Michael Bronikowski1
University of Tampa1
Recent results will be reported from investigations into Carbon Nanotube (CNT) growth using metal catalyst particles composed of catalytic metals such as iron mixed with heavy refractory catalyst stabilizers. The heavy refractory metals, which include high-melting-point elements such as tungsten, ruthenium and hafnium, act to slow down the erosion and Ostwald ripening of the nano-particles of catalytic metals from which the CNTs nucleate and grow, thereby allowing the particles to remain active for longer times and thus to grow longer CNTs. A number of different combinations of catalyst metal and heavy refractory stabilizer are investigated. Ethylene (C<sub>2</sub>H<sub>4</sub>) is used as the carbon source gas for nanotube growth, and growth parameters including temperature, pressure, and gas flow composition and rate, are varied for best CNT growth. Discussion will include implications for growth of CNTS to lengths great enough (tens of cm or more) for application in materials applications such as ultra-high-strength wires and cables.