A kind of preparation method of high electron emission rate composite cathode material

A composite cathode, emissivity technology, applied in cold cathode manufacturing, electrode system manufacturing, discharge tube/lamp manufacturing, etc. The effect of solving high threshold and improving the uniformity of electron emission source density distribution

Active Publication Date: 2019-03-05
INST OF FLUID PHYSICS CHINA ACAD OF ENG PHYSICS
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Problems solved by technology

[0005] In order to solve the problems existing in the prior art, the purpose of the present invention is to provide a method for preparing a composite cathode material with high electron emission rate that can solve the problems of high cathode emission electric field strength threshold, low electron emission density and short service life.

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  • A kind of preparation method of high electron emission rate composite cathode material
  • A kind of preparation method of high electron emission rate composite cathode material

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preparation example Construction

[0024] Such as figure 1 As shown, according to an exemplary embodiment of the present invention, the preparation method of the high electron emission composite cathode material includes the following steps.

[0025] Step A:

[0026] Making a high melting point metal or alloy powder into a porous metal or alloy skeleton with a predetermined shape, grinding ferroelectric or antiferroelectric ceramic materials into powder or mixing raw material powders of said ferroelectric or antiferroelectric ceramic materials uniform.

[0027] Wherein, the refractory metal or alloy powder used in this step can have a melting point or softening temperature higher than the melting point of the ferroelectric or antiferroelectric ceramic material and does not mix with the ferroelectric or antiferroelectric ceramic material melt A metal or alloy that undergoes a chemical reaction. Preferably, it can be tungsten, molybdenum, tantalum, hafnium, chromium, zirconium, titanium, niobium, palladium-iri...

example 1

[0040] Example 1: Barium strontium titanate-tungsten composite cathode material

[0041] According to BaCO 3 Powder 40mol%, TiO 2 Powder 27mol%, SrCO 3 Powder 33mol% molar ratio preparation mixture (requires BaCO 3 、TiO 2 , SrCO 3 The purity of the raw materials should be greater than or equal to 99%), ball milled in an alcohol medium for 4 hours, and dried for later use.

[0042] Mix 5% (mass percentage) of tungsten powder, 93% of sodium bicarbonate powder, and 2% polyethylene glycol and press it into a round cake. Microns. Clamp the tungsten-sodium bicarbonate mixture disc between two disk electrodes, apply a high-intensity pulse current to the tungsten-sodium bicarbonate mixture disc, use the electric field activation sintering method to sinter the tungsten particles, and control the current peak at 100A Between ~200A, the pulse width is 5-10 microseconds. During the sintering process, the tungsten-sodium bicarbonate mixture cake should be well cooled so that the te...

example 2

[0046] Example 2: Barium Strontium Niobate-Molybdenum Composite Cathode Material

[0047] According to BaCO 3 Powder, SrCO 3 Powder, Nb 2 o 5 Powder according to Sr 0.5 Ba 0.5 Nb 2 o 6 The molar ratio of the chemical formula is used to prepare the mixture (requires BaCO 3 , SrCO 3 , Nb 2 o 5 The purity of the raw materials should be greater than or equal to 99%), ball milled in alcohol medium for 4 hours, after drying, add a binder with a mass ratio of no more than 2%, mix evenly, put it into a pre-fired mold for compression molding, and the recommended molding pressure is greater than or equal to 50MPa. Then it is sent to a pre-fired furnace and heated to 1500°C for 1 hour, and then naturally cooled to normal temperature.

[0048] Send the pre-fired strontium barium niobate block into the crusher and crush it into a coarse powder with a particle size of no more than 0.1mm. After sieving, add a binder with a mass ratio of no more than 2%, mix evenly, and then put i...

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Abstract

The invention discloses a method for preparing a high-electron-emissivity composite cathode material, comprising the following steps: making metal with a high melting point or alloy powder into porous metal or alloy frame with a predetermined shape; grinding the ferroelectric or anti-ferroelectric ceramic material or its raw material into powder and mixing the powder uniformly; using a crucible to melt down the ferroelectric or anti-ferroelectric ceramic material or its raw material powder to obtain the ferroelectric or anti-ferroelectric ceramic material molten liquid; guiding the ferroelectric or anti-ferroelectric ceramic material molten liquid slowly to a mold filled with the porous metal or the alloy frame for immersions; and then, carrying out the annealing treatment, cooling to the normal temperature for the high-electron-emissivity composite cathode material. In the invention, the metal or alloy material with a high melting point is composed with the ferroelectric or anti-ferroelectric ceramic material with a large dielectric constant; put more technically, the model made from the porous metal or the alloy frame is used as a mold for the ferroelectric or anti-ferroelectric ceramic material molten liquid to immerse into the porous metal or alloy frame to form the high-electron-emissivity composite cathode material.

Description

technical field [0001] The invention relates to the technical field of cathode material preparation, and more specifically, relates to a method for preparing a composite cathode material with high electron emission rate. Background technique [0002] In the fields of technology research and product development such as accelerators, microwaves, X light sources, material processing and testing, electron beam sources are key devices and research hotspots in related fields. In the electron beam source, the cathode is the core component for emitting electrons, and its material properties have an important impact on parameters such as electron beam quality and beam emission density. [0003] Usually, for cold cathode electron beam sources based on the working principle of field emission or explosive emission, the cathode material is made of low resistivity or high melting point metal or alloy material in order to obtain higher electron emission density and longer service life . ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H01J9/02C04B35/74C04B35/468C04B35/495C04B35/653
CPCC04B35/4682C04B35/495C04B35/653C04B35/74C04B2235/3213C04B2235/3215C04B2235/6562C04B2235/6565C04B2235/6567C04B2235/6581H01J9/022
Inventor 赵娟李博婷李洪涛王波马勋王传伟李波黄宇鹏
Owner INST OF FLUID PHYSICS CHINA ACAD OF ENG PHYSICS
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