applied fracture mechanics

244Applied Fracture Mechanicschronoamperometries. The results indicate that the volumes calculated based on a sphericalgeometry are closer to the volume calculated from the chronoamperometry curves, as seenin Figure 11. Therefore, the volume of a pit, obtained from removal of material, calculatedaccording to a spherical geometry was used for comparison and analysis with the resultsobtained using electrochemical techniques. The values of the volume per pit as a function ofgrowth time were used to calculate the corresponding amount of dissolved material for a pitgrown under potentiostatic control on 304 SS in 3.5 wt% NaCl solution and in seawaternatural. In Figure 12 shows the amount of dissolved material, determinedchronoamperometries and by a method of material removal, as a function of pits growthtime on the 304 stainless steel in NaCl solution and in water natural sea. Also, the figure 13illustrates the pit nucleation and growth process obtained from SRET Maps.Figure 10. SEM image shows the pits potentiostatically generated in artificial seawater hadhemispherical morphology on 316L steel surface under [40].Figure 11. Comparison of the pits volume determined from the material removal method and from theintegration of chronoamperometries for 304 SS in a) 3.5% NaCl and b) natural seawater [55].