Solid state reactions in the Ag-Ti-Si system : periodic layer formation

The isothermal cross-section through the ternary phase diagram Ag—Ti—Si at 1123 K was determined by means of multiphase diffusion couples. No ternary phases are pres ent on this Ag—Ti—Si isotherm. A thermodynamic assessment of this system was performed using the data from the binary systems. The formation of a periodic structure consisting of alternating layers of titanium-silicides and silver was observed in "sandwich" diffusion couples Ag/Ti-foil/Si after annealing between 1023 K and 1123 K. It was attributed to the internal reaction between titanium and silicon within the Ag-layer formed in situ during the solid state interaction, This pro cess, periodic in space and time, resembles the well-known Liesegang phenomenon.