Structure and Corrosion Resistance of Iron Coatings Containing Silicon Powders

Abstract:

Fe + Si coatings were prepared by iron deposition from a bath containing a suspension of silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of jdep=−0.020 A cm−2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 873 K for 2h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a two-phase structure, i.e., iron and silicon. The phase composition for the Fe + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Fe and Si coexist with the new phases: FeSi. Electrochemical corrosion resistance investigations were carried out in 3.5wt% NaCl, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Fe + Si coatings after thermal treatment are more corrosion resistant in 3.5wt% NaCl solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free iron and silicon, the presence of new phases (in particular silicides), and a decrease of the active surface area of the coatings after thermal treatment.

• Periodical: Advanced Materials Research (Volumes 399-401)
• Pages: 1926-1931
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.399-401.1926
• Online since: November 2011
• Authors: Yi Wang, Gang Chen, Wei Dong Liu, Qiong Yu Zhou, Qing Dong Zhong
• Keywords: Corrosion Resistance, Fe + Si Composite Coatings, Silicon, Thermal Treatment

References

[1] Popczyk M, Budniok A, Lasia A. Electrochemical properties of Ni–P electrode materials modified with nickel oxide and metallic cobalt powders. Int. J. Hydrogen Energy 2005;30:265–71.

DOI: 10.1016/j.ijhydene.2004.03.026

[2] Paseka I, Velicka J. Hydrogen evolution and hydrogen sorption on amorphous smooth Me–P(x) (Me = Ni, Co and Fe–Ni) electrodes. Electrochim Acta 1997;42:237–42.

DOI: 10.1016/0013-4686(96)00149-1

[3] Popczyk M, Serek A, Budniok A. Production and properties of composite layers based on an Ni–P amorphous matrix. Nanotechnology 2003;14:341–6.

DOI: 10.1088/0957-4484/14/2/346

[4] Karimi-Shervedani R, Lasia A. Studies of the hydrogen evolution reaction on Ni–P electrodes. J. Electrochem. Soc. 1997;144:511–9.

DOI: 10.1149/1.1837441

[5] Karimi-Shervedani R, Lasia A. Study of the hydrogen evolution reaction on Ni–Mo–P electrodes in alkaline solutions. J. Electrochem. Soc. 1998;145:2219–25.

DOI: 10.1149/1.1838623

[6] Serek A, Budniok A. Electrodeposition and thermal treatment of nickel layers containing titanium. J. Alloys Compd 2003;352:290–5.

DOI: 10.1016/s0925-8388(02)01154-4

[7] Lasia A. Study of electrode activities towards the hydrogen evolution reaction by ac impedance spectroscopy. Int. J. Hydrogen Energy,1993;18:557–60.

DOI: 10.1016/0360-3199(93)90174-9

[8] Lasia A. Nature of the two semi-circles observed on the complex plane plots on porous electrodes in the presence of a concentration gradient. J. Electroanal. Chem. 2001;500:30–5.

DOI: 10.1016/s0022-0728(00)00361-2

[9] Karimi-Shervedani R, Lasia A. Evaluation of the surface roughness of microporous Ni–Zn–P electrodes by in situ methods. J. Appl. Electrochem. 1999;29(8):979–86.