The diffusion-controlled growth of silicides was studied in Nb/Si and Nb/NbSi2 bulk diffusion couples which were annealed at 1200 to 1350C for 2 to 24h. Both compounds were found to grow as parallel layers, according to the parabolic rate law. The concept of the integrated diffusion coefficient was used to describe the growth kinetics of the silicides. The corresponding activation energy was 263kJ/mol for Nb5Si3 and 304kJ/mol for NbSi2. The activation energy (in eV) scaled as 0.98Tm(K)/1000 for Nb5Si3 and as 1.4Tm(K)/1000 for NbSi2; in agreement with the general behavior of transition metal silicides. The position of the Kirkendall plane, within the Nb5Si3 layer that developed in Nb/NbSi2 couples, indicated that the diffusion of Si in Nb5Si3 in the present temperature range was considerably faster than that of Nb.

Reactive Growth of Niobium Silicides in Bulk Diffusion Couples. C.Milanese, V.Buscaglia, F.Maglia, U.Anselmi-Tamburini: Acta Materialia, 2003, 51[16], 4837-46