Low-temperature rapid sintering method of nano-catalysis tungsten-copper composite material

Abstract

The invention relates to the technical field of metal-based composite material preparation, in particular to a low-temperature rapid sintering method of a nano-catalysis tungsten-copper composite material, which comprises the following steps: S1, preparing W-Cu-Ni core-shell structure nano-composite powder which takes nano-tungsten particles as a core, is coated with a copper layer, and is provided with a nickel modified layer at an interface, the average particle size of the powder is 20-50nm; s2, preparing a palladium / graphene composite catalytic sintering agent, wherein the catalytic sintering agent is formed by uniformly loading palladium nanoparticles with the particle size of 2-5nm on a graphene sheet layer; s3, mixing the W-Cu-coated Ni core-shell structure nano composite powder with a composite catalytic sintering agent according to a mass ratio of 100: (0.5-2.0) to obtain mixed powder; s4, the mixed powder is subjected to compression molding under the pressure of 300-500 MPa, and a green body is obtained; and S5, the green body is heated to 900-980 DEG C in the vacuum environment at the speed of 5-10 DEG C / min, heat preservation is conducted for 10-20 min, then cooling is conducted, and the tungsten-copper composite material is obtained.

Description

Technical Field

[0001] This invention relates to the field of metal matrix composite material preparation technology, specifically a low-temperature rapid sintering method for nano-catalytic tungsten-copper composite materials. Background Technology

[0002] Tungsten-copper composites have become key materials in fields such as electronic packaging, thermal management, and high-power devices due to their unique high thermal conductivity, adjustable coefficient of thermal expansion, and excellent electrical properties. However, the significant difference in physical properties between tungsten and copper (melting points differ by approximately 2300°C, and they are immiscible) poses a major challenge to their fabrication process.

[0003] Currently, powder metallurgy is the main industrial method for preparing tungsten-copper composites, including mixed powder methods, melt infiltration methods, and activated sintering methods. Traditional processes require long-term sintering at temperatures above 1200℃, which not only leads to huge energy consumption but also causes serious grain growth problems, affecting the mechanical properties and reliability of the material. Although existing technologies have lowered the sintering temperature to around 1100℃ by adding transition metal catalysts or using mechanically alloyed powders, the following problems still exist: the sintering temperature is still too high, making it difficult to control the grain size below 5μm; the holding time still needs to be 1-2 hours, resulting in low production efficiency; the material density is usually below 97%, affecting thermal conductivity; and traditional catalysts are unevenly dispersed, resulting in limited catalytic effects.

[0004] Therefore, developing a method for preparing tungsten-copper composite materials that can achieve low-temperature rapid sintering and obtain ultrafine grains and high density has become an urgent technical challenge to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a low-temperature rapid sintering method for nano-catalytic tungsten-copper composite materials to solve the problems mentioned in the background art.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a low-temperature rapid sintering method for nano-catalytic tungsten-copper composite materials, comprising the following steps:

[0007] S1. Prepare W-Cu@Ni core-shell structured nanocomposite powder, wherein the W-Cu@Ni core-shell structured nanocomposite powder has tungsten nanoparticles as the core, coated with a copper layer, and has a nickel modification layer at the interface, and the average particle size of the powder is 20-50 nm.

[0008] S2. Prepare a palladium / graphene composite catalytic sintering agent, wherein the catalytic sintering agent is composed of palladium nanoparticles with a particle size of 2-5 nm uniformly loaded on graphene sheets.

[0009] S3, mixing the W-Cu@Ni core-shell structure nanocomposite powder with the composite catalytic sintering agent according to a mass ratio of 100:0.5-2.0 to obtain a mixed powder;

[0010] S4, pressing the mixed powder under a pressure of 300-500 MPa to obtain a green body;

[0011] S5, heating the green body to 900-980℃ at a rate of 5-10℃ / min in a vacuum environment, and cooling after holding for 10-20 minutes to obtain a tungsten-copper composite material.

[0012] According to the above technical solution, in the W-Cu@Ni core-shell structure nanocomposite powder, the tungsten core particle size is 15-40 nm, the copper shell layer thickness is 3-8 nm, and the nickel interface layer thickness is 1-2 nm.

[0013] According to the above technical solution, in the palladium / graphene composite catalytic sintering agent, the palladium nanoparticles are uniformly distributed at a spacing of 5-10 nm, and the mass loading of palladium is 3-8%.

[0014] According to the above technical solution, the mixing process in step S3 is carried out in a protective atmosphere, a planetary ball mill is used, the ball-to-material ratio is 5-10:1, the rotation speed is 200-300 rpm, and the mixing time is 2-4 hours.

[0015] According to the above technical solution, the pressing forming in step S4 is cold isostatic pressing, the pressure is 300-500 MPa, the holding time is 3-5 minutes, and the relative density of the obtained green body is 45-50%.

[0016] According to the above technical solution, the vacuum environment pressure in step S5 is not higher than 1.0×10-2 Pa, the heating rate is 5-10℃ / min, and the cooling rate is 20-30℃ / min.

[0017] According to the above technical solution, the sintering temperature in step S5 is 940-960℃, preferably 950℃.

[0018] According to the above technical solution, the holding time in step S5 is 12-18 minutes, preferably 15 minutes.

[0019] Compared with the prior art, the present application has the following beneficial effects: by using the synergistic effect of W-Cu@Ni core-shell nanometer powder and palladium / graphene composite catalyst, the sintering temperature of tungsten-copper material is reduced from the traditional 1200℃ or more to 950℃, the holding time is shortened from several hours to 15 minutes, a high-performance composite material with a grain size of ≤1.0μm and a density of ≥98% is successfully prepared, the problem of grain coarsening caused by high-temperature sintering is effectively solved, and the energy consumption and production cost are significantly reduced. DETAILED DESCRIPTION

[0020] The technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0021] A low-temperature rapid sintering method of a nano-catalytic tungsten-copper composite material, comprising the following steps:

[0022] S1, preparing W-Cu@Ni core-shell structure nano-composite powder, the W-Cu@Ni core-shell structure nano-composite powder takes nano tungsten particles as the core, is coated with a copper layer outside, and is provided with a nickel modification layer at the interface, and the average particle size of the powder is 20-50 nm; in the W-Cu@Ni core-shell structure nano-composite powder, the tungsten core particle size is 15-40 nm, the copper shell layer thickness is 3-8 nm, and the nickel interface layer thickness is 1-2 nm;

[0023] S2, preparing a palladium / graphene composite catalytic sintering agent, the catalytic sintering agent is composed of palladium nano-particles with a particle size of 2-5 nm uniformly loaded on graphene sheets; in the palladium / graphene composite catalytic sintering agent, the palladium nano-particles are uniformly distributed at a spacing of 5-10 nm, and the mass loading of palladium is 3-8%;

[0024] S3, mixing the W-Cu@Ni core-shell structure nano-composite powder and the composite catalytic sintering agent at a mass ratio of 100:0.5-2.0 to obtain a mixed powder; the mixing process is carried out in a protective atmosphere, a planetary ball mill is used, the ball-to-material ratio is 5-10:1, the rotation speed is 200-300 rpm, and the mixing time is 2-4 hours;

[0025] S4, pressing the mixed powder into a green body under a pressure of 300-500 MPa; the pressing is cold isostatic pressing, the pressure is 300-500 MPa, and the pressure holding time is 3-5 minutes, and the relative density of the obtained green body is 45-50%;

[0026] S5, heating the green body to 900-980℃ at a rate of 5-10℃ / min in a vacuum environment, keeping the temperature for 10-20 minutes, and then cooling to obtain a tungsten-copper composite material; the pressure in the vacuum environment is not higher than 1.0×10-2 Pa, the heating rate is 5-10℃ / min, and the cooling rate is 20-30℃ / min; the sintering temperature is 940-960℃, preferably 950℃; and the holding time is 12-18 minutes, preferably 15 minutes.

[0027] The present application will be described below through specific embodiments:

[0028] Embodiment 1

[0029] Powder preparation: W-Cu@Ni core-shell nanocomposite powder was prepared by chemical plating combined with ultrasonic assistance. Taking tungsten powder with an average particle size of 35 nm, copper layer and nickel layer were deposited by chemical plating, the thickness of copper layer was controlled to be 5 nm, and the thickness of nickel layer was controlled to be 1.5 nm, and the average particle size of the final powder was 42 nm.

[0030] Catalytic sintering agent preparation: Pd / graphene hybrid material was prepared by hydrothermal method. The graphene oxide dispersion liquid was mixed with the palladium precursor, and the hydrothermal reaction was carried out at 180℃ for 12 hours, and the palladium / graphene hybrid material was obtained by reduction, the particle size of palladium particles was 3-4 nm, and the loading amount was 5%.

[0031] Powder mixing: 1000g of core-shell powder was mixed with 10g of catalytic sintering agent (addition amount 1.0%), in a planetary ball mill, the ball-to-material ratio was 8:1, the rotation speed was 250 rpm, and the time was 3 hours.

[0032] Press forming: cold isostatic pressing was carried out at a pressure of 400MPa, the holding time was 3 minutes, and green compact with a diameter of 50mm and a thickness of 5mm was obtained, and the relative density was 48%.

[0033] Low-temperature sintering: under the condition of vacuum degree 5×10-3Pa, the temperature was raised to 950℃ at a rate of 8℃ / min, and then the temperature was cooled to 150℃ at a rate of 25℃ / min and the furnace was discharged.

[0034] Example 2

[0035] The difference from Example 1 is that the sintering temperature is 930℃, the holding time is 20 minutes, the addition amount of catalytic sintering agent is 0.8%, and the others are the same as Example 1.

[0036] Example 3

[0037] The difference from Example 1 is that the sintering temperature is 970℃, the holding time is 10 minutes, the addition amount of catalytic sintering agent is 1.5%, and the others are the same as Example 1.

[0038] Comparative Example 1 (traditional high-temperature sintering)

[0039] Conventional micron-sized W-20Cu composite powder (particle size 3-5μm) was used, and sintering was carried out at 1200℃ for 2 hours.

[0040] Comparative Example 2 (existing activated sintering)

[0041] Mechanical alloying W-Cu-Ni composite powder was used, and sintering was carried out at 1100℃ for 1 hour.

[0042] The tungsten-copper composite materials obtained in Examples 1-3 and Comparative Examples 1 and 2 were detected, and the detection items included sintered body relative density, tungsten grain average size, thermal conductivity and bending strength, and the detection results are shown in Table 1.

[0043] Sintered body relative density Tungsten grain average size Thermal conductivity Bending strength Example 1 98.7％ 0.8 μm 235 W / (m-K) 785 MPa Example 2 97.9％ 0.7 μm 228 W / (m-K) 765 MPa Example 3 98.9％ 0.9 μm 240 W / (m-K) 795 MPa Comparative Example 1 96.2％ 18.5 μm 195 W / (m-K) 520 MPa Comparative Example 2 96.8％ 5.2 μm 210 W / (m-K) 610 MPa

[0044] Table 1 Test Results Table

[0045] As can be seen by comparison, the material properties of the various embodiments of the present application are far superior to the comparative examples, particularly in grain refinement (0.8 μm vs 18.5 μm) and density (98.7% vs 96.2%), while significantly reducing sintering temperature (950 °C vs 1200 °C) and sintering time (15 minutes vs 2 hours).

[0046] Finally, it should be noted that the above description is merely preferred embodiments of the present application, and is not intended to limit the present application. Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art will still be able to modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A low-temperature rapid sintering method for nano-catalyzed tungsten-copper composite materials, characterized in that, Includes the following steps: S1. Prepare W-Cu@Ni core-shell structured nanocomposite powder, wherein the W-Cu@Ni core-shell structured nanocomposite powder has tungsten nanoparticles as the core, coated with a copper layer, and has a nickel modification layer at the interface, and the average particle size of the powder is 20-50 nm. S2. Prepare a palladium / graphene composite catalytic sintering agent, wherein the catalytic sintering agent is composed of palladium nanoparticles with a particle size of 2-5 nm uniformly loaded on graphene sheets. S3. The W-Cu@Ni core-shell structured nanocomposite powder is mixed with the composite catalytic sintering agent at a mass ratio of 100:0.5-2.0 to obtain a mixed powder; S4. Press the mixed powder under a pressure of 300-500MPa to obtain a green body; S5. The green blank is heated to 900-980°C in a vacuum environment at a rate of 5-10°C / min, held at that temperature for 10-20 minutes, and then cooled to obtain a tungsten-copper composite material.

2. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: In the W-Cu@Ni core-shell structured nanocomposite powder, the tungsten core particle size is 15-40 nm, the copper shell layer thickness is 3-8 nm, and the nickel interface layer thickness is 1-2 nm.

3. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: In the palladium / graphene composite catalytic sintering agent, palladium nanoparticles are uniformly distributed with a spacing of 5-10 nm, and the mass loading of palladium is 3-8%.

4. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: The mixing process in step S3 is carried out under a protective atmosphere using a planetary ball mill with a ball-to-material ratio of 5-10:1, a rotation speed of 200-300 rpm, and a mixing time of 2-4 hours.

5. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: The pressing in step S4 is cold isostatic pressing, with a pressure of 300-500 MPa and a holding time of 3-5 minutes, resulting in a green body with a relative density of 45-50%.

6. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: In step S5, the vacuum environment pressure is no higher than 1.0×10-2 Pa, the heating rate is 5-10℃ / min, and the cooling rate is 20-30℃ / min.

7. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: The sintering temperature in step S5 is 940-960℃, preferably 950℃.

8. The low-temperature rapid sintering method for a nano-catalytic tungsten-copper composite material according to claim 1, characterized in that: The heat preservation time in step S5 is 12-18 minutes, preferably 15 minutes.