The diffusion of 60Co in single decagonal Al72.2Co16Ni11.8 quasicrystals was measured by using radioactive tracer methods. The volume diffusion coefficients could be described by an Arrhenius equation. Anisotropic diffusion behaviour was observed, with the mobility of Co being slightly greater in the periodic direction. The activation enthalpies for Co diffusion were equal to 277.4kJ/mol (periodic direction) and 289.0kJ/mol (aperiodic direction). A diffusion mechanism involving vacancies was suggested to operate. Surface self-diffusion coefficients of 60Co were also measured, and activation energies of 147kJ/mol (periodic direction) and 137kJ/mol (quasi-periodic direction) were obtained.

Diffusion in Quasicrystalline Al-Ni-Co and Al-Pd-Mn. T.Zumkley, J.Q.Guo, A.P.Tsai, H.Nakajima: Materials Science and Engineering A, 2001, 294-296, 702-5