An ordered arrangement of columnar clusters of atoms in a rhombic quasiperiodic lattice in an Al?Ni?Co decagonal phase

Quasicrystalline Structures as Catalyst Precursors for Hydrogenation Reactions

“…We can observe several rings of spots of ten-fold symmetry around the center of the diffraction image. It is close to most typical diffraction patterns of AlNiCo systems with decagonal quasicrystalline structure [49,50]. HRTEM image illustrates also the Penrose tiling of the superstructure Fig.…”

Reversible phase changes of Ni-rich Al–Co–Ni decagonal quasicrystals studied by means of transmission electron microscopy and thermal analysis

“…For instance, there exist special spots present at the center of variously-recognized pentagons formed by sharp reflections (some examples are indicated by white solid lines and arrows in the figure). The SAD pattern characterized by these features represents the Type-I superstructure [3,6,11]. Thus, it is summarized that the Al 70 Co 12 Ni 18 alloy has two differently-ordered d-QC states formed at different temperature regions, i.e.…”

“…Various electron diffraction patterns with so-called superlattice reflections, indeed, have been found to occur in a wide composition range of this alloy [3][4][5][6]. However, the real ordered structures stated above had been hardly evidenced by these and other previous TEM observations till very recently [10][11][12][13].…”

“…This imaging technique, which allows to enhance the positions of heavy atoms in the resulting image contrast, has contributed a lot to reveal new structural features of the so-called Ni-rich basic d-QC in Al-Co-Ni system [8,9]. The structural characterizations of Al-Co-Ni d-QC family have been most successfully achieved by Hiraga et al on the basis of appropriate sets of SAD patterns, HRTEM and HAADF-STEM images [10][11][12][13][14]. In fact, they have first evidenced that the ordered structures of Al-Co-Ni d-QCs showing superlattice reflections in their diffraction spectra have two groups of atom clusters with pentagonal symmetry, each of which differs in orientation, arranged orderly in unique quasiperiodic lattices.…”

Synchrotron X-ray Studies of Phason and Phonon Strains in a Co-rich Al-Ni-Co Decagonal Quasicrystal

“…[7][8][9] Ritsch et al 9) have constructed a precise phase diagram and shown that at least eight types of decagonal phases exist over wide temperature and composition ranges. And the structures of these types have been studied by atomic-scale observations of high-angle annular detector scanning transmission electron microscopy (HAADF-STEM), for basic Ni-rich, 10,11) S1-state, 12) type-I superstructure, 13) type-II superstructure, 14) and 5f HT 15) phases. These examinations, however, were mainly conducted by electron diffraction and electron microscopy techniques.…”