Development of non-shrinkable ceramic composites for use in high-power microwave tubes
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Al2O3-CaO-SiC-based ceramic composites with four different compositions were sintered at 1700°C for 3 h in an air furnace. The phase analysis, microstructural characterization, and elemental composition determination of the developed composites were performed by X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDAX) analysis, respectively. The shrinkage, thermal properties, and electrical resistivity of the composites were also studied. The experimental results showed the effects of adding silicon carbide and calcia to alumina on the thermal, electrical, and shrinkage properties of the resultant composites. Among the four investigated ceramic composites, the one composed of 99wt% alumina, 0.5wt% CaO, and 0.5wt% SiC exhibited the best characteristics for use as a potting material in a dispenser cathode of a microwave tube. The material exhibited slight expansion instead of shrinkage during drying or firing. Other properties of the composite powder, such as its thermal properties and electrical resistivity, were comparable to those of a commercial alumina powder.
KeywordsAl2O3-CaO-SiC composite expansion potting material dispenser cathode microwave tube
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The authors acknowledge the financial support of Council of Scientific and Industrial Research (CSIR), India Through network Project (No. MTDDC-PSC0101).
- L. Wolverton, J.O. Tarter, Thermal, R.E. Eitel, M. Weisenberger, and C. Dowden, Properties of alumina cathode heater potting materials, [in] International Vacuum Electronics Conference (IVEC), IEEE International, USA, 2010, p. 165.Google Scholar
- R.B. True, M.F. Kirshner, L. Turek, G.R. Good, R.J. Hanse, T.M. Bemis, and R.J. Bartkowski, Dispenser cathode high power gridded klystron gun, [in] International Vacuum Electronics Conference (IVEC), IEEE International, USA, 2004, p. 328.Google Scholar
- T.J. Grant and L.R. Falce, Impact of dispenser cathode thickness on useful operating life, [in] International Vacuum Electronics Conference (IVEC), IEEE International, USA, 2004, p. 305.Google Scholar
- VB. Shields, Applications of silicon carbide for high temperature electronics and sensors, NASA Jet Propulsion Laboratory, Tech Briefs, 20(1996), p. 55.Google Scholar
- P. Swartzentruber, M. Collier, R. Dewees, W. Epperson, C. Poole, B. Rupp, D. Bowling, E. Fadde, A. Floyd, P. Rottmann, R. Wilson, T.J. Balk, S. Roberts, J. Tarter, and M. Effgen, Alternative ceramic potting materials for dispenser cathodes, [in] International Vacuum Electronics Conference (IVEC), IEEE International, USA, 2012, p. 483.Google Scholar
- R. Bhattacharya, H. Khatun, N.K. Singh, U. Singh, and A.K. Sinha, Design of cathode heater assembly for high power gyrotron, Frequenz, 67(2013), No. 5–6, p. 163.Google Scholar
- L. Ives, G. Miram, M. Read, M. Mizuhara, P. Borchard, L. Falce, and K. Gunther, Development of improved cathodes for high power RF sources, [in] Proceedings of the Particle Accelerator Conference, IEEE International, USA, 2003, p. 1113.Google Scholar
- C.D. Marchewka, Non-Uniform Emission Studies of a Magnetron Injection Gun [Dissertation], Massachusetts Institute of Technology (MIT), USA, 2006, p. 1.Google Scholar
- A.S. Gilmour, Jr., Microwave Tubes, Artech House, Boston, 1986, p. 733.Google Scholar
- D.J. Kaczynski and K. A. Walsh, Beryllium Oxide, [in] Conference of Raw Materials for Advanced and Engineered Ceramics, 6(1985), No. 9–10, p. 1261.Google Scholar
- T.V. Thamaraiselvi and S.S. Rajeswari, Biological evaluation of bioceramic materials—A review trends, Trends Biomater. Artif. Organs, 18(2004), No. 1, p. 9.Google Scholar
- O.S.S. Lamba, S.C. Nangru, L.M. Joshi, A. Sharma, VP. Singh, and N.C. Gupta, Choice of alumina ceramics for 5MW pulsed power klystron, Indian J. Eng. Mater. S., 7(2000), No. 5, p. 443.Google Scholar
- S. Roberts, Sources of temperature variance in dispenser cathodes, [in] International Vacuum Electronics Conference (WEC), IEEE International, USA, 2004, p. 299.Google Scholar
- P. Swartzentruber, M. Collier, R. DeWees, W. Epperson, C. Poole, B. Rupp, D. Bowling, E. Fadde, A. Floyd, P. Rottmann, R. Wilson, T.J. Balk, S. Roberts, J. Tarter, and M. Effgen, Alternative ceramic potting materials for dispenser cathodes, [in] International Vacuum Electronics Conference (IVEC), 2012, IEEE International, Monterey, CA, USA, p. 483.Google Scholar