Diffusion in Decagonal and Icosahedral Quasicrystals and a Related Hexagonal Phase

摘要

We present investigations of gallium diffusion in decagonal AlNiCo quasicrystals in both principal directions and of gallium diffusion in icosahedral AlPdMn quasicrystals. Gallium was used to approximate aluminium self-diffusion, which cannot be measured using conventional tracer techniques. The depth-profiles of the stable isotopes were analysed by SIMS profiling. We compare our results in decagonal AlNiCo with experimental data on self-diffusion of cobalt and nickel and with MD-simulations of Al self-diffusion from literature. Our experiments and the MD simulations show that the diffusion parallel to the decagonal axis is faster than perpendicular to it. In addition we carried out diffusion studies of the major component zinc in icosahedral ZnMgY, icosahedral ZnMgHo (fci-phases) and a related hexagonal ZnMgY composition (Z-phase) along both principal directions. We report the Arrhenius parameters and compare the diffusion behaviour of the various materials.