Deposition current density-induced grain boundary engineering of electrodeposited cobalt coatings for enhanced electrochemical stability

ABSTRACT

Cobalt coatings were electrodeposited at different deposition current densities (10 mA·cm⁻², 20 mA·cm⁻², 30 mA·cm⁻², 40 mA·cm⁻², 60 mA·cm⁻²) over mild steel substrate. The coating deposited at 30 mA·cm⁻² showed the highest corrosion resistance (R_p= 7515Ω·cm²) due to a higher fraction of Low energy grain boundary constitution (i.e. coincidence site lattices (CSLs) and low angle grain boundaries (LAGB)) and exhibited higher fraction of stabler Co₃O₄ passive oxide layer. The coatings electrodeposited at 60 mAcm⁻² exhibited lower corrosion resistance (R_p= 1304 Ω·cm²) due to a higher fraction of high-angle grain boundaries and a higher fraction of relatively lesser stable Co(OH)_2.

KEYWORDS:

• Cobalt coatings
• electrodeposition
• texture
• grain boundaries
• corrosion

Acknowledgements

The authors acknowledge the funding received from the CSIR government of India. The authors also acknowledge the electron microscopy facilities in AFMM, IISc Bangalore.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by CSIR India: [Grant Number CSIR].