高功率脉冲氙灯铈钨电极工作过程中表面稀土元素分布和价态演变

Surface Cerium Element Distribution and Valence Evolution of the Cerium-Tungsten Electrode in High-Power Pulsed Xenon Lamp During Operation

为阐明高功率脉冲氙灯铈钨电极运行过程中的演变过程及工作机理,采用金相显微镜、扫描电镜(SEM)、X射线光电子能谱(XPS)等手段研究了运行不同发次的高功率脉冲氙灯阴极表面形貌、铈元素的价态演变及其浓度-深度分布状况。结果表明:铈钨电极工作表面出现大量的龟裂纹,其裂纹程度和深度、烧蚀状况均与运行发次有关,工作次数越多裂纹和烧蚀情况越严重;随着运行发次增加,阴极表面铈元素含量向表面扩散,含量升高,最高达12%,分布更加均匀;通过对Ce_(3+)/Ce^(4+)比例分析发现:运行10083发次的铈钨阴极表面活性处于较佳状态;运行14486发次的铈钨阴极表面活性层厚度明显减小,仅有6.66 nm,氙灯性能处于下降状态。

The cerium tungsten electrode in the operation of high power pulsed xenon lamp was analyzed by metallographic microscope,scanning electron microscope(SEM)and X-ray photoelectron spectroscopy(XPS).The evolution process and working mechanism of cerium tungsten electrode were confirmed and the cathode surface morphology,valence evolution and concentration depth distri bution of cerium were studied.The results show that a large number of turtle cracks appear on the working surface of cerium tungsten e lectrode,and the degree and depth of cracks and ablation status are related to the operation times.The more working times lead to more serious cracks and ablation.With the increase of operation times,the cerium element in the cathode diffuses to the surface,and the cerium content on th e surface increases,up to 12%and the distribution on the surface is more uniform.Through the analysis of Ce_(3+)/Ce^(4+) ratio,it is found that the surface activity of cerium tungsten cathode running 10083 times is in a better state.The thickness of the surface active layer of cerium tungsten cathode running 14486 times decreases significantly,only 6.66 nm,and the performance of xenon lamp decreases.