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Effect of exposure time on the morphology of corrosion on high chromium white cast iron in high temperature caustic solutions
Author(s) -
McLeod A. J.,
Clegg R. E.
Publication year - 2013
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.201106318
Subject(s) - spinel , chromium , metallurgy , materials science , carbide , corrosion , oxide , chromium carbide , morphology (biology) , caustic (mathematics) , high temperature corrosion , cast iron , phase (matter) , chemistry , physics , organic chemistry , genetics , mathematical physics , biology
High chromium white irons are important candidate materials for use in alumina refineries to combat wear and corrosion. The effect of exposure time on the formation of oxide films was studied in a 23% Cr white cast iron exposed at 260 °C in 110 g/l caustic soda solutions. It was found that whilst well‐formed octahedral M(II)O.M(III) 2 O 3 spinel type oxides initially formed and spread across the surface of the material, these were gradually replaced by a background oxide with a higher Cr/Fe ratio and the morphology of the octahedral crystals became less well formed. Also, the oxidation was found to be predominantly in the matrix material, leaving carbide particles unsupported on the surface and in the later stages, significant corrosion was found along the carbide/matrix phase boundary.