Naslov
Electrochemical corrosion and hydrogen diffusivity in dual-phase steel

Autori
Malina, Jadranka ; Begić Hadžipašić, Anita ; Nižnik, Štefan

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
2nd International Conference Corrosion and Material Protection (Proceedings), EFC Event No. 322 / SVUOM.Praha - Prag : SVUOM.Praha, 2010, CD-ROM: P036

ISBN
978-80-903933-6-3

Skup
2nd International Conference Corrosion and Material Protection, EFC Event No. 322

Mjesto i datum
Prag, Češka Republika, 19.04.2010. - 22.04.2010

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
DP steel; electrochemical corrosion; hydrogen diffusivity; ferrite; martensite

Sažetak
Due to application in automotive industries, dual phase (DP) steels have received enormous attention over the last three decades. Thanks to both constituents (soft ferrite and hard martensite) they possess a number of unique properties which make them very good quality sheet materials. However, electrochemical corrosion of DP results in the evolution of hydrogen atoms migrating in steel. In order to understand and quantify the effects of hydrogen migration in dual phase steel, diffusion properties of absorbed H were investigated. The specimens of DP steel were electrochemically corroded in a solution of 2M H2SO4 at room temperature in order to achieve a hydrogen saturated condition. This was performed by installing the membrane specimen in an electrolytic cell consisting of 2 compartments: H-entry and H-exit. In the exit compartment filled with 1M NaOH, a weak anodic potential of 200 mV vs SCE was applied in order to maintain a zero hydrogen concentration at surface. Anodic current of H+-ions was monitored until steady state conditions were achieved. In that way the diffusion rate of hydrogen through the sample, and hydrogen flux were recorded as a function of time. Optical micrography and SEM observations with EDS analysis of DP steel before and after hydrogen charging were performed. Experiments have shown that evolution of the hydrogen flux (J) with time (t) exhibits a sigmoid relationship. The apparent hydrogen solubility, Sapp and the apparent hydrogen diffusivity, Dapp were determined. The data for corrosion potential (Ecorr) and corrosion current (Icorr) have been derived from the experimentally obtained cathodic and anodic polarization (E vs log I) curves using Tafel’s linear extrapolation method. SEM/EDS analyses have shown that ferrite and martensite in DP steel govern the behaviour of absorbed hydrogen.

Izvorni jezik
Engleski

Znanstvena područja
Metalurgija

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