CRISTIANE HIGASHI
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Artigo IPEN-doc 16776 Investigation of electron emitting barium-calcium aluminate fabrication process for impregnated microwave tube cathodes2005 - HIGASHI, C.; LIMA, N.B. de; MATOS, J.R.; GIOVEDI, C.; MOTTA, C.C.In this paper it is reported the fabrication process of electron emitting barium-calcium aluminates used on impregnated cathodes which constitute high power vaccum microwave devices such as klystrons and TWTs (traveling wave tubes). The compound thermal behavior and the analysis of the formed phases during processing are evaluated, respectively, by means of thermal analysis and XRay diffraction. Results about the influence of firing temperature and atmosphere are also presented. Index Terms — Aluminates, cathodes, electron thermionic emission, thermal analysis, X-Ray diffraction.Artigo IPEN-doc 16775 Electron emitting barium-calcium aluminate obtained from chemical solution techniques2005 - HIGASHI, C.; LIMA, N.B. de; MATOS, J.R.; GIOVEDI, C.; MOTTA, C.C.This paper reports a chemical technique to obtain barium-calcium aluminates used in impregnated thermionic cathodes. This procedure has been employed to improve the thermionic emission characteristics of the cathodes and to facilitate the preparation process of the emitting material. The crystallized powders were obtained using a mixed solution that contains barium, calcium, and aluminum in their chemical formula. Thermogravimetry and X-Ray diffraction were used to investigate the final product of the experiments. Results reported from solid state reaction are compared with those obtained using crystallization techniques.Artigo IPEN-doc 16774 The effects of synthesis process on aluminate emitters thermionic properties2006 - HIGASHI, C.; GIOVEDI, C.; MOTTA, C.C.