CN116441557A - A method for preparing diamond/copper composite materials combined with binder jetting 3D printing technology - Google Patents

Abstract

The invention discloses a method for preparing a diamond/copper composite material combined with a binder jetting 3D printing technology. The method comprises the following steps: uniformly mixing tungsten powder and diamond powder, putting the mixture into a tubular reduction furnace under hydrogen Thermal diffusion treatment is carried out under the atmosphere. After the heat preservation is completed and cooled to room temperature, the powder is separated by a standard sieve with a hole diameter smaller than the diamond particle size to obtain tungsten-coated diamond; the tungsten-coated diamond powder and copper powder are mixed in a powder mixer to obtain diamond /copper mixed powder; add the diamond/copper mixed powder into the printing equipment, and print the diamond/copper green body through the binder jet 3D printing equipment; place the printed diamond/copper green body in the tube furnace, in Carry out sintering under argon atmosphere to obtain diamond/copper composite material. The invention improves the wettability between the diamond and copper by modifying the diamond surface, and improves the interface bonding strength and comprehensive performance of the diamond/copper composite material.

Description

A method of preparing diamond/copper composite materials combined with binder jetting 3D printing technology method

technical field

The invention relates to the field of diamond composite materials, in particular to a method for preparing diamond/copper composite materials combined with binder jetting 3D printing technology.

Background technique

With the rapid development of the electronic information age, the output power of electronic devices and the integration of integrated circuits have increased sharply, and the requirements for the heat dissipation performance of electronic devices are getting higher and higher. Electronic devices generate a lot of heat under high-frequency operation. Temperature will reduce the stability and service life of the device. Therefore, the development of a new generation of electronic packaging materials has become the key to solving the heat dissipation problem of electronic devices.

Diamond is the material with the highest thermal conductivity known in the world. Its thermal conductivity at room temperature is as high as 2200W·m ^-1 ·K ^-1 , and it has a low thermal expansion coefficient (0.86×10 ^-6 /°C). Copper is a commonly used metal in the electronics industry. It has good electrical and thermal conductivity, with a thermal conductivity of 398W·m ^-1 ·K ^-1 , but a relatively large thermal expansion coefficient of 17.5×10 ^-6 /°C. Using diamond as a reinforcing phase, the diamond/copper composite material obtained by compounding with a high thermal conductivity copper matrix has excellent thermal conductivity, and the thermal expansion coefficient matches with semiconductor materials such as Si, GaAs, GaN, SiC and so on. Representative of a new generation of heat sink materials in the field. At present, the relatively mature methods for preparing diamond/copper composite materials mainly include powder metallurgy and infiltration. However, these methods are difficult to prepare materials with complex shapes, and the materials prepared by these methods need to be machined to obtain the final product. Due to the high hardness of diamond, the processing process is difficult and the cost is high.

Binder jetting 3D printing is an additive manufacturing technique that deposits powder materials layer by layer, selectively connects each layer with a liquid binder, and then sinters to achieve densification. Compared with powder metallurgy and infiltration methods, binder jet 3D printing technology can prepare diamond/copper composite materials with complex shapes, which solves the difficulty that diamond/copper composite materials are difficult to machine. Compared with 3D printing technologies (SLS, SLM, SEBM) that produce complex metallurgical processes, binder jet 3D printing is molded at low temperature, and samples will not produce defects such as thermal cracks and high-temperature warping.

However, when diamond/copper composite materials are manufactured by binder jetting 3D printing technology, due to the poor wettability of diamond and copper, when diamond and copper are directly composited, the bonding strength of the interface between the two is small, resulting in low density of the composite material and the composite material Overall performance is poor.

Contents of the invention

The purpose of the present invention is to provide a method for preparing diamond/copper composite materials combined with binder jetting 3D printing technology, which improves the wettability between diamond and copper after tungsten plating on the diamond surface, while avoiding high temperature During the sintering process, the diamond is graphitized, which improves the interface bonding strength of the diamond/copper composite material and helps to obtain a dense diamond/copper sintered body.

In one aspect of the present invention, the present invention proposes a method for preparing diamond/copper composite materials combined with binder jet 3D printing technology. According to an embodiment of the present invention, comprising the following steps:

(1) Tungsten plating: Mix tungsten powder with degreasing and roughened diamond powder evenly, put the mixture into a tubular reduction furnace for thermal diffusion treatment in a hydrogen atmosphere, the temperature is 750-900°C, and the holding time is 1-3h, after cooling to room temperature at the end of the heat preservation, the powder is separated with a standard sieve whose hole diameter is smaller than the diamond particle size to obtain tungsten-coated diamond;

(2) powder mixing: tungsten-plated diamond powder and copper powder are put into a powder mixing machine and mixed to obtain a diamond/copper mixed powder;

(3) Printing: adding the diamond/copper mixed powder into the printing equipment, and printing the diamond/copper green body through the binder jetting 3D printing equipment;

(4) Sintering: The printed diamond/copper green body is placed in a tube furnace and sintered in an argon atmosphere to obtain a diamond/copper composite material.

In addition, a method for preparing a diamond/copper composite material combined with binder jet 3D printing technology according to the above-mentioned embodiments of the present invention may also have the following additional technical features:

In some embodiments of the present invention, in the step (1), the degreasing method is as follows, the diamond powder is put into a 10wt% NaOH solution, ultrasonically oscillated at 60° C. for 30 min, and cleaned with deionized water for 2 -3 times.

In some embodiments of the present invention, in the step (1), the roughening method is as follows, the diamond powder after degreasing is placed in 10wt% HNO solution, _{ultrasonically} cleaned at 60°C for 30min, and then used after taking it out Wash with deionized water for 2-3 times, and then put the diamond powder in a drying oven to dry.

In some embodiments of the present invention, in the step (1), the particle size of the diamond powder is 50-150 μm, the particle size of the tungsten powder is 1-3 μm, and the volume ratio of the diamond powder to the tungsten powder is 1:1, The thickness of the tungsten layer of tungsten-coated diamond is 100-300nm.

In some embodiments of the present invention, in the step (2), the copper powder is prepared by the plasma spheroidization method and the shape is spherical, the powder particle size is 15-80 μm, the mixing time is 5-10h, and the diamond/copper mixed powder The volume percentage of diamond powder is 30%-70%.

In some embodiments of the present invention, in the step (3), the diamond/copper mixed powder is added to the printing device, and the saturation of the binder, the thickness of the printing layer, the recoating speed, the oscillator speed, the powder Bed temperature and drying time, after printing, put the green body into the curing box for curing to remove the moisture in the binder.

In some embodiments of the present invention, the binder saturation is 50%-120%, the thickness of the printing layer is 50-120μm, the recoating speed is 80-130mm/s, the oscillator speed is 1500-2200rpm, the powder The bed temperature is 45-75°C and the drying time is 7-15s.

In some embodiments of the present invention, the curing temperature during the curing is 120-220° C., and the curing time is 4-8 hours.

In some embodiments of the present invention, in the step (4), the sintering temperature is 1150-1400° C., and the holding time is 2-5 hours.

In another aspect of the present invention, the present invention proposes a diamond/copper composite material prepared according to the method for preparing a diamond/copper composite material combined with a binder jet 3D printing technology.

Compared with prior art, the beneficial effect of the present invention is:

(1) The present invention uses thermal diffusion technology to plate tungsten on the diamond surface, and by controlling the proportion of reactants and the plating temperature, a uniform and dense tungsten plating layer can be obtained, the process parameters are easy to control, the operability is strong, and it can be produced in batches;

(2) The present invention can reduce the wetting angle between diamond and copper by modifying the surface of diamond and plating tungsten on the surface of diamond, which is conducive to improving the wettability between diamond and copper and improving the diamond/copper ratio. The interfacial bonding strength and density of the composite material. At the same time, after the diamond surface is coated with tungsten, the tungsten coating protects the diamond and prevents the graphitization of the diamond during high-temperature sintering;

(3) The present invention is especially suitable for the preparation of complex-shaped diamond/copper composite materials, solves the problem of difficult machining of diamond/copper composite materials, has simple preparation process, low cost, and expands the application field of diamond/copper composite materials.

Description of drawings

Fig. 1 is the SEM picture of the tungsten-coated diamond prepared in the embodiment of the present invention 1;

Fig. 2 is the SEM picture of the diamond/copper composite material prepared in the embodiment of the present invention 1 under 100 times;

Fig. 3 is the SEM picture of the diamond/copper composite material prepared in the embodiment of the present invention 1 under 2000 times;

Fig. 4 is the XRD spectrum of the diamond/copper composite material prepared in Example 1 of the present invention.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

A method for preparing diamond/copper composite materials in combination with binder jetting 3D printing technology, the specific steps are as follows:

(1) Degreasing, put the diamond powder with an average particle size of 100 μm in 10 wt% NaOH solution, ultrasonically vibrate for 30 min at 60° C., take it out and wash it 3 times with deionized water;

(2) coarsening, then place the diamond powder in 10wt% _HNO3 solution, ultrasonically clean it for 30min at 60°C, take it out and wash it with deionized water for 3 times, then put the diamond powder in a drying oven to dry;

(3) For tungsten plating, put the dried diamond powder and tungsten powder with an average particle size of 2 μm into a powder mixer and mix evenly, wherein the volume ratio of diamond powder to tungsten powder is 1:1, and then put the mixture into Thermal diffusion treatment is carried out in a tubular reduction furnace under a hydrogen atmosphere at a temperature of 900°C and a holding time of 2 hours. After the holding is completed and cooled to room temperature, the powder is separated with a standard sieve whose hole diameter is smaller than the diamond particle size to obtain tungsten-coated diamond. The tungsten coating thickness of the tungsten-coated diamond is 300nm;

(4) powder mixing, tungsten-plated diamond powder and spherical copper powder with an average particle diameter of 33 μm are put into a powder mixing machine and mixed for 10 hours to obtain a diamond/copper mixed powder, wherein the volume percentage of diamond in the diamond/copper mixed powder is 50%, and the volume percentage of copper is 50%;

(5) Printing, adding the diamond/copper mixed powder into the printing device, setting the saturation of the binder to 65%, the thickness of the printing layer to 100 μm, the recoating speed to 100mm/s, and the oscillator speed to 1800rpm, The temperature of the powder bed is 50°C, and the drying time is 10s. The diamond/copper green body with a size of 1.2×1.2×0.3cm is printed by the binder jetting 3D printing equipment. After the printing is completed, the green body is put into the curing box for curing In order to remove the moisture in the adhesive, the curing temperature is 130°C during curing, and the curing time is 6 hours;

(6) Sintering. Place the printed diamond/copper green body in a tube furnace and sinter in an argon atmosphere. The sintering temperature is 1300°C and the holding time is 2 hours. copper composite.

Fig. 1 is the SEM picture of the tungsten-coated diamond prepared in this example. It can be seen from the figure that the obtained tungsten-coated layer is uniform and dense, and the combination of the coating and the substrate is good.

Fig. 2 is the SEM picture of the diamond/copper composite material prepared in this embodiment at 100 times, as can be seen from the figure, the sample surface is compact, without obvious holes, and the diamond is evenly distributed in the copper matrix, which is conducive to improving the Density and comprehensive performance of composite materials.

Figure 3 is the SEM picture of the diamond/copper composite material prepared in this example at 2000 times. It can be seen from the figure that the interface between the diamond surface and copper is well bonded after tungsten plating, and there are no obvious cracks and pores at the interface .

Fig. 4 is the XRD spectrum of the diamond/copper composite material prepared in this example. There is no diffraction peak of graphite in the XRD spectrum, indicating that after the diamond surface is plated with tungsten, graphitization can be avoided during high temperature sintering.

After testing, the diamond/copper composite material obtained in this embodiment has a density of 96.67% and a shrinkage rate of 15.5%, and the obtained composite material has good compactness and high interface bonding strength.

Example 2

A method for preparing diamond/copper composite materials in combination with binder jetting 3D printing technology, the specific steps are as follows:

(1) Degreasing, put the diamond powder with an average particle size of 100 μm in 10 wt% NaOH solution, ultrasonically vibrate for 30 min at 60° C., take it out and wash it 3 times with deionized water;

(2) coarsening, then place the diamond powder in 10wt% _HNO3 solution, ultrasonically clean it for 30min at 60°C, take it out and wash it with deionized water for 3 times, then put the diamond powder in a drying oven to dry;

(3) For tungsten plating, put the dried diamond powder and tungsten powder with an average particle size of 2 μm into a powder mixer and mix evenly, wherein the volume ratio of diamond powder to tungsten powder is 1:1, and then put the mixture into Thermal diffusion treatment is carried out in a tubular reduction furnace under a hydrogen atmosphere at a temperature of 900°C and a holding time of 2 hours. After the holding is completed and cooled to room temperature, the powder is separated with a standard sieve whose hole diameter is smaller than the diamond particle size to obtain tungsten-coated diamond. The tungsten coating thickness of the tungsten-coated diamond is 300nm;

(4) powder mixing, tungsten-plated diamond powder and spherical copper powder with an average particle diameter of 33 μm are put into a powder mixing machine and mixed for 10 hours to obtain a diamond/copper mixed powder, wherein the volume percentage of diamond in the diamond/copper mixed powder is 30%, and the volume percentage of copper is 70%;

(5) Printing, adding the diamond/copper mixed powder into the printing device, setting the saturation of the binder to 65%, the thickness of the printing layer to 100 μm, the recoating speed to 100mm/s, and the oscillator speed to 1800rpm, The temperature of the powder bed is 50°C, and the drying time is 10s. The diamond/copper green body with a size of 1.2×1.2×0.3cm is printed by the binder jetting 3D printing equipment. After the printing is completed, the green body is put into the curing box for curing In order to remove the moisture in the adhesive, the curing temperature is 130°C during curing, and the curing time is 6 hours;

(6) Sintering. Place the printed diamond/copper green body in a tube furnace and sinter in an argon atmosphere. The sintering temperature is 1300°C and the holding time is 2h. 95.30%, 14.9% shrinkage diamond/copper composite material.

Example 3

A method for preparing diamond/copper composite materials in combination with binder jetting 3D printing technology, the specific steps are as follows:

(1) Degreasing, put the diamond powder with an average particle size of 100 μm in 10 wt% NaOH solution, ultrasonically vibrate for 30 min at 60° C., take it out and wash it 3 times with deionized water;

(2) coarsening, then place the diamond powder in 10wt% _HNO3 solution, ultrasonically clean it for 30min at 60°C, take it out and wash it with deionized water for 3 times, then put the diamond powder in a drying oven to dry;

(3) For tungsten plating, put the dried diamond powder and tungsten powder with an average particle size of 2 μm into a powder mixer and mix evenly, wherein the volume ratio of diamond powder to tungsten powder is 1:1, and then put the mixture into Thermal diffusion treatment is carried out in a tubular reduction furnace under a hydrogen atmosphere at a temperature of 900°C and a holding time of 2 hours. After the holding is completed and cooled to room temperature, the powder is separated with a standard sieve whose hole diameter is smaller than the diamond particle size to obtain tungsten-coated diamond. The tungsten coating thickness of the tungsten-coated diamond is 300nm;

(4) powder mixing, tungsten-plated diamond powder and spherical copper powder with an average particle diameter of 33 μm are put into a powder mixing machine and mixed for 10 hours to obtain a diamond/copper mixed powder, wherein the volume percentage of diamond in the diamond/copper mixed powder is 50%, and the volume percentage of copper is 50%;

(5) Printing, adding the diamond/copper mixed powder into the printing device, setting the saturation of the binder to 65%, the thickness of the printing layer to 100 μm, the recoating speed to 100mm/s, and the oscillator speed to 1800rpm, The temperature of the powder bed is 50°C, and the drying time is 10s. The diamond/copper green body with a size of 1.2×1.2×0.3cm is printed by the binder jetting 3D printing equipment. After the printing is completed, the green body is put into the curing box for curing In order to remove the moisture in the adhesive, the curing temperature is 130°C during curing, and the curing time is 6 hours;

(6) Sintering. Place the printed diamond/copper green body in a tube furnace and sinter in an argon atmosphere. The sintering temperature is 1400°C and the holding time is 2h. 97.12%, 15.8% shrinkage diamond/copper composite material.

The above content is only an example and description of the structure of the present invention. Those skilled in the art make various modifications or supplements to the described specific embodiments or replace them in similar ways, as long as they do not deviate from the structure of the present invention. Or beyond the scope defined in the claims, all should belong to the protection scope of the present invention.

Claims (10)

1. A method for preparing a diamond/copper composite material by combining a binder jetting 3D printing technology, comprising the following steps:

(1) Plating tungsten: uniformly mixing tungsten powder with deoiled and coarsened diamond powder, putting the mixture into a tubular reduction furnace, performing thermal diffusion treatment under hydrogen atmosphere at 750-900 ℃ for 1-3h, cooling to room temperature after heat preservation, and separating the powder by using a standard sieve with aperture smaller than the diamond particle size to obtain tungsten-plated diamond;

(2) Mixing powder: putting the tungsten-plated diamond powder and copper powder into a powder mixer for mixing to obtain diamond/copper mixed powder;

(3) Printing: adding the diamond/copper mixed powder into printing equipment, and spraying the 3D printing equipment through a binder to print a diamond/copper green body;

(4) Sintering: and placing the printed diamond/copper green body in a tubular furnace, and sintering under an argon atmosphere to obtain the diamond/copper composite material.

2. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (1), the oil removal method is as follows, diamond powder is put into 10wt% NaOH solution, ultrasonic oscillation is carried out for 30min at 60 ℃, and deionized water is used for cleaning for 2-3 times after the diamond powder is taken out.

3. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (1), the roughening method is as follows, diamond powder after oil removal is placed in 10wt% HNO ₃ And (3) in the solution, ultrasonically cleaning for 30min at 60 ℃, taking out, cleaning for 2-3 times by using deionized water, and then putting the diamond powder into a drying oven for drying.

4. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (1), the grain diameter of the diamond powder is 50-150 mu m, the grain diameter of the tungsten powder is 1-3 mu m, the volume ratio of the diamond powder to the tungsten powder is 1:1, and the tungsten plating layer thickness of the tungsten-plated diamond is 100-300nm.

5. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (2), the copper powder is prepared by a plasma spheroidization method and is spherical in shape, the particle size of the powder is 15-80 mu m, the mixing time is 5-10h, and the volume percentage of diamond powder in the diamond/copper mixed powder is 30-70%.

6. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (3), the diamond/copper mixed powder is added into printing equipment, the saturation of the binder, the thickness of the printing layer, the recoating speed, the speed of an oscillator, the temperature of a powder bed and the drying time are set, and after printing, the green compact is placed into a curing box for curing so as to remove the moisture in the binder.

7. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 6, wherein: the saturation degree of the binder is 50-120%, the thickness of the printing layer is 50-120 mu m, the recoating speed is 80-130mm/s, the oscillator speed is 1500-2200rpm, the temperature of the powder bed is 45-75 ℃, and the drying time is 7-15s.

8. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 6, wherein: the curing temperature is 120-220 ℃ and the curing time is 4-8h during curing.

9. A method of preparing a diamond/copper composite in combination with a binder jetting 3D printing technique according to claim 1, wherein: in the step (4), the sintering temperature is 1150-1400 ℃, and the heat preservation time is 2-5h.

10. A diamond/copper composite material prepared by a method of preparing a diamond/copper composite material according to any one of claims 1 to 9 in combination with a binder jetting 3D printing technique.