Properties and Microstructure of TiSiC- and TiSiCN-Based Coatings Produced by RPS

This work presents a comparative study of TiSiC and TiSiCN composite coatings deposited on stainless steel by reactive plasma spraying using mechanically activated powders. Microstructure, phase composition, and hardness were assessed by SEM/EDS, XRD, and Vickers indentation, while corrosion, erosion, and high-temperature tribological behavior were systematically evaluated. The TiCN + SiC + Si system forms a stable TiCxN1−x solid solution with amorphous Si3N4 grain-boundary phases, leading to densification and enhanced chemical stability. Compared with TiSiC, TiSiCN coatings exhibit higher hardness (2599 N/mm2, ≈324 HV), lower erosion loss (<1 mg), and stable friction coefficients (0.45–0.50 at 600 °C) due to protective oxide/nitride tribofilms. Electrochemical tests in 3.5 wt.% NaCl show a >6-fold reduction in corrosion rate (from 0.0506 to 0.008 mm·year−1) relative to bare steel. Overall, TiSiCN coatings deposited at 500–600 A provide an optimal balance of hardness, wear, and corrosion resistance, indicating strong potential for gas-turbine and power-generation components operating in aggressive environments.