The NiTi shape memory alloy sample is subjected to a plasma spraying technique to form a layer of 400 um thick titanium coating on its surface. The corrosion resistance of the samples can be compared by the electrochemical measurement in the simulated body fluid environment. Thus, the presence of galvanic corrosion between the titanium coating and the nickel-titanium shape memory alloy substrate can be measured. The anodic polarization curves show that the NiTi shape memory alloy after titanium coating has a decrease in the current density of the dopant, while the polarization resistance increases with the corrosion potential and the passivation potential. In addition, the galvanic current time curve shows that the tantalum coating and nickel-titanium alloy between the galvanic current density is minimal. The experiments demonstrate that the surface modification of nickel titanium shape memory alloy surface coating can effectively improve the corrosion resistance of the matrix metal and there is no galvanic corrosion between the coating and the base metal.
