Copper-based material radiator and preparation method thereof

Abstract

The invention relates to a copper-based material radiator and a preparation method thereof. The preparation method comprises the following steps: (1) mixing copper powder, Cu-Al alloy powder and a binder, banburying and granulating to obtain an injection molding feed; (2) the injection molding feed is injected on an injection machine, and an injection blank of the copper-based material radiator is obtained; (3) pre-degreasing the injection blank to obtain a pre-degreased blank; (4) the pre-degreased blank is subjected to pre-oxidation sintering in mixed gas of inert gas and oxygen, and a pre-oxidation sintering product is obtained; and (5) the pre-oxidation sintering product is subjected to reduction and high-temperature sintering in hydrogen, and the copper-based material radiator is obtained. According to the preparation method, aluminum oxide dispersion strengthening copper powder does not need to be prepared in advance, only Cu-Al alloy powder needs to be added, atmosphere control is carried out in the sintering process, additional procedures are not needed, adding of an aluminum oxide strengthening phase can be achieved, and the dispersion strengthening effect is achieved.

Description

Technical Field

[0001] The present application relates to the field of metal powder injection molding, and in particular to a copper-based material heat sink and a preparation method thereof. Background Art

[0002] In recent years, semiconductor chips have developed rapidly in the direction of high power and miniaturization, and the heat flux density of chips has become increasingly higher, which in turn requires higher performance heat sinks. The heat dissipation efficiency of the heat sink is mainly determined by the thermal conductivity of the material and the heat exchange area of ​​the heat sink. In terms of materials, pure copper has excellent thermal conductivity and is one of the most commonly used thermal conductive materials in the civilian field. In terms of heat exchange area, with the continuous optimization and innovation of structural design, the structure of the heat sink has become more and more complex, and the specific surface area has become higher and higher, thereby greatly improving the heat exchange area and heat dissipation efficiency.

[0003] In order to improve the heat dissipation capacity of the radiator, the most advanced design is to make the copper radiator fins into densely packed pin fins to increase the specific surface area and thus improve the heat exchange efficiency. Traditional forging and casting processes are greatly restricted by molds, making it difficult to manufacture radiators with high aspect ratios, dense arrangements, and complex structures, and the material utilization rate is low. Metal powder injection molding technology can solve various problems existing in traditional processes, and can realize the production of radiators with high pin fin arrangement density, large aspect ratio, and complex structure. It also has high material utilization, high production efficiency, and low cost, and has very good application prospects.

[0004] The high-performance pure copper heat sink is prepared by metal powder injection molding process, and generally needs to be kept at above 1000℃ for several hours during the sintering stage. Since no hardening process such as heat treatment or deformation processing is performed after sintering, the hardness and strength of the material are often lower than those obtained by traditional forging process. Alumina dispersion-strengthened copper powder is added to pure copper powder, and then alumina dispersion-strengthened copper injection molding parts are prepared through banburying granulation, injection, pre-degreasing, hot degreasing and high-temperature sintering. With the help of alumina dispersion strengthening, on the one hand, the thermal conductivity reduction caused by copper alloying can be avoided, and on the other hand, the hardness and strength of injection molded copper-based materials can be improved. However, alumina dispersion-strengthened copper powder is generally prepared by internal oxidation method, which requires multiple processes such as preparation of Cu-Al alloy powder, preparation of oxidant, mixing of Cu-Al alloy powder and oxidant, heating internal oxidation, high-temperature reduction, powder crushing, etc. There are many process flows, high cost, and the morphology of the crushed powder is poor, which is not conducive to the fluidity of injection molding feed. Therefore, the process of adding alumina dispersion strengthening phase into the injection molded copper matrix efficiently and at low cost needs to be further improved. Summary of the invention

[0005] In view of the above problems, the present application provides a copper-based material heat sink and a preparation method thereof. The preparation method described in the present application does not require the advance preparation of alumina dispersion-strengthened copper powder. It only requires the addition of Cu-Al alloy powder and the atmosphere control during the sintering process of injection molding. No additional steps are required to achieve the addition of alumina strengthening phase, achieve the effect of dispersion strengthening, and obtain a high-strength and high-conductivity injection-molded copper-based material heat sink. The entire process flow of the present application is short and the cost is low.

[0006] In a first aspect, the present application provides a method for preparing a copper-based material heat sink, the preparation method comprising the following steps:

[0007] (1) copper powder, Cu-Al alloy powder and a binder are mixed, kneaded and granulated to obtain injection molding feed;

[0008] (2) injecting the injection molding feedstock on an injection molding machine to obtain an injection blank of a copper-based material heat sink;

[0009] (3) pre-degreasing the injection blank to obtain a pre-degreasing blank;

[0010] (4) pre-oxidizing and sintering the pre-degreased blank in a mixed gas of an inert gas and oxygen to obtain a pre-oxidized and sintered product;

[0011] (5) The pre-oxidation sintering product is reduced and sintered at high temperature in hydrogen to obtain the copper-based material heat sink.

[0012] In the technical solution of the embodiment of the present application, during the pre-oxidation sintering process, a mixed gas is first introduced to slowly oxidize the copper powder and the Cu-Al alloy powder to generate copper oxide and aluminum oxide. Then, reduction and high-temperature sintering are performed in hydrogen, and the copper oxide is reduced to copper, while the aluminum oxide is not reduced and becomes a strengthening phase dispersed in the material. And after the oxidized copper powder is reduced, the effect of activated sintering can be achieved during the sintering process.

[0013] Compared with conventional powder injection molding preparation technology, the preparation method described in the present application does not require the advance preparation of alumina dispersion-strengthened copper powder. It only requires the addition of Cu-Al alloy powder and the atmosphere control during the sintering process of injection molding. No additional steps are required to achieve the addition of alumina strengthening phase, achieve the effect of dispersion strengthening, and obtain a high-strength and high-conductivity injection-molded copper-based material heat sink. The entire process flow of the present application is short and the cost is low.

[0014] Preferably, in step (1), copper powder and Cu-Al alloy powder are first mixed to obtain a mixed powder of copper powder and Cu-Al alloy powder, and then the mixed powder is mixed with a binder.

[0015] Preferably, in step (1), based on the total mass of copper powder and Cu-Al alloy powder as 100%, the mass of the Cu-Al alloy powder is ≤40%, for example, 5%, 10%, 15%, 20%, 25%, 30%, 35%, etc.

[0016] In the technical solution of the implementation mode of the present application, the mass ratio of the added Cu-Al powder can be flexibly adjusted according to the requirements of the hardness and strength of the product, so as to achieve the effect of flexible regulation of material properties.

[0017] Preferably, based on the total mass of the Cu-Al alloy powder as 100%, the mass content of Al therein is 0.1% to 2.0%, for example, 0.2%, 0.4%, 0.6%, 0.8%, 1%, 1.2%, 1.4%, 1.6%, 1.8%, etc.

[0018] Preferably, the D90 particle size of the Cu-Al alloy powder is ≤20 μm, for example, 2 μm, 5 μm, 10 μm, 15 μm, etc.

[0019] In the present application, the D90 particle size refers to the particle size value corresponding to when the cumulative distribution percentage from small to large reaches 90% in the particle size distribution.

[0020] In the technical solution of the implementation mode of the present application, the D90 particle size of the added Cu-Al powder can be flexibly adjusted according to the requirements of product hardness and strength, so as to achieve the effect of flexible regulation of material properties.

[0021] Preferably, the D90 particle size of the copper powder is ≤50 μm, for example, 2 μm, 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, etc.

[0022] Preferably, in step (3), the adhesive comprises a plastic-based adhesive and / or a wax-based adhesive.

[0023] Preferably, the binder is selected from plastic-based binders, and the pre-degreasing method includes oxalic acid degreasing.

[0024] The present application does not limit the type of plastic-based binder as long as it meets the use requirements. As an example, the plastic-based binder includes any one of polyoxymethylene, ethylene-vinyl acetate copolymer, polyethylene or styrene-acrylonitrile copolymer, or a combination of at least two of them; for example, the mass ratio of polyoxymethylene, ethylene-vinyl acetate copolymer, polyethylene and styrene-acrylonitrile copolymer can be (70-90): (1-10): (5-15): (1-10), wherein 70-90 can be 75, 80, 85, etc.; 1-10 can be 2, 4, 5, 6, 8, etc., and 5-15 can be 6, 8, 10, 12, 14, etc.

[0025] Preferably, the adhesive is selected from a wax-based adhesive, and the pre-degreasing method includes solvent degreasing.

[0026] Preferably, in step (4), the inert gas comprises nitrogen.

[0027] Preferably, based on the total volume of the mixed gas as 100%, the volume of the oxygen is 0.1% to 5.0%, for example, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, etc.

[0028] Preferably, in step (4), the temperature of the pre-oxidation sintering is 300-800°C, for example, 350°C, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, etc.

[0029] Preferably, the heating rate of the pre-oxidation sintering is 1-4°C / min, such as 2°C / min, 3°C / min, etc.

[0030] Preferably, the pre-oxidation sintering time is 0.5-30 h, for example, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 25 h, etc.

[0031] Preferably, in step (4), the pre-oxidation sintering specifically includes the following process: in a mixed gas of inert gas and oxygen, heating the temperature to 350-450°C (for example, 360°C, 380°C, 400°C, 420°C, 440°C, etc.) at a heating rate of 1-4°C / min (for example, 2°C / min, 3°C / min, etc.), keeping warm for 0.5-2h, and then heating the temperature to 600-800°C (for example, 650°C, 700°C, 750°C, etc.) at a heating rate of 1-2°C / min (for example, 1.2°C / min, 1.4°C / min, 1.6°C / min, 1.8°C / min, etc.), and keeping warm for 1-3h (for example, 1.5h, 2h, 2.5h, etc.).

[0032] Preferably, in step (5), gas replacement is performed before the reduction.

[0033] Preferably, the gas replacement includes: maintaining the pre-oxidation sintering temperature unchanged, stopping the introduction of oxygen, continuously introducing an inert gas to replace the residual oxygen in the system with an inert gas, then stopping the introduction of the inert gas, and continuously introducing hydrogen to replace the residual inert gas in the system with hydrogen.

[0034] Preferably, in step (5), the reduction temperature is 600-800°C, such as 650°C, 700°C, 750°C, etc.

[0035] Preferably, the reduction time is 1 to 3 hours, such as 1.5 hours, 2 hours, 2.5 hours, etc.

[0036] Preferably, in step (5), the high temperature sintering temperature is 1000-1100°C, such as 1020°C, 1040°C, 1060°C, 1080°C, etc.

[0037] Preferably, the heating rate of the high temperature sintering is 1-5°C / min, such as 2°C / min, 3°C / min, 4°C / min, etc.

[0038] Preferably, the high temperature sintering time is 0.5-20 h, for example, 1 h, 2 h, 4 h, 6 h, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, etc.

[0039] Preferably, in step (5), the high temperature sintering specifically comprises the following process: in hydrogen, heating the temperature to 1000-1080°C (e.g. 1020°C, 1040°C, 1060°C, etc.) at a heating rate of 1-5°C / min (e.g. 2°C / min, 3°C / min, 4°C / min, etc.), keeping the temperature for 1-5h (e.g. 2h, 3h, 4h, etc.),

[0040] Preferably, the high temperature sintering further includes a cooling operation.

[0041] As a preferred technical solution, the preparation method comprises the following steps:

[0042] (1) firstly mixing copper powder and Cu-Al alloy powder to obtain a mixed powder of copper powder and Cu-Al alloy powder, then mixing the mixed powder with a binder, mixing, and granulating to obtain an injection molding feed;

[0043] (2) injecting the injection molding feedstock on an injection molding machine to obtain an injection blank of a copper-based material heat sink;

[0044] (3) pre-degreasing the injection blank to obtain a pre-degreasing blank;

[0045] (4) heating the pre-debinded blank in a mixed gas of inert gas and oxygen at a heating rate of 1 to 4°C / min to 350 to 450°C, keeping the temperature for 0.5 to 2 hours, and then heating the blank at a heating rate of 1 to 2°C / min to 600 to 800°C, keeping the temperature for 1 to 3 hours, to obtain a pre-oxidized sintered product;

[0046] (5) Maintaining the temperature of the pre-oxidation sintering product at 600-800°C, stopping the introduction of oxygen, continuously introducing inert gas to replace the residual oxygen in the system with inert gas, then stopping the introduction of inert gas, continuously introducing hydrogen to replace the residual inert gas in the system with hydrogen, maintaining the temperature at 600-800°C for 1-3h in hydrogen, then increasing the temperature to 1000-1080°C at a rate of 1-5°C / min, maintaining the temperature for 1-5h, and then cooling to obtain the copper-based material heat sink.

[0047] In a second aspect, the present application provides a copper-based material heat sink, which is obtained by the preparation method described in the first aspect.

[0048] Compared with the prior art, the technical solution of the present application has at least the following beneficial effects:

[0049] The preparation method described in the present application does not require the advance preparation of alumina dispersion-strengthened copper powder. It only requires the addition of Cu-Al alloy powder and the atmosphere control during the sintering process of injection molding. No additional steps are required to achieve the addition of alumina strengthening phase and achieve the effect of dispersion strengthening, thereby obtaining a high-strength and high-conductivity injection-molded copper-based material heat sink. The entire process flow of the present application is short and the cost is low. At the same time, according to the requirements of product hardness and strength, the proportion and particle size of the added Cu-Al powder can be flexibly adjusted to achieve the effect of flexible regulation of material properties.

[0050] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. DETAILED DESCRIPTION

[0051] The following is a detailed description of the embodiments of the technical solution of the present application. The following embodiments are only used to more clearly illustrate the technical solution of the present application, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present application.

[0052] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" in the description and claims of this application and any variations thereof are intended to cover non-exclusive inclusions.

[0053] In the description of the embodiments of the present application, the technical terms "first", "second", etc. are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly indicating the number, specific order or primary and secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "multiple" is more than two, unless otherwise clearly and specifically defined.

[0054] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0055] The "range" disclosed in the present application is defined in the form of a lower limit and an upper limit, and a given range is defined by selecting a lower limit and an upper limit, and the selected lower limit and upper limit define the boundaries of the particular range. The range defined in this way can be inclusive or exclusive of the end values, and can be arbitrarily combined, that is, any lower limit can be combined with any upper limit to form a range. For example, if a range of 60 to 120 and 80 to 110 is listed for a particular parameter, it is understood that a range of 60 to 110 and 80 to 120 is also expected. In addition, if the minimum range values ​​1 and 2 are listed, and if the maximum range values ​​3, 4 and 5 are listed, the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5. In the present application, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are both real numbers. For example, the numerical range "2-10" means that all real numbers between "2-10" are listed in this document, and "2-10" is just an abbreviation of these numerical combinations. In addition, when a parameter is expressed as an integer ≥ 2, it is equivalent to disclosing that the parameter is, for example, an integer of 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0056] In the description of the embodiments of the present application, the term "and / or" is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can represent: A exists, A and B exist at the same time, and B exists. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0057] Example 1

[0058] This embodiment provides a method for preparing a copper-based material heat sink, the preparation method comprising the following steps:

[0059] S1. Take water-atomized copper powder and gas-atomized Cu-Al alloy powder, and mix them evenly in a weight ratio of 8:2. The D90 particle size of the water-atomized copper powder is 30 μm, the D90 particle size of the gas-atomized Cu-Al alloy powder is 15 μm, and the weight ratio of Al element to Cu-Al alloy is 0.2%;

[0060] S2, mixing the above-mentioned mixed copper-based powder with the plastic-based binder, and putting them into an internal mixer for internal mixing, and then preparing them into injection molding feed on a granulator; wherein the copper-based powder loading is 60%, and the weight proportions of the components of the plastic-based binder are: polyoxymethylene (POM) 80%, ethylene-vinyl acetate copolymer (EVA) 5%, polyethylene (PE) 10%, styrene-acrylonitrile copolymer (SA) 5%;

[0061] S3, using the injection molding feed prepared above to perform injection molding on an injection molding machine to obtain an injection blank of a copper-based material heat sink;

[0062] S4, performing oxalic acid degreasing on the above-mentioned injection blank;

[0063] S5, placing the pre-degreased blank into an atmosphere sintering furnace, first introducing a mixed atmosphere of N2 and O2, wherein the volume proportion of O2 in the atmosphere is 1%; firstly heating the temperature to 350°C at a heating rate of 2°C / min, and keeping the temperature for 1h, then heating the temperature to 700°C at a heating rate of 1°C / min, and keeping the temperature for 2h, during which the copper powder and Cu-Al alloy powder in the pre-degreased blank are slowly oxidized;

[0064] S6, keep the temperature at 700°C unchanged, stop introducing O2, continue to introduce N2 to replace the oxygen in the furnace, then introduce H2 to replace the N2 in the furnace, and then keep it at 700°C for 2h under the condition of H2 reducing atmosphere to reduce the copper oxide in the material, and then raise the temperature to 1070°C at 2°C / min for high-temperature sintering, and keep it for 4h;

[0065] S7, cooling to room temperature to obtain an alumina dispersion strengthened injection molded copper-based material heat sink.

[0066] Example 2

[0067] This embodiment provides a method for preparing a copper-based material heat sink, the preparation method comprising the following steps:

[0068] S1. Take gas atomized copper powder and gas atomized Cu-Al alloy powder, and mix them evenly at a weight ratio of 9:1. The particle size of the water atomized copper powder D90 is 20 μm, the particle size of the gas atomized Cu-Al alloy powder D90 is 10 μm, and the weight ratio of Al element to Cu-Al alloy is 0.5%;

[0069] S2, mixing the above-mentioned mixed copper-based powder with the plastic-based binder described in Example 1, and putting them into an internal mixer for internal mixing, and then preparing them into injection molding feed on a granulator, wherein the copper-based powder loading amount is 60%;

[0070] S3, using the injection molding feed prepared above to perform injection molding on an injection molding machine to obtain an injection blank of a copper-based material heat sink;

[0071] S4, performing oxalic acid degreasing on the above-mentioned injection blank;

[0072] S5. Place the pre-degreased blank into an atmosphere sintering furnace, first introduce a mixed atmosphere of N2 and O2, with the volume proportion of O2 in the atmosphere being 2%. First, heat up to 400°C at a rate of 3°C / min, keep warm for 1h, then heat up to 650°C at a rate of 1.5°C / min, keep warm for 1.5h. During this process, the copper powder and Cu-Al alloy powder in the pre-degreased blank are slowly oxidized;

[0073] S6, keep the temperature at 650°C unchanged, stop introducing O2, continue to introduce N2 to replace the oxygen in the furnace, then introduce H2 to replace the N2 in the furnace, and then keep it at 650°C for 1.5h under the condition of H2 reducing atmosphere to reduce the copper oxide in the material, and then raise the temperature to 1060°C at 3°C / min for high-temperature sintering, and keep it at this temperature for 3h;

[0074] S7, cooling to room temperature to obtain an alumina dispersion strengthened injection molded copper-based material heat sink.

[0075] The preparation method described in the present application does not require the advance preparation of alumina dispersion-strengthened copper powder. It only requires the addition of Cu-Al alloy powder and the atmosphere control during the sintering process of injection molding. No additional steps are required to achieve the addition of alumina strengthening phase and achieve the effect of dispersion strengthening, thereby obtaining a high-strength and high-conductivity injection-molded copper-based material heat sink. The entire process flow of the present application is short and the cost is low. At the same time, according to the requirements of product hardness and strength, the proportion and particle size of the added Cu-Al powder can be flexibly adjusted to achieve the effect of flexible regulation of material properties.

[0076] Embodiment 3-4

[0077] The difference between this embodiment and embodiment 1 is that in the mixed atmosphere of N2 and O2, the volume proportion of O2 in the mixed atmosphere is 5% (embodiment 3) and 6% (embodiment 4), and the rest is the same as embodiment 1.

[0078] Compared with Example 3, the strength of the copper-based material heat sink prepared in Example 4 will be lower, which proves that during pre-oxidation sintering, adjusting the volume proportion of oxygen in the mixed gas to within the range of 0.1% to 5.0% is more conducive to simply and efficiently preparing high-strength and high-conductivity injection-molded copper-based material heat sinks.

[0079] Embodiment 5-7

[0080] The difference between this embodiment and embodiment 1 is that in the gas atomized Cu-Al alloy powder, the mass proportion of Al element is 0.05% (embodiment 5), 2% (embodiment 6) and 2.2% (embodiment 7), and the rest is the same as embodiment 1.

[0081] Compared with Examples 1 and 6, Examples 5 and 7 have lower strength than Examples 1 and 6. The mass proportion of Al in the Cu-Al alloy powder of the present application is in the range of 0.1% to 2.0%, which is more conducive to the simple and efficient preparation of high-strength and high-conductivity injection-molded copper-based material heat sinks.

[0082] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them; although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application, and they should all be included in the scope of the claims and specification of the present application. In particular, as long as there is no structural conflict, the various technical features mentioned in the various embodiments can be combined in any way. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions that fall within the scope of the claims.

Claims

1. A method for preparing a copper-based material heat sink, characterized in that: The preparation method comprises the following steps: (1) copper powder, Cu-Al alloy powder and a binder are mixed, kneaded and granulated to obtain injection molding feed; (2) injecting the injection molding feedstock on an injection molding machine to obtain an injection blank of a copper-based material heat sink; (3) pre-degreasing the injection blank to obtain a pre-degreasing blank; (4) pre-oxidizing and sintering the pre-degreased blank in a mixed gas of an inert gas and oxygen to obtain a pre-oxidized and sintered product; (5) The pre-oxidation sintering product is reduced and sintered at high temperature in hydrogen to obtain the copper-based material heat sink.

2. The preparation method according to claim 1, characterized in that: In step (1), copper powder and Cu-Al alloy powder are first mixed to obtain a mixed powder of copper powder and Cu-Al alloy powder, and then the mixed powder is mixed with a binder.

3. The preparation method according to claim 1 or 2, characterized in that: In step (1), based on the total mass of the copper powder and the Cu-Al alloy powder being 100%, the mass of the Cu-Al alloy powder is ≤40%; Preferably, based on the total mass of the Cu-Al alloy powder being 100%, the mass content of Al therein is 0.1% to 2.0%; Preferably, the D90 particle size of the Cu-Al alloy powder is ≤20 μm.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step (4), the inert gas includes nitrogen; Preferably, based on the total volume of the mixed gas being 100%, the volume of the oxygen is 0.1% to 5.0%.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (4), the temperature of the pre-oxidation sintering is 300-800°C; Preferably, the heating rate of the pre-oxidation sintering is 1-4°C / min; Preferably, the pre-oxidation sintering time is 0.5-30h.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (4), the pre-oxidation sintering specifically includes the following process: in a mixed gas of inert gas and oxygen, heating to 350-450°C at a rate of 1-4°C / min, keeping warm for 0.5-2h, then heating to 600-800°C at a rate of 1-2°C / min, keeping warm for 1-3h.

7. The preparation method according to any one of claims 1 to 6, characterized in that: In step (5), before the reduction, gas replacement is first performed; Preferably, the gas replacement includes: maintaining the pre-oxidation sintering temperature unchanged, stopping the introduction of oxygen, continuously introducing an inert gas to replace the residual oxygen in the system with an inert gas, then stopping the introduction of the inert gas, and continuously introducing hydrogen to replace the residual inert gas in the system with hydrogen.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (5), the reduction temperature is 600-800° C.; Preferably, the reduction time is 1 to 3 hours; Preferably, the high temperature sintering temperature is 1000-1100°C; Preferably, the heating rate of the high temperature sintering is 1 to 5°C / min; Preferably, the high temperature sintering time is 0.5-20h; Preferably, in step (5), the high temperature sintering specifically comprises the following process: heating to 1000-1080° C. at a heating rate of 1-5° C. / min in hydrogen, and keeping the temperature for 1-5 hours; Preferably, the high temperature sintering further includes a cooling operation.

9. The preparation method according to any one of claims 1 to 8, characterized in that: The preparation method comprises the following steps: (1) firstly mixing copper powder and Cu-Al alloy powder to obtain a mixed powder of copper powder and Cu-Al alloy powder, then mixing the mixed powder with a binder, mixing, and granulating to obtain an injection molding feed; (2) injecting the injection molding feedstock on an injection molding machine to obtain an injection blank of a copper-based material heat sink; (3) pre-degreasing the injection blank to obtain a pre-degreasing blank; (4) heating the pre-debinded blank in a mixed gas of inert gas and oxygen at a heating rate of 1 to 4°C / min to 350 to 450°C, keeping the temperature for 0.5 to 2 hours, and then heating the blank at a heating rate of 1 to 2°C / min to 600 to 800°C, keeping the temperature for 1 to 3 hours, to obtain a pre-oxidized sintered product; (5) Maintaining the temperature of the pre-oxidation sintering product at 600-800°C, stopping the introduction of oxygen, continuously introducing inert gas to replace the residual oxygen in the system with inert gas, then stopping the introduction of inert gas, continuously introducing hydrogen to replace the residual inert gas in the system with hydrogen, maintaining the temperature at 600-800°C for 1-3h in hydrogen, then increasing the temperature to 1000-1080°C at a rate of 1-5°C / min, maintaining the temperature for 1-5h, and then cooling to obtain the copper-based material heat sink.

10. A copper-based material heat sink, characterized in that: The copper-based material heat sink is obtained by the preparation method according to any one of claims 1-9.