Investigation of Structural, Mechanical and Electrochemical Properties of Temperature‐Dependent Dual AlN/TiAlN Coating Synthesized by CVD Process

ABSTRACT This investigation focuses on the development of dual‐layer coating of AlN and TiAlN by Chemical vapor deposition (CVD) to improve surface protection for advanced engineering applications. The Aluminium nitride (AlN) interlayer was first deposited on p ‐type c‐Si (100) substrates over a temperature range of 200°C to 800°C, followed by the TiAlN top layer. The effect of deposition temperature on the structural, morphological, mechanical, and electrochemical properties of the coatings was systematically investigated. Surface morphology and microstructure were examined using Field emission scanning electron microscope (FESEM), while phase composition was studied by X‐ray diffraction (XRD). Atomic force microscope (AFM) provided insights into nanoscale surface roughness, and Raman spectroscopy confirmed the vibrational modes of the coating phases. The X‐ray photoelectron spectroscopy (XPS) analysis confirmed the formation of strong Titanium‐Nitride (Ti─N), Aluminium nitride (Al─N), and Aluminium Titanium nitride (Al─Ti─N) bonds, indicating successful synthesis of a chemically stable dual‐layer structure. Nanoindentation revealed that the dual‐layer coating deposited at 700°C exhibited superior hardness and Young's modulus values of 29.64 and 209.69 GPa, respectively, indicating improved mechanical integrity. Electrochemical corrosion testing demonstrated excellent corrosion resistance, with the lowest corrosion current density observed for the coating formed at 700°C. Collectively, the results confirm that CVD‐deposited AlN/TiAlN dual‐layer coating offer a promising route for surface engineering applications that requires high hardness, better tribological property, and corrosion resistance in aggressive environments.