TiSiC, TiSiC-Zr, and TiSiC-Cr Coatings—Corrosion Resistance and Tribological Performance in Saline Solution

TiSiC coatings alloyed with Zr and Cr were deposited on Si and 316 L steel substrates by a cathodic arc method in a CH₄ reactive atmosphere. The corrosion and wear behavior of the coatings in 0.9% NaCl solution was investigated. Corrosion resistance of the coatings was evaluated by electrochemical tests. The electrochemical polarization measurements were conducted at room temperature in the potential range −1 and 1.5 V, with a 0.167 mVs⁻¹ scan rate. Compared to the uncoated 316 L substrates, the coated ones showed nobler characteristics, with more electropositive corrosion potentials, lower corrosion current densities, and higher polarization resistances. TiSiC-Zr exhibited the lowest corrosion current density (0.62 μAcm⁻²) and the highest protection efficiency (69.5%). The tribological performance of the coatings under corrosive conditions (0.9% NaCl solution) was investigated using a ball-on-disc tribometer (6-mm-diameter sapphire ball, 5 N load, 0.15 ms⁻¹ sliding speed, 400 m sliding distance). The TiSiC-Cr coating demonstrated the best wear behavior, with a wear rate of 3.2 × 10⁻⁶ mm³N⁻¹m⁻¹, followed by TiSiC and TiSiC-Zr. The morphologies and compositions of the worn surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) in order to identify the wear mechanism. Corrosion, debris adhesion, and oxidation were found to be the dominant wear processes.