methodology/approach The potential trends and potential fluctuations of carbon steels in seawater were separated by Hodrick–Prescott filter. The Spearman correlation coefficient and max information coefficient were used to explore the correlation of alloy compositions and potential fluctuations. Findings After long-term immersion, potential fluctuation resistance (PFR) can be used to characterize the corrosion resistance of metals and its rust layers. In the 1,500 to 2,500 h exposure period, Fe, C and S compositions have strong negative correlations, whereas PFR and P composition have weak negative correlations. Mn, Cu and Ti alloy compositions help the rust layer of carbon steels have higher PFRs. These elements that exhibit higher PFRs in this period have been confirmed to have the effect on improving the corrosion resistance of rust layer. Originality/value A new computing method for alloy composition optimization of carbon steels based on the OCP fluctuations was put forward. This method combines electrochemical monitoring with the long-term actual seawater environmental tests of various carbon steels.

“…On 10th day, the obvious local corrosion area on Q235 steel occurred in seawater and dry-wet alternating environment, while the smallest general corrosion rate (v 1 ) in figure 3 were observed on 15th day in the soil environment. Furthermore, the corrosion of Q235 steel was aggravated in different environments with time [41]. Compared with the Q235 steel in seawater environment, the pitting corrosion characteristics of Q235 steel were more obvious in soil environment and drywet alternating environment.…”

Section: Corrosion Morphologymentioning

confidence: 94%

Study on corrosion characteristics of Q235 steel in seawater, soil and dry-wet alternating environments focusing on Shengli oilfield

Yang

Wang

et al. 2022

Mater. Res. Express

The coastal pipelines are the key link between the offshore and the onshore pipelines, which are located in the soil dry-wet alternating environment. Even though higher corrosion risk of metals in coastal soil dry-wet alternating environment, few papers focused on this condition, while much research about ocean and atmospheric dry-wet alternating environment was paid attention to. In this paper, a self-designed soil dry-wet alternating experimental device was used to investigate the corrosion characteristics of Q235 steel in seawater, soil and dry-wet alternating environment based on mass loss experiments, corrosion morphology analysis and electrochemical experiments. The results showed that the general corrosion rate of Q235 steel in soil and seawater environments basically remained unchanged, and in dry-wet alternating environment increased with time, while the pitting rates were 0.280 mm/a (soil), 0.420 mm/a (seawater) and 0.567 mm/a (dry-wet alternation), respectively, which was caused by the oxygen concentration cell and salt concentration cell. Meanwhile, the growth rate of pitting size in dry-wet alternating environment was much higher than that in the other two environments with different corrosion characteristics of pitting corrosion (seawater and dry-wet alternation) and a changed from general corrosion to pitting corrosion (soil). In three environments, the corrosion current density (I corr) increased, in which on the 30th day of experiment, I corr = 79.72 μA/cm2 in dry-wet alternating environment, which was much higher than I corr = 47.89 μA/cm2 in seawater environment. In dry-wet alternating environment, the mass diffusion impedance at 10-2 Hz and the maximum phase angle changed significantly, while the logf-log|Z| curve in low-middle frequency decreased significantly, and charge transfer resistance at 105 Hz reduced from 10.4 Ω to 4.3 Ω, illustrating an increasing corrosion rate.