MAO-based self-healing phase-change solid-like slippery composite coating with superior corrosion resistance and robust machinery performance

• An MAO-based Self-healing Phase-change solid-like slippery composite coating is manufactured. • The coating combines mechanical pinning effects of MAO and super repulsive water performance of PSSC. • The coating has excellent mechanical, adhesion, chemical stability, and self-healing ability. • The coating exhibits a long-term anti-corrosion effect for magnesium-lithium alloy LA81. Super-slippery surfaces have exhibited significant promise for corrosion protection of metals. However, challenges remain in the way of broad engineering applications, including limited mechanical durability, conflict between mechanical performance and self-healing ability, and volatilization and leakage of lubricant caused by long-term usage. This study aims to improve mechanical strength and minimize liquid loss of super-slippery surfaces by using a silane coupling agent (KH550) as bridging agent to bind phase-change paraffin wax, hydrophilic nano-silica, and low-surface-energy polydimethylsiloxane (PDMS) onto epoxy-functionalized surfaces via a series of dehydration, condensation, and cross-linking reactions. This method yields a super-slippery, corrosion-resistant composite coating with phase-change self-healing properties on magnesium-lithium alloy LA81. It demonstrates a high water-contact angle (> 110°) and a low sliding angle (< 8°), indicative of favorable hydrophobic and slippery characteristics. Electrochemical tests reveal a profound increment (seven orders of magnitude) in impedance modulus, substantiating its enhanced anti-corrosive performance. In addition, coating integrity was maintained after 168 h of salt spray exposure. Adhesion tests and 3D synchrotron X-ray imaging confirm a strong bond between the coating and substrate. Due to paraffin’s phase-change properties, the composite coating exhibits rapid self-healing when thermally stimulated. Such a self-cleaning, corrosion-resistant, and self-healing composite coating, with exceptional mechanical properties, offers an alternative solution to extending material lifespans in engineering applications.