论文部分内容阅读
序言六硼压镧(LaB_6)具有2.3—2.4eV 的低功函并且是一个电子发射源的有用材料。在 LaB_6阴极的应用中,需要高纯度和尖锐的顶端以增大电子束电流。单晶比烧结物体较易干满足这些要求。此外可选用合适的结晶方向作为顶端的轴线。然而,高熔点(约2400℃)及熔体活泼性使其难以制备成高质量单晶。曾应用金属熔剂
Preface Six Boron lanthanum (LaB_6) has a low work function of 2.3-2.4 eV and is a useful material for electron emission sources. In LaB_6 cathode applications, high purity and sharp tips are needed to increase the beam current. Monocrystals are easier to meet these requirements than sintered objects. In addition you can choose the appropriate direction of crystallization as the top of the axis. However, high melting point (about 2400 ° C) and melt activity make it difficult to prepare high quality single crystals. Used metal flux