On the Use of Surfactant Polarity for Grain Boundary Engineering in Electrodeposited Cobalt Coatings and Its Direct Effect on the Coating Corrosion Behavior

Mohan Kumar, G and Srivastava, C (2023) On the Use of Surfactant Polarity for Grain Boundary Engineering in Electrodeposited Cobalt Coatings and Its Direct Effect on the Coating Corrosion Behavior. In: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science .

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Abstract

Electrodeposition of cobalt coatings on mild steel was carried out by employing surfactants of different polarities (SLS (anionic), CTAB (cationic), and Triton X-100 (non-ionic). Corrosion behavior and micro-texture of the electrodeposited Co coatings were investigated and correlated. From electrochemical impedance spectroscopy (EIS) measurement, the resistance polarization (Rp) value which is a measure of corrosion resistance was determined. The highest Rp value was reported for the CTAB-containing coating followed by the SLS-containing coating and coating without surfactant The lowest Rp value was exhibited by the Triton X-100-containing coating The corrosion parameters (corrosion current density (icorr) and corrosion potential (Ecorr)) acquired from the potentiodynamic polarization analysis agreed with the trend in the Rp values. The coating with CTAB and the pristine coating showed a lower strain and higher crystallite size than the coatings with surfactants SLS and Triton X-100 which showed a higher strain and lower crystallite size. Pristine and Triton X-100-containing coatings showed strong (11 2 ¯ 0) texture and the coatings containing SLS and CTAB exhibited both (11 2 ¯ 0) and (0 1 ¯ 10) textures. As the textures exhibited by all the coatings were high energy, the observed distinct changes in the corrosion rate of the coatings were, therefore, correlated with the grain boundary constitution. A direct correlation was observed. The coating produced using the Triton X-100 showed the lowest corrosion resistance due to the presence of a higher fraction of high-energy high-angle grain boundaries (HAGBs). The CTAB surfactant-containing coating showed the highest corrosion resistance due to the lowest fraction of HAGBs, highest fraction of low-energy special boundaries along 0 1 ¯ 10 and 11 2 ¯ 0 axis, and highest fraction of CSL boundaries. © 2023, The Minerals, Metals & Materials Society and ASM International.

Item Type:	Journal Article
Publication:	Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Publisher:	Springer
Additional Information:	The copyright for this article belongs to Springer.
Keywords:	Cationic surfactants; Corrosion rate; Corrosion resistant coatings; Corrosive effects; Crystallite size; Dyes; Electrochemical corrosion; Electrochemical impedance spectroscopy; Electrodeposition; Electrodes; Grain boundaries; Polarization; Steel corrosion; Textures, Cobalt coating; Corrosion behaviour; CTAB (cationic); Electrodeposited cobalt; Energy; Grain boundary engineering; High angle grain boundaries; Resistance polarization; SLS (anionic); Triton X-100, Corrosion resistance
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	20 Mar 2023 09:27
Last Modified:	20 Mar 2023 09:27
URI:	https://eprints.iisc.ac.in/id/eprint/81027

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