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Experimental Characterization and Computer‐Based Simulation of Thermodynamics and Kinetics of Corrosion of Steels at High Temperatures
Author(s) -
Trindade V. B.,
Krupp U.,
Christ H.J.,
Monteiro M. J.,
Rizzo F. C.
Publication year - 2005
Publication title -
materialwissenschaft und werkstofftechnik
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.285
H-Index - 38
eISSN - 1521-4052
pISSN - 0933-5137
DOI - 10.1002/mawe.200500904
Subject(s) - vanadium , gibbs free energy , metallurgy , thermodynamics , materials science , microstructure , austenite , grain boundary , chemistry , physics
This study aims to an experimental and theoretical description of three different corrosion phenomena of steels during high‐temperature exposure: (i) the effect of vanadium content during oxidation of tool steels, (ii) the grain size effect during oxidation of low‐Cr boiler steels, and (iii) the carburization of austenitic steels. The experimental part was carried out by means of thermogravimetric measurements and scanning electron microscopy observations. Computational thermodynamics investigations were carried out by performing complex equilibrium calculations of the Fe‐Cr‐V‐W‐Mo‐O‐C system using the commercial software FactSage. The kinetics of oxidation and carburization processes were accounted for by solving the diffusion differential equation numerically (finite‐difference method) taking the material's microstructure into consideration, by distinguishing between precipitation along the grain boundaries and within the grain interior as well as incorporating local thermodynamic equilibrium by means of the subroutine ChemApp, which works according to Gibbs energy minimization criteria.