Field-assisted sustainable O- ion emission from fluorine-substituted 12CaO·7Al2O3 with improved thermal stability

Jiang Li, Katsuro Hayashi, Masahiro Hirano, Hideo Hosono

研究成果: Contribution to journalArticle査読

10 被引用数 (Scopus)

抄録

We examined the electric field-assisted thermionic emission of atomic oxygen radical anion (O-) in a vacuum from fluorine-substituted derivatives of 12CaO·7Al2O3 (C12A7) with a composition of (12 - x)CaO·7Al2O3·xCaF2 (0 ≤ x ≤ 0.8). Unsubstituted C12A7 easily decomposed into 5CaO{bullet operator}3Al2O3 (C5A3) and 3CaO{bullet operator}Al2O3 (C3A) above 830 °C during the emission experiment in a vacuum. The decomposition temperature range became narrower as the amount of F- ion substitution increased, e.g. the sample with x = 0.4 kept a single phase after the emission experiment at 900 °C. The emitted anionic species from the x = 0.4 sample were dominated by O- ions (∼ 92%) together with a small amount of O2- ions (∼ 4%) and F- ions (∼ 4%). The absence of an O2 gas supply to the opposite side of the emission surface led to a nearly steady co-emission of O- ions and electrons with a ratio of < 1/1. The O2 gas supply markedly enhanced the O- ion emission, and suppressed the electron emission. A sustainable and high-purity O- ion emission with a current density of 11 nA cm- 2 was achieved at 830 °C with the supply of 40 Pa O2 gas. The similarity in these emission features to the unsubstituted C12A7, together with the improved thermal stability demonstrates that the F- ion-substituted C12A7 is a promising material for higher intensity O- ion emission at higher temperatures.

本文言語英語
ページ(範囲)1113-1117
ページ数5
ジャーナルSolid State Ionics
180
17-19
DOI
出版ステータス出版済み - 7 16 2009
外部発表はい

All Science Journal Classification (ASJC) codes

  • 化学 (全般)
  • 材料科学(全般)
  • 凝縮系物理学

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