Naslov
Passivity of Nitrogen-Bearing Stainless Steel in Acidic Solution

Autori
Martinez, Sanja ; Metikoš-Huković, Mirjana ; Lajci, Nushe

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Passivity-9, Program and abstracts / Marcus, Philippe - Pariz : CEFRACOR, 2005

Skup
Passivity-9, The 9th International Symposium on the Passivation of Metals and Semiconductors and the Propetries of Thin Oxide Layers

Mjesto i datum
Pariz, Francuska, 27.06.2005. - 01.07.2005

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
stainless steel; nitrogen-bearing; point defect model
(stainless steel; nitrogen-bearing; point defect model.)

Sažetak
The mechanism and kinetics of the passivation process, the mechanisms of charge transfer and potential distribution in the system NTR50 steel/passive film/0.5 M H_2SO_4, were studied using transient electrochemical techniques in combination with cyclic voltammetry and the earlier results of XPS analysis. It has been established that the point defect model that takes into account the interfacial kinetic effects presents the best fit to the experimental data yielding physically reasonable parameters. It has been applied to quasi-stationary experimental data to determine: (i) the transfer coefficient for the metal dissolution reaction through the barrier film equals 0.017 (ii) the coefficient of proportionality between the barrier film/solution potential and the applied potential equals 0.446 and (iii) the electric field equals 4.4 x 106 V cm^-1. Cation vacancies, VCr_3^- represent the main charge carriers under quasi – stationary conditions of formation and growth of the barrier Cr_2O_3 film. The barrier layer on NTR50 stainless steel is essentially a cation conductor. The outward migrating species are presumed to be the Fe^3+ ions and the molybdenum Mo^4+ and Mo^6+ ions, in concordance with the film composition comprised of an inner Cr_2O_3 barrier layer and a Fe-rich outer hydrated layer.

Izvorni jezik
Engleski

Znanstvena područja
Kemija, Kemijsko inženjerstvo

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