|A Study of Hot Corrosion of Fe-Cr Alloys Induced by a Thin Film of Fused (Na,K)(2)SO4 by Electrochemical Impedance Spectroscopy|
|S. N. Liu; W. Su; W. Y. Lu; Z. F. Wei; C. L. Zeng
|Source Publication||High Temperature Materials and Processes
|Abstract||To understand the hot corrosion mechanism of materials it is of significance to establish electrochemical measurements under a thin film of fused salts. In this paper, the hot corrosion behavior of Fe-Cr alloys con-taining 5, 10 and 25wt% Cr, respectively, in the presence of a fused film of 0.9Na(2)SO(4)-0.1K(2)SO(4) (mole fraction) at 1173 K in air has been investigated by electrochemical impedance spectroscopy using a two-electrode system. The Nyquist plots for the corrosion of both Fe-5Cr and Fe-10Cr are composed of a very small semicircle at high frequencies and a line at low frequencies indicating that the corrosion is controlled by the diffusion of oxidants in the fused salt film. The alloys were severely corroded, forming a thick porous corrosion layer containing large amounts of non-protective precipitated Fe oxide particles. Conversely, the Nyquist plots for the corrosion of Fe-25Cr are composed of double capacitive loops, with significantly larger impedance values, which are associated with the formation of a protective Cr2O3 scale. Based on the experimental diffusion impedance results and the theoretic solubility and diffusion coefficient of oxygen in molten salts, respectively, a theoretical value of the diffusion flux of molecular O-2 has been calculated.|
|description.department||[liu, s. n.
; su, w.
; lu, w. y.
; wei, z. f.] guangdong power grid corp, elect power res inst, guangzhou, guangdong, peoples r china.
; zeng, cl (reprint author), chinese acad sci, inst met res, state key lab corros & protect, shenyang 110016, peoples r china.
S. N. Liu,W. Su,W. Y. Lu,et al. A Study of Hot Corrosion of Fe-Cr Alloys Induced by a Thin Film of Fused (Na,K)(2)SO4 by Electrochemical Impedance Spectroscopy[J]. High Temperature Materials and Processes,2013,32(5):493-501.
S. N. Liu,W. Su,W. Y. Lu,Z. F. Wei,&C. L. Zeng.(2013).A Study of Hot Corrosion of Fe-Cr Alloys Induced by a Thin Film of Fused (Na,K)(2)SO4 by Electrochemical Impedance Spectroscopy.High Temperature Materials and Processes,32(5),493-501.
S. N. Liu,et al."A Study of Hot Corrosion of Fe-Cr Alloys Induced by a Thin Film of Fused (Na,K)(2)SO4 by Electrochemical Impedance Spectroscopy".High Temperature Materials and Processes 32.5(2013):493-501.
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