The self-diffusivity of 54Mn in icosahedral quasi-crystals was investigated at temperatures ranging from 723 to 1022K. The concentration depth profiles of the radio-isotope were measured by using an ion-beam sputter-sectioning technique. It was found that the temperature dependence of the self-diffusivity of Mn in Al72Pd20Mn8 icosahedral quasi-crystals could be described by:

D (m2/s) = 1.1 x 10-10exp[-134.0(kJ/mol)/RT]

The self-diffusivity of Mn in Al60Pd25Mn15 icosahedral quasi-crystals was some 2 orders of magnitude smaller:

D (m2/s) = 3.6 x 10-10exp[-109.4(kJ/mol)/RT]

The self-diffusivity of Mn in the quasi-crystals was 3 to 4 orders of magnitude lower than that in crystalline Al.

H.Nakajima, J.Asai, K.Nonaka, I.Shinbo, A.P.Tsai, T.Masumoto: Philosophical Magazine Letters, 1993, 68[5], 315-20