Abstract
Abstract Nano-crystalline ZrN films were successfully deposited on Si (100) and AISI 304 stainless steel substrates using unbalanced magnetron sputtering (UBM) system. The effect of nitrogen flow rate was investigated on the composition, structures, properties, and corrosion resistance of the ZrN film. The N/Zr ratio increases with increasing nitrogen flow rate. The preferred orientation (111) peak is dominant for all specimens. The roughness decreases with increasing the nitrogen flow rate for all samples. The electrical resistivity of ZrN films decreases from 271.6 to 34.6 then increases to 56.3 μΩ-cm. The residual stress of the ZrN film deposited on Si is lower than that on AISI 304 stainless steel. This may be due to the difference in thermal stress and conductivity of the substrate. The results of potentiodynamic polarization dynamics scan in both 5% NaCl and 0.5M H2SO4 + 0.05M KSCN solutions indicate that packing factor is more effective than film thickness to the corrosion resistance for the coating. However in the 5% NaCl solution, crystallinity and saturated bond ratio are more important than packing factor. For salt spray test, the corrosion area increases with the films roughness. The more saturated bonds exist in the ZrN thin films, the less defects in the film structure, the less corrosion area is observed. If a nano-crystalline ZrN film is thicker than 220 nm, it could effectively protect the substrate from the corrosive medium. High packing factor is good for corrosion resistance. Better crystallinity also improves the corrosion resistance of nano-crystal thin film.