The diffusion process of hydrogen in aluminum melts was investigated. The pair correlation function, first peak position, and coordination number were calculated and differences in the structural properties among Al-H, Cl-H, and Al-Cl pair were examined. The mechanism of chlorine with regard to improving hydrogen diffusion was considered. According to an ab initio molecular dynamics calculations, the diffusivity of hydrogen in liquid aluminum was given by:

D(m2/s) = 0.118 x 10-4exp[-0.316(eV)/kT]

in good agreement with the experimental data. Correspondingly the diffusivity in the presence of chlorine was given by:

D(m2/s) = 0.09 x 10-4exp[-0.251(eV)/kT]

It was concluded that the diffusion of hydrogen in aluminum melts could be enhanced by the presence of chlorine.

Hydrogen Diffusion in Aluminum Melts: an ab initio Molecular Dynamics Study. Liu, Y., Dai, Y., Wang, J., Shu, D., Sun, B.: Journal of Wuhan University of Technology - Materials Science, 2012, 27[3], 560-7