Abstract
This paper describes the consumption mechanism of Ru-Y2O3 electrode for air plasma cutting torch during arc discharge.
To clarify the consumption mechanism, the direct observation by stereoscope and CCD camera was carried out during arcing, and the analyses by EMPA and micro X-ray diffractmeter of cathode surface after arcing were carried out.
In case of Ar shielding gas, it was cleared during arcing that the fusion area of 80Ru-20Y2O3 cathode surface was sparated into the two regions of Ru and Y2O3 components and sputtering of the molten particles mostly occurred from Ru part. On the other hand, in case of Ar+20%O2 and air, the top of cathode surface was covered with the molten layer of Y2O3 and the plasma was stably sustained during arcing. The reason why the difference arises is considered due to possibility of oxygen supply during arcing.
