Hydrogen Compatibility and Suitability of Metallic Materials in Hydrogen Atmosphere

Abstract

Hydrogen embrittlement (HE) of metallic materials, in particular hydrogen gas embrittlement (HGE) is reviewed to contribute the safety of hydrogen energy. Metal-hydrogen potential energy behavior on the metal surface and inside the metal is summarized by the current literatures and recent HE mechanism of hydrogen-enhanced strain-induced vacancy (HESIV) theory is described. Historical R&D of hydrogen technology is described from R&D of NASA space shuttle to that of high-pressure hydrogen storage of fuel cell vehicles (FCVs). Materials testing equipment in high-pressure hydrogen up to 230 MPa are developed. HGE of the engineering materials are examined in high-pressure hydrogen and summarized in the table of the AIST HGE evaluation of materials. Effects of hydrogen pressure up to 210 MPa, chemical composition by Ni equivalent and temperature from 77 to 773 K on HGE are discussed. Mechanical behavior of materials in liquid hydrogen and gaseous helium at 20 K is also discussed. Prevention of HGE using metallic structure control, surface coating on the surface and inhibitor gases added to hydrogen atmosphere is introduced.