Micron-sized porous tungsten and preparation method thereof

A porous tungsten, micron-scale technology, applied in metal processing equipment, transportation and packaging, etc., can solve problems such as low production efficiency, high sintering temperature, low porosity, etc., and achieve high automation level, simple process equipment, and high production efficiency. Effect

Active Publication Date: 2017-10-10
WUHAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] However, the extremely high melting point and high density of tungsten make the preparation of porous tungsten difficult. For example, high heating temperature is required, and it is difficult to select a suitable pore-forming agent.
As far as the common traditional sintering method and the organic matrix immersion drying sintering method are concerned, there are the following obvious disadvantages: the sintering temperature of the traditional sintering method is extremely high, the porosity is low, and the pore distribution is uneven; the organic matrix immersion drying sintering method Although the operation is simple and the pore size distribution is uniform, the sintering temperature is still high and the production efficiency is low
The current research status also shows that the relevant reports on the preparation of porous tungsten by pore-forming agents at home and abroad are unable to simultaneously achieve low-cost pore-forming agents, good pore-forming effects, controllable pore size, regular pore shape, and variable porosity range. Big

Method used

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  • Micron-sized porous tungsten and preparation method thereof
  • Micron-sized porous tungsten and preparation method thereof
  • Micron-sized porous tungsten and preparation method thereof

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preparation example Construction

[0034] A method for preparing micron-scale porous tungsten, comprising the following steps:

[0035] 1) The raw materials NaCl, ethanol and ball milling medium are ball milled, and then vacuum dried at 60° C. for 12 hours to obtain NaCl powder;

[0036] 2) Raw material preparation: 50-60% of tungsten powder, 0%-8.5% of NaCl powder, 32.6-38.4% of organic solvent and 5.3-7.4% of organic additives are prepared according to the mass percentage, wherein organic additives include 2.5%-3.5% % of polyvinyl butyral, 0.8%-1.2% of Hypermer KD-1 and 2.0%-2.7% of glycerin;

[0037] 3) Preparation of casting slurry: adding NaCl powder, tungsten powder and organic additives into an organic solvent for ball milling to obtain casting slurry;

[0038] 4) Processing of the cast ribbon: cast the cast slurry obtained in step 3) in the cast machine to dry and set the shape to obtain the cast ribbon, cut the cast ribbon into a specific shape, and cut the cast ribbon into a specific shape, and cut t...

Embodiment 1

[0041] This embodiment provides a method for preparing micron-scale porous tungsten, including the following steps:

[0042]A. Preparation of casting slurry: 100g NaCl and 50g ethanol were added into a nylon tank, and ball milled in a planetary ball mill for 36 hours, wherein the NaCl raw material had a purity of 99.9%, passed through a 60-mesh sieve, and the ball milling speed was 250rpm. Pour the obtained suspension into a beaker, let it stand at room temperature in a vacuum drying oven for 1 hour, pour out the upper liquid, and vacuum-dry the remaining material in the beaker at 60°C for 12 hours in a vacuum oven, and take 2.4g of NaCl powder and 56g of particle size 5μm W powder, 0.9g of Hypermer KD-1 (analytical pure), add 18.3g of absolute ethanol (analytical pure) and 18.3g of methyl ethyl ketone (analytical pure) solvent, ball mill in a high energy mixer for 3h , the ball milling medium is a stainless steel ball, and the mass of the steel ball is 100g. Then 2.6 g of po...

Embodiment 2

[0047] This embodiment provides a method for preparing micron-scale porous tungsten, including the following steps:

[0048] A. The preparation of casting slurry: get 60g particle diameter and be the W powder of 0.5 μm, the Hypermer KD-1 (analytical pure) of 1.2g, add the dehydrated alcohol (analytical pure) of 16.3g and the butanone of 16.3g ( Analytical pure) solvent, ball milled in a high-energy mixer for 3 hours, then added 3.5 g of polyvinyl butyral (analytical pure), 2.7 g of glycerin (analytical pure), and ball milled for 3 hours to obtain casting slurry.

[0049] B. The processing of casting ribbon: the casting slurry obtained in step A is cast and dried in a casting machine to obtain a casting ribbon, and the casting ribbon is cut into a disc with a diameter of 20mm. 100-layer die stack. The vacuum degree of the laminated strip is better than 9.9×10 -3 In the environment of Pa, heat treatment at 780°C for 2h for debinding; followed by a sintering to obtain a green b...

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Abstract

The invention discloses micron-sized porous tungsten and a preparation method thereof, and belongs to the technical field of porous metal materials. The preparation method comprises the following steps: micron-sized pore-forming agent NaCl obtained through ball milling breaking, tungsten powder and an organic additive are added to an organic solvent for ball milling and tape-casting slurry is obtained, and after the slurry is subjected to tape casting, a thin strip is formed and is cut into the specific shape; the thin strips are laminated and then are put in a mould, low-temperature heat treatment rubber discharging is carried out in a vacuum, and then low-temperature hot pressing sintering is carried out in a vacuum and a green body is obtained; and the green body is placed in flowing deionized water for removing the pore-forming agent, the green body is put in a vacuum drying oven for drying and a porous tungsten green body is obtained, and the porous tungsten green body is subjected to high-temperature sintering at Ar atmosphere and the micron-sized porous tungsten is obtained. The density of the prepared porous tungsten is 35-90%, the pore diameters of large pores are 3-6 micrometers, the pore diameters of small pores are 0.1-0.7 micrometer, and the porous tungsten has the advantages that the pore distribution is uniform, the pore size is controllable, the porosity factor variation range is large, and the sintering temperature is lowered obviously.

Description

technical field [0001] The invention relates to the technical field of porous metal materials, in particular to a micron-scale porous tungsten and a preparation method thereof. Background technique [0002] Tungsten is a refractory non-ferrous metal. Its melting point, boiling point and density are the highest among all metals. Its chemical properties are also extremely stable. extremely important use. Therefore, tungsten is widely used in contemporary communication technology, electronic computer, aerospace development, medical and health care, photosensitive materials, photoelectric materials, energy materials and catalyst materials, etc., especially its porous body or porous matrix material can be widely used as a high current density Porous cathodes, emitters charged with electron emission materials in ion engines, vaporizers for mercury gas-liquid separation in mercury ion rocket engines, high-temperature fluid filters, and electronic packaging materials, etc. [0003...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B22F3/11B22F3/22B22F1/00
CPCB22F3/1134B22F3/22B22F1/107
Inventor 张建周东清罗国强沈强张联盟
Owner WUHAN UNIV OF TECH
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