DESIGN AND OPERATION OF A NANOCLUSTER GENERATION AND COLLECTION SYSTEM

Nanophase materials, which are formed from nanoclusters, show promise of improved properties and characteristics. One way of generating thes e materials is through the gas condensation process in which metal vap ors are condensed at low pressure resulting in the nucleation of small clusters. This article describes the design and operation of a cluste r generator in which a metal vapor is obtained by boiling the metal in a ceramic tube and expanding the vapor in a free, supersonic jet from a hole in the ceramic tube. The central part of the jet passes into a collection chamber where thermophoresis is used to attract the cluste rs toward the collection surface. The clusters are then removed from t he collector and transferred to a compaction device to form test speci mens.