Growth of hollow annular zinc oxide structures

The conditions and mechanisms of the growth of hollow crystals, dendrite structures, and whiskers of zinc oxide during the annealing of pressed zinc oxide-carbon mixtures were studied. The growth of hollow structures is due to the interaction of reagents in pressed tablets, which is accompanied by the formation of a gas-impermeable external ZnO shell and the transport of Zn vapor and CO2 along the growing tube. Orientation of the hollow crystals is determined by the direction of Zn vapor transport. The process was modeled by the Zn vapor emission from a Knudsen effusion cell. (C) 2000 MAIK "Nauka/Interperiodica".