Electrochemical Noise Measurements of Steel Corrosion in the Molten NaCl-K2SO4 System

Electrochemical noise measurements have been carried out on AISI347, 10CrMo910, 15Mo3, and X20CrMoV121 steels in molten NaCl-K2SO4 at 630DGC. Different types of current noise have been identified for pitting, intergranular and peeling corrosion. The corrosion mechanism was the so-called active corro...

Full description

Saved in:
Bibliographic Details
Published in:Journal of the Electrochemical Society 2005-01, Vol.152 (7), p.B228-B235
Main Authors: Cappeln, F, Bjerrum, N J, Petrushina, I M
Format: Article
Language:English
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Electrochemical noise measurements have been carried out on AISI347, 10CrMo910, 15Mo3, and X20CrMoV121 steels in molten NaCl-K2SO4 at 630DGC. Different types of current noise have been identified for pitting, intergranular and peeling corrosion. The corrosion mechanism was the so-called active corrosion (i.e., the corrosion proceeds with no passivation due to the influence of chlorine), characterized by the formation of volatile metal chlorides as a primary corrosion product. It was found possible to obtain an empirical separation of general and intergranular corrosion using kurtosis (a statistical parameter calculated from the electrochemical noise data). It was found that average kurtosis values above 6 indicated intergranular corrosion and average values below 6 indicated general corrosion. The response time for localized corrosion detection in in-plant monitoring was approximately 90 min on this basis. Approximate values of polarization resistances of AIS1347 and 15Mo3 steels were determined to be 250 and 100 Omega cm2, respectively.
ISSN:0013-4651
DOI:10.1149/1.1928187