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Surface analytical studies of metal dusting of iron in CH 4 ‐H 2 ‐H 2 S mixtures
Author(s) -
Schneider A.,
Viefhaus H.,
Inden G.
Publication year - 2000
Publication title -
materials and corrosion
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.487
H-Index - 55
eISSN - 1521-4176
pISSN - 0947-5117
DOI - 10.1002/(sici)1521-4176(200005)51:5<338::aid-maco338>3.0.co;2-k
Subject(s) - cementite , metal , carbide , metallurgy , chemistry , auger electron spectroscopy , materials science , austenite , microstructure , physics , nuclear physics
Abstract The metastable iron carbide, cementite (Fe 3 C), occurs as an intermediate phase during the high temperature corrosion process called “metal dusting”. The kinetics and thermodynamics of metal dusting of iron have been studied by Grabke et al. [1–5] using CO‐H 2 ‐H 2 O and CH 4 ‐H 2 gas mixtures. H 2 S additions to carburising atmospheres impede the carbon transfer and retard the onset of metal dusting [6–14], thus allowing to study the early stages of the process. In this work the metal dusting process was studied in CH 4 ‐H 2 ‐H 2 S atmospheres at 700 °C. Segregation experiments and surface analyses showed that S segregates on iron surfaces as well as on cementite surfaces. By means of Auger electron spectroscopy (AES), scanning Auger electron microscopy (SAM) and energy dispersive X‐ray analysis (EDX) it was shown that coke contains graphite, cementite and iron particles with adsorbed sulphur.