Corrosion Resistance and Durability of Superhydrophobic Coating on AZ31 Mg Alloy via One-Step Electrodeposition

Abstract

To enhance durability and adhesion of superhydrophobic surface, an integrated superhydrophobic calcium myristate (Ca[CH 3 (CH 2 ) 12 COO] 2 ) coating with excellent corrosion resistance was fabricated on AZ31 magnesium (Mg) alloy via one-step electrodeposition process. Field-emission scanning electron microscopy, Fourier transform infrared spectrometry and X-ray photoelectron spectroscopy as well as X-ray diffraction were employed to investigate the surface characteristics (morphology, composition and structure) of the coatings. Hydrophobicity of the coating was evaluated by means of contact and sliding angles. Additionally, potentiodynamic polarization, electrochemical impedance spectroscopy and hydrogen evolution tests were conducted to characterize the corrosion resistance. Results indicated that the coating exhibited super-hydrophobicity with large static water contact angle (CA) and small sliding angle of 155.2° ± 1.5° and 6.0° ± 0.5°, respectively, owing to spherical rough structure and low surface energy (7.01 mJ m −2 ). The average hydrogen evolution rate (HER a ) and corrosion current density (i corr ) of the coated sample were 5.3 μL cm −2 h −1 and 5.60 × 10 −9 A cm −2 , about one and four orders of magnitude lower than that of AZ31 substrate, respectively, implying the excellent corrosion resistance. The CA of the coating remained 155.6° ± 0.9° after soaking for 13 days, showing the super-hydrophobicity and stability of the coating. Simultaneously, the large critical load (5004 mN) for the coating designated the outstanding adhesion to the substrate by nano-scratch test.

Research advances on superhydrophobic coating for metal surfaces via one-step electrodeposition

“…The coating in pulse mode with a 50% duty cycle can provide the best corrosion protection for the substrate. Yin et al (2021) used a one-step electrodeposition process to prepare an integrated superhydrophobic calcium myristate (Ca[CH 3 (CH 2 ) 12 COO] 2 ) coating with excellent corrosion resistance on an AZ31 magnesium (Mg) alloy. As a result, the maximum CA of the surface can reach 155.6°.…”

Recent Progress in Functionalized Coatings for Corrosion Protection of Magnesium Alloys—A Review

“…Electrodeposition is an alternative method to fabricate nano-micro structures on Mg alloys [ 58 ]. The process is simple and easy to control, so the cost is low, and the preparation efficiency is high, and batch preparation can be realized [ 7 , 59 , 60 , 61 , 62 ].…”

Electrochemical analysis of the corrosion resistance of annealed steel with nickel coating in marine environment simulations: chronoamperometric and voltametric study

“…Nickel (II) Chloride Hexahydrate has been utilized in electrodeposition, as demonstrated in studies for creating Ni-B composite coatings on steel substrates [6]. This approach promises to enhance the corrosion resistance of steel wires while preserving the structural integrity of steel and other materials [7][8][9][10]. Marine corrosion conditions were simulated using a Sodium Chloride solution, mimicking seawater's chemical properties [11].…”