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Method for preparing impregnated MM type cathode through microwave sintering

A microwave sintering and impregnation technology, which is applied in cathode manufacturing, cold cathode manufacturing, electrode system manufacturing, etc., can solve the problem that the emission current density of tungsten-iridium alloy cathode cannot meet the high current density, etc., and achieve fine grains and high-intensity emission. , the effect of high emission

Active Publication Date: 2020-05-08
BEIJING UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Chinese patent 03123137.3 discloses an impregnated barium tungsten cathode based on tungsten-iridium alloy and its preparation method is to use a hydrogen furnace to sinter the cathode substrate. The zero-field emission current density of the obtained tungsten-iridium alloy cathode at a test temperature of 1100 ° Cb is difficult to meet the high current density requirements

Method used

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  • Method for preparing impregnated MM type cathode through microwave sintering
  • Method for preparing impregnated MM type cathode through microwave sintering
  • Method for preparing impregnated MM type cathode through microwave sintering

Examples

Experimental program
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Effect test

Embodiment 1

[0025] (1) Take 10g of micron-sized W powder (2.3μm) and 10g of micron-sized Ir powder (5μm), put them into crucibles respectively, and anneal at 1000°C for 1h in a tube furnace filled with hydrogen to ensure the original powder purification.

[0026] (2) According to the mass ratio of 15% Ir and 85% W, the above-mentioned powders were weighed and mechanically mixed and ground respectively, and passed through a 200-mesh sieve after being uniformly mixed to ensure the uniformity of the particle size of the mixed powder. Take a small amount of mixed powder, and use a stainless steel mold to cold press at a pressure of 4.0-7.0t / cm 2 Within the range, it is pressed into a green body with a diameter of 3mm and a height of 1.2-2mm.

[0027] (3) the green compact that step (2) is pressed is put into Al 2 o 3 In the crucible, they are placed together in a cavity surrounded by zirconia balls with a diameter of 3 mm as the auxiliary heat material, and are heated in argon-hydrogen (8%...

Embodiment 2

[0032] (1) Take 10g of micron-sized W powder (2.3μm) and 10g of micron-sized Ir powder (5μm), put them into crucibles respectively, and anneal at 1000°C for 1h in a tube furnace fed with hydrogen to ensure the original powder purify.

[0033] (2) According to the mass ratio of 20% Ir and 80% W, the above-mentioned powders were weighed, mechanically mixed and ground, and passed through a 200-mesh sieve after being uniformly mixed to ensure the uniformity of the particle size of the mixed powder. Take a small amount of mixed powder, and use a stainless steel mold to cold press at a pressure of 4.0-7.0t / cm 2 Within the range, it is pressed into a green body with a diameter of 3mm and a height of 1.2-2mm.

[0034] (3) the green compact that step (2) is pressed is put into Al 2 o 3 In the crucible, they are placed together in a cavity surrounded by zirconia balls with a diameter of 3 mm as the auxiliary heat material, and are heated in argon-hydrogen (8% H 2 ) under a protectiv...

Embodiment 3

[0039] (1) Take 10g of micron-sized W powder (2.3μm) and 10g of micron-sized Ir powder (5μm), put them into crucibles respectively, and anneal at 1000°C for 1h in a tube furnace fed with hydrogen to ensure the original powder purify.

[0040] (2) According to the mass ratio of 25% Ir and 75% W, the above-mentioned powders were weighed and mechanically mixed and ground, and passed through a 200-mesh sieve after being uniformly mixed to ensure the uniformity of the particle size of the mixed powder. Take a small amount of mixed powder, and use a stainless steel mold to cold press at a pressure of 4.0-7.0t / cm 2 Within the range, it is pressed into a green body with a diameter of 3mm and a height of 1.2-2mm.

[0041] (3) the green compact that step (2) is pressed is put into Al 2 o 3 In the crucible, they are placed together in a cavity surrounded by zirconia balls with a diameter of 3 mm as the auxiliary heat material, and are heated in argon-hydrogen (8% H 2 ) under a protec...

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Abstract

The invention discloses a method for preparing an impregnated MM type cathode through microwave sintering, and belongs to the technical field of rare earth refractory metal cathode materials. The method comprises: mechanically mixing 15%-25% by mass of Ir powder and 75%-85% by mass of W powder, pressing into a green body, and carrying out microwave sintering to obtain a cathode matrix. Compared with conventional sintering, microwave sintering not only can greatly shorten the sintering time, avoid abnormal growth of crystal grains and change the microstructure of the cathode to obtain a cathodematrix with uniform structure, fine crystal grains and high strength, but also can obtain a cathode matrix with a complete porous tungsten-iridium alloy skeleton structure, and is beneficial to impregnation of active salt. The matrix sintered by the microwaves not only improves the strength of the matrix, but also improves the impregnation amount of the cathode, so that the strength and the emission performance of the cathode are improved.

Description

technical field [0001] The invention relates to an impregnated MM cathode, in particular to a method for preparing an impregnated MM cathode by microwave sintering, and belongs to the technical field of rare earth refractory metal cathode materials. Background technique [0002] In recent years, in order to meet the development needs of existing and future military and civilian electronic systems, research on high-current-density electron tubes and terahertz vacuum electronic devices has attracted widespread attention from scholars at home and abroad. The cathode is one of the key components of electronic devices, and its performance directly affects the application of components. Therefore, it is very urgent and important to further improve the mechanical properties and emission performance of the cathode of electronic devices. [0003] The MM type cathode is directly mechanically mixing, pressing, and sintering tungsten powder and iridium powder into a porous matrix and im...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01J9/02H01J1/02C22C27/04B22F3/105B22F3/26
CPCH01J9/02H01J1/02C22C27/04B22F3/105B22F3/26H01J2209/02B22F2003/1054
Inventor 王金淑高俊妍胡鹏杨韵斐张小可吴浩李世磊骆凯捷
Owner BEIJING UNIV OF TECH
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