Dissolution of chromium in sulfuric acid

Dissolution of chromium in sulfuric acid

By combining electrochemical corrosion rate measurements and spectrophotometric analysis of the electrolyte it was shown that at room temperature chromium dissolves in deaerated 0.1M Na2SO4 + H2SO4 (pH1) solution as Cr(II) and Cr(III) ions in he ratio Cr(II):Cr(III)≈7:1. This process was stable over...

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Bibliographic Details
Published in:Journal of the Serbian Chemical Society Vol. 67; no. 11; pp. 777 - 782
Main Authors: Dražić Dragutin M., Popić Jovan P.
Format: Journal Article
Language:English
Published: Serbian Chemical Society 01-01-2002
Subjects:
acid solutions
anomalous dissolution
chromium
corrosion
corrosion products
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Summary:By combining electrochemical corrosion rate measurements and spectrophotometric analysis of the electrolyte it was shown that at room temperature chromium dissolves in deaerated 0.1M Na2SO4 + H2SO4 (pH1) solution as Cr(II) and Cr(III) ions in he ratio Cr(II):Cr(III)≈7:1. This process was stable over 4h without any detectable change. The total corrosion rate of chromium calculated from the analytical data is about 12 times higher, than that determined electrochemically by cathodic Tafel line extrapolation to the corrosion potential. This finding was confirmed by applying the weight-loss method for the determination of the corrosion rate. This enormous difference between these experimentally determined corrosion rates can be explained by the rather fast, "anomalous" dissolution process proposed by Kolotyrkin and coworkers (chemical reaction of Cr with H2O molecules) occurring simultaneously with the electrochemical corrosion process.
ISSN:0352-5139
1820-7421
DOI:10.2298/JSC0211777D