Study of the corrosion behaviour of sensitized 904L austenitic stainless steel in Cl- solution

Electron Probe Micro Analyzer (EPMA) was used to study the grain boundary sensitization behaviour of high-nickel austenitic stainless steel 904L. After sensitization for different ageing times at 650 degrees C, 904L was corroded in 1 M HCl for 7 days. There was an obvious 3 mu m-wide corrosion-sensitized zone around the grain boundary. The EPMA results showed no significant segregation of elements around the grain boundaries. Transmission electron microscopy (TEM) results showed that the sigma phase was detected along the grain boundary. The sigma phase caused discontinuity in the passivation film near the grain boundary and the grain boundary sensitization of 904L.

Automated summary

By using EPMA and TEM, it was found that there is a corrosion-sensitized zone around the grain boundary of high-nickel austenitic stainless steel 904L, with no significant element segregation, and the presence of sigma phase near the grain boundary.