Plasma spray coating enhances the corrosion and wear resistance of the stainless steel structures installed in marine applications. Hence, it is imperative to study the effectiveness of various coating combinations on the material's performance. The present work investigates the effects of three different plasma-sprayed coatings on the wear and corrosive resistance of austenitic stainless steel (SS316). The three compositions of the coating were prepared using (i) Tungsten carbide (WC), (ii) 8 wt. % Yttria Stabilized Zirconia (8YSZ), and (iii) 50 wt. % Tungsten carbide (WC) with 50 wt. % Yttria Stabilized Zirconia (8YSZ). Experiments were conducted as per ASTM G76 to determine the erosive wear with a mixture of high-velocity air and Al2O3 abrasive particles. The corrosive medium used in the electrochemical polarisation tests was 3.5 wt.% NaCl. A scanning electron microscope (SEM) was used to examine the surface morphology of the eroded and corroded coatings. Energy Dispersive X-ray Analysis (EDAX) and X Ray Diffractrometry (XRD) analysis were carried out to reveal the phase composition, elemental distribution, and lattice parameters of uncoated and coated samples. The study reveals that the composite coating (WC+8YSZ) have superior wear resistance when exposed to a high-velocity erodent. Due to the robust particle adhesion and cohesiveness of the (WC + 8YSZ) composite coating, crack initiation and propagation are rarely found on the surface of the composite coating, as evidenced by the surface wear morphology analysis. Further investigation reveals that the 8YSZ coating has excellent corrosion resistance. The SEM-based corrosive wear topography analysis reveals that the 8YSZ phase on the coated surface acts as a diffusion barrier to the electrolytic medium and a passive protective layer over the coating. Consequently, the micro-chipping of particles during exposure to the corrosive medium is prevented.

Austenitic Stainless Steel (SS316) is a commonly used material in marine and offshore locations. The components' surface in such environments degrades due to chloride and moisture exposure. Hence, adding a ceramic coating to the surface enhances its functionality. In the present work, Cr3C2 and 8YSZ powders are mixed in an equal ratio to deposit unique composite coated layers on the SS316 substrate by plasma spray coating method. The performance of the composite coating is also compared to that of uncoated, Cr3C2-coated, and 8YSZ-coated substrates. The surface morphology and cross-sectional microstructures of the coated SS316 substrate are examined using scanning electron microscope (SEM) images and The presence of chemical elements in the coatings is determined using Energy Dispersive X-ray Analysis (EDAX) with elemental mapping. Further, the corrosion resistance of the substrate is evaluated using potentiodynamic polarisation and Electrochemical Impedance Spectroscopy (EIS) methods. The results shows that the composite coating has a decreased porosity of 1.33 % area and a higher microhardness of 880.02HV compared to bare and other coated surfaces. The corrosion analysis reveals that the composite coating has a decreased corrosion current density (Icorr) of 3.233×10-6 mA/cm2 and an enhanced charge transfer resistance of 2396.23 ohms.cm2 due to strong passivation and restricted electrolyte penetration into the coating. Further, the electrochemical corrosion study reveals that the composite coating exhibits the lowest corrosion rate of 0.00004306 mm/year.