Effect of pH, temperature and Cl- concentration on electrochemical behavior of NiTi shape memory alloy in artificial saliva.

The cooperation of pH, temperature and Cl- concentration on electrochemical behavior of NiTi shape memory alloy in artificial saliva was studied using orthogonal test method. The results showed that the pitting potential for NiTi in artificial saliva decreased at low and high pH; at 25 degrees C, the pitting potential was the lowest compared to those at 10 degrees C, 37 degrees C and 50 degrees C; when the Cl- concentration was not less than 0.05 mol/L the pitting potential decreased with the increase of Cl- concentration. The free corrosion potential of austenitic NiTi was lower than that of mixture of austenite and martensite.