The electronic structure and hydrogen gas-induced environmental embrittlement in Ni4Mo alloy

Atomic ordering is known to result in hydrogen gas-induced environmental embrittlement in Ni4Mo alloy. This paper addresses the question of why atomic ordering exacerbates the hydrogen gas-induced environmental embrittlement from the electronic structure using electron energy loss spectroscopy (EELS). EELS of the Ni L3,2 edges showed that the atomic ordering increases the 3d occupancy per Ni atom and therefore increases the surface catalytic activity to dissociation molecular hydrogen into atomic hydrogen.