<i>Ab initio</i> investigation of the surface properties of dispenser B-type and scandate thermionic emission cathodes

Vlahos, V.; Lee, Yueh‐Lin; Booske, John H.; Morgan, Dane; Turek, L.; Kirshner, M.F.; Kowalczyk, Richard; Wilsen, C.B.

doi:10.1063/1.3129193

Cited by 38 publications

(19 citation statements)

References 23 publications

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“…BaO is often used. The oxygen atom (ion) is embedded in the tungsten surface, and the Ba atom (ion) is outermost at the surface-vacuum interface [4][5][6]. Practical cathodes, however, are made with bulk powder loading of a porous tungsten plug [7].…”

Section: Introductionmentioning

confidence: 99%

Thermionic electron emission microscopy of metal-oxide multilayers on tungsten

et al. 2011

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Section: Introductionmentioning

confidence: 99%

Thermionic electron emission microscopy of metal-oxide multilayers on tungsten

et al. 2011

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“…Furthermore, Vlahos et al [98] certified that multicomponent surface coatings also have influence on the work functions of obtained cathodes. According to their work, Ba 0.25 Sc 0.25 O with the lowest wok function of 1.16 eV is the most thermodynamically stable phase in Ba x Sc y O z alloy that possibly formed on W (001) plane by DFT calculation.…”

Section: Scandia-doped Dispenser (Sdd) Cathodementioning

confidence: 99%

A review on recent progress of thermionic cathode

et al. 2020

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As the performance of vacuum electron devices is essentially governed by the properties of their cathodes, developing efficient and durable thermionic cathode is necessary and highly desired to meet the boosting requirements of vacuum electron devices. This review summarized the progress made in the past decades with a detailed discussion on the occurred various thermionic cathodes and their features, and the understandings of the correlation between the emission properties and the composition, where structure and synthesis method are well illustrated. Furthermore, dispenser cathodes with novel structures and emission mechanism are highlighted to indicate the recent achievement in this area of research, and Sc-cathode is considered as a promising candidate for the next-generation vacuum electron devices due to the greatly improved efficiency. However, challenges still exist to meet the ever-growing demands of thermionic cathode with collaborative requirement of high performance, easy fabrication and inadequate reproducibility.

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“…Recently, Zhou et al [47] claimed that Sc 2 O 3 and BaAl 2 O 4 crystallites with the particle size of 100 nm were separated, distinct, interspersed and Ba or BaO dots with diameters of ~ 10 nm were distributed on the surface of the W grain. Meanwhile, a serial of works [48][49][50][51][52] are done to explore the surface structure and stability of Ba x Sc y O z monolayer cathodes by the method of ab initio modeling. These calculations provide modifications of the work function of the (001) facet of W crystal induced by Ba-and Scmonomers, together with Ba-O and Sc-O dimers, as a function of surface coverage (Fig.…”

Section: Mechanism Study Of the Sdi Cathodementioning

confidence: 99%

A review on scandia doped tungsten matrix scandate cathode

et al. 2019

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As the cathode with the highest electron emission capability in the thermionic cathode, the scandate cathode has attracted more and more attention in recent years, especially the scandia doped tungsten matrix scandate cathode. Experimental studies show that scandia doped tungsten matrix scandate cathodes with submicron microstructures exhibit excellent emission capacity, and the pulse emission current density in the space-charge region can be over 35 A cm −2 at 850 °C b. In the direct current (DC) condition with temperature compensation, the emission current density could reach 25 A cm −2 at 850 °C b. The device lifetime is over 3700 h after operating at 950 °C b with the DC loading of 40 A cm −2. The emission mechanism of the scandate cathode including the effect of the surface structure and composition on the work function of the cathode are systematically reviewed.

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Ab initio investigation of the surface properties of dispenser B-type and scandate thermionic emission cathodes

Cited by 38 publications

References 23 publications

Thermionic electron emission microscopy of metal-oxide multilayers on tungsten

Thermionic electron emission microscopy of metal-oxide multilayers on tungsten

A review on recent progress of thermionic cathode

A review on scandia doped tungsten matrix scandate cathode

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