Use of SECM to study the electrochemical behavior of DIN 1.4575 superferritic stainless steel aged at 475 °C

Abstract

In order to lower the excessive costs of metallic prosthesis materials alternatives to Ti and Ti alloys have been searched. In this study, the corrosion resistance of the DIN 1.4575 superferritic stainless steel, either solution annealed or solution annealed and aged at 475 8C for periods varying from 100 to 1080 h, was investigated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods in Hanks' solution. The solution annealed and the aged for 1080 h samples were also tested using scanning electrochemical microscopy (SECM) in a 0.1 mol/L NaCl solution at 25 8C. The EIS results showed that the corrosion resistance of the DIN 1.4575 steel decreases with heat treatment time at 475 8C probably due to alpha prime formation. Besides the diminution of the overall impedance values, the low frequency limit of the Nyquist diagrams show a progressive change from an almost capacitive response to a resistive behavior as the heat treatment time increases. Pitting corrosion resistance also decreased with aging time at 475 8C.

Corrosion Versus Mechanical Tests for Indirect Detection of Alpha Prime Phase in UNS S32520 Super Duplex Stainless Steel

“…The results indicated that the passive layer becomes increasingly less protective because of rising amounts of defects caused by alpha prime precipitation during aging treatments. 26 Cyclic potentiodynamic polarization curves are presented in Figure 8 and support the EIS results, also showing that the resistance to localized corrosion decreases with aging time. The film resistance to breakdown largely decreased from 12 h to 48 h showing that the material is progressively more prone to localized corrosion.…”

“…As the amount of alpha prime increases, dislocation blockage also increases, leading to embrittlement. [26][27] The solution-annealed fractured surface showed morphology typical of ductile fracture, with large and predominant dimples areas, as Figure 5(a) shows. The transition from a predominant ductile fracture to a brittle one is clearly seen in Figures 5(b) and (c), with decreased quantities of dimples.…”

Passive film properties of Z3CN20.09M duplex stainless steel aged for different times

“…Zhang et al investigated the effect of isothermal aging on the pitting corrosion of UNS S82441 duplex stainless steel, and found that the pitting corrosion resistance of the specimens decreased with increasing temperature and aging time. The similar phenomenon was also found in Z3CN20.09M stainless steel aged at a lower temperature by Wang et al The decrease of pitting corrosion resistance is always attributed to the existence of chromium‐depleted zones around precipitates . However, the zones size is approximately several nanoscale, which is difficult to study the pitting corrosion of aged Z3CN20.09M DSS.…”

Effect of spinodal decomposition on the pitting corrosion resistance of Z3CN20.09M duplex stainless steel

“…Comparing with the Cr‐rich area, the Cr contents in the Fe‐rich and G phases are lower than that in the Cr‐rich phase . In fact, a Cr‐depleted region formed around the Cr‐rich phase will result in the decrease of pitting corrosion resistance of the DSSs . On the other hand, pits which prefer to initiate in the Cr‐depleted region are the crack source of stress corrosion cracking and corrosion fatigue.…”