Zr掺杂形式对钨电子发射材料组织性能的影响

采用中频感应加热烧结方法制备了W-1.5%La₂O₃-0.1%Y₂O₃-0.1%ZrO₂和W-1.5%La₂O₃-0.1%Y₂O₃-0.08%ZrH₂电子发射材料，烧结样品的致密度约为95.5%。热电子发射测试结果表明，添加氢化锆的热电子发射材料样品的零场发射电流密度大于添加氧化锆的样品，分析认为是添加的氢化锆在烧结时，发生分解，生成活性的Zr可以捕获钨晶界中的杂质氧，净化晶界，从而提高了电子发射；维氏显微硬度表明添加氢化锆样品的硬度高于添加氧化锆的样品，分析表明是氢化锆的添加有效改善了钨晶粒之间的结合性，提升了钨电子发射材料的硬度。利用SEM，EDS，XRD、金相显微镜等表面分析设备对样品进行了表征，样品结构显示添加氢化锆与添加氧化锆相比，不仅钨晶粒尺寸由13.63 μm降至11.63 μm,而且稀土相尺寸由1.87 μm降至1.66 μm，这种组织结构的变化有利于电子发射。

Effect of Zr doping material on the structure and performance of tungsten electrode

The W-1.5%La₂O₃-0.1%Y₂O₃-0.1%ZrO₂ and W-1.5%La₂O₃-0.1%Y₂O₃-0.08%ZrH₂ electron emission materials were prepared by the intermediate frequency induction heating sintering method. The density of the sintered sample is about 95.5%. The thermionic emission test results show that the zero field emission current density of the thermionic emission material sample added with zirconium hydride is greater than that of the sample added with zirconia. The analysis illustrates that the added zirconium hydride decomposes during sintering, and the active Zr can capture tungsten. The impurity oxygen in the grain boundary purifies the grain boundary, thereby improving electron emission; Vickers microhardness measurement shows that the hardness of the sample with zirconium hydride added is higher than that of the sample with zirconium oxide. Analysis shows that the addition of zirconium hydride effectively improves the bonding between the tungsten crystal grains and enhances the hardness of the tungsten electron-emitting material. The samples were characterized by SEM, EDS, XRD, metallographic microscope and other surface analysis equipment. The structure shows that the addition of zirconium hydride, compared with the addition of zirconia, not only decreases the size of tungsten grains from 13.63 μm to 11.63 μm, but also decreases the size of the rare earth phase from 1.87 μm to 1.66 μm. This change in organizational structure is conducive to electron emission.