Rare Earth Affected Rare Earth Tungsten Electrode Reduction Process

Rare earth tungsten electrode usually uses powder metallurgy to produce. Using this method for rare earth tungsten electrode manufacturing, the powder quality will directly affect the sintering and processing properties of the electrodes. During mixed powder reduction process, the phase will usually go through WO_2.9, WO_2.72, WO₂, W and β-W phase change. β-W in the actual production is difficult to obtain, but in the mixed rare earth tungsten powder reduction process can often find this material. After the first reduction observed XRD pattern can find β-W diffraction peaks. With the rare earth content increases, the peak intensity increases. In the second reduction, there are also appeared in the same law, indicating rare earth is favor to produce β-W. On the other hand, the presence of β-W powder causes second-step reduction reaction is not complete, and therefore during rare-earth doped, the reduction temperature should higher than pure tungsten. It can be seen, doped with rare earth will change tungsten powder reduction way. During tungsten powder reduction will first to form β-W, and then converted into α-W. β-W is the A15-type structure, which has a superconducting nature, it attracted widespread attention. But for the good performance tungsten electrode production to produce stable α-W is the ultimate goal of reduction. And to improve the reduction temperature can obtain α-W which is complete reduction.

Doped with different rare earth components, under the same conditions, the reduction particle size obtained is not the same. Under the same reduction conditions, the rare earth tungsten powder particle size is significantly smaller than pure tungsten powder, because rare earth can help to refine tungsten oxide grain size. In various rare earth oxides, Y₂O₃ has better refinement effect and for tungsten powder particle size refinement is the most obvious. In addition, produce multi rare earth tungsten electrode the higher Y₂O₃ content, tungsten powder refinement is better.

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