氧作用下浸漬鋇鎢陰極中鈣的強化表面擴(kuò)散
CALCIUM SURFACE DIFFUSION IN IMPREGNATED CATHODE ENHANCED BY OXYGEN
-
摘要: 由于探測技術(shù)上的困難,至今對鋁酸鋇鈣擴(kuò)散陰極表面鈣的研究極少。本文利用低壓氧銹導(dǎo)下Ca向陰極表面的強化擴(kuò)散,并借助俄歇電子能譜儀探索了Ca的行為和作用。主要結(jié)果是:(1)相當(dāng)部分Ca以金屬態(tài)形式存在于鎢孔隙中活性物質(zhì)的近表層區(qū);(2)鈣向表面擴(kuò)散的數(shù)量和速度與陰極溫度、氧的暴露量成正比,它是一種界面反應(yīng)驅(qū)動下的強化擴(kuò)散,其激活能約為1.34eV;(3)氧作用下陰極表面氧化鈣的增加是導(dǎo)致陰極發(fā)射衰減的重要原因,而恢復(fù)中毒的再激活機制之一,則是高溫下表面鈣的蒸發(fā)逸離過程。
-
關(guān)鍵詞:
- 擴(kuò)散陰極; 浸漬鋇鎢陰極; 表面擴(kuò)散; 俄歇電子能譜
Abstract: The Ca behavior of an impregnated cathode is studied with enhanced diffusion of Ca to the cathode surface induced by low pressure oxygen, and the changes of surface composition are analysed with AES and the method of surface accumulation. The experimental results show that: (1) a significant part of Ca exist in metallic form in the near surface region of the active material in the pores of impregnated cathode ; (2) the diffusion rate of Ca to the surface is proportional to the O2 exposure quantity and the cathode temperature, the activation energy of Ca surface diffusion enhanced by O2 is about 1.34eV; (3) one of the reasons of emission decay under oxygen effect may be considered due to the increase of calcium oxide on the cathode surface, and the one of principal mechanisms of the seactivation is the high temperature cleaning process of the Ca by evaporation. -
Zhang Yonglrang,wang Yiman, et al., Studies of surface Behavior of Dispenser Cathodes Dispenser of Glass AES Apparatus, The Proc. of the Surface Science Symposium, Oct., 1981, XEROX Palo Alto Research Center, p. 83.[2]D. Brion, J. C. Tonnerce, A. M. Shroff, Appl, Surf. Sci., 16(1983),55.[3]C. E. Maloney, C.R. K. Marrian, G. Wyss, Appl. Surf. Sci., 2(1979),284.[4]B. C. Lamartine, W. V. Lampert, T. W. Haas, Appl. Surf. Sci., 8(1981),171.[5]張永康, 真空科學(xué)與技術(shù), 4(1984), 350.[6]張永康, 電子管技術(shù), 1975年, 第4-5期, 第103頁.[7]張永康, 朱清元, 張貽英, 電子科學(xué)學(xué)刊, 9(1987), 42.[8]張永康等, 真空科學(xué)與技術(shù), 2(1981), 61.[9]D. Gupta, R. Campbell, P. S. Ho, Thin Films--Interdiffusion and Reaction, Ed. by J. M. Poate, K. N. Tu, J. W. Mayer, 1978,(張永康譯, 薄膜的相互擴(kuò)散和反應(yīng), 1983年11月, 國防工業(yè)出版社, 第7章, p. 153.[10]張永康, 王亦曼, 龐世瑾, 真空物理與技術(shù)及其在電子器件中的應(yīng)用,胡漢泉, 王遷主編,下冊,第十一章,國防工業(yè)出版社, 1985年, 4月, p.535.[11]A. K. Sinha, J. M. Poate, 文獻(xiàn)[9]一書中的第11章, p.410.[12]G. A. Haas, A. Shih, R. E. Thomas, Appl. Saurf. Sci., 2(1979), 293. -
計量
- 文章訪問數(shù): 2053
- HTML全文瀏覽量: 183
- PDF下載量: 394
- 被引次數(shù): 0
下載:
