Fabrication of titanium nitride coatings for 316 L stainless steel with improved antifouling property and corrosion resistance

This study demonstrates that titanium nitride (TiN) coating effectively enhances the anticorrosion and antifouling performance of 316 L stainless steel (SS). The TiN coating was successfully applied to 316 L SS using physical vapor deposition (PVD). X-ray diffraction (XRD) confirmed the crystalline nature of the coating. The low surface roughness of the TiN coating, which is linked to greater surface energy and hydrophobic characteristics that increase corrosion resistance. Electrochemical analyses showed that TiN-coated samples exhibited higher Bode-impedance modulus and charge-transfer resistance than uncoated 316 L SS, confirming improved corrosion protection. Biofilm-forming ability of the test marine biofilm-forming bacterial strains revealed that they were in the following order: Abyssicococcus albus (4.01 OD) > Exiguobacterium aestuarii (3.37 OD) > Enterobacter cancerogenus (2.03 OD) > Citrobacter freundii (1.05 OD). TiN-coated SS exhibited remarkably reduced biofilm formation and EPS production in both monoculture and polyculture conditions compared with uncoated SS. Similarly, TiN-coated SS displayed notably reduced microalgal adherence and cell accumulation under monoculture ( Nannochloropsis oculata ) and polyculture ( N. oculata and Chlorella sp.) comparable to uncoated SS. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) images revealed sparse, discontinuous biofilms of marine biofilm-forming bacteria and microalgae in both mono- and polycultures on TiN-coated surfaces, compared with thick deposits on uncoated SS. Antimicrobial and antimicroalgal rates (%) showed that TiN coating exhibited enhanced antimicrofouling activity against both bacterial and microalgal strains, with inhibition increasing significantly over time and showing pronounced efficacy under polyculture conditions. In silico BIOWIN™ models indicated that TiN is more environmentally compatible. In conclusion, the in silico and experimental results confirmed that TiN coating provided durable surface protection by enhancing corrosion resistance and mitigating microfouling.