A Diffusivities of Point Defects Study of Passive State on 316L and 2205 Stainless Steel

Corrosion sensitivity of 2205 and 316L stainless steel in 3.5% NaCl solution was studied by potentiodynamic polarization, EIS and Mott-Schottky. The results show that the 2205 duplex stainless steel has better corrosion resistance than 316L stainless steel and the results of EIS spectra measurements in different formation potential shows that the thickness of passive film formed on 2205 SS is on average thicker than that on 316L SS under the same formation potential. Further investigation by Mott-Schottky analysis proves that the diffusivity of the point defects was 3.67×10
^-15
cm
²
/s for 316L SS and 2.8×10
^-16
cm
²
/s for 2205 SS, it shows that the Dd value of 2205 SS decreases about ten times compared with that of 316L SS, a less-defective passive film can be formed on the 2205 duplex stainless steel.