The effect of chlorine on the high temperature corrosion of SiO2-coated Incoloy 800H

V.A.C. Haanappel; H.D. van Corbach; R. Hofman; T. Fransen; P.J. Gellings

doi:doi:10.1051/jp4:1993995

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) C9-921-C9-930
DOI: 10.1051/jp4:1993995

The effect of chlorine on the high temperature corrosion of SiO₂-coated Incoloy 800H

V.A.C. Haanappel, H.D. van Corbach, R. Hofman, T. Fransen and P.J. Gellings

University of Twente, Department of Chemical Technology, P.O. Box 217, 7500 AE Enschede, The Netherlands

Abstract
The effect of chlorine in coal gasification atmospheres was investigated on the high temperature corrosion of Incoloy 800H coated with SiO₂. The experiments were performed in a representative gas mixture between 450 and 750°C. The weight gain in this environment was significantly decreased with coating thicknesses to about 1.4 µm. Larger thicknesses led to an increased corrosion attack. The coating contained small cracks filled with iron-nickel sulphides. Probably, pre-existing cracks in the SiO₂-coating due to internal stresses, were responsible for this behaviour of the coating. With increasing temperature or [MATH], the corrosion rate increased. The mechanism of the chlorine-induced corrosion is unclear as yet.