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On the oxidation of Co35 w% Cr at high temperatures
Author(s) -
Kofstad P. K.,
Hed A. Z.
Publication year - 1970
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.19700211104
Subject(s) - oxide , torr , materials science , atmospheric temperature range , oxygen , coupon , analytical chemistry (journal) , chemistry , metallurgy , physics , thermodynamics , organic chemistry , finance , chromatography , economics
The oxidation behaviour of coupon and spherical specimens of Co‐35 w/o Cr have been studied in the temperature range 900–1300°C and at oxygen pressures from 0.2 to 760 torr. For coupon specimens the oxidation is approximately parabolic at and below 1100°C. Protective scales of Cr 2 O 3 are formed on flat surfaces. Corners and edges show enhanced oxidation, and in these regions the surface oxide also contains CoCr 2 O 4 . Oxidation of spherical specimens is nonparabolic and the oxide scales consist of Cr 2 O 3 , CoCr 2 O 4 , and interspersed particles of CoO. During initial oxidation spherical specimens oxidize faster than coupon specimens.