The liquid metal was situated on top of a ceramic diaphragm whose porosity and nature were selected so that the melt could not enter it under the influence of the applied pressure difference. This method was used, for the determination of H diffusion in molten Cu, by using a Hg diffusion pump to remove evolved H from the lower side of the diaphragm and introduce it into a gas chromatograph for quantitative analysis. At temperatures of 1376 to 1634K, the data could be described by:

D (cm2/s) = 5.12 x 10-3 exp[-24.6(kJ/mol)/RT]

P.Sigrist, H.K.Feichtinger, B.Marincek: Zeitschrift fur Physikalische Chemie, 1977, 107[2], 211-8