实用Cu-Al-Mg合金次级电子发射体的表面研究  

THE SURFACE STUDY OF Cu-Al-Mg ALLOY TYPE SECONDARY ELECTRON EMITTER

作　　者：王成[1] 陈其略[1] 王亦曼[1] 

机构地区：[1]北京真空电子技术研究所

出　　处：《真空科学与技术学报》1991年第5期341-349,共9页Chinese Journal of Vacuum Science and Technology

摘　　要：一、引言随着电子技术的发展,次级电子发射现象已经广泛地应用到各个领域中(如光电倍增管,电子倍增器,磁控管,正交场放大器,图像增强器等等),因而引起了很多学者的极大兴趣,并且进行了大量的研究工作。The alloy type secondary electron emitters have been widely used as cold cathodes in high frequency Cross-field Am-plifiers and other devices. However, sometimes the emitters could not provide stable emission and satisfied life-time.Therefore, it is neccessary to recognize the characteristic of alloy type secondary electron emitters. The Cu-Al-Mg (6.43wt% of Al, 1. 44wt% of Mg) alloy which is one of the test secondary electron emitters for Cross-field Amplifiers hasbeen studied by means of SEM, XPS and SAM in combination with the measurement of secondary electron emissionyield. The surface compostion,the chemical state,and three-dimension distribution of Cu, Al, Mg, O as well as their in-fluence on the secondary electron emission yield have been observed from the Cu-Al-Mg alloys under different processingprocedures. From the results of investigation, a model for charaterizing the emission mechanism of Cu-Al-Mg alloy type sec-ondary electron emitters was proposed,that is,after suitable processing procedures,a MgO segregation layer forms atsurface of the Cu-Al-Mg alloy due to the segregation and migration of Mg along the grain boundaries of Cu and the com-bination of Mg with the absorbed oxygen,while the copper acts as a conducting frame. That results a significant increasein secondary electron emission yield. The value of secondary electron emission yield for Cu-Al-Mg mainly depends onthe segregation extent of MgO. Instead,Al exists in the form of ALOX and distributes nearly uniformly in three-dimen-sion and has little effect on secondary electron emission yield. It has also been concluded from the investigation that conventional polishing and acid etching procedures can hardlyproduce a MgO segregation layer for raising the secondary eletron emission yield,but an activating procedure at suitabletemperature and in oxygen atmosphere is the key to the improvement of Cu-Al-Mg alloy secondary electron emissioncharacteristics.

关 键 词：次级电子 表面研究 正交场放大器 像增强器 电子回轰 磁控管 次级发射 冷阴极 酸洗工艺 机械抛光 

分 类 号：TB7-55[一般工业技术—真空技术]