Microbiologically influenced corrosion of ferritic steel–zirconium-based metal waste form alloy under simulated geological repository environment

ABSTRACT

The present work focused on investigating the microbiologically influenced corrosion (MIC) susceptibility of ferritic steel–Zr-based metal waste form (MWF) alloy in simulated ground water media, cultured with a common biofilm former Bacillus sp. Total viable count studies showed a good bacterial attachment on the surface of MWF alloy. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) examination of the biofilm MWF surface revealed preferential adhesion of microbes on Fe–Zr-rich intermetallic phases. Anodic polarisation and electrochemical impedance spectroscopic (EIS) studies showed active corrosion potential (E_corr), higher passive current density (I_pass) and decreased polarisation resistance (R_p) values, confirming the corrosion susceptibility of MWF alloy under Bacillus sp. biofilm.

KEYWORDS:

• Ferritic steel – Zr based metal waste form
• simulated ground water media
• Fe–Zr-rich intermetallic phases
• biofilm
• corrosion susceptibility

Acknowledgements

The authors acknowledge Dr John Philip, Dr Saroja Saibaba and Dr G. Amarendra for their support and encouragement. The authors also acknowledged the suggestion and fruitful discussion with Dr U. Kamachi Mudali and Dr C. Mallika during the course of this work. The authors thank Dr S. C. Vanithakumari for the help in AFM images. The authors would like to appreciate the contributions of Mrs U. Carolin Suji, in some of the experimental work.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

S. Ningshen http://orcid.org/0000-0002-2078-7870