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Experimental determination of the behaviour of heat‐resisting alloys in complex atmospheres
Author(s) -
Tachikart M. M.,
Armanet F.,
Coddet C.,
Bèranger G.,
Davidson J. H.
Publication year - 1987
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/maco.19870381009
Subject(s) - corrosion , coal gasification , process engineering , coal , thermodynamics , high temperature corrosion , oxygen , materials science , water vapor , environmental science , metallurgy , chemistry , waste management , engineering , physics , organic chemistry
Designers of industrial plants are often confronted with problems of high temperature corrosion in complex atmospheres. The selection and development of economically and technically viable new materials for such applications requires the use of experimental rigs capable of simulating as closely as possible the real operating conditions. With this aim, a new laboratory installation has been built, which enables precisely defined mixtures of up to four gases to be obtained (plus water vapour, if required). It is thus possible to fix the activities of O, H, C and S at the working temperature. The composition is monitored at various points in the rig, using a chromatograph. The first tests were carried out on three Fe‐Cr‐Ni alloys exposed to complex gas mixtures (CO/CH 4 /H 2 /H 2 S) similar to those encountered in coal‐gasification plant. The observations show that, due to the low oxygen partial pressures, the multi‐layered scales are composed mainly of sulphides. These results are compared with predictions based on calculated thermodynamic phase stability diagrams.