Effect of texture, grain boundary constitution, and molybdenum partitioning on corrosion and hydrogen permeation behavior of pulse electrodeposited Ni-Mo coatings

Banerjee, S and Singh, AP and Kumar, GM and Srivastava, C (2024) Effect of texture, grain boundary constitution, and molybdenum partitioning on corrosion and hydrogen permeation behavior of pulse electrodeposited Ni-Mo coatings. In: Materialia, 38 .

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Abstract

Microstructural evolution, electrochemical corrosion and hydrogen permeation in pulse electrodeposited Ni-Mo coatings (2, 4, 8, and 11wt Mo) were investigated. Electrochemical impedance spectroscopy and potentiodynamic polarization measurements revealed improved corrosion resistance at an optimum Mo content. The corrosion current density icorr and polarization resistance Rp values obtained were 13.8 μA/cm2 and 1745 Ωcm2 respectively for pure Ni coating while the icorr and Rp values obtained were 1.7 μA/cm2 and 5406 Ωcm2 respectively for Ni-4wt Mo coating. Further, increase in the Mo content beyond 4 wt increased the corrosion rate. Nevertheless, corrosion resistance of Ni-Mo coatings was found to be higher than the pure Ni coating. Ni-Mo coatings contained relatively Mo-enriched clusters in a solid solution matrix. The highest corrosion resistance of Ni-4wt Mo coating was due to lower energy (001) and (111) textures, lower energy grain boundary constitution, and low coating strain. In Ni-4wt Mo coating, Mo-enriched Ni-Mo nanoclusters inhibited hydrogen passage by providing a torturous path. In contrast, a high fraction of high-angle grain boundaries (compared to pure Ni coating) facilitated hydrogen permeation leading to a similar extent of hydrogen permeation through pure Ni and Ni-4wt Mo coatings. © 2024 Acta Materialia Inc.

Item Type:	Journal Article
Publication:	Materialia
Publisher:	Elsevier B.V.
Additional Information:	The copyright for this article belongs to publishers.
Keywords:	Atomic emission spectroscopy; Corrosion rate; Corrosion resistance; Corrosion resistant coatings; Corrosive effects; Molybdenum; Molybdenum metallography; Molybdenum metallurgy; Nickel coatings; Textures; Vacuum welding, Clusterings; Grain-boundaries; Hydrogen permeation; Micro-structural; Mo coatings; Mo content; Ni coating; Ni-Mo coatings; P-values; Permeation behavior, Electrochemical corrosion
Department/Centre:	Division of Mechanical Sciences > Materials Engineering (formerly Metallurgy)
Date Deposited:	04 Dec 2024 16:50
Last Modified:	04 Dec 2024 16:50
URI:	http://eprints.iisc.ac.in/id/eprint/86882

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