A new crucible design of the arc-discharge method for the synthesis of graphite encapsulated metal (GEM) nanoparticles
Journal
Diamond and Related Materials
Journal Volume
20
Journal Issue
3
Pages
330-333
Date Issued
2011
Author(s)
Abstract
Graphite encapsulated metal (GEM) nanocrystal is a core-shell structured nanomaterial which is capable of surviving in severe environments, such as strong-acid or strongly-oxidizing conditions. Many researches have proven GEM to be useful for its potential multiple applications. However, there is a serious problem: its low production rate hinders future research on possible applications. Although the tungsten arc-discharge method produces more GEM nanoparticles than all the other methods do, the production rate remains unsatisfactory. Based on a previous study, it is known that the temperature gradient in the molten liquid metal pool during arcing is inadequate, i.e., the bottom is cooler than its surroundings, thus preventing the occurrence of convection and the homogeneous evaporation process. In this study, a new crucible design, with a thermal insulating alumina piece at the bottom of the graphite crucible, effectively modifies the temperature gradient inside the molten liquid pool. As a result, the as-made production rate approximately quadruples. This work demonstrates, as attested by experimental evidence, how an alumina piece can effectively change the temperature profile in the crucible and facilitate the synthesis of GEM in a tungsten arc-discharge system. © 2011 Elsevier B.V. All rights reserved.
Type
journal article