Yttrium Tungsten Electrode Composite

At present, a method for manufacturing a yttrium tungsten electrode is mainly to obtain a metal blank by a powder metallurgy method. There are three kinds of traditional mixing processes.

One is to add the oxide into the tungsten oxide powder or the molybdenum oxide powder in the form of rare earth salt such as La(NO₃)₃, and then thermally decompose, reduce and sieve in a hydrogen furnace. A uniform mixed powder of strontium-containing tungsten; the second is to add an appropriate amount of La₂O₃ powder in a solid-solid form in the oxide powder, and after two reductions, a mixed powder of cerium-containing tungsten or molybdenum having a suitable particle size can be obtained; The La₂O₃ powder is directly added to the tungsten powder, and the tungsten mixed powder containing cerium is obtained by direct mechanical mixing. Finally, the finished products of various specifications are obtained by pressing, pre-sintering, sintering, rotary forging (rolling, drawing), straightening, polishing and the like.

For the first kind of pulverizing process, although the uniformity of wet method is higher than that of dry method, the pyrolysis and reduction of nitrate make the particle size grow rapidly, and produce a large number of nitric oxide pollution, and also need steam heating and drying process, waste energy and low production efficiency. The second pulverizing processes can increase the mixing uniformity by prolonging the mixing time, but the two pulverizing processes require two reduction operations of the hydrogen furnace, which increases the complexity of the preparation process and increases the production cost of the material. In the third pulverizing processes, the La₂O₃ particles are easy to combine with the moisture in the air to produce a larger lanthanum hydroxide particle, resulting in the cracking of the compressed formed billets due to the volume expansion of the internal particles.

In order to overcome the existing problems of existing technology, some scholars have proposed a different process for manufacturing lanthanum tungsten electrodes. The main method is to mix the powder of lanthanum hydroxide and tungsten powder into the raw material, and then the static pressing of the raw material powder is formed into the blank body, and the composite is obtained by sintering the body by medium frequency furnace sintering.

The composite material containing cerium-containing tungsten or molybdenum is replaced by the traditional technology, and the method for preparing cerium-containing mixed powder by using cerium nitrate is replaced by the traditional technology, thereby avoiding various defects of the above method and making the composite material of the multi-doped rare earth element composite material. The composite materials with multielement doped rare earth elements have high yield, long service life, cost saving and no pollution, and have wide application prospects.

• < Prev
• Next >