The effect of solution pH on the electrochemical performance of nanocrystalline metal ferrites MFe2O4 (M=Cu, Zn, and Ni) thin films

E M Elsayed,M M B El-Sabbah,H F Y Khalil,M R Hussein,M M Rashad,I A Ibrahim

doi:10.1007/s13204-015-0453-3

E M Elsayed, M M B El-Sabbah + Show 4 more

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https://doi.org/10.1007/s13204-015-0453-3

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Abstract

Nanocrystalline metal ferrite MFe2O4 (M=Cu, Zn, and Ni) thin films have been synthesized via electrodeposition–anodization process. Electrodeposited (M)Fe2 alloys were obtained from aqueous sulfate bath. The formed alloys were electrochemically oxidized (anodized) in aqueous (1 M KOH) solution, at room temperature, to the corresponding hydroxides. The parameters controlling the current efficiency of the electrodeposition of (M)Fe2 alloys such as the bath composition and the current density were studied and optimized. The anodized (M)Fe2 alloy films were annealed in air at 400 °C for 2 h. The results revealed the formation of three ferrite thin films were formed. The crystallite sizes of the produced films were in the range between 45 and 60 nm. The microstructure of the formed film was ferrite type dependent. The corrosion behavior of ferrite thin films in different pH solutions was investigated using open circuit potential (OCP) and potentiodynamic polarization measurements. The open circuit potential indicates that the initial potential E im of ZnFe2O4 thin films remained constant for a short time, then sharply increased in the less negative direction in acidic and alkaline medium compared with Ni and Cu ferrite films. The values of the corrosion current density I corr were higher for the ZnFe2O4 films at pH values of 1 and 12 compared with that of NiFe2O4 and CuFe2O4 which were higher only at pH value 1. The corrosion rate was very low for the three ferrite films when immersion in the neutral medium. The surface morphology recommended that Ni and Cu ferrite films were safely used in neutral and alkaline medium, whereas Zn ferrite film was only used in neutral atmospheres.

Highlights

Nanocrystalline metal ferrite MFe2O4 (M=Cu, Zn, and Ni) thin films have been synthesized via electrodeposition–anodization process
The open circuit potential indicates that the initial potential Eim of ZnFe2O4 thin films remained constant for a short time, sharply increased in the less negative direction in acidic and alkaline medium compared with Ni and Cu ferrite films
The surface morphology recommended that Ni and Cu ferrite films were safely used in neutral and alkaline medium, whereas Zn ferrite film was only used in neutral atmospheres

Summary

Introduction

Nanocrystalline metal ferrite MFe2O4 (M=Cu, Zn, and Ni) thin films have been synthesized via electrodeposition–anodization process. 12.0 1 M NaOH laser deposition (Bilovol et al 2014), sol–gel (Li et al 2014b), chemical vapor deposition (CVD) (Shen et al 2014), and dip coating (Sathaye et al 2003) have been employed for ferrite film deposition. Such methods are effective, expensive equipment limits large-scale operation. The high deposition temperature limits the option of the substrate material as well as restricts different applications of ferrite thin films. In this paper, three nanocrystalline spinel ferrite thin films MFe2O4 (M=Cu, Zn, Ni) have been synthesized using electrochemical deposition technique.

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