Influence of RF Power on Structural and Corrosion Properties of Sputter-Deposited CrN Films

This study examines the deposition of chromium nitride (CrN) films on 304 stainless steel (304SS) substrates using radio-frequency (RF) magnetron sputtering, with RF power varied from 20 to 160 W in an argon atmosphere. The structural, topographical, and corrosion resistance properties of the films were analyzed using X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemical polarization measurements. Employing the atomic force microscope, morphological characteristics of CrN films under constant conditions using Minkowski Functionals were analyzed. Subsequently, by examining parameters like root-mean-square roughness, skewness, and kurtosis, the study revealed the variations in the particle distribution and their probability density as a function of deposition power alterations. Results indicate that increasing RF power enhances film crystallinity, as evidenced by intensified XRD peaks. With an increase in RF power reaching up to 80 W, there is a significant enhancement in the uniformity of the surface, resulting in an evenly spread grain pattern. Corrosion tests in 0.5 M sulfuric acid, assessed via potentiodynamic polarization, identify 80 W as the optimal RF power for maximizing corrosion resistance. This study provides insights into the relationship between film structure, surface characteristics, and corrosion behavior, highlighting key factors influencing protective performance.