Barium strontium oxide functionalized carbon nanotubes thin film thermionic emitter with superior thermionic emission capability

2017 ◽  
Vol 35 (4) ◽  
pp. 041202 ◽  
Author(s):  
Feng Jin ◽  
Allyn Beaver
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Thermionic Emission ◽  
Strontium Oxide ◽  
Functionalized Carbon Nanotubes ◽  
Barium Strontium

A New Thermionic Cathode Based on Carbon Nanotubes with a Thin Layer of Low Work Function Barium Strontium Oxide Surface Coating

2008 ◽  
Vol 1142 ◽  
Author(s):  
Feng Jin ◽  
Yan Liu ◽  
Scott A Little ◽  
Chris M Day
Keyword(s):  
Work Function ◽  
Current Density ◽  
Enhancement Factor ◽  
Thermionic Emission ◽  
Field Enhancement ◽  
Oxide Coating ◽  
Emission Current Density ◽  
Emission Current ◽  
Strontium Oxide ◽  
Barium Strontium

ABSTRACTWe have created a thermionic cathode structure that consists of a thin tungsten ribbon; carbon nanotubes (CNTs) on the ribbon surface; and a thin layer of low work function barium strontium oxide coating on the CNTs. This oxide coated CNT cathode was designed to combine the benefits from the high field enhancement factor from CNTs and the low work function from the emissive oxide coating. The field emission and thermionic emission properties of the cathode have been characterized. A field enhancement factor of 266 and a work function of 1.9 eV were obtained. At 1221 K, a thermionic emission current density of 1.22A/cm2 in an electric field of 1.1 V/μm was obtained, which is four orders of magnitude greater than the emission current density from the uncoated CNT cathode at the same temperature. The high emission current density at such a modest temperature is among the best ever reported for an oxide cathode.

Preparation and Characterization of Functionalized CNTs Using Plasma Combined with Maleic Anhydride Induced-Graft Polymerization

2012 ◽  
Vol 624 ◽  
pp. 72-75
Author(s):  
Run Ping Jia ◽  
Chun Hua Xu ◽  
Cheng Zhang ◽  
Lin Hao Wang ◽  
Kai Tian ◽  
...  
Keyword(s):  
Thin Film ◽  
Carbon Nanotubes ◽  
Maleic Anhydride ◽  
Surface Properties ◽  
Graft Polymerization ◽  
Polyurethane Elastomers ◽  
Functionalized Carbon Nanotubes ◽  
Fluorinated Polyurethane ◽  
Polymerization Method

In this work, plasma combined with maleic anhydride induced-graft polymerization method was employed to fabricate highly-functionalized carbon nanotubes, whose surface was coated by uniform polymaleic anhydride thin film. Their compositions and structures were characterized by FTIR, SEM and XPS techniques. In order to evaluate the modification effect, they were further used as modifier to improve the tensile and surface properties of fluorinated polyurethane elastomers.

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