Corrosion of chromium containing alloys in non-steady state environments containing oxygen, carbon, and chlorine

M.J. McNallan; S. Thongtem; J.C. Liu; Y.S. Park; P. Shyu

doi:doi:10.1051/jp4:1993912

Proceedings of the 3rd International Symposium on High Temperature Corrosion and Protection of Materials
Actes du 3ème Colloque International sur la Corrosion et la Protection des Matériaux à Haute Température

J. Phys. IV France 03 (1993) C9-143-C9-150
DOI: 10.1051/jp4:1993912

Corrosion of chromium containing alloys in non-steady state environments containing oxygen, carbon, and chlorine

M.J. McNallan, S. Thongtem, J.C. Liu, Y.S. Park and P. Shyu

CEMM Dept., m/c 246, University of Illinois at Chicago, P.O. Box 4348, Chicago, IL 60680, U.S.A.

Abstract
Internal attack of chromium containing alloys in mixed oxygen-chlorine environments occurs by the formation of pores which penetrate down grain boundaries of the alloys. No internal attack was detected in a binary Fe-20 %Cr alloy at 1200 K in environments containing 2500 ppm Cl₂. The rate of internal attack of alloy 800H in such environments was increased by replacing the O₂ in the gas by CO₂. In mixed oxygen-carbon-chlorine environments, the internal attack occurs by selective chlorination of chromium carbides which precipitate along the grain boundaries.