Measurements of solute GB diffusion in Cu and Ag polycrystals were carried out in Harrisons type-B and type-C kinetic regime using ~75Se, ~195Au, ~63Ni radioisotopes. In the B-regime at high temperatures, the GB diffusion parameter s#delta#D_GB was determiend (s being the GB segregation factor, #delta# the GB width and D_GB the GB diffusion coefficient), while in the C-regime at low temperatures D_GB values were measured directly. The investigations of these differently behaving solute - solvent systems on Cu and Ag basis yield information on solute GB diffusion and segregation in relation to solute - solvent atomic binding and solute - vacancy interaction i nthe bulk and in GBs. The GB diffusion of ~64Cu and ~195Au in a series of near #SIGMA# = 7, #THETA# = 36.9 deg (310) [001] Cu tilt GBs and of ~71Ge in a series of near #SIGMA# = 7, #THETA# = 38.2 (123) [111] Al tilt GBs in dependence on the tilt angle #THETA# and on the temperature was studied. A characteristic minimum in the GB diffusion aprameter and a maximum in the activatio nenergy was observed at the ideal CSL GBs.
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