TUNGSTEN ELECTRODES CONTAINING THREE TYPES OF RARE EARTH OXIDES①
(School of Materials Science and Engineering,BeijingPolytechnic University, Beijing100022, P. R. China)
Abstract: Three types of tungsten electrodes containing three rare earth oxides, namely Y2O3, La2O3, and CeO2 and one with Y2O3 and CeO2were prepared, in which the total contents of rare earth oxides are 2.2% in mass, and the characteristics of these electrode materials were studied. By TIG welding, the welding characteristics including arc starting, arc static properties and electrode consumption of these electrodes were also analyzed. The results suggest that the electrodes added three rare earth oxides are more favorable for processing than that added two rare earth oxides. All the electrodes activated with two or more rare earth oxides are more superior to W-ThO2in operating, and the electrode combined with Y2O3 and CeO2shows the best properties when it is used at a heavy current for a long time. The analyses of the results of electrode consumption indicates that the rim forming during arcing is one of the important reasons for electrode’s heavy erosion, and the increased Y2O3 content in electrodes is beneficial to retard the formation of rim, and leads to the improvement of consumption resistance of the electrodes.
Key words: rare earth oxides tungsten electrode welding rim Y2O3+La2O3+CeO2