Long-Life C12A7 Heaterless Cathode for Electric Propulsion Thrusters
Abstract
Hollow cathodes are the most frequently used neutralizers and electron sources for electric propulsion like ion or hall thrusters. They are usually made using BaO or LaB6 inserts that need high temperatures and therefore heaters to operate. These heaters greatly add to complexity and often fail due to spark discharges. Recently, a new ceramic material called C12A7 has been developed that has a low enough work function to enable hollow cathodes without a heater. Up to now, the production quality of C12A7 was not good enough to make solid inserts and no stable long term tests could be made. The institute of aerospace engineering at TU Dresden together with the Fraunhofer IKTS institute and GWT-TUD GmbH developed a production process that ensures high-quality and high-purity C12A7 inserts. These inserts allow us to make the first-ever study of the long-term operational characteristics and performance of C12A7 hollow cathodes. We propose to thoroughly investigate this new material by sintering inserts with different grain sizes testing their work function, mechanical stability and long term performance in vacuum and under the influence of a plasma discharge consitions relevant to electric propulsion applications. We then propose to build hollow cathode prototypes targeting low and medium power ranges (1 and 5 A). Finally, a test campaign will be carried out together with a Hall thruster at TU Dresden as well as at an AFRL lab/thruster to investigate the cathode in a real application.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Sep 11, 2017
- Source ID
- FA95501710336
Entities
People
- Martin Tajmar
Organizations
- Air Force Office of Scientific Research
- Technische Universität Dresden
- United States Air Force