Equations were derived which describe self-diffusion and interdiffusion in non-equilibrium grain boundaries. The influence of the degree of the non-equilibrium state of the boundaries on the development of the process of grain-boundary diffusion was examined. The kinetics of the variation of the non-equilibrium excess volume due to the diffusional mass transfer along grain boundaries was analyzed. Equations of Diffusion in Nonequilibrium Grain Boundaries. V.N.Perevezentsev, A.S.Pupynin: Physics of Metals and Metallography, 2008, 105[4], 322-6