水中脉冲放电金属电极烧蚀机理

采用板-板电极, 在放电间隙距离为2 mm、放电电流峰值为22 kA条件下, 对黄铜、钨铜电极的烧蚀特性进行了对比研究。利用高精度天平测量放电过程中的电极质量损失, 分别获取了阴极、阳极及总的平均烧蚀速率。通过放电后电极表面微观形貌、微观元素组成的分析及液体中金属离子的含量分析, 对水中脉冲放电金属电极的烧蚀机理进行了探讨。结果表明, 水中脉冲放电时, 钨铜电极的抗烧蚀性能明显高于黄铜电极。黄铜电极的主要烧蚀是以中心的大量孔洞及其边缘的波纹结构为表现形式的液体金属的溅射；钨铜电极的突出物及较平整的表面暗示了气相侵蚀的作用。以电弧的焦耳热效应为催化剂, 钨铜与水的电化学反应更为强烈, 因此电化学腐蚀是水中放电电极烧蚀的形式之一。

Erosion mechanism research of metal electrode under pulse current in water

The pattern of plate-plate electrodes with the gap of 2 mm and the discharge current peak of 22 kA is used to compare and research the erosion characteristics of the brass and W-Cu electrodes. The mass loss of the eroded electrode during the pulsed discharge process can be obtained by a high precision balance. Then, the erosion rates of the anode, cathode and total average erosion rates of the electrodes can be calculated, respectively. The micro morphology analysis about the surface of the eroded electrode and the comparison about the content of the metal ions will help to investigate the erosion mechanism of metal electrodes in water. The results show that anti-erosion performance of the W-Cu is obviously better than that of the brass under pulsed discharge in water. For the brass electrodes, large amounts of holes and craters in the central area and the wave structure in the edge area indicate that sputtering of the molten metal is the major erosion form while the unique protuberances and relatively smooth surface of the W-Cu electrode imply the action of the vapor-phase erosion. When regarding Joule heating effect as the powerful catalyst, the electrochemical reaction of the W-Cu behaves more fiercely than that of the brass. Therefore, its unreasonable to neglect the influences of the electrochemical corrosion on the eroded surface when the pulsed discharge occurs in water.