A magnesium-aluminum alloy surface gas-liquid dual-repellent anti-corrosion composite coating and a preparation method thereof

By employing a method of phosphate-chromium salt mixed etching and fluorosilane modification on the surface of magnesium-aluminum alloy, a multi-level micro-nano composite structure was constructed in situ. This solved the problem of balancing superhydrophobic and anti-corrosion performance with economy in the surface modification technology of magnesium-aluminum alloy, and realized a highly efficient and safe gas-liquid dual-hydrophobic anti-corrosion coating, which is suitable for aerospace, marine equipment and other fields.

CN122406205APending Publication Date: 2026-07-17XIAMEN UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
XIAMEN UNIV
Filing Date
2026-06-12
Publication Date
2026-07-17

AI Technical Summary

Technical Problem

Existing magnesium-aluminum alloy surface modification technologies lack an effective balance between achieving superhydrophobic and dihydrophobic properties, long-term corrosion resistance, and process economy. Etching methods suffer from corrosion product residues, galvanic corrosion effects, and reliance on high-cost equipment, leading to a decline in coating corrosion resistance and a shortened functional life.

Method used

By employing phosphate-chromium salt mixed etching combined with fluorosilane modification under no applied current conditions, and utilizing the natural potential difference between the α and β phases in the magnesium-aluminum alloy substrate, a multi-level micro-nano composite structure is constructed in situ to form a phosphate-chromium salt conversion film and a fluorosilane layer, thereby achieving a gas-liquid dual-hydrophobic anti-corrosion composite coating.

Benefits of technology

A coating with extremely high bonding strength and resistance to mechanical damage was constructed, significantly improving corrosion resistance. It is suitable for dynamic working conditions, reduces equipment investment and operating costs, and is suitable for large-scale production.

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Abstract

This invention discloses a gas-liquid dual-repellent anti-corrosion composite coating for magnesium-aluminum alloy surfaces and its preparation method. The method includes: immersing a pretreated magnesium-aluminum alloy with α-phase and β-phase microstructures into a phosphate-chromium salt mixed etching solution under no applied current conditions; selectively etching using the natural potential difference between the two phases; preferentially dissolving the α-phase to construct micron-level "valleys" while simultaneously depositing a phosphate-chromium salt conversion film in situ covering the surface of the continuous network of β-phase "peaks," resulting in a tightly interwoven "peak-valley" multi-level micro / nano composite structure; subsequently, immersing it in an ethanol solution containing fluorinated silane for treatment; and drying to obtain the composite coating. This coating has an integrated structure with the substrate, possessing excellent gas-liquid dual-repellent properties, long-term anti-corrosion performance, and good mechanical stability. This invention features a simple process, low cost, and safe and controllable operation, making it suitable for applications such as corrosion protection in marine equipment and underwater transmission components, and has great potential for industrial application.
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