A Lactoglobulin-Composite Self-Healing Coating for Mg Alloys

Corrosion issue is one of the most crucial bottlenecks for extensive employment of Mg alloys, in particular under harsh engineering conditions. Differing from traditional approaches, a self-healing protective coating composed of lactoglobulin is proposed herein to offer sustainable protection to the underlying Mg parts. Corrosion resistance, evaluated by electrochemical measurements and hydrogen evolution tests, indicates that the lactoglobulin composite film exhibits nobler corrosion potential (-1.28 V_SCE), smaller corrosion current density (8.4 × 10^-6 A/cm²), and lower average corrosion rate (∼0.03 mm/y) than those of its bare counterparts. Moreover, the pre-made cracks in the film were evidently self-healed within 24 h of exposure to corrosive media. The proposed self-healing lactoglobulin composite film provides opportunities to tackle the corrosion challenges of Mg alloys.