Microstructure, mechanical properties, and corrosion resistance of TiSiN coating prepared by FCVA technique with different N₂ flow rates

TiSiN coatings have attracted extensive attention due to excellent performance in cutting tools, Marine engineering equipment and ship critical components. However, due to the many microparticles and micropores on the coating surface prepared by traditional PVD techniques, the performance of the coatings, especially corrosion resistance, is seriously affected. Therefore, the preparation of high quality TiSiN coatings is very important for the industrial applications. In this study, high-quality TiSiN coatings were prepared by FCVA technique. The effect of N₂ flow rate on microstructure, mechanical properties and corrosion resistance of TiSiN coating was investigated. The results showed that all TiSiN coatings presented smooth and compact microstructure without cracks. Meanwhile, TiSiN coatings had a nanocomposite structure of amorphous Si₃N₄ encapsulated TiN crystallites and possessed a preferred orientation of TiN (200) plane. With the increase of N₂ flow rate, the grain size and hardness increased first and then decreased. When N₂ flow rate is 20 sccm, the hardness of TiSiN coating reached the maximum owing to the fine grain strengthening effect. Moreover, TiSiN coating deposited N₂ flow rate of 40 sccm had the best corrosion resistance, with the highest charge transfer resistance and pore resistance, which was primarily related to the best surface quality.