Optimization of the basic parameters of deposition of titanium-based conversion coating on cold rolled steel

In the present study, the corrosion protection of Ti-based conversion layer on cold rolled steel was investigated. The coating was applied by immersing the samples in hexafluorotitanic acid (H2TiF6) solution and the influence of immersion time and concentration of H2TiF6 acid on coating performance has been determined. In order to evaluate the corrosion behavior of the samples, electrochemical impedance spectroscopy (EIS) and potentiodynamic curves were used. The coating which was formed in the bath with acid concentration of 1 g/L and pH=2 with immersion time of 120 seconds, exhibits the best anti-corrosion performance, with corrosion current density of 4.3 μA/cm2, Therefore, this sample corrodes much more slowly than the bare substrate (icorr=14.67 μA/cm2) .