Abstract
Corrosion behavior of TiN coated steel was studied in terms of thickness of interlayer Ti and TiN coating TiN was are ion plated to a thickness of 1$\mu\textrm{m}$ and 2$\mu\textrm{m}$ respectively with interlayer coating of Ti of 1$\mu\textrm{m}$, 2$\mu\textrm{m}$ and 3$\mu\textrm{m}$. Corrosion resistance of TiN coated steel was evaluated by anodic palarization test in 1N H2SO4 as well as salt spray test. Porosity of each coating was also tested by using SO2 test method. Corrosion current density decreased with increasing TiN coating thickness and Ti interlayer coating markedly enhanced the corrosion resistance. Ti interlayer coating of 2$\mu\textrm{m}$ and 3$\mu\textrm{m}$ prior to 2$\mu\textrm{m}$ TiN coating decreased the corrosion current density of active range by an order of 4 and that of passive range by an order of 2. This improvement was associated with the retardation of corrosive agent penetration with increasing coating thickness and inherent corrosion resistance of Ti interlayer. Ti interlayer coating was also very effective in improvement of corrosion resistance under salt atmosphere.
