<p>Magnesium alloys, particularly AZ91, are widely used in industries such as aerospace, automotive, and electronics due to their lightweight and high-strength properties. However, their susceptibility to corrosion limits their application in harsh environments. This study presents the development of a novel tri-layer coating composed of nickel (Ni), polyaniline (PANI), and a silane-based sol-gel layer to enhance the corrosion resistance of AZ91 magnesium alloy. The Ni layer provides a robust foundation, while the PANI coating, with its coral-like porous structure, improves adhesion and corrosion resistance. The top silane layer, formed from tetraethylorthosilicate (TEOS) and vinyltriethoxysilane (VTES) by a sol-gel method, offers a smooth, hydrophobic surface that significantly enhances corrosion protection. A range of characterization techniques, including field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), were applied to analyze the microstructure, surface morphology, and chemical composition of the coatings. The electrochemical performance of the coating was evaluated through electrochemical impedance spectroscopy (EIS) in a 3.5% NaCl solution, revealing a remarkable enhancement in corrosion resistance (86.9 kΩ cm²) compared to bare Mg alloy (0.2 kΩ cm²). Notably, the coating exhibited a corrosion resistance of 12.1 kΩ cm² after 168 h of exposure, still much higher than that of bare Mg, highlighting its long-term protective capacity. The synergistic effects of the Ni, PANI, and silane components were found to be crucial in improving the overall resistance to corrosion. This tri-layer coating presents a promising solution for enhancing the longevity and performance of magnesium alloys in industrial applications.</p><p></p>