阅读说明：本技术 一种高导热性防泄漏的导热材料及其制备方法和应用 (High-thermal-conductivity leakproof heat conduction material and preparation method and application thereof ) 是由 杨城 郑立聪 谢开旺 李正荣 盛磊 刘静 于 2019-10-12 设计创作，主要内容包括：本发明属于液态金属应用技术领域,具体涉及一种高导热性防泄漏的导热材料及其制备方法和应用。所述导热材料包括：基体和掺杂粉体；所述基体为液态金属；所述掺杂粉体至少包括碳化硅。在一定温度和压力下,所述导热材料具有优异的导热性能,同时在熔化时呈膏状,因而避免现有导热片受热后泄漏的问题。(The invention belongs to the technical field of liquid metal application, and particularly relates to a high-thermal-conductivity leakproof heat conduction material, and a preparation method and application thereof. The heat conductive material includes: a matrix and doped powder; the substrate is liquid metal; the doped powder at least comprises silicon carbide. Under a certain temperature and pressure, the heat conducting material has excellent heat conducting performance and is pasty when being melted, so that the problem that the conventional heat conducting sheet leaks after being heated is solved.)

1. A thermally conductive material, comprising: a matrix and doped powder; the substrate is a liquid metal alloy; the doped powder at least comprises silicon carbide.

2. The thermally conductive material of claim 1, wherein the mass ratio of the liquid metal alloy to the silicon carbide is (2-10): 1; preferably (4-7): 1.

3. a heat conductive material according to claim 1 or 2, wherein the liquid metal alloy has a melting point between 60-200 ℃;

preferably, the liquid metal alloy is one or more of bismuth indium alloy, bismuth tin alloy, bismuth zinc alloy, tin zinc alloy, indium tin alloy, bismuth indium zinc alloy, bismuth indium tin alloy, bismuth tin zinc alloy, bismuth indium tin zinc alloy; bismuth indium tin alloys are preferred.

4. The heat conductive material of any of claims 1-3, wherein the doped powder further comprises alumina powder and/or copper powder;

preferably, the adding amount of the alumina powder is not more than 15% of the mass of the matrix;

and/or, preferably, the copper powder is added in an amount not exceeding 20% by mass of the matrix.

5. The heat conducting material according to any one of claims 1 to 4, wherein when the alumina powder and the copper powder are added simultaneously, the heat conducting material comprises the following doped powder in percentage by mass: 10-25% of silicon carbide, 10-15% of alumina powder and 1-20% of copper powder; and the particle sizes of the doped powder are all in the 5 mu m level.

6. A method of preparing the thermally conductive material of any of claims 1-5, comprising: uniformly stirring and mixing the matrix and the doped powder under a vacuum condition;

preferably, the silicon carbide is passivated before being stirred; the passivation treatment mode is selected from baking and/or hydrofluoric acid acidification drying, and preferably baking is carried out after hydrofluoric acid acidification drying; further preferably, the baking temperature is 600-.

7. The method of claim 6, wherein the temperature of the system is maintained at a temperature slightly above 5-10 ℃ of the melting point of the liquid metal matrix alloy during the vacuum stirring.

8. Use of the thermally conductive material of any of claims 1-5 for heat dissipation of high heat flux components and electronic devices.

9. A heat conductive sheet, which is produced from a raw material comprising the heat conductive material according to any one of claims 1 to 5.

10. The use of the thermally conductive sheet as claimed in claim 9, wherein the use is carried out under any one of the following interface conditions:

(1) the interface temperature is less than or equal to 100 ℃, and the pressure is less than or equal to 60 ps;

(2) the interface temperature is less than or equal to 150 ℃ and the pressure is less than or equal to 40 psi;

(3) the temperature of the interface is less than or equal to 200 ℃ and the pressure is less than or equal to 20 psi.

Technical Field

The invention belongs to the technical field of liquid metal application, and particularly relates to a high-thermal-conductivity leakproof heat conduction material, and a preparation method and application thereof.

Background

The heat conducting fin is one kind of heat interface material and is used between the heating device and the heat sink to fill the gap between the heating device and the heat sink, so as to form excellent heat conducting channel and raise heat dissipating efficiency.

The liquid metal thermal interface material is a high-end heat conduction interface material based on low-melting point metal, and is a breakthrough innovation in the international heat dissipation field in recent years. The thermal conductivity of the liquid metal is 10-60W/K DEG C, which is 5-10 times of that of the traditional silicone oil-based material, the liquid metal has obvious performance advantages, stable physicochemical properties, no toxicity, no harm and difficult volatilization, and is more suitable for long-term application in high-temperature and high-heat flow field.

The liquid metal heat conducting fin is a solid flaky thermal interface product, and can ensure that interface gaps can be fully filled to form a good heat conducting channel by utilizing the characteristic of low melting point of the liquid metal heat conducting fin and melting the liquid metal heat conducting fin through heating of the heating body. The liquid metal heat conducting sheet has excellent heat conducting capacity, is convenient to operate and does not need to be smeared.

The traditional liquid metal heat conducting fin is a solid flake pure metal product and is made of pure liquid metal. However, the conventional low-melting-point liquid metal is not limited in its kinds and high in price, and particularly, the heat conductivity of the conventional liquid metal is not considered to be outstanding among metal materials.

In addition, although the liquid metal heat conducting sheet has high heat conducting efficiency, the liquid metal has high fluidity, so that the liquid metal is easy to leak or seep into the heat dissipation device or the material of the electronic component to cause flowing failure in the long-term use process, and the application of the liquid metal heat conducting sheet is seriously hindered. In view of the above-mentioned drawbacks of the liquid metal heat-conducting strip, researchers have developed many different packaging methods to overcome the drawbacks, but the packaging methods are not satisfactory.

Disclosure of Invention

In order to overcome the above problems, the present invention proposes a highly heat conductive and leak-proof heat conductive material. Under a certain temperature and pressure, the heat conducting material has excellent heat conducting performance and is pasty when being melted, so that the problem that the conventional heat conducting sheet leaks after being heated is solved.

The high thermal conductivity, leak resistant, thermally conductive material comprising: a matrix and doped powder; the substrate is a liquid metal alloy; the doped powder at least comprises silicon carbide.

According to the invention, silicon carbide is selected as the doped powder, and when the material is melted, the silicon carbide can well fill gaps between liquid metal interfaces, so that the heat conduction material is in a paste shape, the problem that the existing liquid metal heat conduction sheet leaks after being heated is avoided, and the use safety of the heat conduction sheet is improved.

The mass ratio of the liquid metal alloy to the silicon carbide is (2-10): 1; preferably (4-7): 1.

the melting point of the matrix liquid metal alloy is between 60 and 200 ℃.

The matrix liquid metal alloy is one or more of bismuth indium alloy, bismuth tin alloy, bismuth zinc alloy, tin zinc alloy, indium tin alloy, bismuth indium zinc alloy, bismuth indium tin alloy, bismuth tin zinc alloy and bismuth indium tin zinc alloy; bismuth indium tin alloys are preferred.

In order to further improve the performance of the heat conducting material, the doped powder also comprises alumina powder and/or copper powder.

The addition amount of the alumina powder is not more than 15% of the mass of the matrix.

The adding amount of the copper powder is not more than 20% of the mass of the matrix.

The particle size of the silicon carbide is between 1nm and 100 μm, preferably 5 μm.

The particle size of the alumina powder is between 1nm and 100 μm, preferably 5 μm.

The particle size of the copper powder is between 1nm and 100 μm, preferably 5 μm.

Preferably, the particle sizes of the doped powder are all in the order of 5 μm.

As one of the preferred embodiments of the present invention, when alumina powder and copper powder are added simultaneously, the heat conducting material comprises the following doped powders in percentage by mass: 10-25% of silicon carbide, 10-15% of alumina powder and 1-20% of copper powder; and the particle sizes of the doped powder are all in the 5 mu m level.

The melting point of the heat conduction material is within 60-200 ℃, and the heat conductivity of the heat conduction material is between 30-50W/m x k.

The invention also provides a preparation method of the high-thermal-conductivity leakproof heat-conducting material, which comprises the following steps: and uniformly stirring the matrix and the doped powder under the vacuum condition.

For better performance, the silicon carbide is passivated before the stirring. The passivation treatment mode is selected from baking and/or hydrofluoric acid acidification drying, and preferably baking is carried out after hydrofluoric acid acidification drying. The purpose of the passivation treatment is to reduce the sharp edges and corners of the silicon carbide particles and to minimize damage to the silicon carbide particles due to thermal motion during heat transfer.

Wherein the baking temperature is 600-1200 ℃, preferably 1200 ℃; the baking time can be determined according to actual conditions, such as 10 hours.

In the present invention, an inert shielding gas may be introduced during the vacuum stirring. During the vacuum stirring process, the temperature of the system is kept to be slightly higher than the melting point of the liquid metal matrix alloy by 5-10 ℃ all the time. Therefore, the viscosity of the liquid metal matrix can be ensured as much as possible under the condition of ensuring that the liquid metal matrix is in a liquid state, and the powder material added in the liquid metal matrix can be better doped and stirred.

In the invention, when the alumina powder and/or the copper powder is added into the liquid metal, the silicon carbide is added after being uniformly stirred, so that the system is more uniform, and the performance of the heat conduction material is more favorably improved.

The invention also provides application of the heat conduction material in the aspects of heat dissipation of high-heat-flux components, heat dissipation of electronic equipment and the like.

The invention also provides a heat conducting sheet which is prepared from the raw materials comprising the heat conducting material. The heat conducting sheet is applied between various electronic elements with high heat flow density and a radiator, and the problem of interface thermal barrier can be effectively solved.

As one embodiment of the present invention, a method for producing the thermally conductive sheet is as follows:

1) preparing a matrix liquid metal: weighing raw material simple substances of liquid metal according to a component formula, uniformly mixing, adding into a vacuum smelting furnace for smelting, and carrying out vacuum cooling;

2) preparing doped powder: weighing powder materials with different qualities according to the component formula of the doped powder; processing the powder to a certain degree;

3) weighing, mixing and stirring the matrix liquid metal prepared in the step 1) and the powder prepared in the step 2) according to the mass ratio of the matrix liquid metal to the doped powder of 2-10: 1;

4) pouring and shaping the liquid metal mixture prepared in the step 3) by adopting a mould with a certain shape;

5) and (4) cold rolling the liquid metal mixture cooled in the step 4), pressing the mixture into a thin material with a certain thickness, and cutting the thin material by a laser cutting machine to obtain the liquid metal phase change heat conducting sheet.

The invention also provides a use method of the heat conducting sheet, which is implemented in any one of the following use interface conditions:

(1) the heat transfer liquid metal sealing material is used under the conditions that the interface temperature is less than or equal to 100 ℃ and the pressure is less than or equal to 60ps, so that the heat transfer effect can be ensured, and the liquid metal does not leak;

(2) the heat transfer liquid metal sealing material is used under the conditions that the temperature of a used interface is less than or equal to 150 ℃ and the pressure is less than or equal to 40psi, so that the heat transfer effect can be ensured, and the liquid metal does not leak;

(3) the heat transfer liquid metal sealing material is used under the conditions that the temperature of a used interface is less than or equal to 200 ℃ and the pressure is less than or equal to 20psi, so that the heat transfer effect can be ensured, and the liquid metal does not leak.

The invention has the following advantages:

the invention improves the thermal conductivity of the liquid metal by doping the specific dopant, can also reduce the application cost of the liquid metal and broaden the application range of the liquid metal as a cooling working medium.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.