Review and evaluation of metals and alloy’s compatibility with hydrogen-fueled internal combustion engines

Hydrogen internal combustion engines (H2-ICEs) are being examined primarily owing to their low criteria pollutants and zero carbon dioxide emissions. However, there are many components and systems of a H2-ICE (including, i.e., gaskets, fuel injection system, piston, cylinder head, exhaust manifolds,…) that are exposed to direct or indirect high-pressure and temperature hydrogen that can lead to deterioration and degradation of the materials, in particular rubbers, metals and their alloys. In the present article, the implications on the characteristics of metals and their alloys exposed to a hydrogen atmosphere are examined with reference to the typical materials and respective operating conditions found in H2-ICEs. The effects of direct or indirect exposure of high pressure and low/high-temperature hydrogen on the properties including mechanical properties of metals and their alloys have been explored. Finally, based on the previous review, a critical assessment of their suitability for a safe and reliable operation on H2-ICEs is provided.