The elastic response of Nb in the region of the critical point of a H lattice gas was measured. The diffusion coefficients exhibited a so-called critical slowing-down behavior.

Ferroelasticity of Niobium due to Hydrogen as a Lattice Gas. G.Alefeld, G.Schaumann, J.Tretkowski, J.Volkl: Physical Review Letters, 1969, 22, 697-700

 

Table 92

Diffusion of H in NbH0.033 at 297.6K

 

Pressure (bar)

Method

D (cm2/s)

1

summed spectra

6.787 x 10-6

5000

summed spectra

6.883 x 10-6

1

single spectra

6.586 x 10-6

5000

single spectra

6.688 x 10-6