Permeation barriers for hydrogen embrittlement prevention in metals – A review on mechanisms, materials suitability and efficiency

To develop large-scale use of hydrogen as an environmentally sensible alternative to fossil energy sources, the design of safe and innovative storage and transportation infrastructure is a crucial issue. In direct contact with the high-pressure hydrogen, structural materials, especially traditional alloys, are indeed susceptible to degradation of their mechanical properties due to the diffusion of hydrogen atoms into their atomic lattice structure. This phenomenon leads to materials' embrittlement and results in severe damage to the employed components. Therefore, the prevention of hydrogen atom diffusion is one key consideration to avoid its adverse effects on materials' mechanical properties. This paper aims to review the mechanisms and factors responsible for the hydrogen embrittlement phenomenon. The main specifications to fulfill while selecting appropriate materials are hence considered for hydrogen energy uses. Finally, the effective surface modification solutions are reviewed for implementation as a permeation barrier to protect the structural materials from hydrogen degradation.