Investigations of the ignition of cathode spots by arcs operated in atmospheric pressure noble gas atmosphere on electrodes made of Al, Cu, Ti and graphite are extended to electrodes made of Au, Pd and Pt. Rods with a diameter of 2 mm are inserted in a UHV tight stainless steel vessel filled with Ar 5.6 or Kr 4.8. The negatively biased electrodes are brought into interaction with arc plasma by a magnetic blast field. Their end faces are mostly polished with diamond grinding powder, some Pd electrodes are additionally glowed, and other Pd electrodes are pasted with Pd powder. The arc spot ignition is observed by short time photography, streak camera records and temporally highly resolved optical spectroscopy for a lower and higher voltage applied between the arc plasma and the commutation electrode. Measurements of the commutation time t_c elapsing between a signal generated by the arc plasma in front of the commutation electrode and the start of the commutation current show that at low voltages t_c is in parts drastically increased by oxide layers. The measurements of t_c for different electrode materials demonstrate that t_c decreases with decreasing boiling temperature of the material. It confirms that not only ions of the filling gas but also of vaporized electrode material in front of the commutation electrode initiate and promote the arc spot ignition. SEM records show that different electrode treatments cause primarily different arc traces on the electrode surface.

中文翻译：

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致密惰性气体等离子体与冷阴极相互作用的研究：Au、Pd 和 Pt 阴极上的 II 电弧点点火

通过在大气压惰性气体气氛中操作的电弧在由 Al、Cu、Ti 和石墨制成的电极上点燃阴极点的研究扩展到由 Au、Pd 和 Pt 制成的电极。将直径为 2 mm 的棒插入填充有 Ar 5.6 或 Kr 4.8 的 UHV 密封不锈钢容器中。负偏压电极通过磁场爆炸场与电弧等离子体相互作用。它们的端面大多用金刚石磨粉抛光，一些Pd电极额外发光，其他Pd电极用Pd粉粘贴。通过短时摄影、条纹照相机记录和时间上高分辨率的光谱法观察电弧点点火，以在电弧等离子体和换向电极之间施加较低和较高的电压。换向时间的测量在换向电极前面的电弧等离子体产生的信号和换向电流的开始之间经过的t _c表明，在低电压下，t _c部分地由于氧化层而急剧增加。对不同电极材料的t _c测量表明，t _c随着材料沸腾温度的降低而降低。它证实，不仅填充气体的离子，而且换向电极前的汽化电极材料的离子引发并促进了电弧点点火。SEM 记录表明，不同的电极处理主要导致电极表面上的电弧轨迹不同。