放电等离子固相烧结制备高密度LaB6阴极性能
Properties of high density LaB6 cathode prepared by spark plasma solid phase sintering
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摘要: 采用放电等离子烧结（SPS）技术，以碳化硼还原法制备的LaB6粉末为原料，制备了高致密LaB6多晶块体阴极，并系统研究了烧结温度、压力对LaB6烧结样品的物相、结构和性能的影响。确定了SPS烧结LaB6的最佳工艺为：压力50 MPa，烧结温度1 650 ℃，保温时间10 min。实验结果表明：与其它LaB6多晶制备方法相比，SPS制备得到的LaB6烧结块体的力学及发射性能均有大幅提高，样品相对密度达到96.2％，维氏硬度达到1 720 kg/mm2，抗弯强度达到203.2 MPa。样品在1 520 ℃温度下发射电流密度达到17.41 A/cm2，功函数为2.40 eV。SPS制备法显著降低了LaB6的烧结温度，缩短了烧结时间。Abstract: High density LaB6 polycrystalline bulks were fabricated by spark plasma sintering(SPS) LaB6 powders prepared by boron carbide reduction method. The effects of sintering temperature and pressure on the phase formation, microstructure and properties of the sintered LaB6 bulks were studied systematically. The optimal technological parameters are sintering temperature of 1 650 ℃, sintering pressure of 50 MPa and holding time of 10 mins. It is shown that, the mechanical and emissive properties of the sintered LaB6 bulks are much better than that prepared by other methods. The relative density of the LaB6 sintered by SPS is up to 96.2%, and its vickers hardness reaches 1 720 kg/mm2. The highest bend strength is 203.2 MPa. The electron emitting density of the polycrystalline LaB6 sintered by SPS
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