Thesis-2000-Shen.pdf (4.46 MB)
Novel processing routes for oxide cathode emission materials
thesis
posted on 2012-10-31, 14:25 authored by Xiangqian ShenAn investigation has been carried out into the production of the alkaline earth carbonate and
oxide powders and coatings suitable as cathode emission materials by the
ethylenediaminetetraacetic acid (EDT A) gel method for potential application as cathode
emission materials. The emission performance of thermionic cathodes coated with these
materials has been measured, and found to give encouraging results, comparable with
conventionally prepared oxide emission materials, despite the former having not been
optimised. Amorphous gels of composition Ca-EDTA, Sr-EDTA, Ba-EDTA, [SrO.5 Bao.5J-EDTA and
[SrO.5 Bao.5 Cao.05J-EDTA were successfully prepared from aqueous solutions of alkaline earth
nitrates and EDT A. Subsequently, the thermal decomposition of the gels and the effects of
temperature and atmospheres on the decomposition have been studied by thermogravimetric
analysis (TGA) and differential scanning calorimetry (DSC). The gels and the powders
derived from calcination of these gels at different temperatures have been characterised by
Fourier transform infrared spectroscopy (FTIR) , X-ray diffraction (XRD) analysis, scanning
electron microscopy (SEM) with X-ray energy dispersive (EDX) spectroscopy. Coatings prepared by dip-coating, spraying and electrophoretic deposition (EPD) from the
EDT A-sols have been characterised by FTIR, XRI> and SEM techniques. In addition, an
attempt was made to study the coating of the colloidal particles in the suspension of methanolethanediol-
EDTA sol by electrochemical impedance spectroscopy.
History
School
- Aeronautical, Automotive, Chemical and Materials Engineering
Department
- Materials
Publisher
© Xiangqian ShenPublication date
2000Notes
A Doctoral Thesis. Submitted in partial fulfilment of the requirements for the award of Doctor of Philosophy of Loughborough University.EThOS Persistent ID
uk.bl.ethos.251017Language
- en