摘要
ZrN thin films were deposited on AISI 304 stainless steel (304SS) by unbalanced magnetron sputtering (UBMS). Afterwards, the specimens were annealed at 1000 °C in vacuum (4 × 10 −6 Torr) for a duration ranging from 1 to 4 h. The purpose of this study was to investigate the oxidation behavior and corrosion resistance of the vacuum annealed ZrN-coated 304SS prepared by UBMS method. The results of X-ray diffraction indicated that ZrN remained as the major phase in the oxidized thin films even after heat treating at 1000 °C for 4 h in vacuum. The surface grain size of the oxidized film increased with heat treating duration. The oxidized ZrN thin film on 304SS formed two oxide layers, the outer layer on the film surface and the inner layer nearby the film/substrate interface, which could be attributed to the simultaneous diffusion of oxygen from film surface and the edge of film/substrate interface, respectively. The results of potentiodynamic polarization scan showed that the corrosion resistance of the oxidized ZrN-coated 304SS was excellent and increased by at least 100 times relative to that of bare 304SS, based on the decrease of corrosion current density. The oxidized ZrN-coated 304SS also showed excellent durability after 500-hr salt spray test with corrosion area less than 4% for all specimens, and the oxidized ZrN films showed better durability than the as-deposited ZrN film in salt spray test. The results suggested that the electrical conductivity of the film may be a significant factor on I corr , and the relative corrosion resistance of ZrN and ZrO 2 in NaCl solution may also play an important role in salt spray test. The fully oxidized ZrN thin film showed high corrosion resistance and remained intact on 304SS substrate after potentiodynamic polarization scan, which was associated with the enhanced adhesion by the interdiffusion layer due to heat treatment. The adhesive problem of ZrO 2 on stainless steel could be solved either with or without ZrN interlayer, if the vacuum annealing could produce a large interdiffusion zone and thereby enhancing the adhesion.