CN107234241B - A kind of micron-scale porous tungsten and preparation method thereof - Google Patents

Abstract

The present invention is a kind of micrometer level porous tungsten and preparation method thereof, belong to porous metal material technical field, its preparation step is: using the micron order pore creating material NaCl obtained through ball mill crushing, tungsten powder and organic additive be added in organic solvent carry out ball milling obtain curtain coating slurry, slurry is cast to form strip after be cut into specific shape；It is put into mold after lamination, carries out Low Temperature Heat Treatment dumping in a vacuum, low temperature hot-press sintering in a vacuum after dumping obtains green compact；Green compact are placed in the deionized water of flowing and remove pore creating material, are dried in a vacuum drying oven, obtain POROUS TUNGSTEN green compact, POROUS TUNGSTEN green compact high temperature sintering under an ar atmosphere obtains the POROUS TUNGSTEN.POROUS TUNGSTEN consistency prepared by the present invention is 35%-90%, and macropore diameter is 3-6 μm, and small aperture is 0.1 μm -0.7 μm, has the advantages of pore size distribution is uniform, pore size is controllable, and porosity change range is big, sintering temperature is substantially reduced.

Description

A kind of micron-scale porous tungsten and preparation method thereof

technical field

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

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. It can resist all acid and alkali erosion at room temperature. extremely important use. Therefore, tungsten is widely used in contemporary communication technology, electronic computers, aerospace development, medicine and health, photosensitive materials, optoelectronic materials, energy materials and catalyst materials, especially its porous body or porous matrix material can be widely used as high current density. Porous cathodes, emitters into which electron-emitting materials are flushed into ion engines, vaporizers for mercury-gas-liquid separation in mercury-ion rocket engines, high-temperature fluid filters, and electronic packaging materials, etc.

However, the extremely high melting point and high density of tungsten make the preparation of porous tungsten difficult. As far as the traditional sintering method and the organic matrix impregnation drying sintering method are concerned, there are the following obvious shortcomings: the sintering temperature of the traditional sintering method is extremely high, the porosity is low, and the pore distribution is uneven; the organic matrix impregnation 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.

By consulting domestic and foreign patents and literature, it can be found that in order to improve the shortcomings of traditional methods, many scholars have adopted new methods to prepare porous tungsten. Patent CN103774184A discloses a method for preparing porous tungsten by electrolysis. The method utilizes the characteristics of tungsten being electrolyzed by electrochemical action in molten salt solution, and uses alternating current power supply and direct current power supply to electrolyze tungsten metal in NaOH solution containing additives. Porous tungsten is prepared. Although the porous tungsten prepared by this method has a uniform pore size distribution, the pore size is uncontrollable and the porosity is low. The document "Reactive sintering of porous tungsten: A costeffective sustainable technique for the manufacturing of high current density cathodes to be used in flashlamps" discloses a method for preparing porous tungsten by reactive activation sintering using aluminum as pore-forming agent and sintering aid. The method adopts the technical route of cold pressing of aluminum and pre-oxidized tungsten powder mixture, and then pressureless sintering of the molded body under reducing gas. Since the self-propagating reaction of aluminum and tungsten oxide provides a lot of energy, the sintering temperature is significantly reduced. , the hardness distribution is uniform, but the porous tungsten prepared by this method has low porosity and uncontrollable pore size and morphology. All in all, the preparation of porous tungsten is in the process of continuous exploration and continuous improvement. The current research status also shows that the current domestic and foreign reports on the preparation of porous tungsten by the pore-forming agent method cannot simultaneously realize the low cost of the pore-forming agent, the good pore-forming effect, the controllable pore size, the regular pore morphology, and the change of the porosity range. big.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is: aiming at the deficiencies of the existing preparation technology, there is provided a micron-scale porous tungsten obtained by adding a pore-forming agent in the casting slurry, and combining the casting molding with hot pressing or pressureless sintering, and the same. Preparation. The method has the advantages of simple equipment, continuous operation, high production efficiency, high automation level and stable process. The size is adjustable, and the trace C element remaining in the casting slurry can significantly reduce the sintering temperature.

The present invention solves its technical problem and adopts following technical scheme:

A preparation method of micron-scale porous tungsten, comprising the following steps:

1) Ball milling raw material NaCl, ethanol and ball milling medium, and then drying to obtain NaCl powder;

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

3) preparation of casting slurry: NaCl powder, tungsten powder and organic additive are added into organic solvent and ball-milled to obtain casting slurry;

4) Treatment of the casting thin strip: the casting slurry obtained in step 3) is cast, dried and shaped in a casting machine to obtain a casting thin strip, and the casting thin strip is cut into a specific shape. Thin strips are laminated, and the laminated strips are kept under vacuum for thermal insulation and debinding, and then thermally sintered under the same vacuum degree for hot pressing and sintering to obtain green bodies;

5) Sintering to obtain porous tungsten: the green body is rinsed in flowing water, and then dried to obtain a porous tungsten green body, and the porous tungsten green body is sintered at high temperature in an inert atmosphere to obtain the porous tungsten.

In the above scheme, the specific feeding sequence in the step 3) is: first add tungsten powder, NaCl and Hypermer KD-1 to the organic solvent for ball milling, then add polyvinyl butyral and glycerin, and ball mill to obtain a casting material. pulp.

In the above scheme, the particle size of the NaCl powder in the step 1) is 3-6 μm.

In the above-mentioned scheme, the organic solvent in the described step 1) is ethanol and butanone mixed by mass ratio of 1:1.

In the above scheme, the purity of the tungsten powder in the step 2) is 99.9%, and the particle size is 0.5-5 μm.

In the above scheme, the sintering temperature of the high-temperature sintering in the step 5) is 1300-1700° C., the holding time is 1-3 h, and the sintering pressure is 0-10 MPa.

In the above scheme, the vacuum condition in the step 4) is a vacuum degree better than 9.9×10 ^-3 Pa, the holding temperature is 780°C, the holding time is 2h, and the sintering pressure is 10-30MPa.

In the above scheme, the drying in the step 5) is vacuum drying, the drying temperature is 80 degrees, and the drying time is 12 hours.

In the above scheme, the purity of the raw material NaCl in the step 1) is 99.9%, and it passes through a 60-mesh sieve.

The micro-scale porous tungsten prepared by the method for preparing micro-scale porous tungsten has a macro-pore diameter of 3-6 μm, a small-pore diameter of 0.1 μm-0.7 μm, and a density range of 35%-90%. .

Compared with the prior art, the porous tungsten obtained by the present invention has the following obvious advantages:

First, using the casting technology to make the composition of the membrane tape uniform, and then to make the obtained porous material evenly distributed. At the same time, the casting technology also has the advantages of simple process equipment, continuous operation, high production efficiency, high automation level and stable process.

Second, the cost of the pore-forming agent NaCl is low, and the size and morphology can be controlled by a simple process. At the same time, the casting slurry is a stable multi-phase slurry, which can solve the settlement caused by the large difference in the density of the pore-forming agent NaCl and W. Stable, enabling precise control over a wide range of porous W porosity.

Third, the organic matter introduced by the casting technology will leave a very small amount of amorphous C in the debinding process, which is beneficial to the diffusion and mass transfer of W, and significantly reduces the temperature of W sintering. The temperature is lowered to 1400-1700°C.

Description of drawings

FIG. 1 is a flow chart of the preparation process of porous tungsten.

Fig. 2 is the SEM spectrum of the NaCl powder obtained by ball milling for 24h in Example 5 of the present invention.

FIG. 3 is the SEM spectrum of the green body in Example 5 of the present invention.

FIG. 4 is a SEM image of the porous tungsten green body in Example 5 of the present invention.

FIG. 5 is the SEM spectrum of porous tungsten in Example 5 of the present invention.

Detailed ways

SEM patterns were obtained by a Quanta FEG 250 (FEI, USA) field emission scanning electron microscope.

The density was measured by the Archimedes drainage method. The sample was sealed with a very thin layer of Vaseline before the test, and the density was the ratio of the measured density to the theoretical density (19.30 g/cm ³ ).

The process for preparing porous tungsten by tape casting combined with high temperature sintering adopted in the present invention is as follows:

A preparation method of micron-scale porous tungsten, comprising the following steps:

1) Ball milling raw material NaCl, ethanol and ball milling medium, and then vacuum drying at 60°C for 12 hours to obtain NaCl powder;

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

3) preparation of casting slurry: NaCl powder, tungsten powder and organic additive are added into organic solvent and ball-milled to obtain casting slurry;

4) Treatment of the casting thin strip: the casting slurry obtained in step 3) is cast, dried and shaped in a casting machine to obtain a casting thin strip, and the casting thin strip is cut into a specific shape. Thin tape stacks. The laminated ribbons were kept at 780℃ for 2h under the vacuum degree better than 9.9×10 ^-3 Pa, degummed, and the organic matter was cracked and discharged, and then kept at 780℃ for 2h under the same vacuum degree, and the sintering pressure was 10- 30MPa, hot-press sintering to obtain green body;

5) Sintering to obtain porous tungsten: the green body is rinsed in flowing deionized water for 12 hours, and then placed in a vacuum drying oven at 80° C. for 12 hours to obtain a green porous tungsten body. The porous tungsten green body is sintered at a high temperature in an Ar atmosphere to obtain the porous tungsten.

Example 1:

The present embodiment provides a preparation method of micron-scale porous tungsten, comprising the following steps:

A. Preparation of casting slurry: 100g NaCl and 50g ethanol were added to a nylon tank, and ball milled in a planetary ball mill for 36 hours, wherein the NaCl raw material purity was 99.9%, passed through a 60 mesh sieve, and the ball milling speed was 250 rpm. Pour the obtained suspension into a beaker, let it stand at room temperature for 1 hour in a vacuum drying oven, pour out the upper liquid, and vacuum dry the remaining material in the beaker at 60 °C for 12 hours in a vacuum drying oven, and take 2.4 g of NaCl powder and 56 g of particle size. It is 5μm W powder, 0.9g of Hypermer KD-1 (analytical grade), added 18.3g of absolute ethanol (analytical grade) and 18.3g of butanone (analytical grade) solvent, and ball-milled in a high-energy mixer for 3h , the ball milling medium is stainless steel ball, and the mass of the steel ball is 100g. Then 2.6 g of polyvinyl butyral (analytical grade) and 2.1 g of glycerol (analytical grade) were added, and ball milled for 3 hours to obtain a casting slurry.

B. the treatment of the casting thin strip: the casting slurry obtained in the step A is cast, dried and shaped in a casting machine to obtain the casting thin strip, and the casting thin strip is cut into a disc with a diameter of 20 mm, and the 100-layer wafer stack. The laminated ribbons were heat-treated and debonded at 780°C for 2h in an environment where the vacuum degree was better than 9.9×10 ^-3 Pa; and then a green body was obtained by sintering at a temperature of 780°C for 2h at a temperature of When the temperature is below 750°C, a pressure of 30MPa is applied, and when the temperature is above 750°C, there is no pressure.

C. Sintering to obtain porous tungsten: After washing the green body obtained in step B in flowing deionized water for 12 hours, the green body was taken out and dried in a vacuum drying oven at 80°C for 12 hours to obtain a porous tungsten green body. The porous tungsten green body was sintered in an Ar atmosphere. The sintering system was 10°C/min to 1100°C, 5°C/min to 1400°C, holding time for 3h, 10°C/min to 1100°C, 20°C/min to increase the temperature to 1100°C. At room temperature, a pressure of 10 MPa was applied throughout the sintering process to obtain the porous tungsten.

The density of the porous tungsten measured by the Archimedes drainage method is 82.0%, the pore distribution is uniform, the pore diameter of the large pores is 3-5 μm, and the pore diameter of the small pores is 0.2 μm-0.7 μm.

Example 2:

The present embodiment provides a preparation method of micron-scale porous tungsten, comprising the following steps:

A. Preparation of casting slurry: take 60g of W powder with a particle size of 0.5μm, 1.2g of Hypermer KD-1 (analytical grade), add 16.3g of absolute ethanol (analytical grade) and 16.3g of butanone ( analytically 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 glycerol (analytical pure), and ball-milled for 3 hours to obtain a casting slurry.

B. the treatment of the casting thin strip: the casting slurry obtained in the step A is cast, dried and shaped in a casting machine to obtain the casting thin strip, and the casting thin strip is cut into a disc with a diameter of 20 mm, and the 100-layer wafer stack. The laminated ribbons were heat-treated and debonded at 780°C for 2h in an environment where the vacuum degree was better than 9.9×10 ^-3 Pa; and then a green body was obtained by sintering at a temperature of 780°C for 2h at a temperature of When the temperature is below 750°C, a pressure of 30MPa is applied, and when the temperature is above 750°C, there is no pressure.

C. Sintering to obtain porous tungsten: After washing the green body obtained in step B in flowing deionized water for 12 hours, the green body was taken out and dried in a vacuum drying oven at 80°C for 12 hours to obtain a porous tungsten green body. The porous tungsten green body was sintered in an Ar atmosphere. The sintering regime was 10°C/min to 1100°C, 5°C/min to 1700°C, holding time for 1h, 10°C/min to 1100°C, 20°C/min to increase At room temperature, a pressure of 10 MPa was applied throughout the sintering process to obtain the porous tungsten.

The density of the porous tungsten measured by the Archimedes drainage method is 90%, the pore distribution is uniform, and the pore diameter of the pores is 0.1 μm-0.6 μm.

Example 3:

The present embodiment provides a preparation method of micron-scale porous tungsten, comprising the following steps:

A. Preparation of casting slurry: 100g NaCl and 50g ethanol were added to a nylon tank, and ball milled in a planetary ball mill for 24 hours, wherein the NaCl raw material purity was 99.9%, passed through a 60 mesh sieve, and the ball milling speed was 250 rpm. Pour the obtained suspension into a beaker, let it stand at room temperature for 1 hour in a vacuum drying oven, pour out the upper liquid, and vacuum dry the remaining material in the beaker at 60 °C for 12 hours in a vacuum drying oven, and take 2.4 g of NaCl powder and 50 g of particle size. W powder of 1 μm, 0.8g of Hypermer KD-1 (analytical grade), added 22.15g of absolute ethanol (analytical grade) and 22.15g of butanone (analytical grade) solvent, ball milled in a high-energy mixer for 3h , the ball milling medium is stainless steel ball, and the mass of the steel ball is 100g. Then 2.5 g of polyvinyl butyral (analytical grade) and 2.0 g of glycerol (analytical grade) were added, and ball-milled for 3 hours to obtain a casting slurry.

B. the treatment of the casting thin strip: the casting slurry obtained in the step A is cast, dried and shaped in a casting machine to obtain the casting thin strip, and the casting thin strip is cut into a disc with a diameter of 20 mm, and the 100-layer wafer stack. The laminated ribbons were heat-treated and debonded at 780°C for 2h in an environment where the vacuum degree was better than 9.9×10 ^-3 Pa; and then a green body was obtained by sintering at a temperature of 780°C for 2h at a temperature of When the temperature is below 750°C, a pressure of 30MPa is applied, and when the temperature is above 750°C, there is no pressure.

C. Sintering to obtain porous tungsten: After washing the green body obtained in step B in flowing deionized water for 12 hours, the green body was taken out and dried in a vacuum drying oven at 80°C for 12 hours to obtain a porous tungsten green body. The porous tungsten green body was sintered in an Ar atmosphere. The sintering regime was 10°C/min to 1100°C, 5°C/min to 1500°C, holding time for 3h, 10°C/min to 1100°C, 20°C/min to increase When the temperature reaches room temperature, the whole process of sintering is pressureless, and the porous tungsten is obtained.

The density of the porous tungsten measured by the Archimedes drainage method is 74.4%, the pore distribution is uniform, the pore diameter of the large pores is 4-6 μm, and the pore diameter of the small pores is 0.1 μm-0.5 μm.

Example 4:

The present embodiment provides a preparation method of micron-scale porous tungsten, comprising the following steps:

A. Preparation of casting slurry: 100g NaCl and 50g ethanol were added to a nylon tank, and ball milled in a planetary ball mill for 24 hours, wherein the NaCl raw material purity was 99.9%, passed through a 60 mesh sieve, and the ball milling speed was 250 rpm. Pour the obtained suspension into a beaker, let it stand at room temperature for 1 hour in a vacuum drying oven, pour out the upper liquid, and vacuum dry the remaining material in the beaker at 60 °C for 12 hours in a vacuum drying oven, and take 8.2 g of NaCl powder and 50 g of particle size. It is 1μm W powder, 1g of Hypermer KD-1 (analytical grade), added 16.2g of absolute ethanol (analytical grade) and 16.2g of butanone (analytical grade) solvent, ball milled in a high-energy mixer for 3h, The ball milling medium is stainless steel ball, and the mass of the steel ball is 100g. Then 3 g of polyvinyl butyral (analytical grade) and 2.4 g of glycerol (analytical grade) were added, and ball-milled for 3 h to obtain a casting slurry.

B. the treatment of the casting thin strip: the casting slurry obtained in the step A is cast, dried and shaped in a casting machine to obtain the casting thin strip, and the casting thin strip is cut into a disc with a diameter of 20 mm, and the 100-layer wafer stack. The laminated ribbons were heat-treated and debonded at 780°C for 2h in an environment where the vacuum degree was better than 9.9×10 ^-3 Pa; and then a green body was obtained by sintering at a temperature of 780°C for 2h at a temperature of When the temperature is below 750°C, a pressure of 10MPa is applied, and when the temperature is above 750°C, there is no pressure.

C. Sintering to obtain porous tungsten: After washing the green body obtained in step B in flowing deionized water for 12 hours, the green body was taken out and dried in a vacuum drying oven at 80°C for 12 hours to obtain a porous tungsten green body. The porous tungsten green body was sintered in an Ar atmosphere. The sintering regime was 10°C/min to 1100°C, 5°C/min to 1300°C, holding time for 3h, 10°C/min to 1100°C, 20°C/min to increase When the temperature reaches room temperature, the whole process of sintering is pressureless, and the porous tungsten is obtained.

The density of the porous tungsten measured by the Archimedes drainage method is 35%, the pore distribution is uniform, the pore diameter of the large pores is 4-6 μm, and the pore diameter of the small pores is 0.2 μm-0.7 μm.

Example 5:

The present embodiment provides a preparation method of micron-scale porous tungsten, comprising the following steps:

A. Preparation of casting slurry: 100g NaCl and 50g ethanol were added to a nylon tank, and ball milled in a planetary ball mill for 24 hours, wherein the NaCl raw material purity was 99.9%, passed through a 60 mesh sieve, and the ball milling speed was 250 rpm. Pour the obtained suspension into a beaker, let it stand at room temperature for 1 hour in a vacuum drying oven, pour out the upper liquid, and vacuum dry the remaining material in the beaker at 60 °C for 12 hours in a vacuum drying oven, and take 5.6 g of NaCl powder and 50 g of particle size. It is 1μm W powder, 1g of Hypermer KD-1 (analytical grade), added to 19.2g of absolute ethanol (analytical grade) and 19.2g of butanone (analytical grade) solvent, and ball-milled in a high-energy mixer for 3h, The ball milling medium is stainless steel ball, and the mass of the steel ball is 100g. Then 2.7 g of polyvinyl butyral (analytical grade) and 2.3 g of glycerol (analytical grade) were added, and ball-milled for 3 hours to obtain a casting slurry.

B. the treatment of the casting thin strip: the casting slurry obtained in the step A is cast, dried and shaped in a casting machine to obtain the casting thin strip, and the casting thin strip is cut into a disc with a diameter of 20 mm, and the 100-layer wafer stack. The laminated ribbons were heat-treated and debonded at 780°C for 2h in an environment where the vacuum degree was better than 9.9×10 ^-3 Pa; and then a green body was obtained by sintering at a temperature of 780°C for 2h at a temperature of When the temperature is below 750°C, a pressure of 10MPa is applied, and when the temperature is above 750°C, there is no pressure.

C. Sintering to obtain porous tungsten: After washing the green body obtained in step B in flowing deionized water for 12 hours, the green body was taken out and dried in a vacuum drying oven at 80°C for 12 hours to obtain a porous tungsten green body. The porous tungsten green body was sintered in an Ar atmosphere. The sintering system was 10°C/min to 1100°C, 5°C/min to 1400°C, holding time for 3h, 10°C/min to 1100°C, 20°C/min to increase the temperature to 1100°C. When the temperature reaches room temperature, the whole process of sintering is pressureless, and the porous tungsten is obtained.

The density of the porous tungsten measured by the Archimedes drainage method is 44.1%, the pore distribution is uniform, the pore diameter of the large pores is 4-6 μm, and the pore diameter of the small pores is 0.2 μm-0.7 μm.

The above-mentioned embodiments only represent several embodiments of the present invention, and the descriptions thereof are relatively detailed, but should not be construed as a limitation on the scope of the patent of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications and improvements can be made, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims (10)

1. a preparation method of micron-level porous tungsten, is characterized in that, comprises the following steps: 1) Ball milling raw material NaCl, ethanol and ball milling medium, and then drying to obtain NaCl powder; 2) Material preparation: prepare materials according to the mass percentage of 50-60% tungsten powder, 0%-8.5% NaCl powder, 32.6-38.4% organic solvent and 5.3-7.4% organic additives, wherein the organic additives include 2.5%-3.5% % polyvinyl butyral, 0.8%-1.2% Hypermer KD-1 and 2.0%-2.7% glycerin; 3) preparation of casting slurry: NaCl powder, tungsten powder and organic additive are added into organic solvent and ball-milled to obtain casting slurry; 4) Treatment of the casting thin strip: the casting slurry obtained in step 3) is cast, dried and shaped in a casting machine to obtain a casting thin strip, and the casting thin strip is cut into a specific shape. Thin strips are laminated, and the laminated strips are kept under vacuum for thermal insulation and debinding, and then thermally sintered under the same vacuum degree for hot pressing and sintering to obtain green bodies; 5) Sintering to obtain porous tungsten: the green body is rinsed in flowing water, and then dried to obtain a porous tungsten green body, and the porous tungsten green body is sintered at high temperature in an inert atmosphere to obtain the porous tungsten. 2. the preparation method of micron-level porous tungsten as claimed in claim 1, is characterized in that, the concrete feeding sequence in described step 3) is: first join tungsten powder and NaCl and Hypermer KD-1 in organic solvent for ball milling , and then add polyvinyl butyral and glycerin, and ball mill to obtain a casting slurry. 3 . The method for preparing micron-sized porous tungsten according to claim 1 , wherein the particle size of the NaCl powder in the step 1) is 3-6 μm. 4 . 4. The preparation method of micron-scale porous tungsten according to claim 1, wherein the organic solvent in the step 1) is ethanol and butanone mixed in a mass ratio of 1:1. 5 . The method for preparing micron-sized porous tungsten according to claim 1 , wherein the tungsten powder in the step 2) has a purity of 99.9% and a particle size of 0.5-5 μm. 6 . 6. The preparation method of micron-scale porous tungsten according to claim 1, wherein the sintering temperature of the high-temperature sintering in the step 5) is 1300-1700 DEG C, the holding time is 1-3h, and the sintering pressure is 0 -10MPa. 7. The preparation method of micron-scale porous tungsten according to claim 1, wherein the vacuum condition in the step 4) is a vacuum degree better than 9.9× ^10-3 Pa, the holding temperature is 780°C, and the holding temperature is 780°C. The time is 2h, and the sintering pressure is 10-30MPa. 8 . The method for preparing micron-sized porous tungsten according to claim 1 , wherein the drying in the step 5) is vacuum drying, the drying temperature is 80 degrees, and the drying time is 12 hours. 9 . 9 . The method for preparing micron-sized porous tungsten according to claim 1 , wherein the raw material NaCl in the step 1) has a purity of 99.9% and passes through a 60-mesh sieve. 10 . 10. The micron-sized porous tungsten prepared by the method for preparing micron-sized porous tungsten according to claim 1, wherein the macropore diameter of the porous tungsten is 3-6 μm, and the small pore diameter is 0.1 μm-0.7 μm , the density range is 35%-90%.