Round table discussion "Grain boundary diffusion: Experiments and modeling" DSS 2010, 1-4 June, Moscow

Abstract

Several experts shared their views on grain boundary diffusion with the experiments and the modeling during the discussion at DSS 2010, held on June 1-4, 2010, Moscow. The discussion covered diffusion & segregation in bicrystals, diffusion in triple junctions, atomistic mechanisms of diffusion, and GB diffusion in semiconductors and ionic conductors. Another expert, Glickman, pointed out that GB diffusion is an entropy driven process and, in contrast to equilibrium GB segregation (adsorption), it should not necessary reduce the GB energy. Glickman stated that according to the Gibbs equation, decrease of the surface energy always results in the positive adsorption. Glickman mentioned that if GB diffusion decreases the total free energy (due to mixing entropy), it is a spontaneous process and it takes place at T>0. Another expert, Schmitz, mentioned that the total Gibbs energy must decrease and the Gibbs energy is important for the reaction.