A new series of icosahedral quasierystals in Zn-M-Sc (M = Ag, An, Pd, Pt) alloys

A new series of icosahedral quasicrystals has been found in Zn75M10Sc15 (M = Ag, Au, Pd and Pt) as-cast alloys. Electron and powder X-ray diffraction analyses indicated that these quasicrystals are of the P-type (primitive type) and have six-dimensional lattice parameters a(6D) = 0.7112-0.7151 nm. The quasicrystals are formed as main phases in these alloys. In the Zn80Ag5Sc15 alloy annealed at 981 K for 24h, a Zn85Sc15-type cubic phase is formed exclusively, which has the lattice parameter a = 1.3867 nm. The cubic phase is interpreted as a 1/1 approximant of Zn75Ag10Sc15. This observation, as well as intensity similarity in the X-ray diffraction patterns, suggests that Zn(75)M10Sc(15) quasicrystals belong to the same group as the Zn80Mg5Sc15 quasicrystal from the viewpoint of a local atomic configuration.