WO2021189798A1 - Method for preparing cuw90 material by using spherical tungsten powder - Google Patents

Abstract

A method for preparing a CuW90 material by using a spherical tungsten powder, comprising the following steps: preparation before printing: inputting data of a workpiece to be prepared to a 3D adhesive-spraying printer, dividing the workpiece into a plurality of slabs arranged in parallel, and filling the 3D adhesive-spraying printer with a tungsten powder and an adhesive; adhesive-spraying 3D printing: applying a layer of adhesive on every tungsten powder layer laid, and applying a further layer of adhesive after the adhesive has penetrated into the tungsten powder, and performing repeated applications until a rough workpiece blank is obtained; sintering and adhesive removal: sending the rough workpiece blank to a high-pressure and vacuum dual-purpose high-temperature sintering furnace, and evaporating and blowing off the adhesive in the rough workpiece blank at a high temperature under negative pressure, and obtaining a sintered tungsten blank by means of high temperature and high pressure sintering; and copper infiltration: preparing a copper powder into a copper powder blank that can be sleeved outside the sintered tungsten blank, and sleeving the copper powder blank outside the sintered tungsten blank, and placing the sleeved blank in a high-temperature sintering furnace and performing infiltration to obtain the CuW90 material.

Description

A method for preparing CuW90 material by using spherical tungsten powder

This application claims the priority of the Chinese patent application 202010206834.3 whose filing date is 2020/3/23. This application quotes the full text of the aforementioned Chinese patent application.

Technical field

The invention belongs to the technical field of material preparation, and specifically relates to a method for preparing CuW90 material by using spherical tungsten powder.

Background technique

The tungsten-copper alloy electrode is a composite metal material made of high-purity tungsten powder and high-purity, high-plasticity, high-conductivity copper powder, and refined through static pressing, high-temperature sintering, and melting. Good electrical conductivity, low thermal expansion, no softening at high temperature, high strength, high density, and high hardness. The CuW90 material is widely used. It is often used in the electrical contact contact industry of power switches, rocket nozzles in aerospace and heat dissipation materials of semiconductor integrated circuit chips. Especially as a heat dissipation material for chips, it has high thermal conductivity and low expansion characteristics and is widely used.

3D printing technology was originally called rapid prototyping technology or rapid prototyping technology. It was developed based on modern CAD/CAM technology, mechanical engineering, layered manufacturing technology, laser technology, computer numerical control technology, precision servo drive technology and new material technology. Advanced manufacturing technology. It is based on a computer three-dimensional digital model, which is decomposed into multi-layer plane slices through software. Then the CNC molding system uses laser beams, hot melt nozzles, etc. to layer and bond the bondable materials layer by layer, and finally stack and make the product.

The commonly used manufacturing methods of CuW90 materials on the market are mold forming-high temperature pre-fired skeleton-high temperature copper infiltration, and then processed into required parts by subsequent machining, which can only be produced into simple shapes. For some occasions with small quantity and many types, the mold production cycle is long and the cost is high. For some parts with complex shapes that cannot be machined, they cannot be produced. Therefore, the present invention designs a method for preparing CuW90 material by using spherical tungsten powder.

Summary of the invention

In view of the above-mentioned problems, the present invention provides a method for preparing CuW90 material by using spherical tungsten powder.

The technical scheme of the present invention is: a method for preparing CuW90 material by using spherical tungsten powder, which mainly includes the following steps:

S1: Preparation before printing

Input the workpiece model data to be prepared into the 3D glue-spraying printer, divide the workpiece model into multiple flat models in parallel, and fill the 3D glue-spraying printer with tungsten powder as the workpiece printing material and the adhesive for bonding the tungsten powder ；

S2: Spray glue 3D printing

First lay a layer of adhesive on the printing plate, and then lay tungsten powder from the bottom to the top according to the flat model separated in S1. Each layer of tungsten powder is laid on the tungsten powder layer with a layer of adhesive, adhesive After infiltrating the tungsten powder, lay a layer of adhesive and overlap it repeatedly until the top layer of tungsten powder is laid. The printed workpiece model is left in the 3D spray printer for 8-10 hours to obtain a rough workpiece;

S3: Sintering degumming

The rough workpiece is sent to a high-pressure, vacuum dual-purpose high-temperature sintering furnace, the temperature in the high-temperature sintering furnace is increased to 100-200 degrees for preheating for 5-8 minutes, the high-temperature sintering furnace is first filled with hydrogen, and then the furnace is vacuumed To a negative pressure of 2.0±0.3×10 ^-1 Pa, raise the temperature of the high-temperature sintering furnace to 1000-1100°C at a heating rate of 5°C/min, and blow a directional hydrogen gas flow upward from the bottom of the high-temperature sintering furnace, and the top of the high-temperature sintering furnace continues Vacuum, keep the pressure in the high-temperature sintering furnace balanced, evaporate and blow off the adhesive in the rough blank of the workpiece, and the blowing time is 5-8h;

Close the gas outlet of the high-temperature sintering furnace, continue to inject hydrogen to make the pressure in the high-temperature sintering furnace 2.0±0.5×10 ^-2 MPa, increase the temperature in the high-temperature sintering furnace to 1600-2200℃, and the sintering temperature for 16-18h. After the sintering is completed, pass in The cooling gas is rapidly refrigerated to obtain a sintered tungsten billet;

S4: Copper infiltration

The copper powder is made into a copper powder embryo that can be sleeved outside the sintered tungsten billet, and the copper powder embryo is sleeved outside the sintered tungsten billet and placed in a high-temperature sintering furnace, sintered and infiltrated at 1350-1400°C for 40-60 minutes, after cooling Obtain CuW90 material.

Further, if a more complex or bulky workpiece is prepared, in S1, the workpiece model can be split into the part model, and the rough parts of the lead parts can be obtained according to the process of S2, and the parts are separated between the S3 process. The rough blank is assembled and bonded firmly, and the subsequent processing is carried out as a whole, which can meet the preparation of more precise and complex workpieces.

Preferably, the tungsten powder is industrial tungsten powder with a purity of 15-65 μm and a purity of 99.99%, and the copper powder is copper powder with a purity of 5-7 μm and a purity of 99.99%. The mass ratio of tungsten powder to copper powder is 9:1. .

Preferably, the adhesive is any one of urea-formaldehyde-modified furan resin, phenol-formaldehyde-modified furan resin, ketone-formaldehyde-modified furan resin, and urea-formaldehyde-phenol-formaldehyde-modified furan resin. The artifact has an impact.

Further, in the S3, a collection device for collecting vaporized adhesive gas is installed at the mouth of the high-temperature sintering furnace to prevent the removed adhesive from being directly discharged into the air, causing air pollution.

Preferably, in the S3, the density of the prepared sintered tungsten billet is 15-15.5 g/cm ³ to ensure the performance of the sintered tungsten billet.

Further, in the S3, the flow rate of the directional hydrogen gas flow blown upward from the bottom of the high-temperature sintering furnace is 3-5m/s, and the directional hydrogen gas flow is blown by the rough workpiece, not directly to the rough workpiece. It will cause damage to the rough blank of the workpiece, and it can avoid the disordered movement of the adhesive in the high-temperature sintering furnace by not directly blowing the rough blank of the workpiece.

Preferably, the processes of S1-S4 are all performed in a dust-free environment to avoid environmental impurities from affecting the process.

Further, in the S4, the preparation process of the copper kit is: directly print the adhesive model with the same shape as the rough blank of the workpiece made of tungsten powder through the 3D spray printer with the adhesive, and then print the adhesive model on the adhesive model. Pave the copper powder evenly to obtain a copper workpiece with an adhesive model inside. After standing for 8-10 hours, cut the copper workpiece, remove the adhesive model, and then use the S3 process to sinter the cut copper workpiece after degumming The copper powder blank is obtained, and the sintered copper blank can completely cover the sintered tungsten blank for copper infiltration, the copper infiltration is uniform, and the obtained workpiece has excellent mechanical properties.

The beneficial effects of the present invention are: the method for preparing CuW90 material using spherical tungsten powder provided by the present invention has the following advantages compared with the prior art:

(1) Using spherical tungsten powder spray glue layer by layer to quickly manufacture some tungsten blanks of complex small parts, and then shrink the tungsten blanks to the required density through high temperature shrinkage, which is suitable for mass production of complex CuW90 material product parts;

(2) Use negative pressure degumming technology to remove the adhesive mixed in the workpiece by 3D spray printing, and use the method of directional air blowing to not damage the workpiece, but also to remove the adhesive to the greatest extent, and set the adhesive Adhesive recovery device to prevent the removed adhesive from being directly discharged into the air, causing air pollution;

(3) Using 3D glue spray printing technology, the copper powder is made into a sintered copper billet that can be sleeved outside the sintered tungsten billet. The sintered copper billet can completely cover the sintered tungsten billet for copper infiltration, and the copper infiltration is uniform. The resulting workpiece mechanics Excellent performance.

Detailed ways

In order to facilitate the understanding of the technical solutions of the present invention, the present invention will be further explained in conjunction with specific embodiments below, and the embodiments do not constitute a limitation on the protection scope of the invention.

Embodiment 1: A method for preparing CuW90 material by using spherical tungsten powder, which mainly includes the following steps:

S1: Preparation before printing

Input the workpiece model data to be prepared into the 3D glue-spraying printer, divide the workpiece model into multiple flat models in parallel, and fill the 3D glue-spraying printer with tungsten powder as the workpiece printing material and the adhesive for bonding the tungsten powder , The tungsten powder is 15μm industrial tungsten powder with a purity of 99.99%, and the adhesive is phenolic modified furan resin;

S2: Spray glue 3D printing

First lay a layer of adhesive on the printing plate, and then lay tungsten powder from the bottom to the top according to the flat model separated in S1. Each layer of tungsten powder is laid on the tungsten powder layer with a layer of adhesive, adhesive After infiltrating the tungsten powder, lay a layer of adhesive and overlap it repeatedly until the top layer of tungsten powder is laid, and the printed workpiece model is placed in a 3D glue-spraying printer for 10 hours to obtain a rough workpiece;

S3: Sintering degumming

The rough workpiece is sent to a high-pressure, vacuum dual-purpose high-temperature sintering furnace, the temperature in the high-temperature sintering furnace is increased to 180 degrees for preheating for 8 minutes, the high-temperature sintering furnace is first filled with hydrogen, and then the furnace is vacuumed to a negative pressure of 2.0 ×10 ^-1 Pa, raise the temperature of the high-temperature sintering furnace to 1100°C at a heating rate of 5°C/min, and blow a directional hydrogen gas flow from the bottom of the high-temperature sintering furnace upwards, with a flow rate of 3m/s, and the directional hydrogen gas flow through the workpiece. Blow by the side of the blank, not directly to the rough workpiece. The top of the high-temperature sintering furnace is continuously vacuumed to keep the pressure in the high-temperature sintering furnace balanced, and the adhesive in the rough workpiece is evaporated and blown away. The blowing time is 6h, and the high-temperature sintering The furnace mouth is provided with a collection device for collecting vaporized adhesive gas;

Close the gas outlet of the high-temperature sintering furnace, continue to feed hydrogen to make the pressure in the high-temperature sintering furnace 2.0×10 ^-2 MPa, raise the temperature in the high-temperature sintering furnace to 1800℃, and the sintering temperature for 18 hours. After the sintering is completed, the cooling gas is rapidly cooled to obtain Sintered tungsten blank with a density of 15.5g/cm ^3;

S4: Copper infiltration

Select 7μm copper powder with a purity of 99.99%, the mass ratio of tungsten powder to copper powder is 9:1, and the copper powder is made into a copper powder embryo that can be sleeved outside the sintered tungsten billet. The preparation process of the copper kit is as follows: : Directly print the adhesive model with the same shape as the rough workpiece made of tungsten powder with the adhesive through the 3D spray printer, and then evenly spread the copper powder on the adhesive model to obtain the copper with the adhesive model inside. For the workpiece, cut the copper workpiece after standing for 10 hours, remove the adhesive model from it, and then use the S3 process to sinter and degum the cut copper workpiece to obtain a copper powder embryo;

The copper powder embryo is sleeved outside the sintered tungsten blank and placed in a high-temperature sintering furnace, sintered and infiltrated at 1400°C for 50 minutes, and cooled to obtain CuW90 material;

The processes of S1-S4 are all carried out in a dust-free environment.

Example 2: Basically the same as Example 1, but the difference is that a more complex or larger-sized workpiece is prepared. In S1, the workpiece model can be split into the part model, and the collars are respectively prepared according to the process of S2. For the rough parts, the rough parts are assembled and bonded firmly between the S3 process, and the subsequent processing is carried out as a whole.

Embodiment 3: It is basically the same as Embodiment 1, except that: in S3, the directed hydrogen gas flow is directly blown to the rough workpiece to blow away the evaporated adhesive on the rough workpiece.

Example 4: Basically the same as Example 1, the difference is: in S4, the copper powder is made into a copper block, the sintered tungsten billet is placed in a high-temperature sintering furnace, and the copper block is placed on top of the sintered tungsten billet. Sintering and infiltrating at ℃ for 50 minutes, turning the sintered tungsten blank after cooling, repeating the above copper infiltration step, and finally obtaining CuW90 material.

Experimental example 1: Study the effect of copper infiltration method on the preparation of CuW90 material

The methods of Example 1 and Example 4 were used to prepare CuW90 materials, and the properties of the prepared CuW90 materials were tested. The results are shown in Table 1.

Table 1 Comparison of properties of CuW90 materials obtained by different copper infiltration methods

Group	Density/(g/cm 3 )	Conductivity/IACS	Hardness/(HB)	Softening temperature/℃
Example 1	17.75	29.34	273.44	950

Example 4

18.64

61.34

293.54

980

Conclusion: The CuW90 material prepared by the method provided in the examples has high density, excellent conductivity, high hardness and high softening temperature, and the overall performance is better than that of the CuW90 material in Example 1 and the prior art.

Experimental example 2: Study the influence of the blowing direction of the directional hydrogen gas flow on the process in the sintering degumming process

The sintering and degumming processes provided in Example 1 and Example 3 were used to perform sintering and degumming of rough workpieces with the same parameters, and the content of the binder in the prepared sintered tungsten blanks were detected respectively.

Result: The binder content in the sintered tungsten billet prepared by the process provided in Example 1 is less than 0.33%, the surface of the sintered tungsten billet and the interior of the high-temperature sintering furnace have no adhesive residue, and the surface of the sintered tungsten billet is intact;

However, the binder content in the sintered tungsten blank prepared by the process provided in Example 3 is greater than 5%, the surface of the sintered tungsten blank and the inside of the high-temperature sintering furnace both have the binder remaining, and there are pits on the surface of the sintered tungsten blank.

Conclusion: In the sintering degumming process, the directional hydrogen gas flow is blown by the side of the rough workpiece, instead of directly blowing to the rough workpiece, the appearance of pits on the sintered tungsten blank can be avoided, and the adhesive removal efficiency is high, and the surface of the high-temperature sintering furnace There is no adhesive residue and will not pollute the high-temperature sintering furnace.

Although the specific embodiments of the present invention are described above, those skilled in the art should understand that these are only examples, and various changes or modifications can be made to these embodiments without departing from the principle and essence of the present invention. Revise. Therefore, the protection scope of the present invention is defined by the appended claims.

Claims (9)

1. A method for preparing CuW90 material by using spherical tungsten powder is characterized in that it mainly includes the following steps:

   S1: Preparation before printing

   Input the workpiece model data to be prepared into the 3D glue-spraying printer, divide the workpiece model into multiple flat models in parallel, and fill the 3D glue-spraying printer with tungsten powder as the workpiece printing material and the adhesive for bonding the tungsten powder ；

   S2: Spray glue 3D printing

   First lay a layer of adhesive on the printing plate, and then lay tungsten powder from the bottom to the top according to the flat model separated in S1. Each layer of tungsten powder is laid on the tungsten powder layer with a layer of adhesive, adhesive After infiltrating the tungsten powder, lay a layer of adhesive and overlap it repeatedly until the top layer of tungsten powder has been laid. The printed workpiece model is placed in a 3D spray printer for 8-10 hours to remove excess powder to obtain a rough workpiece. Billet

   S3: Sintering degumming

   The rough workpiece is sent to a high-pressure, vacuum dual-purpose high-temperature sintering furnace, the temperature in the high-temperature sintering furnace is increased to 100-200 degrees for preheating for 5-8 minutes, the high-temperature sintering furnace is first filled with hydrogen, and then the furnace is vacuumed To a negative pressure of 2.0±0.3×10 ^-1 Pa, raise the temperature of the high-temperature sintering furnace to 1000-1100°C at a heating rate of 5°C/min, and blow a directional hydrogen gas flow upward from the bottom of the high-temperature sintering furnace, and the top of the high-temperature sintering furnace continues Vacuum, keep the pressure in the high-temperature sintering furnace balanced, evaporate and blow off the adhesive in the rough blank of the workpiece, and the blowing time is 5-8h;

   Close the gas outlet of the high-temperature sintering furnace, continue to inject hydrogen to make the pressure in the high-temperature sintering furnace 2.0±0.5×10 ^-2 MPa, increase the temperature in the high-temperature sintering furnace to 1600-2200℃, and the sintering temperature for 16-18h. After the sintering is completed, pass in The cooling gas is rapidly refrigerated to obtain a sintered tungsten billet;

   S4: Copper infiltration

   The copper powder is made into a copper powder embryo that can be sleeved outside the sintered tungsten billet, and the copper powder embryo is sleeved outside the sintered tungsten billet and placed in a high-temperature sintering furnace, sintered and infiltrated at 1350-1400°C for 40-60 minutes, after cooling Obtain CuW90 material.
2. The method for preparing CuW90 material using spherical tungsten powder according to claim 1, wherein the tungsten powder is selected from 15-65 μm industrial tungsten powder with a purity of 99.99%, and the copper powder is selected from 5-7 μm with a purity of 99.99%. 99.99% copper powder, the mass ratio of tungsten powder to copper powder is 9:1.
3. The method for preparing CuW90 material using spherical tungsten powder according to claim 1 or 2, wherein the adhesive is urea-formaldehyde-modified furan resin, phenol-formaldehyde-modified furan resin, ketone-formaldehyde-modified furan resin, Any of urea-formaldehyde-modified furan resins.
4. The method for preparing CuW90 material by using spherical tungsten powder according to at least one of claims 1 to 3, characterized in that, in said S3, a collection device for collecting vaporized adhesive gas is provided at the mouth of the high-temperature sintering furnace.
5. The method for preparing CuW90 material by using spherical tungsten powder according to at least one of claims 1 to 4, characterized in that, in the S3, the density of the prepared sintered tungsten green is 15-15.5 g/cm ³ .
6. The method for preparing CuW90 material by using spherical tungsten powder according to at least one of claims 1 to 5, characterized in that, in the S3, the flow rate of the directional hydrogen gas flow blown upward from the bottom of the high-temperature sintering furnace is 3 -5m/s, and the directional hydrogen gas flow is blown by the rough blank of the workpiece, not directly to the rough blank of the workpiece.
7. The method for preparing CuW90 material by using spherical tungsten powder according to at least one of claims 1 to 6, characterized in that, in the S3, the flow rate of the directed hydrogen gas flow blown upward from the bottom of the high-temperature sintering furnace is 3 -5m/s.
8. The method for preparing CuW90 material by using spherical tungsten powder according to at least one of claims 1-7, wherein the processes of S1-S4 are all performed in a dust-free environment.
9. The method for preparing CuW90 material using spherical tungsten powder according to at least one of claims 1-8, characterized in that, in the S4, the preparation process of the copper kit is: using an adhesive for a 3D spray printer Directly print the adhesive model with the same shape as the rough blank of the workpiece made of tungsten powder, and then evenly spread the copper powder on the adhesive model to obtain a copper workpiece with the adhesive model inside. After standing for 8-10 hours, the copper The workpiece is cut, the adhesive model is removed, and then the cut copper workpiece is sintered and degummed using the S3 process to obtain a copper powder embryo.