Multi-Rare Earth Tungsten Electrode Composite Strategy

In the existing technology, the main used elements are thorium tungsten electrode (containing ThO₂), lanthanum tungsten electrode (containing La₂O₃), cerium tungsten electrode (CeO₂), zirconium tungsten electrode (ZrO₂), and other rare earth tungsten electrodes. All kinds of materials have their advantages and disadvantages. In addition to the shortcoming of radiation, the comprehensive welding properties of rare earth tungsten electrode materials for various units are not comparable to those of thorium tungsten electrode.

Although individual combat is difficult, the combined strength is not necessarily certain. Many scholars have found that the combination of lanthanum, yttrium, zirconium and other rare earth elements with tungsten can make up for the performance deficiencies of the rare earth tungsten electrode materials of each unit. For example, a multi-element composite rare earth tungsten electrode published by scholars has been fabricated as follows:

Firstly, according to the weight percentage of the final product, the content of La₂O₃ is 2%, Y₂O₃ is 0.16%, ZrO₂ is 0.16%, and the rest is W. La₂O₃, Y₂O₃ and ZrO₂ rare earth oxide nitrate mixed solution with nitrate solution concentration of 100 g/L was prepared.

Then the APT suspension was mixed and stirred for 1 hour, the drying temperature was 200 °C, and the holding time was 1 hour.

The obtained precursor powder is subjected to hydrogen reduction twice, a reduction temperature of 700 °C, a holding time of 0.5 h, a hydrogen flow rate of 1.2 m³ /h, a secondary hydrogen temperature of 1000 °C, a holding time of 0.5 h, and a hydrogen flow rate of 1.8 m³ /h. Thereby, a multi-element rare earth doped tungsten powder is obtained.

Finally, the doped tungsten powder is loaded into the elastic die sleeve and pressed by cold isostatic press. The forming pressure is 170 Mpa. The tungsten billet is pressed and formed. The tungsten billet is placed in the molybdenum boat. Under the protection of hydrogen, the sintered tungsten billet containing rare earth elements is pre-sintered at 1190-1200 °C for 20-30 minutes. The sintered tungsten billet containing rare earth elements is processed by rotary forging, straightening and grinding electrodes.

The technology scheme can prepare multi-rare earth doped tungsten powders with uniform element distribution and controllable particle size, and then produce multi-rare earth tungsten electrodes with excellent performance. According to the experimental comparison, the performance of the multi-rare earth tungsten electrodes prepared is similar to that of thorium tungsten electrodes, and there is almost no radiation.

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