Localized Corrosion of Ni-Cr-Fe Overlay Weld Alloys with Dispersed NbC in Sodium Chloride Solution

Yasuyuki Takatani, Tomoki Tomita, Genzo Hashizume, Yoshio Harada
1989 Corrosion engineering digest  
Pitting potentials in sodium chloride solution have been measured potentiodynamically for Ni-Cr-Fe overlay weld alloys with dispersed NbC on a carbon steel formed by plasuma transferred arc method. The presence of NbC in the alloys with Fe content more than 40% caused an electronegative shift in pitting potential, and the morphology of the localized attack was found hemisphere or heneycomb. With Fe content less than 5%, the pits of the alloys containing no NbC had crystallographic attack with
more » ... -rich phases undissolved. As NbC content was increased, the pitting potential shifted in electropositive direction and the anodic dissolution was uniform with no pitting. The Ni-Cr-Fe overlay weld alloys with dispersed 40% NbC was coverded with a Cr-Nb-Fe-C composition film after anodizing at 1.0V vs. Ag/AgCl and then had higher resistance to pitting corrosion.
doi:10.3323/jcorr1974.38.8_422 fatcat:sz2mpm67bffkhife3p4z4hfdxy