I am currently using Avesta cell for corrosion studies. Avesta cell is well known for its design to avoid crevice corrosion but when we do tests in this cell for some alloys which has considerable nickel contents it shows crevice formation. I am seeking ideas or brainstorming for the reason of crevice formation in this cell. How does the Nickel contribute to crevice formation? I am looking into papers not getting any solid evidences for this relationship.
Dear Muthukumar Subramanian
Yes, nickel and nickel based alloys contribute to crevice formation even considering the higher Pitting resistance equivalent number (PREN) compared to stainless steels alloys.
Nickel and nickel based alloys has been reported to have higher passive current densities than chromium-alloyed stainless steels. This become a problem while attempting to set a critical current density for the propagation of localized corrosion on Nickel and it's based alloys.
This higher passive current densities could thus lead to a rapid IR-drop (ohmic or potential drop of the creviced surface).
The migration of aggressive species ions into the crevice is highly enhanced with an increased IR-drop and then crevice solution quickly becomes more aggressive and cause the unexpected low crevice corrosion resistance found for nickel alloys.
Best regards
It would be very nice if you have time to share some research papers on the same line. The papers which i came across all are stating an open ended question like Nickel may be the reason or could be kind of.
I am now testing the same cell for stainless steel, i will write to you once I get some results over repetitions. Thanks for reaching out.
Very interesting, thanks for your information. I am super interested to try this out for High nickel alloys.
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