Fe2Ti interlayer for improved adhesion strength and corrosion resistance of TiN coating on stainless steel 316L

Hard TiN coating (with a Vickers hardness higher than 1300 HV) on soft steel (smaller than 200 HV) has a great tendency to mechanical failure due to the significant mismatch in hardness. To tackle this issue, a Fe2Ti metallurgically bonding interlayer was designed and fabricated in between TiN coating and stainless steel 316L substrate. Results reveal that thickness of the Fe2Ti interlayer is tunable and plays an important role in adhesion strength and corrosion resistance of the resulting coating system. Fe2Ti interlayer with 5.0 mu m in thickness significantly enhanced adhesion strength (50 N) and decreased corrosion rate (8.128 x 10(-4) mm/yr), and the corrosion rate is one-tenth of the monolayer TiN coating fabricated by conventional CVD or PVD methods.