In situ measurements of electrode work functions in free-burning arcs during operation at atmospheric pressure
In situ measurements of electrode work functions in free-burning arcs during operation at atmospheric pressure
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DOI：
10.1088/0022-3727/38/1/007
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发表时间：
2005-01-07
影响因子：
3.4
通讯作者：
Kagebayashi, Y
中科院分区：
文献类型：
--
作者：
Tanaka, M;Ushio, M;Kagebayashi, Y
介绍了一种在运行过程中原位测量自燃弧的电极功函数的方法。该技术是一种利用脉冲激光系统在钨阴极表面产生光电效应的技术，该系统由一台脉冲激光器和一台染料激光器组成。本工作使用了三种类型的钨电极，即纯W、W-2%ThO2和W-2%La2O_3。在100A和200A的大气压下，在Ar气氛中运行自燃弧。在200A的电流下，纯W、W-2%ThO2和W-2%La_2O_3电极的有效功函数为。现场测量分别为4.6、2.8和3.0 eV。这些结果与从文献中得到的纯W、ThO2和La_2O_3的功函数非常接近。现场测量表明，纯W、W-2%ThO2和W-2%La_2O_3电极对所有100A电弧的有效功函数分别为2.9 eV。2.6 eV和2.0 eV。结果表明，对于所有类型的钨电极，100A电弧的各有效功函数明显低于200A电弧的有效功函数。
A method of in situ measurement of electrode work functions in free-burning argon arcs during operation is presented. This technique is based oil the photoelectric effect occuring at the surface of a tungsten cathode with the use of a pulse laser system consisting of a Nd-YAG laser and a dye laser. Three types of tungsten electrode, namely, pure W, W-2 % ThO2 and W-2 % La2O3 are used in this work. Free-burning arcs are operated in argon at atmospheric pressure at Currents of 100 A and 200 A. The effective work functions of pure W, W-2 % ThO2 and W-2 % La2O3 electrodes during operation at a current of 200 A are found to be. respectively, 4.6, 2.8 and 3.0 eV from in situ measurements. These results are very close to the work functions of pure W, ThO2 and La2O3 obtained from the literature. The in situ measurements, however, show that the effective work functions of pure W, W-2 % ThO2 and W-2 % La2O3 electrodes for all 100 A arc are, respectively, 2.9 eV. 2.6 eV and 2.0 eV. It is shown that each effective work function for an 100 A arc clearly becomes lower than that for a 200 A arc for all types of tungsten electrodes.