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一、前言低气压弧光放电光源一般采用加少量ZrO-2的三元碳酸盐作阴极的电子发射材料。此发射材料经分解、激活后,功函数较低,在220V交流电压下只需启辉器这类光源就能启动。但此发射物质涂敷于钨丝表面,阴极前存在强电场,且热点温度很高,引起发射物质的溅射和蒸发,导致管壁发黑。本文分析了发射物质消耗机理,探讨了管壁发黑原因。并为减少发黑现象提出了设想。
I. Introduction Low-pressure arc discharge light source generally uses a small amount of ZrO-2 ternary carbonate as cathode electron emission material. The launch of the material after decomposition, activation, the work function is low, at 220V AC voltage only need to start this type of light source can start. However, the emitting substance is coated on the surface of the tungsten wire, and there is a strong electric field in front of the cathode, and the hot spot temperature is very high, causing sputtering and evaporation of the emitting substance, resulting in blackening of the tube wall. This paper analyzes the consumption mechanism of the emitting material, and discusses the reasons for the blackening of the tube wall. And to reduce the black phenomenon put forward the idea.