Rare Earth Doped Tungsten Electrode

With the continuous development and progress of the welding industry, the reliability and stability of the electrode material is proposed more stringent requirements. Rare earth doped tungsten electrode with its high melting point, low electron work function, excellent thermal electron emission property, as the main material in place of thorium tungsten electrode. Besides, it successful replaces thoriated tungsten electrodes used in the small-scale welding. But in AC it has poor arcing property, short service life and other problems. In general, the arcing performance of the tungsten electrode doped with three rare earth oxides is superior to tungsten electrodes doped with single rare earth oxides. In rare earth doped tungsten electrode, ternary complex is better than binary complex.

In the late 1980s, a group of Japanese scholars have made some progress in the development of new tungsten electrode material, particularly in rare earth doped tungsten electrode material. They have operated a lot of work on electrode component design, performance comparison and mechanism study found tungsten electrode doped with two rare earth oxides can improve the performance of the tungsten electrode. For the binary rare earth tungsten electrodes, CeO₂: Y₂O₃ = 1: 3 (CeO₂ 0.5%, Y₂O₃ 1.5%), Ce₂O₃: La₂O₃ = 1: 1, La₂O₃: Y₂O₃ = 1: 3, has better performance and durability property. 1: 3 (La₂O₃ + Y₂O₃) tungsten electrode after 4h (180A) arcing still has good performance and arcing 10h durability remains better condition than single rare earth doped electrode.

For the ternary tungsten electrodes, the best rare earth oxide ratio is CeO₂: La₂O₃: Y₂O₃ = 1: 1: 3. This electrode having good operating performance can sustain 10h (180A) operating. In rare earth doped tungsten electrodes, this electrode having low operating temperature, high electron emissivity, lowest electron work function and other properties, the overall performance is more prominent.

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