Electrochemical studies of the inhibition of the cathodic delamination of organically coated galvanised steel by thin conversion films

Improving the Processability of a One-Step Hydrophobic Coating for Hot-Dipped Galvanised Steel for Industrial Applications

Hydrophobicity on steel-based metallic surfaces provides an advantage in limiting corrosion and debris buildup on the surface, thereby, improving the substrate performance. An experimental investigation was conducted on the development of zinc stearate and silicon dioxide coatings on the surface of hot-dipped galvanised zinc-coated steel substrates, which could be used to induce superhydrophobicity. Under optimal formulation and processing conditions, a contact angle of 146° could be produced within a 120-min processing window. This represents a reduction in processing time of 67% over previous literature using similar chemistry. In addition, we proved that costly nano silicon dioxide can be replaced by lower cost micro silicon dioxide without decreasing the performance of the coating contact angle. Under standard accelerated exposure tests, the coating was shown to reduce oxide build up by a factor of 3 compared to uncoated galvanized steel.

Electrochemical Characterization of Polymeric Coatings for Corrosion Protection: A Review of Advances and Perspectives

The development of anti-corrosion polymeric coatings has grown exponentially in the fields of material science, chemistry, engineering, and nanotechnology during the last century and has prompted the evolution of efficient characterization techniques. Nowadays, polymeric coatings represent a well-established protection system that provides a barrier between a metallic substrate and the environment. However, the increase in complexity and functionality of these coatings requires high-precision techniques capable of predicting failures and providing smart protection. This review summarizes the state of the art for the main electrochemical techniques, emphasizing devices that track the anti-corrosion properties of polymeric coatings from the macroscale to the nanoscale. An overview of the advances in accelerated corrosion testing and the electrochemical characterization of coatings is explored, including insights into their advantages and limitations. In addition, the challenges and potential applications of the theoretical approaches are summarized based on current knowledge. Finally, this work provides the reader with the trends and challenges of designing future technologies and models capable of tracking corrosion and predicting failures.

Preparation of superhydrophobic coatings on zinc as effective corrosion barriers

Stable superhydrophobic films with a contact angle of 151 +/- 2 degrees were prepared on zinc substrates by a simple immersion technique into a methanol solution of hydrolyzed 1H,1H,2H,2H-perfluorooctyltrichlorosilane [CF3(CF2)5(CH2)2SiCl3, PFTS] for 5 days at room temperature followed by a short annealing at 130 degrees C in air for 1 h. The superhydrophobic film provides an effective corrosion-resistant coating for the zinc interface when immersed in an aqueous solution of sodium chloride (3% NaCl) for up to 29 days. The corrosion process was investigated by following the change of the water contact angle over time and by electrochemical means. The results are compared to those of unprotected zinc interfaces.