Metal structural parts used in combination with gallium-based liquid metal and their preparation method and application

Abstract

The present invention discloses a metal structure for use with gallium-based liquid metal, which has a high-phosphorus nickel alloy layer on the surface of the metal structure in contact with the gallium-based liquid metal. When the metal structure is in contact with the gallium-based liquid metal, it will not react with the gallium-based liquid metal, thereby avoiding the reduction of heat dissipation performance due to the consumption of the gallium-based liquid metal. The present invention also discloses a method for preparing the metal structure and its application in heat dissipation of computer chips, mobile phone chips, communication products, high-power LEDs, insulated gate bipolar transistors, and high-power electronic products.

Description

Technical Field

[0001] The present invention belongs to the field of heat conduction of electronic equipment, and in particular relates to a metal structural part used in conjunction with gallium-based liquid metal, and a preparation method and application thereof. Background Art

[0002] There are tiny uneven gaps between the surface of electronic materials and the heat sink. If they are directly installed together, the actual contact area between them is only 10% of the area of ​​the heat sink base, and the rest is air gap. Because the thermal conductivity of air is only 0.024W / (mK), the contact thermal resistance between the electronic components and the heat sink will be very large, which seriously hinders the conduction of heat and causes low efficiency of the heat sink. Therefore, thermal interface materials with high thermal conductivity are needed to fill these gaps, remove the air in them, and establish a heat conduction channel between the electronic components and the heat sink, so as to greatly increase the contact area between the heat source and the heat sink, reduce the contact thermal resistance, and make the heat sink work well.

[0003] Thermal silicone grease is a traditional thermal interface material and is currently widely used. However, with the rise of emerging fields such as 5G communications, the Internet of Things, new energy automotive electronics, wearable devices, and smart cities, related electronic devices are developing in the direction of miniaturization, high power density, and multifunctionality, which will cause the overheating risk of related electronic devices to continue to increase. Traditional silicone grease has low thermal conductivity and cannot meet the needs of use. The development of high-performance thermal interface materials is critical to improving the heat dissipation of electronic devices, and it has also become the biggest challenge facing academia and the electronic device application industry. Gallium-based liquid metal thermal interface materials have gained increasing attention in recent years due to their high thermal conductivity and ability to meet modern high-power density applications.

[0004] However, gallium-based liquid metal can react with aluminum or its alloys, and can also form intermetallic compounds with copper or its alloys. Most heat sink materials are copper, aluminum or their alloys. In this case, the liquid phase gallium will be consumed by the reaction and eventually the interface will become dry, resulting in no filling effect and failure. Therefore, preventing gallium-based liquid metal from reacting with copper, aluminum or their alloys is an urgent problem to be solved for the widespread application of liquid metal as a thermal interface material.

[0005] The information disclosed in this background technology section is only intended to enhance the understanding of the overall background of the invention and should not be regarded as an acknowledgment or any form of suggestion that the information constitutes the prior art already known to a person skilled in the art. Summary of the invention

[0006] The purpose of the present invention is to provide a metal structural part for use with gallium-based liquid metal, which will not react with the gallium-based liquid metal when in contact with the gallium-based liquid metal, thereby avoiding the degradation of heat dissipation performance due to the consumption of the gallium-based liquid metal, and solving the technical problem in the prior art that the gallium-based liquid metal reacts with aluminum or its alloy in the heat sink material, resulting in the consumption of liquid gallium and eventually causing the interface to dry out and lose the filling effect.

[0007] To achieve the above object, the present invention provides a metal structure for use with gallium-based liquid metal, wherein a high-phosphorus nickel alloy layer is provided on the surface of the metal structure in contact with the gallium-based liquid metal.

[0008] In one embodiment of the present invention, the phosphorus content in the high-phosphorus nickel alloy layer is ≥ 10%.

[0009] In one embodiment of the present invention, the thickness of the high-phosphorus nickel alloy layer is ≥1 μm; preferably, the thickness of the high-phosphorus nickel alloy layer is ≥3 μm; more preferably, the thickness of the high-phosphorus nickel alloy layer is ≥5 μm; most preferably, the thickness of the high-phosphorus nickel alloy layer is ≥10 μm.

[0010] In one embodiment of the present invention, the metal structural part is a heat dissipation component in contact with gallium-based liquid metal, a container or cavity containing gallium-based liquid metal, or a gallium-based liquid metal flow pipeline; preferably, the metal structural part is a fin heat sink, a heat pipe heat sink, a phase change heat sink, a heat sink, a heat spreader, a microchannel heat sink, a liquid metal fluid heat sink, a liquid metal pressure sensor, a liquid metal pressure transmitter, a liquid metal container or its parts in contact with gallium-based liquid metal.

[0011] In one embodiment of the present invention, the surface of the metal structure that contacts the gallium-based liquid metal is a plane or a curved surface.

[0012] In one embodiment of the present invention, the material of the metal structural member is selected from at least one of copper, aluminum, iron, nickel, stainless steel, titanium, zinc, gold or alloys thereof.

[0013] In one embodiment of the present invention, a protective layer of composite ceramic is further included on the surface of the metal structure in contact with the gallium-based liquid metal.

[0014] In one embodiment of the present invention, the gallium-based liquid metal is selected from gallium metal, gallium-containing liquid alloy, gallium-containing metal oxide, gallium-containing thermal interface material, and gallium-containing composite material.

[0015] Another object of the present invention is to provide a method for preparing the above-mentioned metal structure, by performing high-phosphorus chemical nickel plating on the surface of the metal structure in contact with the gallium-based liquid metal thermal interface material, thereby forming a high-phosphorus nickel alloy layer on the surface of the metal structure in contact with the gallium-based liquid metal. The method is mature and stable in technology and low in cost.

[0016] Another object of the present invention is to provide the use of the above metal structure or the metal structure made by the above preparation method in the heat dissipation of computer chips, mobile phone chips, communication products, high-power LEDs, insulated gate bipolar transistors, and high-power electronic products. The present invention prevents the gallium-based liquid metal from alloying with the metal structure by forming a high-phosphorus nickel alloy layer on the surface of the metal structure in contact with the gallium-based liquid metal, so that the high thermal conductivity gallium-based liquid metal can be widely used in products such as computer chips, mobile phone chips, communication products, high-power LEDs, insulated gate bipolar transistors, aviation or military high-power electronic products.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] (1) The high-phosphorus nickel alloy layer on the surface of the metal structure of the present invention can effectively protect metals such as copper and aluminum, and will not react with gallium-based liquid metal for a long time under extreme conditions. According to experimental results, a high-phosphorus nickel coating of more than 1 μm can prevent the metal sheet from reacting with the gallium-based liquid metal, thereby preventing the gallium-based liquid metal from being gradually consumed by the reaction, and preventing the thermal conductivity from being reduced due to the consumption of the gallium-based liquid metal thermal interface material.

[0019] (2) Although a high-phosphorus nickel coating of 1 μm or more has a good protective effect on metal structural parts, for metal structural parts such as heat sinks and temperature spreaders with high-phosphorus nickel coating exposed on the surface, considering that the high-phosphorus nickel coating may be worn or scratched during packaging, transportation and use, the thickness of the high-phosphorus nickel coating is preferably above 3 μm, and more preferably above 5 μm. In the case of severe wear or special requirements such as high stability and long service life, a high-phosphorus nickel coating of 10 μm or more can be formed on the surface of the metal structural part to fully ensure adequate protection and avoid unexpected situations.

[0020] (3) In addition, the phosphorus content in the high-phosphorus nickel alloy layer is also crucial. In Example 2, a medium-phosphorus nickel coating with a phosphorus content of 9% was used for protection. However, the experimental results showed that although the coating of the medium-phosphorus nickel coating played a certain protective role in preventing the metal sheet from reacting with the gallium-based liquid metal, the protective effect was not sufficient. The gallium-based liquid metal eventually reacted with the metal sheet. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1is a cross-sectional schematic diagram of a fin heat sink according to an embodiment of the present invention;

[0022] Figure 2 is a cross-sectional schematic diagram of a heat pipe of a heat pipe radiator according to an embodiment of the present invention;

[0023] Figure 3 is a cross-sectional schematic diagram of a liquid metal container according to one embodiment of the present invention;

[0024] Figure 4 These are photos of metal sheets treated according to the methods of Example 3 of the present invention and Comparative Examples 1-5 after the coating protection effect test.

[0025] Description of main reference numerals:

[0026] 1-metal structural parts, 2-high phosphorus nickel alloy layer, 3-gallium-based liquid metal. DETAILED DESCRIPTION

[0027] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings, but it should be understood that the protection scope of the present invention is not limited by the specific implementation modes.

[0028] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0029] Example 1

[0030] like Figure 1 The figure shows a metal structure 1, specifically a copper fin heat sink, which has a high-phosphorus nickel alloy layer 2 on the bottom surface in contact with the gallium-based liquid metal 3. The preparation method is: clean the bottom surface of the copper fin heat sink in contact with the gallium-based liquid metal, perform high-phosphorus chemical nickel plating for 5 minutes, and then take it out and dry it.

[0031] After measurement, the thickness of the high-phosphorus nickel alloy layer formed on the bottom surface of the copper fin heat sink is 1.2 μm, and the phosphorus content in the high-phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm copper sheet is simultaneously used for high-phosphorus chemical nickel plating, and then the treated copper sheet is used to replace the copper fin heat sink as the test object of Example 1.

[0032] Example 2

[0033] like Figure 2The figure shows a metal structure 1, specifically a heat pipe of a copper heat pipe radiator, which has a high-phosphorus nickel alloy layer 2 on the inner surface in contact with the gallium-based liquid metal 3. The preparation method is: clean the inner surface of the heat pipe of the copper heat pipe radiator in contact with the gallium-based liquid metal, perform high-phosphorus chemical nickel plating for 18 minutes, and then take it out and dry it.

[0034] After measurement, the thickness of the high-phosphorus nickel alloy layer formed on the surface of the copper temperature homogenizer is 3 μm, and the phosphorus content in the high-phosphorus nickel alloy layer is 12%. For the convenience of subsequent experiments, a 2 mm copper sheet is simultaneously used for high-phosphorus chemical nickel plating, and then the treated copper sheet is used to replace the copper heat pipe as the test object of Example 2.

[0035] Example 3

[0036] like Figure 3 The figure shows a metal structure 1, specifically a copper liquid metal container, which has a high-phosphorus nickel alloy layer 2 on the inner surface in contact with the gallium-based liquid metal 3. The preparation method is: clean the inner surface of the copper liquid metal container in contact with the gallium-based liquid metal, perform high-phosphorus chemical nickel plating for 24 minutes, and then take out and dry.

[0037] After measurement, the thickness of the high-phosphorus nickel alloy layer formed on the inner surface of the copper liquid metal container is 5 μm, and the phosphorus content in the high-phosphorus nickel alloy layer is 11%. For the convenience of subsequent experiments, a 2 mm copper sheet is simultaneously used for high-phosphorus chemical nickel plating, and then the treated copper sheet is used instead of the copper liquid metal container as the test object of Example 3.

[0038] Example 4

[0039] The copper microchannel heat sink has a high-phosphorus nickel alloy layer on the inner and outer surfaces in contact with the gallium-based liquid metal. The inner and outer surfaces of the copper microchannel heat sink in contact with the gallium-based liquid metal are cleaned, subjected to high-phosphorus chemical nickel plating for 40 minutes, and then taken out and dried.

[0040] After measurement, the thickness of the high-phosphorus nickel alloy layer formed on the inner and outer surfaces of the copper microfluidic channel heat sink is 10 μm, and the phosphorus content in the high-phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm copper sheet is simultaneously used for high-phosphorus chemical nickel plating, and then the treated copper sheet is used to replace the copper microfluidic channel heat sink as the test object of Example 4.

[0041] Example 5

[0042] The aluminum heat sink has a high-phosphorus nickel alloy layer on the bottom surface in contact with the gallium-based liquid metal. The bottom surface of the aluminum heat sink in contact with the gallium-based liquid metal is cleaned, subjected to high-phosphorus chemical nickel plating for 20 minutes, and then taken out and dried.

[0043] After measurement, the thickness of the high-phosphorus nickel alloy layer formed on the surface of the aluminum heat sink is 5 μm, and the phosphorus content in the high-phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm aluminum sheet is simultaneously used for high-phosphorus chemical nickel plating, and then the treated aluminum sheet is used to replace the aluminum heat sink as the test object of Example 5.

[0044] Example 6

[0045] The copper alloy heat sink has a high-phosphorus nickel alloy layer on the bottom surface in contact with the gallium-based liquid metal. The bottom surface of the copper alloy heat sink in contact with the gallium-based liquid metal is cleaned, subjected to high-phosphorus chemical nickel plating for 20 minutes, and then taken out and dried.

[0046] After measurement, the thickness of the high phosphorus nickel alloy layer formed on the surface of the copper alloy heat sink is 5 μm, and the phosphorus content in the high phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm copper alloy sheet is used instead of a copper alloy heat sink to perform high phosphorus chemical nickel plating as the test object of Example 6.

[0047] Example 7

[0048] The aluminum alloy heat sink has a high-phosphorus nickel alloy layer on the bottom surface in contact with the gallium-based liquid metal. The bottom surface of the aluminum alloy heat sink in contact with the gallium-based liquid metal is cleaned, subjected to high-phosphorus chemical nickel plating for 29 minutes, and then taken out and dried.

[0049] After measurement, the thickness of the high phosphorus nickel alloy layer formed on the surface of the aluminum alloy heat sink is 5 μm, and the phosphorus content in the high phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm aluminum alloy sheet is used instead of an aluminum alloy heat sink to perform high phosphorus chemical nickel plating as the test object of Example 7.

[0050] Example 8

[0051] The stainless steel heat sink has a high-phosphorus nickel alloy layer on the bottom surface in contact with the gallium-based liquid metal. The bottom surface of the stainless steel heat sink in contact with the gallium-based liquid metal is cleaned, subjected to high-phosphorus chemical nickel plating for 29 minutes, and then taken out and dried.

[0052] After measurement, the thickness of the high phosphorus nickel alloy layer formed on the surface of the stainless steel heat sink is 5 μm, and the phosphorus content in the high phosphorus nickel alloy layer is 10%. For the convenience of subsequent experiments, a 2 mm stainless steel sheet is used instead of a stainless steel heat sink for high phosphorus chemical nickel plating as the test object of Example 8.

[0053] Comparative Example 1

[0054] Clean the surface of the 2mm copper sheet without any treatment.

[0055] Comparative Example 2

[0056] The surface of a 2 mm copper sheet was cleaned, subjected to a medium phosphorus chemical nickel plating treatment for 18 minutes, and then taken out and dried. According to measurement, the thickness of the medium phosphorus nickel alloy layer formed on the surface of the copper sheet was 5 μm, and the phosphorus content in the medium phosphorus nickel alloy layer was 9%.

[0057] Comparative Example 3

[0058] The surface of a 2 mm copper sheet was cleaned and electroplated with chromium. The thickness of the electroplated chromium layer formed on the surface of the copper sheet was measured to be 5 μm.

[0059] Comparative Example 4

[0060] The surface of a 2 mm copper sheet was cleaned and subjected to nickel electroplating. The thickness of the nickel electroplating layer formed on the surface of the copper sheet was measured to be 5 μm.

[0061] Comparative Example 5

[0062] The surface of a 2 mm copper sheet was cleaned and coated with 207E high thermal conductivity ceramic coating. According to measurement, the thickness of the high thermal conductivity ceramic layer formed on the surface of the copper sheet was 5 μm.

[0063] Experimental example: coating protection effect test

[0064] The metal sheets treated according to the methods of Examples 1-8 and Comparative Examples 1-4 are used as test objects. Two metal sheets to be tested are grouped together, and the middle position of one of the metal sheets is coated with gallium-based liquid metal. Sealant is coated around the liquid metal to prevent leakage of the liquid metal. The other metal sheet is buckled together with the metal sheet coated with liquid metal. The two metal sheets are kept at a distance of about 1 mm and fixed with clips. Each group of fixed metal sheets is placed in a programmable constant temperature and humidity test chamber, and the temperature of the constant temperature and humidity test chamber is set to be stable at -40°C and 80°C for 30 minutes each. A high and low temperature cycle test is performed with this as one cycle, and the number of cycle tests is 1000. After the test, the groups of metal sheets are separated, the liquid metal is removed, and the reaction between the metal sheets and the liquid metal is checked. The test results are shown in Table 1 below:

[0065] Table 1 Test results

[0066]

[0067]

[0068] The test results show that the surfaces of the metal sheets with high-phosphorus nickel alloy layers treated according to Examples 1-8 have no reaction marks, the coating surface can be cleaned, the surfaces of Comparative Examples 2 and 5 have very few reaction marks, and the surfaces of Comparative Examples 1, 3 and 4 have larger areas of reaction marks.

[0069] The above test results show that a high-phosphorus nickel coating of more than 1 μm can prevent the metal sheet from reacting with the gallium-based liquid metal, thereby preventing the gallium-based liquid metal from being gradually consumed through the reaction, and avoiding the degradation of thermal conductivity due to the consumption of the gallium-based liquid metal thermal interface material. Although a high-phosphorus nickel coating of more than 1 μm has a good protective effect on metal structural parts, for metal structural parts such as heat sinks and temperature spreaders with high-phosphorus nickel coatings exposed on the surface, considering that the high-phosphorus nickel coating may be worn or scratched during packaging, transportation and use, the thickness of the high-phosphorus nickel coating is preferably more than 3 μm, and more preferably more than 5 μm. In the case of severe wear or special requirements such as high stability and long service life, a high-phosphorus nickel coating of more than 10 μm can be formed on the surface of the metal structural part to fully ensure adequate protection and avoid unexpected situations.

[0070] In Comparative Example 1, the surface of the untreated copper sheet was not cleaned well, and the imprint area reached about 35%, indicating that the metal sheet reacted with the gallium-based liquid metal in large quantities, which would cause the consumption of the thermal interface material of the gallium-based liquid metal and lead to a decrease in thermal conductivity. In Comparative Example 2, there were a few imprints on the surface of the metal sheet coated with the medium-phosphorus nickel coating, and the imprint area was about 5% of the contact area with the gallium-based liquid metal, which was significantly less than that in Comparative Example 1, indicating that the medium-phosphorus nickel coating with a phosphorus content of 9% played a certain protective role in preventing the metal sheet from reacting with the gallium-based liquid metal, but the protective effect was not sufficient, and the gallium-based liquid metal eventually reacted with the metal sheet. Comparative Examples 3-5 have similar effects to Comparative Example 2. There are a few marks on the surfaces of the metal sheets coated with the electroplated chromium layer in Comparative Example 3, the electroplated nickel layer in Comparative Example 4, and the ceramic layer in Comparative Example 5. The mark areas are 15%, 25% and 3%, respectively, which are significantly less than Comparative Example 1, indicating that the electroplated chromium layer, the electroplated nickel layer and the ceramic layer all play a certain protective role in preventing the metal sheet from reacting with the gallium-based liquid metal, but the protective strength is significantly weaker than that of the high-phosphorus nickel coating.

[0071] The foregoing description of specific exemplary embodiments of the present invention is for the purpose of illustration and demonstration. These descriptions are not intended to limit the present invention to the precise form disclosed, and it is clear that many changes and variations can be made based on the above teachings. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical application, so that those skilled in the art can realize and utilize various different exemplary embodiments of the present invention and various different selections and changes. The scope of the present invention is intended to be limited by the claims and their equivalents.

Claims

1. A metal structural part used in conjunction with gallium-based liquid metal, characterized in that: A high-phosphorus nickel alloy layer is provided on the surface of the metal structure in contact with the gallium-based liquid metal. The phosphorus content of the high-phosphorus nickel alloy layer is 10-12%, and the thickness of the high-phosphorus nickel alloy layer is ≥1 μm.

2. The metal structural member according to claim 1, characterized in that: The thickness of the high-phosphorus nickel alloy layer is ≥3 μm.

3. The metal structural member according to claim 1, characterized in that: The thickness of the high-phosphorus nickel alloy layer is ≥5 μm.

4. The metal structural member according to claim 1, characterized in that: The thickness of the high-phosphorus nickel alloy layer is ≥10 μm.

5. The metal structural member according to claim 1, characterized in that: The metal structural member is a component in contact with the gallium-based liquid metal, a container or cavity containing the gallium-based liquid metal, or a gallium-based liquid metal flow pipeline.

6. The metal structural member according to claim 1, characterized in that: The metal structural part is a fin radiator, a heat pipe radiator, a phase change radiator, a heat sink, a heat spreader, a microchannel radiator, a liquid metal fluid radiator, a liquid metal pressure sensor, a liquid metal pressure transmitter, a liquid metal container or a part thereof in contact with gallium-based liquid metal.

7. The metal structural member according to claim 1, characterized in that: The surface of the metal structure in contact with the gallium-based liquid metal is a flat surface or a curved surface.

8. The metal structural member according to claim 1, characterized in that: The material of the metal structural part is selected from at least one of copper, aluminum, iron, nickel, stainless steel, titanium, zinc, gold or alloys thereof.

9. The metal structural member according to claim 1, characterized in that: A nanocomposite ceramic coating is further included on the surface of the metal structure that contacts the gallium-based liquid metal.

10. The metal structural member according to claim 1, characterized in that: The gallium-based liquid metal is selected from any one or more of gallium metal, gallium-containing liquid alloy, gallium-containing metal oxide, gallium-containing thermal interface material, and gallium-containing composite material.

11. A method for preparing a metal structural part according to any one of claims 1 to 10, characterized in that: The steps include: A high-phosphorus chemical nickel plating process is performed on the surface of the metal structure in contact with the gallium-based liquid metal thermal interface material, so as to form a high-phosphorus nickel alloy layer on the surface of the metal structure in contact with the gallium-based liquid metal.

12. An application of the metal structural part according to any one of claims 1 to 10 or the metal structural part made by the preparation method according to claim 11 in heat dissipation of computer chips, mobile phone chips, communication products, high-power LEDs, insulated gate bipolar transistors, and high-power electronic products.

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