Eco-Friendly Superhydrophobic Coupling Conversion Coating with Corrosion Resistance on Magnesium Alloy

Abstract

An eco-friendly superhydrophobic conversion coating is fabricated to enhance the corrosion resistance of the AZ31B Mg alloy by combining the deep eutectic solvent pretreatment and electrodeposition. The coral-like micro−nano structure formed by reacting deep eutectic solvent and Mg alloy provides a structural basis for constructing a superhydrophobic coating. Cerium stearate with low surface energy is deposited on the structure, providing the coating's superhydrophobicity and the corrosion inhibition effect. Electrochemical test results demonstrate that the as-prepared superhydrophobic conversion coating (water contact angle at 154.7°) with a 99.68% protection effect significantly improves anticorrosion properties for the AZ31B Mg alloy. The corrosion current density decreases from 1.79 × 10 −4 A•cm −2 of Mg substrate to 5.57 × 10 −7 A•cm −2 of the coated sample. Besides, the electrochemical impedance modulus reaches the value of 1.69 × 10 3 Ω•cm 2 and increases approximately 23 times in magnitude compared with the Mg substrate. Furthermore, the corrosion protection mechanism is attributed to the coupling effect of water-repellency barrier protection and corrosion inhibition, resulting in excellent corrosion resistance. Results demonstrate a promising strategy for the corrosion protection of Mg alloys by replacing the chromate conversion coating with the superhydrophobic coupling conversion coating.

In Situ Construction of a Hydrophobic Honeycomb-like Structured ZnMoO4 Coating Applied for Enhancing Zinc Anode Performance

“…CPE f and CPE dl represent coating capacitance and electric double-layer capacitance, respectively. 48 The fitting electrochemical parameters are listed in Table S2. For bare Zn, there is slight corrosion in the 2 M ZnSO 4 solution, which leads to a corrosive product layer on its surface.…”

“…R s , R f , R ct , and R L represent solution resistance, coating resistance, charge transfer resistance, and inductive resistance, respectively. CPE f and CPE dl represent coating capacitance and electric double-layer capacitance, respectively . The fitting electrochemical parameters are listed in Table S2.…”

Diatomite@MoS2 Nanocomposite Layers as Composite Coating Targeting for Mg Alloys Endowed with Properties of Anticorrosion and Antiwear

“…Magnesium alloys find extensive applications in national defense, communications, aerospace, and machinery manufacturing. − Nevertheless, their susceptibility to high chemical activity and exposure to corrosive ions in operational environments detrimentally affect their lifespan . Hence, the development of efficacious technologies is imperative for addressing corrosion and wear issues throughout their life cycle.…”

Chemical Etching, Thermally Driven Combination Strategy to Fabricate Superhydrophobic Fe-Based Amorphous Coatings with Excellent Anticorrosion Property: Based on Hydroxylation Effect

“…A rough surface with a micro-/ nanohierarchical structure may trap air to form many "air bags". 19,20 The air pockets trapped in the micro-/nanovalleys of SHS can minimize the solid−liquid contact area effectively and support droplets to form the CB state, where droplets roll freely at a low tilted angle. Low surface energy materials with hydrolysis groups are capable of grafting with hydroxyl (−OH) on the substrate surface, thereby reducing the surface energy of the material.…”

“…Based on a series of fundamental theories, including Young’s equation, the Wenzel model, and the Cassie–Baxter (CB) model, the SHS materials have accomplished the transformation from natural to artificial. − The synergy of micro-/nano-multilevel structure and low surface energy materials is considered to be an essential factor in the fabrication of SHS. A rough surface with a micro-/nanohierarchical structure may trap air to form many “air bags”. , The air pockets trapped in the micro-/nanovalleys of SHS can minimize the solid–liquid contact area effectively and support droplets to form the CB state, where droplets roll freely at a low tilted angle. Low surface energy materials with hydrolysis groups are capable of grafting with hydroxyl (−OH) on the substrate surface, thereby reducing the surface energy of the material. , As for the preparation process, typically, two methods, “top-down” and “bottom-up”, have been developed to fabricate SHS.…”