Investigation on the Cathodic Protection Effect of Low Pressure Cold Sprayed AlZn Coating in Seawater via Numerical Simulation

Abstract

Cold spray can deposit a composite coating simply by spraying mechanically-mixed Al and Zn powders, while no quantitative data has been reported on the anti-corrosion performance of different composite cold-sprayed coatings. In the present work, the finite element method was used to estimate the cathodic protection effect by simulating the potential distribution on a damaged cold-sprayed AlZn coating on Q235 steel. The results indicate that AlZn coating can only provide a limiting cathodic protection for substrate, because it can only polarize a very narrow zone negative to −0.78 V (vs. SCE, saturated calomel electrode). The remaining area of the steel substrate still has a very high residual corrosion rate. Computational methods can be used to predict the corrosion rate of AlZn coating, and the simulation results were validated by the results of a weight loss experiment.

Synergistic Inhibition of Mild Steel Corrosion in Seawater and Acidic Medium by Cathodic Protection and Monodora myristica Using Zinc Anode

“…Many different types of structure utilize this common technique. For example, it is used for pipeline, locks, underground storage tanks, and ship hulls protection [17]. The theory behind it is to supply enough electrons to the anodic area so that it becomes cathodic, thus slowing down or eliminating the anode altogether.…”

Sacrificial Thermally Sprayed Aluminium Coatings for Marine Environments: A Review

“…Modelling work done by using the final element method (FEM) that was conducted by Huang et al showed that a cold-sprayed AlZn coating can only provide protection to the substrate when the damage in the coating is not larger than 1 mm in width [66]. However, it should be pointed out that, in this study, the effects of calcareous deposits and corrosion product formations were not included.…”

Coatings for Harsh Environments

“…As such, the presence of (200) planes of the hexagonal Cr 2 N and cubic CrN phases is evident from the peak asymmetry. A distinctive feature of the coatings grown on SS is the presence of a third broad peak at about 63 In the Cr(N,O) coating deposited on Si, three peaks were observed at 37.9 [66]. The observed decrease in the lattice constant and peak shift to higher angles suggests the formation of a solid solution which stabilises the single-phase cubic solid solution of Cr(N,O) [67].…”