US EPA

607848 

Journal Article 

A comparative study on the corrosion behaviour of 304 austenitic stainless steel in sulfamic and sulfuric acid solutions 

Hermas, AA; Morad, MS 

2008 

Yes 

Corrosion Science
ISSN: 0010-938X
EISSN: 1879-0496 

50 

9 

2710-2717 

Abstract: Potentiodynamic polarization and EIS have been employed to compare the corrosion behaviour of 304 stainless steel in NH2SO3H and H2SO4 solutions. Corrosion tests were carried out as a function of the acid’s concentration (0.1–0.5M) and solution temperature (20–60 ^oC). The corrosion rate is higher in H2SO4 than in H2NSO3H in all concentrations and temperatures. Values of the activation energy (E a) revealed that the corrosion process is faster in H2SO4 than in NH2SO3H solution. EIS data showed that the display of Nyquist plots, and hence the mechanism of corrosion, depends not only on the acid concentration but also on the solution temperature. In 0.1M concentration, the equivalent circuits R e(R ct Q dl) and R e(R ct Q dl)(RQ)ads describe the corrosion systems in H2NSO3H and H2SO4 solutions respectively. At concentrations ⩾0.2M, the equivalent circuit R e(R ct Q dl)Q diff is applicable. Adsorption of the counter ion of the acid on the steel surface and the stability of the surface complex may explain the observed corrosion rates. [Copyright 2008 Elsevier] Copyright of Corrosion Science is the property of Elsevier Science Publishing Company, Inc. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts) 

AUSTENITIC stainless steel; SULFURIC acid; CORROSION resistant alloys; POLARIZATION (Electricity); METALS -- Surfaces; STABILITY; SURFACE chemistry