Hydrogen diffusion in disordered metals and alloys

The state of the art of research into the diffusion of hydrogen in metallic systems with chemical and crystalline disorder is reviewed. The physical principles and capabilities of existing experimental methods for studying hydrogen diffusion in equilibrium and nonequilibrium conditions are discussed. The current theoretical understanding of and approaches to the problem are critically analyzed. Based on the authors' original research, a quite general formalism is proposed for describing hydrogen diffusion on disordered media, which allows the analytical solution of the problem and — very importantly — enables diffusion and structural data to be used to identify the structure of amorphous and nanocrystalline alloys.