Diffusion study in NixZr1-x amorphous metallic alloys

The temperature effect of nickel self-diffusion in amorphous NiZr alloy has been determined from interdiffusion measurements by studying the rate of decrease in amplitude of composition-modulated thin films. Temperature and pressure effects of hafnium diffusion in amorphous Ni54Zr46 alloys have also been measured, given the zirconium self-diffusivity behaviour in this material, using secondary ion mass spectrometry (SIMS). Activation energies measured are 1.33 eV/at. for nickel diffusion and 0.76 eV/at. for hafnium diffusion. The dependence on pressure studied by annealing samples at 412 degrees C, 10 h, under hydrostatic pressure from 0.02 to 0.96 GPa led to an activation volume of 8 Angstrom(3)/atom for hafnium diffusion in this amorphous alloy. These present results are then discussed with respect to possible diffusion mechanisms like point defects models and collective 'models' involving several atoms. (C) 1997 Acta Metallurgica Inc.