Abstract
The effect of the nature of oxidising agents on the passivation of stainless steel in sulphuric acid has been investigated, using many kinds of oxidising agents such as K2Cr2O7, KIO4, CuS04, KMn04, H202, HgCI2 and KI03, and the reducing agents FeSO4 and K4Fe(CN)6.
All the oxidising agents tested could inhibit the corrosion of AISI 321 type austenitic steel in 3·4N H2S04 to the extent of 89·3–98·7% in short term (1 h) experiments. The potential of the steel was ennobled in the presence of the oxidising agents.
The stability of the passivity of steel produced by oxidising agents was determined by measuring the decay in potential of passive steel until its breakdown (—200 mV vs SCE), after its transfer to H2S04 containing no oxidising agent. The quality of the passivating film was also judged by the sensitivity of response (reductlon) to cathodic pulses and to the rate of restoration of potential (self passivation) after interruptlon of the pulse.
Get full access to this article
View all access options for this article.