Study of NaCl-induced hot-corrosion behavior of TiN single-layer and TiN/Ti multilayer coatings at 500 °C

Abstract TiN coatings suffer severe hot corrosion under the synergistic effect of NaCl and mid-temperature oxidation. Multilayer microstructure is expected to improve the corrosion resistance of the TiN coatings. In this work, NaCl-induced hot corrosion behavior and mechanism of TiN single-layer coating and TiN/Ti multilayer coating at 500 oC were studied. The TiN coating was seriously corroded along the grain boundary after the hot corrosion test. However, the Ti sublayer of the TiN/Ti coating was severely corroded, while the TiN sublayer was only slightly corroded and remaining intact. The results demonstrate that the formation of micro cells corrosion is one of the reasons for the severe corrosion of the Ti sublayer in the multilayer coating in the presence of solid NaCl electrolyte.