Method for producing thorium-tungsten wire

Abstract

The method includes following steps: adding certain quantity of solution of thorium nitrate into tungsten oxide so as to prepare doped powder of tungsten oxide; deoxidizing the obtained doped powder of tungsten oxide to obtain powder of thorium - tungsten; acid cleaning powder of thorium - tungsten to remove impurity, and producing sintered body of powder of thorium - tungsten; using press work toobtain thorium -tungsten filament with needed diameter, and content of thorium dioxide being 0.7-1.1 wt%, and enwinding thorium -tungsten filament by using wire coil; Finally, straightening filament.The invention raises the rate of finished products, and optimizes working performance of tungsten winding.

Description

technical field [0001] The invention relates to a manufacturing method of a thoriated tungsten wire for a cathode tungsten coil of a magnetron, in particular to a manufacturing method of a thoriated tungsten wire capable of improving the yield, saving costs, and optimizing the working performance of the tungsten coil. Background technique [0002] As we all know, the tungsten coil used in the cathode part of the magnetron is made of thoriated tungsten wire wound into a helical shape. It has the ability to emit electrons after being heated to a specified temperature by a current. This cathode has a short heating time and resistance Strong electron bombardment ability and so on. When the thoriated tungsten cathode in the magnetron is working, the thorium atoms generated in the cathode continuously diffuse to the surface of the tungsten wire to form a thorium atomic layer, which reduces the work function of the cathode surface and increases the radiation capacity. The layer of...

AI Technical Summary

Problems solved by technology

The thoriated tungsten wire manufactured by the original technology, due to the process conditions during drawing, the thoriated tungsten wire has a naturally curved shape feature, which will generate torque when winding, and the tungsten coil is prone to splitting and pitch in the winding process. uneven distribution of deformation

[0008] In addition, when the thoriated tungsten wire is used as the cathode of the launch tube, the sagging deformation is its fatal shortcoming. This is mainly due to the fact that when the recrystallized grains are adjusted and heated at high temperature for a long time, various impurities in the grains undergo multiple creeps and cause fatigue. Accumulated results. After studying the behavior of tungsten powder with impurities added during sintering and the metallographic structure of thoriated tungsten wire, we found that in the process of producing thoriated tungsten wire, while adding thorium oxide, potassium, Iron, nickel, calcium, silicon, aluminum and other impurities enter the tungsten oxide powder (or the remaining impurities in the raw material), and after being reduced by hydrogen gas at a certain temperature, this additive other than thorium oxide enters the tungsten powder, and after sintering When it is used, it can promote the aggregation of thorium oxide particles. As a result of the aggregation of thorium oxide particles, it will be unevenly distributed in the tungsten matrix, which will directly affect the metallographic structure of the thorium tungsten wire and cause the sagging deformation of the wire.

[0009] Therefore, the above-mentioned thoriated tungsten wire has the following problems in the process of making tungsten coils: the produced thoriated tungsten wire has strong brittleness and poor toughness, and it is easy to twist or split when winding, and the helical wire of the tungsten coil is wound out. Torque will be generated and the deformation phenomenon of uneven pitch distribution will occur: the tungsten coil is easy to sag and deform during the working process

These undesirable phenomena will seriously restrict the production cost of tungsten coils, and have a great impact on the working characteristics and life of the magnetron