Electron Microscopic Study And Case Base Of Cathode And Slow Wave Structure Of Traveling Wave Tube

Traveling wave tube(TWT) in high frequency, wide band, large power and so on has certain advantages, in the military satellite radar and jammer and other systems play a major role. Homemade compared with foreign TWT, on the performance gap is smaller, but the gap is bigger in terms of quality and reliability. In order to improve the quality of homemade TWT and reliability, Through the Scanning Electron Microscope(SEM) to the traveling wave tube and material microstructure morphology analysis combined with the Energy Disperse Spectroscopy(EDS) on the material composition analysis. Carried out on the traveling wave tube cathode emission performance variation analysis, slow wave structure heat dissipation performance and shell leakage cause analysis etc, the main work content is as follows.(1) Microscopic analysis technology application in the materials research of the TWT. Select the appropriate raw materials through microscopic analysis technology. Such as, tungsten powder morphology by SEM. Doing research on optimum process, Illustrates by means of microscopic method detection from ammonium molybdate to molybdenum powder of different stages in the process of topography, in order to guide the production technology of molybdenum powder. In terms of failure analysis, enumerate the causes of cathode tube on the assembly.(2) Analysis cathode materials of the TWT. On the cathode emission performance degradation, through to the cathode surface and the body is different the launch material microscopic analysis of micro area, the analysis results show that tungsten sponge body heat unevenly, emitting material excessive precipitation on the surface, and led to the decrease of the cathode current emission performance. Support for molybdenum cathode tube cracking and deformation phenomenon, through the comparative analysis of different structures and different welding process of cathode, find out molybdenum support tube cracking reason for the welding of molybdenum metal grain boundary caused by weakened. Molybdenum support the cause of the tube deformation near to weld tungsten molybdenum produced in welding process of molybdenum tube deformation caused by the tension. Microscopic quality evaluation of the tungsten sponge by SEM, and the contrast effect of the cathode at home and abroad, from the structure, launch surface, thickness of coated and content of all aspects of the microscopic analysis method, this paper compares and analyzes the effect of cathode quality evaluation.(3) Microscopic analysis of material research used in slow wave structure of the TWT. For molybdenum spiral coating fall off phenomenon, analysis of normal and molybdenum spiral off area, find out the cause of the coating fall off for after sandblasting adhesive residue on the surface of molybdenum, lead to subsequent nickel plating and copper plating failure. Heat dissipation performance degradation problem for slow wave structure, analyze the loading bar, find the reasons of the decrease of heat dissipation is slow wave system working temperature is too high to tungsten- copper alloy thermal conductivity performance degradation, slow wave system caused by temperature rise. Problems of spots on surface of attenuator, for normal and macular area were analyzed, finding out the reasons for the introduction of impurities such as calcium in process engineering. Finally, in view of the slow wave structure of nickel copper alloy tube shell leak problem, using the scanning electron microscope and energy spectrometer to shell for microstructure and composition analysis. Results show that the burning hydrogen process introduced in the oxygen react with nickel complex manganese element in copper alloy, reactant weaken the grain boundary cohesion, make the grain boundary prone to cracking, lead to shell leakage.(4) Case base of the microscopic analysis. In the long-term development of traveling wave tube and material analysis and microscopic test work, accumulated a large amount of case study analysis. In order to make the effective storage and rational utilization of these resources, the development of the micro analysis putted forward, and the typical cases from material, process, quality, failure and other sorting after adding into the Treasury. The database can realize the convenient and fast data access and update. The database can realize the convenient and fast data access and update.These results for the traveling wave tube cathode and slow wave structure and materials in the process of further research provides an important analysis data, to the quality and the reliability of traveling wave tube played an important role in guiding.