Effects of reaction heat and self-stress on the transport of hydrogen through metallic tubes under conditions far from equilibrium Original Research Article

A thermokinetic model of hydrogen diffusion across a metallic tube is established. It includes the enthalpy change of the metal–hydrogen reaction, heat losses, dependences of reaction rate and hydrogen diffusion coefficient on temperature, and self-stress effects, etc. A phenomenon, the super fast diffusion of hydrogen before the up-hill diffusion and Fickian diffusion during hydrogen gas charging process, which has been found experimentally for 35 years, is presented by this model. Effects of pressures and other parameters are discussed.