Changes in morphology and field emission property of nano-tendril bundles after high temperature annealing. (June 2022)

• Record Type: Journal Article
• Authors: Zhang, Rongshi; Kajita, Shin; Hwangbo, Dogyun; Sinelnikov, Dmitry; Tanaka, Hirohiko; Ohno, Noriyasu
• Is Part Of: Nuclear materials and energy. Volume 31(2022)
• Publication Date: 2022-06
• Subjects: Nano-tendril bundles -- Tungsten -- Annealing -- Field emission -- Arcing; Nuclear energy -- Periodicals; Nuclear fuels -- Periodicals; Nuclear reactors -- Materials -- Periodicals; Radioactive substances -- Periodicals; 621.4833
• DOI: 10.1016/j.nme.2022.101178
• Languages: English
• ISSNs: 2352-1791

Abstract

Highlights: Helium plasma with additional neon formed nano-tendril bundles. Thermal response of nano-tendril bundles (NTB) was investigated up to 1673 K. Sharp tips disappeared and fiber radius of NTB increased significantly around 1573 K. Field emission from nano-tendril bundles decreased after the thermal treatment. The thermal treatment significantly decreased the probability to ignite arcing. Abstract: Nano-tendril bundles (NTBs) are known to be formed on tungsten by helium plasma exposure with additional neon impurity gas. In this study, the annealing experiments were conducted at the sample temperature of 1473 – 1673 K to investigate the changes of morphology and field emission property of NTBs. With NTBs formed on a W surface, the surface did not fully recover to a smoothed surface and the NTBs remained the fiber-form structures after the annealing at 1673 K for one hour. In addition, the onset electric field for field emission increased, while the emission current from NTBs significantly decreased after the annealing. When the samples were biased at −250 V during helium plasma exposure, arc ignition was confirmed on W surface with NTBs, whereas no arc ignition appeared on W with annealed NTBs.