Reaction-diffusion in the Al-Ag system

Reaction-diffusion of the Al-Ag system was investigated by the electron probe micro-analysis. Experimental results obtained were as follows. (1) Intermediate phases ζ and μ were formed by the diffUsion between aluminum and silver. (2) Thickness of the ζ phase was expressed by the equation of W=k√t, where t was the diffusion time and k the growth rate constant. And the k was expressed as follows. k21=3.1×10-1exp(-28000/RT)cm2/sec (360°C440°C: ζandμphases) k22=6.6×10-1exp(-29000/RT)cm2/sec (480°C560°C: onlyζphase) k23=2.6×10-1exp(-28000/RT)cm2/sec (360°C560°C: all temperature range measured). (3) Interdiffusion coefficients in the ζ phase were expressed as follows. D1=2.1×10-1exp(-27000/RT)cm2/sec (360°C440°C: ζandμphases) D2=2.1×10-1exp(-27000/RT)cm2/sec (480°C560°C: onlyζphase) D3=2.5×10exp(-27000/RT)cm2/sec (360°C560°C: all temperature range measured). (4) It was shown by the Kirkendal effect that aluminum diffused faster than silver.