In Situ Growth of Ultrathin Dual‐Functional Coatings via Microarc Oxidation for Enhanced Mechanical Property of ZL107 Aluminum Alloy

Aluminum alloys, such as ZL107, are widely used in automotive and aerospace industries; however, their mechanical property often requires improvement for demanding applications. In order to improve the performance of ZL107 aluminum alloy, a new dual‐layer in situ growing ceramic coating composed of alumina (Al 2 O 3 ) and silicon dioxide (SiO 2 ) was prepared on the surface of the alloy by microarc oxidation method, and its microstructure and properties were analyzed by various testing methods. The in situ growth process ensures the formation of a robust, multilayer coating directly on the substrate, ensuring strong adhesion and structural integrity, while SiO 2 enhances both the mechanical properties and overall stability. During coating formation, γ ‐Al 2 O 3 in the outer layer transitions to α ‐Al 2 O 3 in the inner layer, significantly increasing hardness. The dual‐functional layers consist of an outer layer that provides wear resistance and an inner dense layer that offers improved hardness and corrosion protection. The optimized coating achieves a hardness of 1363.19 HV, over 25 times that of the substrate, attributed to its dense ceramic phase. The coating's rapid growth, low friction, and excellent corrosion resistance make it an ideal solution for improving the performance and longevity of ZL107 aluminum alloy components under harsh conditions.