Hydrogen Embrittlement Mitigation in Structural Steels: Role of Nickel-Based Coatings as Permeation Barriers in Simulated Hydrogen Environments

Abstract

The global transition towards cleaner energy has positioned hydrogen as an alternative to fossil fuels, with the potential to lower the carbon footprint from modern energy systems. However, a major challenge with the complete deployment of hydrogen energy is the issue of hydrogen embrittlement (HE) which significantly compromises the reliability of structural materials exposed to hydrogen-rich environments. This study evaluates the HE resistance of nickel-based coatings applied on cold-finished mild steels, with particular emphasis on assessing their performance as permeation barriers to mitigate HE. Hydrogen was introduced into the coated steels via electrochemical hydrogen charging at varying current densities to replicate different levels of hydrogen exposure. The mechanical behaviour of the coated steel was evaluated through tensile, indentation, and fatigue testing. The results demonstrated that nickel coatings provide a measurable degree of resistance to hydrogen-induced degradation, however, their effectiveness is dependent on the level of hydrogen exposure.