SBIR Phase I: Pulsed Plasma Atomization of Rapidly Solidified Hard Magnetic Nanophase Nd-Fe-B Powders

This Small Business Innovation Research (SBIR) Phase I project will investigate a new technique to economically synthesize rapidly solidified magnetic (Nd-Fe-B) powders with diameters in the 1-10 m range. In preliminary experiments using pulsed plasma jets to atomize metal melt streams, the company has produced spherical copper powders down to several hundred nanometers. These pulsed plasma jets produce momentum fluxes 2 to 3 orders of magnitude higher than conventional gas atomization, thus allowing production of fine powders. The objective of this project is to use a fundamentally different configuration, which is more amenable to the production of rapidly solidified hard magnetic nanophase powders. This will be accomplished by coupling the pulsed plasma jet to a pulsed wire arc metal source instead of the more conventional melt stream source. This has the anticipated advantage of eliminating material incompatibilities during processing and avoids the need for large induction melt systems. It can also provide controllable coupling to a repetitively pulsed plasma jet, allow production of refractory metal powders, and provide easier access to the atomization zone for enhancing the cooling rate of the atomized powders. The project will be carried out in cooperation with the University of Utah, which will provide expertise in processing-microstructure-property relationships in hard magnetic materials. Commercial applications of permanent magnets reach virtually every corner of technology, including automobiles, computers, medical technology, power generation equipment, aerospace, and telecommunication industries. These magnets are used in compact powerful electric motors for computer disk drives and fly-by-wire aircraft. They are also find applications as high precision actuators used to focus the laser in a compact disk player and in miniature loudspeakers of personal stereos. Automotive applications include starters, small motors, alternators, sensors, meters, and electric and hybrid vehicle propulsion systems.