Facile fabrication of TiN coatings to enhance the corrosion resistance of stainless steel

Stainless steel, widely used for its excellent mechanical properties, suffers from low surface hardness that reduces its corrosion resistance. Herein, a straightforward ultrasonic shot peening technique was employed to fabricate a TiN coating (USG) that is well-bonded to the substrate. Corrosion tests demonstrated a significant decrease in corrosion current density (i_corr) from 6.09 × 10⁻⁷ A·cm⁻² to 7.40 × 10⁻⁹ A·cm⁻², and the corrosion rate decreased from 299.49 mm/year to 121.67 mm/year. The high-energy processing chamber facilitated rapid formation of a chemically-bonded TiN layer. The chemical inertness of TiN in environments containing water and chloride ions helps to avoid corrosive reactions, thereby enhancing the corrosion resistance of the USG samples. Further AIMD calculations reveal the corrosion-resistant mechanism of TiN at the atomic scale, showing strong chemical bonding between TiN and the substrate, forming a dense protective layer. Additionally, the chemical inertness of TiN in saline environments effectively prevents substrate corrosion. This work demonstrates a novel and effective approach for fabricating corrosion-resistant coatings on stainless steel surfaces.