Investigation of CuCr Electrodes Microstructure After Effect of a High Current Vacuum Arc

The paper presents the results of studies of the microstructure of a CuCr composite material with a different content and particle size of chromium in the initial material exposed to a high current vacuum arc. An investigation of the electrodes cross-sections showed that for both, the anode and the cathode, two characteristic regions can be distinguished: 1 is the region of arc action and 2 is the region of the initial material. The first region is located on the surface of the electrodes and is the part of the electrode that crystallizes out of the melt after melting due to the action of a high-current vacuum arc. It should be noted that in the case of a CuCr composite with a chromium content of 40%, on the anode a narrow transition layer is formed (about 10 microns), enriched with chromium from the arc side and enriched with copper from the side of initial material. At the cathode, the formation of such layer has not been observed. In the case of a CuCr composite with a chromium content of 25 %, parts of the crystallized layer were observed which in addition to fine chromium precipitates contained a large (about 50-100 microns) primary chromium particle.