Fast Doping of Thorium And Tungsten in Magnetic Control Coil

The core component of the magnetron cathode component magnetic control coil requires the uniform distribution of ThO2 particles in the tungsten matrix. At present, the preparation process of the magnetic control coil material powder for magnetron cathode used in foreign countries is to use ammonium paratungstate to burn into the tungsten WO₃ as the raw material, through doping, high temperature sintering, one reduction to doping WO₂ and two times. It was originally doped with W powder. But this method has long working procedure and high manufacturing cost.

In addition, thorium solid doping method is to add thorium oxide particles directly into the tungsten powder and then make the doped tungsten powder by mechanical grinding mixture. This method is a major obstacle to the fabrication of the cathode component of the magnetron because of the low amount of thorium oxide and the use of mechanical mixture to make the thorium particle in the tungsten powder difficult to distribute in tungsten powder.

To solve the problems mentioned above. Some scholars have provided a unique thorium doped tungsten method to ensure the uniformity of thorium nitrate doping by controlling the nucleation and precipitation of the grain of thorium nitrate, and effectively controlling the iron Fe content of the harmful impurities, so as to ensure the effective process of subsequent processing. The main ideas of the scheme are as follows: in the doping process, the ammonia solution is added to the solution of thorium nitrate and stirred to form a white colloidal mixture, and the configured tungsten powder is added in the doping pot, and the mixed solution is evenly sprayed to the surface of the tungsten powder.

Through improvement, the scheme can produce raw material powder with uniform distribution of thorium oxide ThO₂ and controllable content of harmful impurity iron Fe. The manufacturing cost is greatly reduced and the production efficiency is increased.

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