CN110438457B - Modified diamond particles, modification method, application of modified diamond particles as reinforcing phase and obtained metal-based composite material - Google Patents

Abstract

The invention discloses a modified diamond particle, a modification method, an application as a reinforcing phase and a obtained metal matrix composite material, belonging to the field of composite materials. The method for modifying diamond particles of the present invention uses vacuum rolling coating equipment to stir the particles in the drum to increase the uniformity of the diamond particle coating; the multi-arc ion plating process is used to directly generate plasma from the surface of the target material, which adheres to the The particle energy of the matrix is high, the density of the coating is high, and the metal is more likely to form carbides with diamond, so that the mechanical bonding becomes metallurgical bonding, which can greatly reduce the interface thermal resistance; and the magnetron sputtering method is used for coating, which improves the multi-arc The surface of the ion-plating layer makes the surface smoother, increases the fluidity of diamond particles, improves the hot-pressing ability, and reduces the formation of pores; on the other hand, it prevents the multi-arc ion-plating metal from diffusing into the base metal to prevent the thermal conductivity of the base from being reduced. performance. The modified diamond particles of the invention are compact and not easy to fall off.

Description

A kind of modified diamond particle, modification method, application as reinforcing phase and obtained metal matrix composites

technical field

The invention belongs to the field of composite materials, and relates to a modified diamond particle, a modification method, an application as a reinforcing phase, and a obtained metal matrix composite material.

Background technique

The heat sink material for electronic packaging has undergone three generations of development, and can no longer meet the increasing heat dissipation demand of power devices. The heat dissipation problem has become a technical bottleneck for the development of the electronic information industry. Metal-based diamond composite material is a new type of heat sink material for electronic packaging. It has excellent properties of high thermal conductivity and low thermal expansion coefficient. hot spot. Diamond is the material with the highest thermal conductivity among natural substances, and it has always been a research hotspot of heat dissipation materials, but its high price discourages researchers. With the maturity of synthetic diamond technology, the price of synthetic diamond particles has gradually declined, making the application of diamond composite materials a reality.

After theoretical research, the diamond particle dispersion-strengthened metal matrix composite material obtained by compounding diamond particles with a high thermal conductivity metal matrix as the second phase can theoretically obtain extremely excellent thermal conductivity, and the thermal conductivity can theoretically reach 1000W/( m·K). However, the thermal conductivity of metal-based diamond composites prepared by traditional processes is actually only 200W/(m·K), which is due to the poor wettability of diamond and metal matrix. The interface bonding of the matrix to reduce the interface thermal resistance between the diamond and the metal matrix has become the core of related research work. The study found that there are two main ways to improve the interface bonding between the two: matrix alloying and diamond surface metallization modification. In comparison, although matrix alloying is easy to operate and has a wide range of optional elements, its process conditions are harsh, and it is difficult to control the interface morphology and composition of alloyed metal and diamond, and it is difficult to ensure the integrity of the carbide film. The biggest advantage of diamond surface metallization is that it can directly and effectively control the morphology and composition of the two-phase interface.

There are many methods for metallization modification of diamond surface. The traditional process includes electroplating method, and the new method also includes chemical vapor deposition, salt bath coating method, overlay combustion coating method, vacuum micro-evaporation coating method and so on. However, methods such as electroplating or electroless plating are relatively technical in operation, and the solution ratio needs to be precisely controlled, and other impurities will be introduced.

SUMMARY OF THE INVENTION

The purpose of the present invention is to overcome the problem of poor metal-based diamond interface bonding, and to provide a modified diamond particle, a modification method, an application as a reinforcing phase and the obtained metal-based composite material.

To achieve the above object, the present invention adopts the following technical solutions to realize:

A method for modifying diamond particles, comprising the following steps:

1) the diamond particles are metallized to generate metal carbide and metal coating on their surface, the thickness of the coating is 100-500nm, and the metal element in the coating is one of Cr, W, Ti and Zr or more;

2) generating a metal layer with a thickness of 5-15 μm on the coating;

Both step 1) and step 2) are performed in a vacuum roll coating equipment.

Further, the particle size of the diamond particles is 20-400 μm.

Further, in step 1) the surface metallization of the diamond particles adopts a multi-arc ion plating method.

Further, the specific process parameters of the multi-arc ion plating method are: the working atmosphere is Ar, the working pressure is 0.6-1.2Pa, the arc source power is 600-1500W, the coating time is 10-30min, and the vacuum chamber heating temperature is 60-150 °C.

Further, in step 2) a magnetron sputtering coating method is used to generate a metal layer on the metal carbide layer.

Further, the specific process parameters of the magnetron sputtering coating method are: the working atmosphere is Ar, the working pressure is 0.2-0.6Pa, the magnetron sputtering power is 800-1200W, the sputtering time is 50-120min, and the vacuum chamber heating temperature 40-80℃.

Further, the rotating speed of the vacuum rolling coating equipment is 10-30r/min.

The modified diamond particles obtained by the above-mentioned modification method of diamond particles.

In the application of the above-mentioned modified diamond particles as a reinforcing phase in a metal matrix, the element type of the metal layer is the same as that of the metal matrix.

The metal matrix composite obtained by the above application.

Compared with the prior art, the present invention has the following beneficial effects:

The method for modifying diamond particles of the present invention adopts vacuum rolling coating equipment to stir the particles in the drum, which greatly increases the uniformity of diamond particle coating; The particles attached to the substrate have high energy, the density of the coating is high, and the metal is more likely to form carbides with diamond, thereby changing from mechanical bonding to metallurgical bonding, and the adhesion strength is better, which can greatly reduce the interface thermal resistance; and the magnetron sputtering method is adopted. Coating, on the one hand, improves the surface of the multi-arc ion coating, makes the surface smoother, increases the fluidity of diamond particles, improves the hot-pressing ability, and reduces the formation of pores; In order to avoid reducing the thermal conductivity of the substrate. The invention adopts the combination of the multi-arc ion plating process and the magnetron sputtering process to form a double-layer film structure on the diamond surface, which can not only solve the problem of non-wetting between diamond and metal, but also improve the hot-pressing forming ability and ensure the thermal conductivity of the base metal. Good performance.

The modified diamond particles of the present invention have a flat coating surface, are compact and are not easy to fall off, and have good wettability with metal substrates.

The application of the modified diamond particles of the present invention as a reinforcing phase in a metal matrix, the obtained composite has good thermal conductivity.

Description of drawings

Fig. 1 is the SEM image of diamond particle after Cr plating in the multi-arc ion plating process of embodiment 1;

Fig. 2 is the SEM image of diamond particles after the coating magnetron sputtering of Cu in Example 1;

Fig. 3 is the SEM image of diamond particle after electroplating Cr plating;

FIG. 4 shows the thermal conductivity of unmodified diamond, electroplated modified diamond and modified diamond of Example 1 after composite with metal as a reinforcing phase.

Detailed ways

In order to make those skilled in the art better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only Embodiments are part of the present invention, but not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

It should be noted that the terms "first", "second" and the like in the description and claims of the present invention and the above drawings are used to distinguish similar objects, and are not necessarily used to describe a specific sequence or sequence. It is to be understood that the data so used may be interchanged under appropriate circumstances such that the embodiments of the invention described herein can be practiced in sequences other than those illustrated or described herein. Furthermore, the terms "comprising" and "having" and any variations thereof, are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those expressly listed Rather, those steps or units may include other steps or units not expressly listed or inherent to these processes, methods, products or devices.

The invention adopts the composite plating method of the multi-arc ion plating process and the magnetron sputtering process to carry out the surface metallization modification of the diamond particles, which can greatly reduce the interface thermal resistance between the diamond particles and the metal matrix, so that the metal-based diamond composite material can be used as a composite material. The performance of the heat sink material is improved.

A method for modifying diamond particles, comprising the following steps:

1) Pretreatment of diamond particles

Put the diamond particles into the acetone solution, wash with ultrasonic vibration for 0.5h, wash to remove hydrocarbons, take out and wash with deionized water until neutral;

The diamond particles were placed in a 10g/L NaOH solution, cleaned with ultrasonic vibration for 0.5h, cleaned and degreasing, and washed with deionized water until neutral after taking out;

Then, the diamond particles were placed in HNO ₃ with a mass fraction concentration of 10%, cleaned with ultrasonic vibration for 0.5 h, cleaned and coarsened, and then taken out and cleaned with deionized water until neutral. Finally the diamond particles are placed in an oven to dry.

2) using vacuum rolling coating equipment, put the diamond particles obtained in step 1 into the drum, and ensure that the drum rotation speed is 10-30r/min during the deposition process;

Firstly, the multi-arc ion plating process is adopted, the working atmosphere is Ar, the working pressure is 0.6-1.2Pa, the arc source power is 600-1500W, the coating time is 10-30min, and the heating temperature in the vacuum chamber is 60-150℃, to obtain a single-layer coating coated diamond particles;

3) on the surface of the diamond particles obtained in step 2), a magnetron sputtering process is used, the working atmosphere is Ar, the working pressure is 0.2-0.6Pa, the magnetron sputtering power is 800-1200W, and the sputtering time is 50-120min, The heating temperature of the vacuum chamber is 40-80°C.

Example 1

Weigh 50g of diamond powder (particle size is 100-150μm) with an analytical balance, first put the diamond particles into acetone solution, clean with ultrasonic vibration for 0.5h, clean to remove hydrocarbons, take out and clean with deionized water until neutral Then the diamond particles were placed in a 10g/L NaOH solution, cleaned with ultrasonic vibration for 0.5h, cleaned and degreasing, and washed with deionized water to neutrality after taking out; then the diamond particles were placed in 10% HNO ₃ In the process, ultrasonic vibration was used to clean for 0.5h, and the roughening was carried out. After taking out, it was cleaned with deionized water until neutral; finally, the diamond particles were placed in an oven to dry.

Using vacuum rolling coating equipment, the diamond particles obtained by pretreatment are put into the drum. During the deposition process, the rotation speed of the drum is guaranteed to be 20r/min to ensure the vacuum degree in the vacuum chamber. Firstly, the method of multi-arc ion plating is adopted, Cr target is used, the power is 1300W, and the coating time is 20min to obtain single-layer coated diamond particles;

Then, the method of magnetron sputtering is adopted, a Cu target is used, the power is 1000W, and the sputtering time is 70min to obtain surface-modified diamond particles with a double-film structure.

Below in conjunction with accompanying drawing, the present invention is described in further detail:

Referring to Fig. 1, Fig. 1 is a SEM image of diamond particles after Cr plating by the multi-arc ion plating process in Example 1; it can be seen from Fig. 1 that the surface of the chrome-plated diamond prepared by this method has a uniform and dense Cr coating.

Fig. 2 is the SEM image of the diamond particles after the coating magnetron sputtering coating Cu in Example 1. It can be seen from Fig. 2 that the surface of the tungsten-plated diamond prepared by this method has a layer of smooth and dense Cu coating, and the coating is analyzed and tested. The diamond particles are all covered, the surface is smooth and tight, and the heat sink material after sintering and molding has a thermal conductivity of 540W/m·K.

Referring to Figure 3, Figure 3 is the SEM image of diamond particles after electroplating Cr plating. It can be seen that the coating of diamond is very rough, and the particles on the coating are not combined into one surface, but are in the shape of coral reefs. Weak, easy to fall off during subsequent processing and use, and can not fully play the role of the coating.

Referring to Figure 4, Figure 4 shows the thermal conductivity of the unmodified diamond, the electroplated modified diamond and the modified diamond of Example 1 as the reinforcing phase and the metal composite, the volume ratio of the diamond to the Cu powder is 0.6:1, and the subsequent sintering Under the same conditions, it can be seen that the thermal conductivity of unmodified is 80W/m·K, the thermal conductivity of electroplating modification is 260W/m·K, and the thermal conductivity of the composite obtained in Example 1 is 540W/m ·K.

Table 1 and Table 2 are respectively the specific parameters of diamond coating by multi-arc ion plating and magnetron sputtering. The coating formed by multi-arc ion plating includes metal carbide and metal element, and examples 2-7 The thickness distribution range of the generated coating is 100-500 nm; the modified diamond obtained in Example 2-7 is used to do magnetron sputtering, and the specific parameters of the magnetron sputtering are as shown in Table 2, and the obtained coating is the upper metal layer, and the thickness distribution 5-15μm.

Table 1 uses the specific parameters of the multi-arc ion plating method

Table 2 uses the specific parameters of magnetron sputtering method

Table 3 Thermal conductivity and density values of the composites obtained in Examples 2-7

Compared with the unmodified thermal conductivity of 80W/m·K and the electroplated modified thermal conductivity of 260W/m·K, the thermal conductivity of the composite prepared by the invention is greatly improved.

The above content is only to illustrate the technical idea of the present invention, and cannot limit the protection scope of the present invention. Any modification made on the basis of the technical solution proposed in accordance with the technical idea of the present invention falls within the scope of the claims of the present invention. within the scope of protection.

Claims (8)

1. A method for modifying diamond particles, comprising the steps of:

1) carrying out metallization treatment on diamond particles to generate a metal carbide and metal coating on the surfaces of the diamond particles, wherein the thickness of the coating is 100-500nm, and the metal elements in the coating are one or more of Cr, W, Ti and Zr;

2) generating a metal layer with the thickness of 5-15 mu m on the plating layer;

the step 1) and the step 2) are both carried out in vacuum rolling coating equipment;

step 1), metallizing the surfaces of diamond particles by adopting a multi-arc ion plating method;

and 2) generating a metal layer on the coating by adopting a magnetron sputtering coating method.

2. The method for modifying diamond particles according to claim 1, wherein the diamond particles have a particle size of 20 to 400 μm.

3. The method for modifying diamond particles according to claim 1, wherein the specific process parameters of the multi-arc ion plating method are as follows: the working atmosphere is Ar, the working pressure is 0.6-1.2Pa, the arc source power is 600-1500W, the coating time is 10-30min, and the heating temperature of the vacuum chamber is 60-150 ℃.

4. The method for modifying diamond particles according to claim 1, wherein the specific process parameters of the magnetron sputtering coating method are as follows: the working atmosphere is Ar, the working pressure is 0.2-0.6Pa, the magnetron sputtering power is 800-1200W, the sputtering time is 50-120min, and the heating temperature of the vacuum chamber is 40-80 ℃.

5. The method for modifying diamond particles according to claim 1, wherein the rotation speed of the vacuum roll coating device is 10 to 30 r/min.

6. Modified diamond particles obtained by the method for modifying diamond particles according to any one of claims 1 to 5.

7. Use of modified diamond particles according to claim 6 as a reinforcing phase in a metal matrix, wherein the metal layer is of the same elemental type as the metal matrix.

8. A metal matrix composite obtained according to the use of claim 7.

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