The isotope exchange technique and a highly sensitive chemical sectioning method were used to study the diffusion of 82Br in single crystals. The results revealed a strong effect of dislocations and grain boundaries upon diffusion. The intrinsic diffusivity at 400 to 700C could be described by:

D (cm2/s) = 3 x 104 exp[-2.61(eV)/kT]

while pipe diffusion at 400 to 700C was described by:

D (cm2/s) = 3 x 10-3 exp[-1.49(eV)/kT]

The results also showed that Br diffusion was independent of the ambient Br pressure (table 15).

Measurement of Anionic Diffusion in KBr by Means of Isotopic Exchange. D.K.Dawson, L.W.Barr: Proceedings of the British Ceramic Society, 1967, 9, 171-9

Table 15

Diffusivity of 82Br in KBr Single Crystals at 600C,

under Various Ambient Br Pressures