A new high-thermal-conductivity kovar alloy composite material and a preparation method thereof

Abstract

The application discloses a novel high-thermal-conductivity Kovar alloy composite material and a preparation method thereof, and the preparation method comprises the following steps: taking a Kovar alloy powder as a matrix, plating a uniform silver coating layer on the surface of the Kovar alloy powder through a chemical plating method, obtaining the Kovar alloy composite material powder by hydrogen reduction of the silver-plated powder, and finally preparing the high-thermal-conductivity Kovar alloy composite material through hot-pressing sintering of the Kovar alloy composite material powder. The silver in the Kovar alloy composite material prepared by the preparation method is distributed in a three-dimensional network structure, and the Kovar alloy composite material has a high thermal conductivity on the basis of retaining a low expansion coefficient of the Kovar alloy.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of composite materials, and particularly relates to a novel high-thermal-conductivity Kovar alloy composite material and a preparation method thereof. BACKGROUND

[0002] Kovar alloy is widely used in the matching sealing of glass ceramic materials due to its low expansion coefficient, and plays an important role in the industrial fields of aerospace, chemical industry, electronics, semiconductors, integrated circuits, instruments, mechanical manufacturing, and electric light sources. As a sealing material, it is usually required to have a low thermal expansion coefficient, to reduce or avoid the generation of thermal stress, to have very good thermal conductivity to provide heat dissipation, and to have good processing or forming performance. However, the thermal conductivity of Kovar alloy is extremely low, which greatly limits the application of Kovar alloy. The current commonly used method for improving the thermal conductivity of Kovar alloy mainly focuses on combining Kovar alloy with metals or alloys with high thermal conductivity to form a composite material, for example, high-pressure rolling and then annealing of Cu and Kovar alloy to form a solid solution connection, and forming a sandwich structure of Cu layered composite material, which has adjustable CTE and variable thermal conductivity, but the material performance is heterogeneous.

[0003] Therefore, it is urgent to develop a Kovar alloy composite material with high thermal conductivity, low thermal expansion coefficient, and isotropic material performance. SUMMARY

[0004] The main purpose of the present application is to provide a novel high-thermal-conductivity Kovar alloy composite material and a preparation method thereof, which aims to at least solve one of the problems pointed out in the background art.

[0005] To this end, the present application provides, in one aspect, a novel high-thermal-conductivity Kovar alloy composite material preparation method, which uses Kovar alloy powder as the matrix, coats a uniform silver coating layer on the surface of the Kovar alloy powder by chemical plating, obtains Kovar alloy composite material powder by hydrogen reduction of the silver-coated powder, and finally prepares the high-thermal-conductivity Kovar alloy composite material by hot-pressing sintering of the Kovar alloy composite material powder.

[0006] Principle and advantages

[0007] In the present application, a uniform silver coating layer is coated on the surface of the Kovar alloy powder by chemical plating. Since the solid solubility of silver with each element of the Kovar alloy powder is low, silver will not diffuse to the Kovar alloy matrix during the sintering process, so that silver is distributed in a three-dimensional network structure in the composite material. On the basis of retaining the low expansion coefficient of Kovar alloy, the thermal conductivity of the composite material can be improved, and the performance of the material in each direction is basically consistent, without anisotropy.

[0008] In addition, the surface of the powder after chemical plating may be oxidized during the drying process, causing silver to form oxides. By adding a reduction step, the oxygen content of the surface coating layer is reduced, and the influence of oxides on the performance of the material is reduced.

[0009] Specifically, the specific process of electroless silver plating is as follows: configuring silver plating solution in a certain proportion, adding the pretreated Kovar alloy powder into the silver plating solution, then adding reducing solution, stirring until the reaction is completed, reducing metal silver ions into metal particles by the reducing agent and depositing the metal particles on the surface of the Kovar alloy powder, and then washing with deionized water until neutral.

[0010] Specifically, the silver plating solution is a mixed solution of AgNO3, NH3·H2O and NaOH, and the reducing solution is a mixed solution of glucose, polyethylene glycol and ethanol, that is, the silver plating solution in the present application is a silver-ammonia solution containing main salt, complexing agent and pH regulator, wherein the main salt is AgNO3, the complexing agent is NH3·H2O, and the pH regulator is NaOH.

[0011] The inventor further found that, in terms of the volume of the silver plating solution, the addition amount of the Kovar alloy powder is 20-50 g / L, the addition amount of AgNO3 is 5-20 g / L, the addition amount of NH3·H2O is 100-200 ml / L, the addition amount of NaOH is 5-10 g / L, the addition amount of glucose is 20-40 g / L, the addition amount of ethanol is 50-100 ml / L, and the addition amount of polyethylene glycol is 15-30 g / L, which is more appropriate, because too much ammonia and sodium hydroxide will cause the reaction to be too fast, silver is easy to deposit on the cup wall or be free in the solution, too little addition will cause silver nitrate to be not completely complexed and easy to precipitate, and glucose has strong reducing property in an alkaline environment; too little addition of glucose as a reducing agent will cause the reaction to be slow and not completely reacted, and too much addition will cause silver to deposit on the cup wall; too much polyethylene glycol as a stabilizer will make the silver complex too stable and difficult to be reduced, and too little polyethylene glycol will cause the reaction to be too fast, the generated silver plating layer to be not dense and easy to deposit on the cup wall; and too much or too little ethanol as a diluent will cause the concentration of the reducing agent to be not controlled and the reaction speed to be not controlled, and the generated silver plating layer to be not uniform and dense.

[0012] Specifically, in the process of electroless silver plating, the temperature of the silver plating solution is maintained at room temperature.

[0013] Specifically, the reduction temperature is 300-500℃, and the reduction time is 1-3h in the atmosphere of hydrogen. The reason why the reduction temperature and the reduction time are controlled in the above range is that when the reduction temperature exceeds the above range, the plating layer on the surface of the powder diffuses to the substrate at a faster speed, and when the reduction time is too long, the diffusion time is longer, which are not conducive to the effective maintenance of the plating layer; and when the temperature is too low and the time is too short, the reduction effect is not good because the oxide reduction temperature is not reached.

[0014] Specifically, during hot-press sintering, the vacuum degree is controlled to be less than or equal to 10 -3 MPa, the temperature rising rate is 20-50 DEG C / min, the sintering temperature is 650 DEG C-800 DEG C, the pressure is 5-20 MPa, and the holding time is 5-20 min.

[0015] The above parameters are set as above because, if the vacuum degree is too low, the material is prone to react with oxygen at a high temperature, which affects the performance of the material, if the temperature is too high, the plating layer becomes liquid phase, if the temperature is too low, the density of the composite material is too low, the performance is reduced, if the pressure and the holding time are too short, the density is not enough, if the holding time is too long, the diffusion time of the plating layer is increased, the thermal conductivity is not obviously improved, and if the pressure is too large, the mold is prone to burst.

[0016] Specifically, the Kovar alloy powder is an iron-nickel or iron-nickel-cobalt alloy.

[0017] Specifically, the pretreatment process of the Kovar alloy powder includes two processes of oil removal and pickling; wherein,

[0018] The oil removal is to put the Kovar alloy powder into an alkali solution for stirring treatment, the alkali solution is NaOH solution, the concentration of the alkali solution is 100-120 g / L, the stirring time is 30-60 min, and the stirring temperature is 50-60 DEG C, so that the surface of the powder is kept clean, which is beneficial to plating of the plating layer.

[0019] The pickling is to put the Kovar alloy powder after oil removal into an acid solution for stirring treatment, the acid solution is HCl solution, the concentration of the acid solution is 15-20 vol.%, and the stirring time is 5-10 s, so that the surface oxides and dirt are removed, the surface roughness is improved, and the hydrophilicity is improved.

[0020] The application also provides a novel high-thermal-conductivity Kovar alloy composite material prepared by the above method, and the silver in the composite material is distributed in a three-dimensional network structure and wraps the Kovar alloy matrix.

[0021] Compared with the prior art, the application has the following beneficial effects: since the solid solubility of silver and each element of the Kovar alloy powder matrix is low, a uniform silver plating layer is coated on the surface of the powder by adopting the chemical plating method, the silver forms a three-dimensional network structure, the thermal conductivity of the composite material is improved on the basis of retaining the low expansion coefficient of the Kovar alloy, and the performance of the material in each direction is basically consistent; in addition, the composite material is prepared by adopting the chemical plating method, the thickness of the plating layer can be adjusted to realize the mutual cooperation of the thermal conductivity and the expansion coefficient of the composite material.

[0022] The Kovar alloy composite material prepared by the application has the silver distributed in a three-dimensional network structure, has a high thermal conductivity on the basis of retaining the low expansion coefficient of the Kovar alloy, and is beneficial to the application in the industrial fields of aerospace, chemical industry, electronics, semiconductors, integrated circuits, instruments, mechanical manufacturing, electric light sources and the like. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 Here is a SEM image of the iron-nickel powder after chemical silver plating in Example 1;

[0025] Figure 2 EDS-mapping images of the Kovar alloy composite material prepared in Example 1;

[0026] Figure 3 This is a SEM image of the iron-nickel powder after chemical silver plating in Example 2;

[0027] Figure 4 SEM image of iron-nickel powder after chemical silver plating. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] A novel method for preparing a high thermal conductivity Kovar alloy composite material involves using Kovar alloy powder as a matrix, depositing a uniform silver coating layer on the surface of the Kovar alloy powder by chemical plating, reducing the silver-plated powder with hydrogen to obtain Kovar alloy composite material powder, and finally preparing the high thermal conductivity Kovar alloy composite material by hot pressing sintering.

[0030] This invention involves electroless plating to coat a uniform silver layer onto the surface of Kovar alloy powder. Because silver has low solid solubility in Kovar alloy powder, it does not diffuse into the Kovar alloy matrix during sintering, resulting in a three-dimensional network distribution of silver in the composite material. This improves the thermal conductivity of the composite material while maintaining its low coefficient of thermal expansion, and ensures that the material exhibits essentially uniform anisotropy. Furthermore, since oxidation may occur on the powder surface during drying after electroless plating, forming silver oxides, a reduction step is added to reduce the oxygen content of the surface coating and minimize the impact of oxides on the material's properties.

[0031] Specifically, the specific process of electroless silver plating is as follows: configuring silver plating solution in a certain proportion, adding the pretreated Kovar alloy powder into the silver plating solution, then adding reducing solution, stirring until the reaction is completed, reducing metal silver ions into metal particles by the reducing agent and depositing the metal particles on the surface of the Kovar alloy powder, and then washing with deionized water until neutral.

[0032] Specifically, the silver plating solution is a mixed solution of AgNO3, NH3·H2O and NaOH, and the reducing solution is a mixed solution of glucose, polyethylene glycol and ethanol, that is, the silver plating solution in the present application is a silver-ammonia solution containing main salt, complexing agent and pH regulator, wherein the main salt is AgNO3, the complexing agent is NH3·H2O, and the pH regulator is NaOH.

[0033] The inventor further found that, in terms of the volume of the silver plating solution, the addition amount of the Kovar alloy powder is 20-50 g / L, the addition amount of AgNO3 is 5-20 g / L, the addition amount of NH3·H2O is 100-200 ml / L, the addition amount of NaOH is 5-10 g / L, the addition amount of glucose is 20-40 g / L, the addition amount of ethanol is 50-100 ml / L, and the addition amount of polyethylene glycol is 15-30 g / L, which is more appropriate because too much ammonia and sodium hydroxide will cause the reaction to be too fast, silver is easy to deposit on the cup wall or be free in the solution, too little addition will cause silver nitrate to be not completely complexed and easy to precipitate, and glucose has strong reducing property in an alkaline environment; too little addition of glucose as a reducing agent will cause the reaction to be slow and not completely reacted, and too much addition will cause the reaction to be too fast and silver to deposit on the cup wall; too much polyethylene glycol as a stabilizer will make the silver complex too stable and difficult to be reduced, and too little polyethylene glycol will cause the reaction to be too fast, the generated silver plating layer to be not dense and easy to deposit on the cup wall; and too much or too little ethanol as a diluent will cause the concentration of the reducing agent to be not controlled and the reaction speed to be not controlled, and the generated silver plating layer to be not uniform and dense. Too much powder will cause the amount of main salt and complexing agent per liter of plating solution to be increased, the plating to be slow, and silver to be easy to be free or attached to the cup wall or the plating layer to be not uniform and dense, and too little powder will cause the plating solution to be too low in concentration and not easy to be plated, and the efficiency to be low. In the process of electroless silver plating, the temperature of the silver plating solution is maintained at room temperature.

[0034] The inventor further found that the reduction temperature is 300-500℃ and the reduction time is 1-3h in the atmosphere of hydrogen, which is more appropriate. The reason why the reduction temperature and the reduction time are controlled in the above range is that when the reduction temperature exceeds the above range, the plating layer on the surface of the powder diffuses to the substrate at a faster speed, and when the reduction time is too long, the diffusion time is longer, which are not conducive to the effective maintenance of the plating layer; and when the temperature is too low and the time is too short, the reduction effect is not good because the oxide reduction temperature is not reached.

[0035] The inventor further found that, in the process of hot-pressing sintering, the vacuum degree is controlled to be ≤10 -3MPa, the temperature rising rate is 20-50 DEG C / min, the sintering temperature is 650 DEG C-800 DEG C, the pressure is 5-20 Mpa, and the holding time is 5-20 min.

[0036] The above parameters are set for the following reasons: if the vacuum degree is too low, the material is prone to react with oxygen at a high temperature, which affects the performance of the material; if the temperature is too high, the plated layer becomes liquid phase; if the temperature is too low, the density of the composite material is too low, and the performance is reduced; if the pressure and holding time are too short, the density is not enough; if the holding time is too long, the diffusion time of the plated layer is increased, and the thermal conductivity is not obviously improved; and if the pressure is too large, the mold is prone to burst.

[0037] The pre-treatment process of the Kovar alloy powder comprises two processes of oil removal and pickling; and the pre-treatment process of the Kovar alloy powder comprises the following steps:

[0038] The oil removal is to put the Kovar alloy powder into an alkali solution for stirring treatment, the alkali solution is NaOH solution, the concentration of the alkali solution is 100-120 g / L, the stirring time is 30-60 min, and the stirring temperature is 50-60 DEG C; through the oil removal, the surface of the powder can be kept clean, which is beneficial to the plating of the plated layer;

[0039] The pickling is to put the Kovar alloy powder after the oil removal into an acid solution for stirring treatment, the acid solution is HCl solution, the concentration of the acid solution is 15-20 vol.%, and the stirring time is 5-10 s; the pickling can remove the surface oxides and dirt, improve the surface roughness, and improve the hydrophilicity.

[0040] Example 1

[0041] The preparation method of the Kovar alloy composite material comprises the following steps:

[0042] (1) pre-treatment of Kovar alloy powder

[0043] 50 g of spherical iron-nickel powder (Fe-50%Ni) with a particle size of 45 mu m is added into NaOH solution with a concentration of 100 g / L, and stirring is carried out at 60 DEG C for 60 min; after the oil removal is completed, the Kovar alloy powder is washed with deionized water until it is neutral;

[0044] The Kovar alloy powder after the oil removal is added into HCl solution with a concentration of 20 vol.%, and stirring is carried out for 5 s; after the pickling is completed, the Kovar alloy powder is washed with deionized water until it is neutral;

[0045] (2) chemical silver plating

[0046] The silver plating solution is prepared according to a certain proportion, the powder after the pickling in step (1) is added into the silver plating solution, and then the reducing solution is slowly added; stirring is carried out until the reaction is completed, and then the Kovar alloy powder is washed with deionized water until it is neutral; wherein,

[0047] The silver plating solution is a mixed solution of AgNO3, NH3·H2O, and NaOH, and the reducing solution is a mixed solution of glucose, polyethylene glycol, and alcohol. During silver plating, the temperature of the silver plating solution is maintained at room temperature. Based on the volume of the silver plating solution, the amount of AgNO3 added is 15 g / L, the amount of NH3·H2O added is 125 ml / L, the amount of NaOH added is 6 g / L, the amount of glucose added is 30 g / L, the amount of alcohol added is 75 ml / L, the amount of polyethylene glycol added is 20 g / L, and the amount of iron-nickel powder added is 30 g / L.

[0048] (3) Preparation of Kovar alloy composite powder

[0049] The powder prepared in step (2) was reduced at 350°C for 1 hour in a hydrogen atmosphere to obtain Kovar alloy composite powder;

[0050] (4) Preparation of Kovar alloy composite materials

[0051] The Kovar alloy composite powder obtained in step (3) is hot-pressed and sintered, with the vacuum degree controlled to be ≤10. -3 Kovar alloy composite material was obtained by heating at a pressure of MPa, a heating rate of 30℃ / min, a sintering temperature of 700℃, a pressure of 20 MPa, holding at that temperature for 10 min, and then cooling in air.

[0052] In this embodiment, the SEM image of the powder after silver plating during the preparation of Kovar alloy composite material is shown below. Figure 1 EDS-mapping images of Kovar alloy composites are shown below. Figure 2 As can be seen, the silver coating is uniformly distributed, and the silver is ultimately distributed in a three-dimensional network structure in the composite material. The density of the prepared Kovar alloy composite material is 8.3 g / cm³. 3 The thermal conductivity is 33.3 W / (m·K), the coefficient of thermal expansion (10-6 / ℃) is 10.05, and the silver content of the three-dimensional network structure is about 10wt%. The reason for the increased thermal conductivity of the material in this embodiment is that the surface of Kovar alloy powder is coated with a uniform silver coating layer. Because silver and Kovar alloy powder have low solid solubility, silver will not diffuse into the Kovar alloy matrix during sintering. Silver is distributed in the composite material in a three-dimensional network structure, which makes the increase in the coefficient of thermal expansion of the composite material less, but the thermal conductivity increases by 100%.

[0053] Example 2

[0054] Unlike Example 1, in the chemical silver plating process, the following amounts were added based on the volume of the silver plating solution: AgNO3 5 g / L, NH3·H2O 100 ml / L, NaOH 5 g / L, glucose 20 g / L, alcohol 50 ml / L, and polyethylene glycol 15 g / L.

[0055] The SEM picture of the powder after silver plating in the preparation of the Kovar alloy composite material in this example is as shown in Figure 3 It can be seen that the silver is uniformly plated on the surface of the powder. The prepared Kovar alloy composite material has a density of 8.23 g / cm 3 , a thermal conductivity of 28.7 W / (m·K), and a thermal expansion coefficient (10-6 / ℃) of 10.01.

[0056] Example 3

[0057] Different from Example 1, the amount of the Kovar alloy powder added is 40 g / L based on the volume of the silver plating solution. In the chemical silver plating, the amount of AgNO3 added is 20 g / L, the amount of NH3·H2O added is 180 ml / L, the amount of NaOH added is 10 g / L, the amount of glucose added is 30 g / L, the amount of alcohol added is 100 ml / L, and the amount of polyethylene glycol added is 30 g / L based on the volume of the silver plating solution.

[0058] The Kovar alloy composite material prepared in this example has a density of 8.37 g / cm3, a thermal conductivity of 37.9 W / (m·K), and a thermal expansion coefficient (10-6 / ℃) of 10.08.

[0059] Example 4

[0060] Different from Example 1, the Kovar alloy powder is spherical iron-nickel-cobalt powder (Fe-29% Ni-17% Co). The Kovar alloy composite material prepared in this example has a density of 8.21 g / cm3, a thermal conductivity of 31.9 W / (m·K), and a thermal expansion coefficient (10-6 / ℃) of 5.3.

[0061] Comparative Example 1

[0062] (1) Pretreatment of the Kovar alloy powder

[0063] 50 g of spherical iron-nickel powder (Fe-50% Ni) with a particle size of 45 μm was added to a NaOH solution with a concentration of 100 g / L, and stirred at 60℃ for 60 min. After the oil removal was completed, the powder was washed with deionized water until neutral.

[0064] The oil-removed Kovar alloy powder was added to an HCl solution with a concentration of 20 vol.%, and stirred for 5 s. After the acid pickling was completed, the powder was washed with deionized water until neutral.

[0065] (2) Chemical silver plating

[0066] The powder after acid washing in step (1) is added into a silver plating solution of AgNO3, NH3-H2O and NaOH, and the amount of the iron-nickel powder added is 40 g / L based on the volume of the silver plating solution, then a mixed solution of glucose, polyethylene glycol and alcohol is slowly added, and stirring is continued until the reaction is completed and the powder is washed with deionized water until neutral; the amount of AgNO3 added is 30 g / L, the amount of NH3-H2O added is 150 ml / L, the amount of NaOH added is 6 g / L, the amount of glucose added is 40 g / L, the amount of alcohol added is 75 ml / L, and the amount of polyethylene glycol added is 10 g / L, all based on the volume of the silver plating solution.

[0067] (3) Preparation of the Kovar alloy composite powder

[0068] The powder prepared in step (2) is reduced at 450℃ under hydrogen atmosphere for 1 h to obtain the Kovar alloy composite powder;

[0069] (4) Preparation of the Kovar alloy composite material

[0070] The Kovar alloy composite powder prepared in step (3) is hot-pressed and sintered, and the vacuum degree is controlled to be ≤10 -3 MPa, the heating rate is 30℃ / min, the sintering temperature is 600℃, the pressure is 15 MPa, and the holding time is 5 min, and the Kovar alloy composite material is obtained after cooling in air.

[0071] In the preparation of the Kovar alloy composite material in the present comparative example, the SEM image of the powder after silver plating is as shown in Figure 4 , and the silver plated on the surface of the powder is less, mainly because the concentration of the main salt is too high, and a large amount of free silver is generated during the reaction, and the powder surface is almost not plated with silver. The density of the Kovar alloy composite material prepared is 8.2 g / cm3, the thermal conductivity is 22.5 W / (m·K), and the thermal expansion coefficient (10-6 / ℃) is 9.5.

[0072] Comparative Example 2

[0073] Different from Example 1, in the present comparative example, the surface of the Kovar alloy is not plated with silver, and the spherical iron-nickel powder (Fe-50%Ni) is directly hot-pressed and sintered to obtain the Kovar alloy material by using the hot-pressing and sintering process in Example 1. The density of the Kovar alloy prepared in the present comparative example is 8.18 g / cm3, the thermal conductivity is 15.7 W / (m·K), and the thermal expansion coefficient (10-6 / ℃) is 9.3.

[0074] The above examples are merely illustrative for the present application, and are not intended to limit the embodiments. Based on the above description, other different forms of changes or variations can be made by those of ordinary skill in the art. Here, it is not necessary and impossible to exhaust all the examples. The changes or variations thus derived are still within the protection scope of the present application.

Claims

1. A method for preparing a novel high thermal conductivity Kovar alloy composite material, characterized in that: The application discloses a preparation method of a high-thermal-conductivity Kovar alloy composite material. The vacuum degree is controlled to be less than or equal to 10 -3 MPa, the heating rate is 20-50℃ / min, the sintering temperature is 650-800℃, the pressure is 5-20MPa, and the holding time is 5-20min. The specific process of the chemical silver plating is as follows: a silver plating solution is prepared according to a certain proportion, the pretreated Kovar alloy powder is added into the silver plating solution, then a reducing solution is added, stirring is conducted until the reaction is completed, and then deionized water is used for cleaning until the solution is neutral. The pretreatment process of the Kovar alloy powder comprises two processes of oil removal and pickling. The oil removal is that the Kovar alloy powder is put into an alkali solution for stirring treatment, the alkali solution is a NaOH solution, the concentration of the alkali solution is 100-120 g / L, the stirring time is 30-60 min, and the stirring temperature is 50-60 DEG C. The pickling is that the Kovar alloy powder after the oil removal is added into an acid solution for stirring treatment, the acid solution is an HCl solution, the concentration of the acid solution is 15-20 vol.%, and the stirring time is 5-10 s.

2. The method of claim 1, wherein the novel high thermal conductivity Kovar alloy composite is prepared by the following steps of: The silver plating solution is a mixed solution of AgNO3, NH3H2O and NaOH, and the reducing solution is a mixed solution of glucose, polyethylene glycol and ethanol. The adding amount of the Kovar alloy powder is 20-50 g / L, the adding amount of AgNO3 is 5-20 g / L, the adding amount of NH3H2O is 100-200 ml / L, the adding amount of NaOH is 5-10 g / L, the adding amount of glucose is 20-40 g / L, the adding amount of ethanol is 50-100 ml / L, and the adding amount of polyethylene glycol is 15-30 g / L.

3. The method for preparing the novel high thermal conductivity Kovar alloy composite material according to claim 2, characterized in that: In the process of the chemical silver plating, the temperature of the silver plating solution is maintained at room temperature.

4. The method of claim 2, wherein the novel high thermal conductivity Kovar alloy composite is prepared by the following steps of: The reducing temperature is 300-500 DEG C, the reducing time is 1-3 h in the atmosphere of hydrogen.

5. The method for preparing the novel high thermal conductivity Kovar alloy composite material according to claim 1, characterized in that: The Kovar alloy powder is an iron-nickel or iron-nickel-cobalt alloy.

6. A novel high thermal conductivity Kovar alloy composite material characterized by: The new high-thermal-conductivity Kovar alloy composite material is prepared by the method.

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