【作者】 李湘波；

【导师】 张久兴；

【作者基本信息】 北京工业大学 ， 材料学， 2003， 硕士

【摘要】 本文采用粉末冶金和塑性加工方法成功制备出六种高含量(4-4.5wt％)稀土钼热阴极材料，确定了其优良的制备工艺。采用了SEM，X-Ray衍射等分析手段对稀土钼热阴极材料在制备过程中的性能进行了测试和研究，借助了拉伸等实验方法对退火态的稀土钼热阴极材料的力学性能进行了检测与研究，研究了稀土氧化物对钼阴极丝材再结晶过程的影响，最后测量分析了几种碳化后的稀土钼热阴极的热电子发射性能。 掺杂复合稀土元素的钼粉，经过二次氢还原后，粉末颗粒细小而且均匀。稀土氧化物的加入明显提高了烧结钼坯的密度。采用低温长时的中频烧结工艺烧结的稀土钼坯性能较好，烧结的材料中稀土损失较少。 4 wt％左右稀土氧化物的加入，能显著提高钼热阴极丝材的再结晶温度和室温抗拉强度。含量为4wt％左右稀土氧化物的钼热阴极丝材在经过1700℃左右热处理后，其延伸率能够达到电子管热阴极用丝材的塑性要求。 对于采用渗透碳化方式的稀土钼热阴极而言，镧钼阴极，镧铈-钼阴极，铈-钼阴极，镧钇-钼阴极具有良好的热电子发射性能，镧钇铼-钼阴极的热电子发射性能一般。采用流动碳化方式的镧铼-钼阴极的热电子发射性能最差。更多还原

【Abstract】 Six kinds of molybdenum thermionic cathode materials doped with different weight content of rare earth oxides were successfully prepared by powder metallurgy method and metal processing technology, and the fine technics of preparation was confirmed.The properties of the materials during preparation were studied by means of SEM,X-Ray and XRD, the effect of rare earth oxides on the recrystallization and mechanical properties of molybdenum wires were studied by means of experimental method of tension and OM method, thermoinic electron emission character of several kinds of carbonized molybdenum thermionic cathode doped with rare earth oxides were studied.The granules of the reverted molybdenum powder doped with rare earth oxides are fine and uniformity. Density of molybdenum compact is greatly improved by addition of rare earth.The sintering technics by low temperature and long hours can prepare molybdenum compact of fine properties.The recrystallization temperature and the strenth of molybdenum thermionic cathode wires are increased greatly by addition of about 4wt% content of rare earth oxides .The elongation of molybdenum wires after heat treatment at 1700C can reach the needs of the application in vacuum tube.La-Mo, La-Y-Mo, La-Ce-Mo and Ce-Mo thermionic cathode which were infiltrative carbonized show excellent thermoinic electron emission character, La-Y-Re-Mo thermionic cathode which was infiltrative carbonized shows common thermoinic electron emission character,La-Re-Mo thermionic cathode which was flowing carbonized shows poor thermoinic electron emission character.更多还原