%0 Journal Article %A Asinovsky, E. I. %A Isakaev, E. Kh. %A Ivanov, P.P. %A Ochkan', A. L. %A Samoylov, I. S. %A Fauchais, Pierre %D 2004 %I Begell House %N 4 %P 599-603 %R 10.1615/HighTempMatProc.v8.i4.90 %T MEASUREMENT OF THE EROSION OF THE PLASMATRON CATHODE %U https://www.dl.begellhouse.com/journals/57d172397126f956,6034372674a68762,00ffe9b23ac6af5f.html %V 8 %X A method is proposed for the erosion measurement of the tungsten cathode of industrial plasmatrons. The method uses micro-photo shooting of the working surface of the cathode at small depth of field (10 μ) of the optical device. A series of snapshots made under controllable displacement of the cathode along its axis relatively to the microscope lens allows drawing a topographical picture of the working surface. Comparing cathode topograms resulting from a series of consecutive tests the spatial picture of the change of a working surface due to the erosion of the cathode can be registered. The accuracy of the method depends on the choice of microscope objective providing the magnification and consequently the depth of field of the image. If the working surface of the cathode, 2 mm in diameter, fits the microscope image, the accuracy of measurement of the elementary volume of a surface change makes about 1000 cubic microns, resulting for the tungsten to 2e-11 kg. Using the method under consideration the cathode erosion features and intensity were determined through a series of consecutive one hour long tests at 350 A. At the cathode surface two specific zones were observed corresponding to different mechanisms of erosion; one is eroded mainly by the evaporation of the metal while the other suffer from the ablation of large fragments. %8 2004-12-01