Diffusion of Na-24 and Co-59 in Al-Cu-Fe quasicrystals

Diffusion of Na-24 and Co-19 in Al65Cu20Fe15 icosahedral quasicrystals has been investigated over the temperature range from 773 to 1053 K. Concentration depth profiles of Na-24 and Co-59 in Al65Cu20Fe15 icosahedral quasicrystals have been measured using SIMS technique. The temperature dependence of Na-24 and Co-59 diffusivities in Al65Cu20Fe15 icosahedral quasicrystals in the range of temperatures from 773 K to 1053 K can be described by Arrhenius equations: D-Na =[(74 +/- 0.5)x 10(-11)] exp(RT/-124.8 +/- 3.7 kJxmol(-1)) m(2)s(-1), D-Co = [1.3 +/- 0.4) x 10(-12)] exp (RT/-95.4 +/- 4.3 kJ x mol-1) m(2)s(-1). The diffusivities of Na-24 and Co-59 in Al65Cu20Fe15 icosahedral quasicrystals are four to five orders of magnitude lower than Na-24 and Co-59 diffusivities in crystalline Al. The diffusion mechanisms in quasicrystals are discussed.