高压电场中金属丝段的电爆现象

金属丝电爆是制备超细粉的一种新方法,为了解决通常所采用金属丝与电极接触后通入大电流的电爆方法容易发生电极烧蚀这一问题,开发了高压电场中金属丝段与电极非接触电爆的设备。通过改变电极间距、金属丝长度和电场电压,进行了系列高压电场中金属丝段电爆试验。结果表明,在高压电场中电极与金属丝的端部发生气体放电,将大电流导入金属丝段而发生电爆,可减轻对电极的烧蚀;由于金属丝段的端部与电极之间的等离子体旁路作用,金属丝段的端部残留0.5~2 mm长的金属丝不发生电爆;适于制备粉末的电场中金属丝段电爆的工艺条件是,电场电压为6、7、8 kV时,与之匹配的电极间距与丝长之差的范围分别为:1.8~4 mm、2.2~5.8 mm和3.2~8 mm。

Electrical Explosion of Segmented Metal Wire in the High Voltage Field

The electrical explosion of metal wire can be used to prepare the ultra fined powder.In usual wire explosion process,a metal wire is connected with two electrodes,through which the large current flows,therefore the electrodes are ablated easily.For solving above problem,an experimental setup of electrical explosion of segmented metal wire,which isn't contacted with electrodes of the high voltage field,was developed.With variations of the distance between electrodes,length of the segmented metal wire,and voltage of electrical field,a series of explosion experiments of segmented metal wire were carried out in the high voltage field.It was observed that the breakdown between electrodes and tips of the segmented wire provided the channels through which the current flowed in the segmented wire for explosion to occur,so that ablation of the electrodes could be alleviated.The end tips of the segmented metal wire,around the point of air breakdown which is known as the shunting arc,did not explode in the same way as the rest of the wire,the length of the non-exploding tip was about 0.5~2 mm.In order to suit the powder preparation,the processing conditions of wire electrical explosion in the high voltage field are as follows,for the given field voltages of 6,7,8 kV,the corresponding ranges of difference between electrode span and wire length are 1.8~4 mm,2.2~5.8 mm and 3.2~8 mm,respectively.