Formation of Ultrafine Metal Particles by Gas-Evaporation Technique. IV. Crystal Habits of Iron and Fcc Metals, Al, Co, Ni, Cu, Pd, Ag, In, Au and Pb

Abstract

Fine metal crystallites with diameters 200∼2000 Å made by evaporating a metal in an atmosphere of an inactive gas were studied by electron microscopy. It is found that the crystal habit common to Be, Cr, Mn and Fe, which are bcc just below the melting point, is rhombic dodecahedra truncated by {100}. Fcc metals show six different types of crystal habit. However,only one, viz. octahedra truncated by {100}, is a single crystal and all the others have twins. Various degrees of truncation were found both for rhombic dodecahedra and octahedra. Crystallites with certain degrees of truncation are possibly Wulff polyhedra.