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Preparation of low-temperature primary sintering high-density superfine crystal particle pure tungsten material

An ultra-fine grain and secondary sintering technology, which is applied in the field of preparation of high-density ultra-fine grain pure tungsten material by low-temperature primary sintering, can solve the problems of difficulty in forming nano-powders, and achieves lower sintering temperature, high production efficiency and high density. Effect

Inactive Publication Date: 2007-10-03
UNIV OF SCI & TECH BEIJING
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] The purpose of the present invention is to provide a preparation method of low-temperature primary sintering of high-density ultra-fine grain pure tungsten (W) material to solve the problem of difficult nano-powder forming

Method used

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  • Preparation of low-temperature primary sintering high-density superfine crystal particle pure tungsten material

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Experimental program
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Effect test

Embodiment 1

[0033] Embodiment 1: When preparing 10Kg of high-density ultra-fine grain pure tungsten material, it should be completed according to the following steps.

[0034] 1. Preparation of nano-WO with average particle size ≤ 40nm 3 powder

[0035] Weigh 34.08 liters of high-concentration ammonium tungstate solution, its WO 3 The content is 370g / liter, using the supersonic spray heat conversion method, at the air injection pressure 6.5MPa, the air injection speed 830m / s, the nozzle injection angle α=50°, the focal length F=11.5mm, hot air temperature 400 ℃, countercurrently send hot air, liquid The flow rate is 400ml / min, and the high-concentration ammonium tungstate solution is made into 12.6kg of nano-scale WO 3 Powder, average particle size ≤40nm.

[0036] 2. Repeated reduction-oxygen-reduction to prepare blue tungsten powder with finer particle size.

[0037] Nano-WO with an average particle size ≤ 40nm 3 powder in a tubular reduction furnace at 500°C for 45 minutes, and the...

Embodiment 2

[0048] Example 2, when preparing 1Kg of high-density ultra-fine grain pure tungsten material, it should be completed according to the following steps.

[0049] 1. Preparation of nanoscale WO 3 powder

[0050] Weigh 3.41 liters of high-concentration ammonium tungstate solution, its WO 3 The content is 350g / liter, using the supersonic spray heat conversion method, at the air jet pressure 5MPa, jet speed 664m / s, nozzle jet angle α=50° focal length F=11.5mm, hot air temperature 350°C, countercurrent hot air flow, liquid flow The delivery speed is 400ml / min, and the high-concentration ammonium tungstate solution is made into 1.26kg nano-scale WO 3 Powder, average particle size ≤40nm.

[0051] 2. Repeated reduction-oxygen-reduction to prepare blue tungsten powder with finer particle size.

[0052] ≤40nm nano WO 3 powder in a tube-type reduction furnace at 450°C for 60 minutes, and nano-WO 3 All powders are restored to WO 2.9 Blue tungsten powder, then 550 ° air flow in the tu...

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Abstract

The invention was involved in producing pure tungsten with high-density ultra-fine grain at low temperature for one time. The temperature was 350-400deg.C and pressure was 5-6.5Mpa. Supersonic spray heat change was used to produce nano-WO3 powder, the diameter was lower than 40nm. Blue tungsten powder was formed in nanometer grade by deoxidation-oxidation-deoxidation reaction. Then adding furfural- phenolic aldehyde-ethyl carbinol solution, blue tungsten powder was coverd by furfural organic film after mixing by twin-screw agitator. Blue tungsten powder was deacidize in tungsten powder whose diameter was lower than 70nm in the continuous rotary furnace in fluid bed and the nano-tungsten powder was sheared and activated in dry-type high-speed interlaminar shearing machine. Tungsten powder pressed blocks were produced with high-pressure soft dies. Pure tungsten ultra-fine grain with 95%-96% relative density was produced at low temperature for one time and the tungsten crystal grain was smaller than 8-12um.

Description

technical field [0001] The invention belongs to the technical field of high-melting-point metal tungsten preparation, and in particular provides a preparation method of low-temperature primary sintering high-density ultra-fine-grain pure tungsten (W) material, which is suitable for large-scale industrial production. Background technique [0002] The melting point of metal tungsten is as high as 3410°C, ranking first among all metals. What's more valuable is that its boiling point is 5527°C, and its heat of vaporization is 799.4 (J / mol), which is unmatched by any metal. [0003] Pure tungsten bulk materials still have high melting point characteristics, extremely high high temperature strength, high elastic modulus, low expansion coefficient, and radiation shielding and absorption properties. Due to the above characteristics, metal tungsten can become the best material used under high temperature and ultra-high temperature conditions, so metal tungsten is widely used to make ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F9/26C22B34/36B22F3/12
Inventor 张丽英吴成义李燏尤彩虹
Owner UNIV OF SCI & TECH BEIJING
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