Abstract
Nano-crystalline ZrN films were successfully deposited on Si (100) and AISI 304 stainless steel substrates using hollow cathode discharge ion plating (HCD-IP) system. The effect of nitrogen flow rate (ranging from 5 to 35 sccm) was investigated on the composition, structures, properties, and corrosion resistance of the ZrN film. The direct effects of the nitrogen flow rate on the structure of the ZrN film are N/Zr ratio, packing factor, and grain size. The N/Zr ratio increases (0.6 to 0.9) with increasing nitrogen flow rate. The hardness of the nano-crystalline ZrN film is not related with the variation of the residual stress, and the deformation mechanism of the ZrN film may be due to grain rotation and grain boundary sliding instead of slip by dislocation. 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 the substrate effect. The results of potentiodynamic polarization dynamics scan in both 5% NaCl and 1N H2SO4 + 0.05M KSCN solutions are consistent with that by salt spray test. If a nano-crystalline ZrN film is thicker than 420 nm, it could effectively protect the substrate from the corrosive medium. High packing factor is a necessary condition but not a sufficient condition for good corrosion resistance. Texture may be a factor to affect corrosion resistance.