Corrosion study of HK-40m alloy exposed to molten sulfate/vanadate mixtures using the electrochemical noise technique

被引:34
作者
Cuevas-Arteaga, C. [1 ]
机构
[1] UAEM, Ctr Invest Ingn & Ciencias Aplicadas, Cuernavaca 62209, Morelos, Mexico
关键词
molten salts; high temperature corrosion; hot corrosion; localization corrosion;
D O I
10.1016/j.corsci.2007.11.011
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Corrosion performance of HK40m alloy obtained from electrochemical noise technique and polarization curves during 24 h of exposure in high sulfate (80 mol% Na2SO4-20 mol% V2O5) and high vanadate (80 mol% V2O5-20 mol% Na2SO4) Molten salts at 700 degrees C are reported. Electrochemical noise signals were analyzed in the time and frequency domain. A statistical analysis obtaining the resistance noise, the current standard deviation and the localization index are presented as well as the determination of corrosion rates. Corrosion rates were supported by X-ray diffraction analysis of corrosion products and scanning electron microscopy analysis of corroded samples. Results from optical microscope examination of the corroded samples showed that HK-40m alloy suffered inter-granular corrosion when was exposed to the high vanadate salt, whereas exposed to the high sulfate salt, HK40m corroded through a mixed corrosion process. A corrosion mechanism of HK-40m alloy was obtained together with the corrosion rate, showing the different behavior when exposing the alloy to a high vanadate and high sulfate molten salts. (C) 2007 Elsevier Ltd. All rights reserved.
引用
收藏
页码:650 / 663
页数:14
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