Study on the tribological properties and corrosion resistance of the modified NiZnAl-LDH coating on anodic aluminum surface

Abstract

The porous structure of anodized aluminum creates an opportunity for corrosive media to contact the aluminum substrate, resulting in diminished corrosion resistance and wear performance under adverse conditions. In this study, ternary hydrotalcite containing Ni, Zn, and Al elements, named NiZnAl-LDH, was synthesized on anodized aluminum surfaces using an in-situ growth method. The corrosion and wear resistance of the aluminum substrate were further enhanced by intercalation modification with sodium molybdate. The impact of synthesis parameters, including pH, reaction temperature, and reaction time, on the corrosion and wear resistance of the coating was investigated. Morphology, structure, and properties of the coating were analyzed. The results confirm the synthesis of NiZnAl-LDH modified with sodium molybdate intercalation. Electrochemical tests revealed that immersing NiZnAl-LDH in a sodium molybdate solution with a pH of 9.5 for 2.5 h at 35 °C resulted in a minimum self-corrosion current density of 4.131 × 10−8 A cm−2, significantly enhancing the corrosion resistance of the coating. Friction tests demonstrated a coating friction coefficient of 0.28, indicating excellent tribological performance. The discussed process parameters in this study provide valuable insights for the synthesis and application of LDH, expanding the application of aluminum alloys in the field of corrosion resistance and wear resistance.