Study On The Thermionic Emission Performance And Preparation Of Molybodenum Cathode Materials Doped With Rare Earth

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.