Durable photothermal superhydrophobic surface with honeycomb-micropillar biomimetic structure for efficient anti/de-icing on magnesium alloy

Magnesium alloys suffer from severe icing, corrosion, and mechanical degradation under harsh marine and cold environments, which significantly limit their practical applications. Herein, a durable photothermal superhydrophobic surface with a laser-induced honeycomb–micropillar architecture was developed on AZ91D magnesium alloy by integrating TiN nanoparticles and phase-change material (PCM) microcapsules. The laser-generated honeycomb–micropillar structure not only enhances coating adhesion through interfacial mechanical interlocking but also improves solar energy utilization by promoting multiple reflection and scattering of incident light. The TiN nanoparticles provide efficient photothermal conversion, while PCM microcapsules introduce latent heat buffering for thermal regulation during icing and de-icing processes. The optimized SLSHC surface exhibits a water contact angle of 165.2° and achieves an icing delay time of 888 s at −15 °C, which is further extended by the synergistic contribution of the honeycomb–micropillar structure and PCM latent heat. Under 1 sun irradiation, the surface temperature rapidly increases to 73.6 °C and complete ice melting is achieved within 428 s. Electrochemical measurements demonstrate that the SLSHC surface exhibits significantly enhanced corrosion resistance, with improved barrier protection attributed to the reduced solid–liquid contact area and mechanically anchored coating interface. This work provides a multifunctional surface design strategy for magnesium alloys with integrated anti-icing, de-icing, corrosion protection, and mechanical durability in harsh environments.