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Preparation method of lanthanum hexaboride nanometer powder and application of lanthanum hexaboride nanometer powder

A technology of lanthanum hexaboride and nano-powder, which is applied in the field of ceramic powder preparation, can solve the problems of many impurities, low preparation temperature, and coarse powder particle size, and achieve high purity, good dispersion, and uniform particle size Effect

Active Publication Date: 2017-02-15
NAT UNIV OF DEFENSE TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Currently, the commonly used LaB 6 The cathode electron emitter material is mainly composed of LaB 6 The powder is sintered at high temperature, but the existing LaB 6 The powder has shortcomings such as coarse particle size, uneven size, easy agglomeration, and many impurities. On the one hand, these shortcomings make it difficult to sinter and densify. On the other hand, the presence of impurities, especially oxygen and carbon, will lead to LaB 6 The electron work function of the cathode electron emitter material increases, thereby reducing its electron emission performance
These methods all belong to the category of solid-phase reaction method, but the solid-phase reaction method has disadvantages such as high reaction temperature, long atomic diffusion path, incomplete reaction, etc., which easily lead to large particle size, uneven particles, easy agglomeration, and impurities Many, low surface activity, etc.
In addition to the above methods, the patent CN101503198 B discloses a method for the synthesis of lanthanum hexaboride nano-powders by solid-state reaction at low temperature. This method has a low preparation temperature and can obtain nano-sized LaB 6 powder, but it requires many kinds of reactants, which is easy to cause the synthesis of LaB 6 The powder contains many impurities

Method used

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  • Preparation method of lanthanum hexaboride nanometer powder and application of lanthanum hexaboride nanometer powder
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  • Preparation method of lanthanum hexaboride nanometer powder and application of lanthanum hexaboride nanometer powder

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Embodiment 1

[0031] A preparation method of lanthanum hexaboride nanopowder of the present invention comprises the following steps:

[0032] (1) According to the La:B molar ratio of 1:6, weigh 1.23g LaCl respectively 3 , 1.14g NaBH 4 , according to the total mass of KCl-LiCl complex salt as LaCl 3 and NaBH 4 5 times the total mass of LiCl, weigh 6.64g KCl and 5.21g LiCl respectively, fully grind and mix the four into the crucible;

[0033] (2) Place the charged crucible in a tube furnace for heat treatment. Under an argon protective atmosphere, raise the temperature to 600°C at a heating rate of 5°C / min, keep it warm for 1h, and then cool down at a rate of 8°C / min To room temperature, the initial product is obtained;

[0034] (3) The initial product was washed several times with deionized water at 60°C until the AgNO 3 When the solution is added dropwise to the filtered washing liquid until there is no white precipitate, it is finally dried to obtain lanthanum hexaboride nanopowder. ...

Embodiment 2

[0037] A preparation method of lanthanum hexaboride nanopowder of the present invention comprises the following steps:

[0038] (1) According to the La:B molar ratio of 1:8, weigh 1.63g La(NO 3 ) 3 , 1.52g NaBH 4 , according to the total mass of KCl-LiCl complex salt as La(NO 3 ) 3 and NaBH 4 10 times the total mass of LiCl, weigh 17.33g KCl and 14.17g LiCl respectively, fully grind and mix them into the crucible;

[0039] (2) Place the charged crucible in a tube furnace for heat treatment. Under an argon protective atmosphere, raise the temperature to 800°C at a heating rate of 5°C / min, keep it warm for 1h, and then cool down at a rate of 5°C / min To room temperature, the initial product is obtained;

[0040] (3) The initial product was washed several times with deionized water at 60°C until the AgNO 3 When the solution is added dropwise to the filtered washing liquid until there is no white precipitate, it is finally dried to obtain lanthanum hexaboride nanopowder.

...

Embodiment 3

[0043] A preparation method of lanthanum hexaboride nanopowder of the present invention comprises the following steps:

[0044] (1) According to the La:B molar ratio of 1:6, weigh 1.23g LaCl respectively 3 , 1.14g NaBH 4 , according to the mass of KCl single-phase salt as LaCl 3 with NaBH 4 5 times the total mass of KCl, take 11.85g KCl, fully grind and mix the three and put them into the crucible;

[0045] (2) Place the charged crucible in a tube furnace for heat treatment. Under an argon protective atmosphere, heat up to 1000°C at a rate of 5°C / min, keep it warm for 2 hours, and then cool down at a rate of 5°C / min To room temperature, the initial product is obtained;

[0046] (3) The initial product was washed several times with deionized water at 60°C until the AgNO 3 When the solution is added dropwise to the filtered washing liquid until there is no white precipitate, it is finally dried to obtain lanthanum hexaboride nanopowder.

[0047] After detection and analysi...

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Abstract

The invention discloses a preparation method of lanthanum hexaboride nanometer powder and an application of the lanthanum hexaboride nanometer powder. The preparation method includes: mixing a lanthanum source and a boron source with fused salt prior to heating to a molten state to enable the lanthanum source and the boron source to perform liquid phase reaction in the fused salt and allow the lanthanum source to be reduced to lanthanum hexaboride by the boron source, and obtaining an initial product after cooling; washing and filtering the initial product to remove the fused salt, and obtaining the lanthanum hexaboride nanometer powder after drying. The preparation method has the advantages that the prepared lanthanum hexaboride nanometer powder is controllable in particle size, uniform in particle size, agglomeration free, high in purity, wide in source of raw materials, low in reaction temperature, simple and controllable in process, free from specific requirements on equipment, low in cost and the like, the lanthanum hexaboride nanometer powder prepared with the method can be used for preparing lanthanum hexaboride blocks or coated cathode electron emitter materials, and high application value is achieved.

Description

technical field [0001] The invention belongs to the technical field of ceramic powder preparation, and in particular relates to a preparation method and application of lanthanum hexaboride nano powder. Background technique [0002] Lanthanum hexaboride (LaB 6 ) represented by rare earth metal hexaboride has the advantages of high melting point, high hardness, low work function, low evaporation rate, stable chemical properties and resistance to ion bombardment, and is an excellent cathode electron emitter material. , plasma source, scanning electron microscope and Auger spectrometer and other instruments have broad application prospects. Currently, the commonly used LaB 6 The cathode electron emitter material is mainly composed of LaB 6 The powder is sintered at high temperature, but the existing LaB 6 The powder has shortcomings such as coarse particle size, uneven size, easy agglomeration, and many impurities. On the one hand, these shortcomings make it difficult to sin...

Claims

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Application Information

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IPC IPC(8): C01B35/04B82Y40/00
CPCC01B35/04C01P2004/03C01P2004/62C01P2004/64C01P2006/17
Inventor 王松余艺平李伟陈朝辉
Owner NAT UNIV OF DEFENSE TECH
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