Effect of Grain Size on the Corrosion Behavior of Fe-3wt.%Si-1wt.%Al Electrical Steels in Pure Water Saturated with CO2

Materials

Tomasz Mazur¹  Roma Wirecka¹  Dawid Dunikowski²  Gaetano Palumbo²  Jacek Banaś²  Urszula Lelek-Borkowska²  Kinga Wawer³ 

[1] Academic Centre for Materials and Nanotechnology, AGH University of Science and Technology, Mickiewicza St. 30, 30-059 Kraków, Poland;Faculty of Foundry Engineering, Department of Chemistry and Corrosion of Metals, AGH University of Science and Technology, Mickiewicza St. 30, 30-059 Krakow, Poland;Łukasiewicz Research Network–Institute of Aviation, Al. Krakowska 110/114, 02-256 Warsaw, Poland;

关键词: silicon steel;    electrical steel;    grain size;    electrochemical corrosion;    carbon dioxide;    AM-KPFM Volta potential measurements;   

DOI  :  10.3390/ma14175084

来源: DOAJ

【 摘 要 】

The corrosion behavior of two silicon steels with the same chemical composition but different grains sizes (i.e., average grain area of 115.6 and 4265.9 µm²) was investigated by metallographic microscope, gravimetric, electrochemical and surface analysis techniques. The gravimetric and electrochemical results showed that the corrosion rate increased with decreasing the grain size. The scanning electron microscopy/energy dispersive x-ray spectroscopy and X-ray photoelectron spectroscopyanalyses revealed formation of a more homogeneous and compact corrosion product layer on the coarse-grained steel compared to fine-grained material. The Volta potential analysis, carried out on both steels, revealed formation of micro-galvanic sites at the grain boundaries and triple junctions. The results indicated that the decrease in corrosion resistance in the fine-grained steel could be attributed to the higher density of grain boundaries (e.g., a higher number of active sites and defects) brought by the refinement. The higher density of active sites at grain boundaries promote the metal dissolution of the and decreased the stability of the corrosion product layerformed on the metal surface.

【 授权许可】

Unknown