Reduced wetting and friction are two essential surface properties that to a large extent currently embody the technological potential of quasicrystalline coatings. By quasicrystalline compounds, one considers here the whole family of complex Al-(Cu or Pd)-(Fe, Cr or Mn) intermetallics, which comprises true quasicrystals, their approximants and some crystalline materials of related composition.
Although covered by a layer of native Al2O3 oxide, wetting by water on these materials exhibits a clear correlation between the reversible adhesion energy of water and the bulk density of states at the Fermi energy. Similarly, in high vacuum, the friction coefficient measured in contact against a hard-steel rider is characteristically smaller than the one measured against conventional metallic alloys (including steel). Observing that wear is nearly non existent under such friction conditions, experiment allows us for the first time to derive a fair estimate of the true surface energy of quasicrystals and related complex metallic alloys. Similarly to wetting, the electronic density of states seems to determine the friction characteristics of these compounds.