Composite tungsten electrode is produced to meet more stringent requirements on tungsten electrode materials in welding industry - higher reliability and stability. In general, the arcing characteristics of composite tungsten electrode are better than that of tungsten electrode. And among composite tungsten electrode, ternary composite tungsten electrode has better performance than binary composite tungsten electrode. The optimal rare earth oxide ratio of ternary composite tungsten electrode is La2O3: CeO2: Y2O3=1:1:3.
The performance of several tungsten electrodes mixed with rare earth oxides are tested. Their microstructures are studied subsequently. And the roles of rare earth oxides are discussed. It also indicates that the shape of the oxides changes in high temperature and the capillary driven phenomena only acts initially. Because the ratio between oxides migration and vaporization are difference, the surface of W-CeO2 electrode will be short of rare earth oxides. The surface of electrode mixed with 1:2:1 La-Ce-Y oxides will enrich oxide, the surface of electrode mixed with 1:1:3 La-Ce-Y oxides will melt. The oxides migrate to surface through the molten tungsten, therefore the electrode shape, as well as the arc remains stable.
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