Acta Metallurgica Sinica (English Letters) ›› 2016, Vol. 29 ›› Issue (4): 373-381.DOI: 10.1007/s40195-016-0397-y

Special Issue: 2016年钢铁材料专辑

• Orginal Article • Previous Articles     Next Articles

Influence of Direct Current Electric Field on the Formation, Composition and Microstructure of Corrosion Products Formed on the Steel in Simulated Marine Atmospheric Environment

Nian-Wei Dai1, Jun-Xi Zhang1, Qi-Meng Chen1, Xin Zhang1, Fa-He Cao2, Jian-Qing Zhang2()   

  1. 1 Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, Shanghai University of Electric Power, Shanghai 200090, China
    2 Department of Chemistry, Zhejiang University, Hangzhou 310027, China
  • Received:2015-11-19 Revised:2015-12-23 Online:2016-03-12 Published:2016-04-27

Abstract:

X-ray diffraction, Raman spectroscopy and scanning electron microscopy were employed to investigate the effects of the DC electric field on the composition, formation and structure of corrosion products formed on the surface of the steel immersed in NaCl solution. The results show that goethite (α-FeOOH), akaganeite (β-FeOOH), lepidocrocite (γ-FeOOH) and magnetite (Fe3O4) are the major constituents among the corrosion products. The arrangement of different levels of the DC electric field intensity gives rise to the following results. The little higher DC electric field intensity (around 100-200 kV/m) promotes the crystallinity and growth of γ-FeOOH; obviously, much higher DC electric field intensity (greater than 400 kV/m) prevents the growth of α-FeOOH and facilitates the generation of Fe3O4. Both the promotional growth of γ-FeOOH and suppression of α-FeOOH growth indicated the weakness of the protectiveness of the rust layer. Consequently, the suppression of the transformation of α-FeOOH from γ-FeOOH favors the yield of the Fe3O4, which works as a large cathode area and would be about to quicken the subsequent steel corrosion.

Key words: Steel, Atmospheric, corrosion, Rust, Electric, field, Raman, spectroscopy