Bi-In-Sn liquid metal phase change material for chip heat dissipation, preparation method and heat dissipation device

Abstract

The invention relates to the technical field of heat dissipation materials, in particular to a Bi-In-Sn liquid metal phase change material for chip heat dissipation, a preparation method and a heat dissipation device, and is technically characterized in that the liquid metal phase change material is prepared from the following elements in percentage by mass: 42.0%-48.0% of Bi, 33.0%-40.0% of In and 12%-25% of Sn; the preparation method comprises the following steps: weighing Bi, In and Sn metal particles, and sequentially carrying out acid pickling, ultrasonic cleaning and drying treatment; under the high-purity argon protection environment, the pretreated metal particles are subjected to vacuum melting and stirring, and uniform liquid alloy is formed; and after the liquid alloy is cooled and formed, ultrasonic treatment is conducted, the Bi-In-Sn liquid metal phase change material is prepared, the advantage of low melting point is kept, meanwhile, unexpected improvement of latent heat performance is achieved, and the bottleneck problem of instantaneous thermal runaway of a chip in an extreme environment is effectively solved.

Description

Technical Field

[0001] This invention relates to the field of heat dissipation materials technology, specifically to a Bi-In-Sn liquid metal phase change material for chip heat dissipation, its preparation method, and a heat dissipation device. Background Technology

[0002] With the rapid development of the semiconductor industry, the power density and heat flux density of integrated circuit chips are constantly increasing. When the chip temperature exceeds the specified threshold, problems such as decreased processing speed and increased data processing errors will occur. Furthermore, prolonged exposure to high temperatures will accelerate the aging of internal components, severely affecting chip performance and lifespan. Currently, common chip heat dissipation methods include thermal pads, fan cooling, heat pipe cooling, and vapor chamber cooling. However, in special application scenarios such as aerospace and deep-sea exploration, chips are in extreme environments such as confined spaces and vacuum seals, where air convection and natural cooling channels are limited, making them highly susceptible to localized overheating and even thermal runaway. Therefore, the core requirement for chip heat dissipation in sealed environments is the ability to absorb and store large amounts of latent heat, where traditional heat dissipation technologies are ineffective.

[0003] Liquid metal phase change materials (LMWs), as a novel type of chip heat dissipation material, possess advantages such as high latent heat, low melting point, and no need for curing. They provide continuous temperature protection while efficiently storing heat, ensuring that the chip structure and function do not degrade, making them a key solution in the field of chip heat dissipation. Currently, the most widely researched liquid metals are alloys based on Ga (Ga). Ga-based alloys have the advantages of low melting point and relatively low toxicity, but their disadvantages are also significant: for example, they are highly corrosive to common heat sink casings such as Al, limiting their widespread application in chip heat sinks; and oxide films easily form on the surface of liquid Ga-based alloys, affecting fluidity and wettability, and reducing heat storage efficiency. Therefore, developing a Ga-free liquid metal LMW with low melting point, high latent heat, low corrosivity, and good stability has become an urgent direction to meet the thermal management needs of chips in extreme environments.

[0004] Currently, Field's Metal (51%In-32.5%Bi-16.5%Sn) is the most famous eutectic alloy among Bi-In-Sn alloys, with a melting point of 61℃-62℃. However, its latent heat value is too low, only 25.4J / g, which severely limits its ability to absorb instantaneous high heat pulses from chips, thus greatly limiting its application in chip heat dissipation. In addition, Chinese invention patent CN103789593B discloses a Bi-In-Sn ternary alloy heat dissipation material, the specific composition of which is: In 63%–65%, Sn 22%–25%, Bi 11%–13%, melting point of 60℃–65℃, thermal conductivity of 46–50 W / (m·K). It has been applied to heat dissipation tests of devices such as LED lights and projectors, showing a certain cooling effect and solving the problem of low thermal conductivity of traditional thermal interface materials (such as silicone grease). Its technical improvement direction is to improve thermal conductivity to promote heat dissipation. However, it is still difficult to meet the needs of chips to cope with instantaneous high heat load. In the event of a sudden increase in chip power or extreme environment, the low latent heat characteristics will lead to insufficient temperature buffering capacity and cannot avoid local overheating problems.

[0005] Therefore, the development of a phase change material that can absorb instantaneous high-temperature pulses from chips is an urgent problem to be solved. Summary of the Invention

[0006] To address the aforementioned shortcomings of existing technologies, this invention provides a Bi-In-Sn liquid metal phase change material for chip heat dissipation, its preparation method, and a heat dissipation device. This effectively solves the problems of low latent heat value of existing Field metal phase change alloys and the fact that improved Bi-In-Sn liquid metal materials focus on thermal conductivity and cannot simultaneously possess high heat storage capacity, good material compatibility (low corrosivity), and adaptability to extreme closed environments.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a Bi-In-Sn liquid metal phase change material for chip heat dissipation, characterized in that the liquid metal phase change material is composed of the following elements by mass percentage: Bi: 42.0%-48.0%, In: 33.0%-40.0%, Sn: 12%-25%.

[0009] The liquid metal phase change material has a melting peak in the range of 80°C to 87°C, and its latent heat of fusion is at least 40 J / g.

[0010] Preferably, the liquid metal phase change material is composed of the following elements by mass percentage: Bi 42%, In 33%, and Sn 25%.

[0011] Preferably, the liquid metal phase change material is composed of the following elements by mass percentage: 48% Bi, 40% In, and 12% Sn.

[0012] Preferably, the liquid metal phase change material is composed of the following elements by mass percentage: Bi 45%, In 37%, and Sn 18%.

[0013] Secondly, the present invention also provides a method for preparing a Bi-In-Sn liquid metal phase change material for chip heat dissipation, comprising the following steps:

[0014] A. Raw material pretreatment: Weigh Bi, In and Sn metal particles according to the mass percentages of Bi 42.0%-48.0%, In 33.0%-40.0% and Sn 12%-25%, and then perform pickling, ultrasonic cleaning and drying treatment in sequence.

[0015] B. Vacuum Melting: Under a high-purity argon atmosphere, the metal particles obtained after pretreatment in step A are placed in a graphite crucible, and a vacuum is drawn into a vacuum induction melting furnace until the vacuum degree is ≤1×10⁻⁶. -3 Pa, after being purged with argon gas, is heated to 300°C at a heating rate of 5°C / min and held at that temperature for 60 minutes. The mixture is then stirred with a stirring paddle to form a uniform liquid alloy.

[0016] C. Post-forming treatment: The liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and then subjected to ultrasonic treatment to obtain the Bi-In-Sn liquid metal phase change material.

[0017] Thirdly, the present invention also provides a chip heat dissipation device comprising a Bi-In-Sn liquid metal phase change material as described in the first aspect, wherein the Bi-In-Sn liquid metal phase change material serves as a heat dissipation medium for absorbing and storing heat generated by the chip, thereby controlling the chip temperature within a safe threshold.

[0018] The technical solution provided by this invention has the following advantages compared with the known prior art:

[0019] 1. By adjusting the component ratio and optimizing the preparation process, this invention utilizes the low eutectic effect of the three metals to prepare a Bi-In-Sn liquid metal phase change material with similar composition and melting point to Field alloy, achieving an unexpected improvement of approximately 64% in latent heat performance (latent heat value of this invention is 41.74 J / g, while that of Field alloy is 25.4 J / g). The high latent heat characteristic greatly enhances the material's ability to absorb instantaneous thermal pulses from the chip, resulting in better temperature control.

[0020] 2. The vacuum melting preparation process used in this invention is mature, simple and easy to implement. The vacuum environment prevents oxidation and ensures thorough stirring, making it suitable for the heat dissipation needs of different types and specifications of chips.

[0021] 3. The Bi-In-Sn liquid metal phase change material of the present invention does not contain elements such as Ga that corrode the aluminum shell of the heat sink, nor does it contain toxic and harmful metal elements such as lead, mercury, and cadmium. During the preparation, use and recycling of the material, no toxic or harmful gases, liquids or solid wastes are generated. It has good environmental safety and meets the requirements of green development in the electronic information industry. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0023] Figure 1 This is a flowchart illustrating the preparation process of the Bi-In-Sn liquid metal phase change material of this invention.

[0024] Figure 2 This is a DSC data graph of the Bi-In-Sn liquid metal phase change material in Example 2 of the present invention;

[0025] Figure 3 This is a SEM image of the Bi-In-Sn liquid metal phase change material in Example 2 of the present invention;

[0026] Figure 4 This is a DSC data graph of the Bi-In-Sn liquid metal phase change material in Example 3 of the present invention;

[0027] Figure 5 This is a DSC data graph of the Bi-In-Sn liquid metal phase change material in Example 4 of the present invention. Detailed Implementation

[0028] The technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0029] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0030] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "inner," and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the accompanying drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0031] In the description of this invention, unless otherwise explicitly specified and limited, the term "connection" or similar designation indicating a connection between components should be interpreted broadly. For example, it can refer to a fixed connection, a detachable connection, or an integral part; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication between two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0032] The present invention will be further described below with reference to embodiments.

[0033] Based on the increasingly urgent heat dissipation requirements of high-performance, highly integrated chips, this invention provides a ternary Bi-In-Sn liquid metal phase change material (PCM) for chip heat dissipation. By precisely proportioning and optimizing the metal element components, the latent heat value is significantly improved. The aim is to solve the heat dissipation problem of existing low-temperature metal PCMs on chips while maintaining a melting point that matches the chip's operating temperature, thus providing an efficient, reliable, and low-cost thermal management solution for chips.

[0034] Example 1:

[0035] This invention provides a Bi-In-Sn liquid metal phase change material for chip heat dissipation, characterized in that the liquid metal phase change material is composed of the following elements by mass percentage: Bi: 42.0%-48.0%, In: 33.0%-40.0%, Sn: 12%-25%.

[0036] Liquid metal phase change materials exhibit a melting peak in the range of 80℃ to 87℃, and a latent heat of fusion of at least 40 J / g.

[0037] The preparation method of Bi-In-Sn liquid metal phase change material for chip heat dissipation is as follows, refer to... Figure 1 The preparation process flowchart includes the following steps:

[0038] A. Raw material pretreatment: Weigh Bi, In and Sn metal particles with a purity ≥99.999% according to the mass percentages of Bi 42.0%-48.0%, In 33.0%-40.0% and Sn 12%-25%, and perform pickling, ultrasonic cleaning and drying treatment in sequence to remove impurities such as oil and oxide layer on the surface.

[0039] B. Vacuum Melting: Under a high-purity argon protective environment, the metal particles obtained after the pretreatment in step A are placed in a graphite crucible and sent into a vacuum induction melting furnace. The furnace door is closed, ensuring it is fully fitted against the reactor flange. The gas valve is closed, and a vacuum is evacuated inside the vacuum induction melting furnace until the vacuum degree is ≤1×10⁻⁶. -3 After Pa, argon gas is introduced to clean the furnace. After repeated vacuuming, the heating program is started. The temperature is raised to 300°C at a heating rate of 5°C / min and held for 60 minutes to fully melt the metal raw materials. The mixture is then stirred by the stirring paddle in the lowering chamber to form a uniform liquid alloy.

[0040] C. Post-forming treatment: The liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and then ultrasonically treated to remove surface stains to obtain Bi-In-Sn liquid metal phase change material.

[0041] Performance testing:

[0042] The microstructure of the prepared Bi-In-Sn liquid metal phase change material was observed using a scanning electron microscope (SEM), and the SEM image of the Bi-In-Sn liquid metal phase change material was obtained.

[0043] Differential scanning calorimetry (DSC) was used for determination: 5-10 mg of sample was cut, the temperature range was 0℃-150℃, the heating / cooling rate was set to 10 K / min, the test atmosphere was argon, and the DSC curve was obtained. The phase transition temperature range, melting peak, latent heat of phase transition and other values ​​were obtained by analyzing the curve characteristics.

[0044] Example 2:

[0045] In this embodiment, the liquid metal phase change material is composed of the following elements by mass percentage: Bi 42%, In 33%, and Sn 25%.

[0046] The preparation method is as follows:

[0047] A. Raw material pretreatment: Weigh out Bi, In and Sn metal particles with a purity ≥99.999% according to the mass percentages of Bi 42.0%, In 33.0% and Sn 25%, and then perform pickling, ultrasonic cleaning and drying treatment in sequence to remove impurities such as oil and oxide layer on the surface.

[0048] B. Vacuum Melting: Under a high-purity argon protective environment, the metal particles obtained after the pretreatment in step A are placed in a graphite crucible and sent into a vacuum induction melting furnace. The furnace door is closed, ensuring it is fully fitted against the reactor flange. The gas valve is closed, and a vacuum is evacuated inside the vacuum induction melting furnace until the vacuum degree is ≤1×10⁻⁶. -3 After Pa, argon gas is introduced to clean the furnace. After repeated vacuuming, the heating program is started. The temperature is raised to 300°C at a heating rate of 5°C / min and held for 60 minutes to fully melt the metal raw materials. The mixture is then stirred by the stirring paddle in the lowering chamber to form a uniform liquid alloy.

[0049] C. Post-forming treatment: The liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and then ultrasonically treated to remove surface stains to obtain Bi-In-Sn liquid metal phase change material.

[0050] Measurements showed that the material's latent heat of phase change was 41.74 J / g, its phase change temperature range was 80.0℃~87.3℃, and its melting peak was 84.7℃. Figure 2 The displayed DSC data graphs for Bi-In-Sn liquid metal phase change materials Figure 3 The SEM images of the Bi-In-Sn liquid metal phase change material shown are from... Figure 2 It can be seen that the phase transition temperature range corresponds to the interval defined by the starting point and ending point of the highest melting temperature, which is suitable for the chip's operating temperature. The peak shape is sharp and symmetrical, the melting is uniform, and there is no peak broadening caused by impurities or segregation. The phase transition process exhibits excellent thermodynamic stability. The latent heat value is as high as 41.74 J / g, demonstrating excellent heat storage capacity. Figure 3 As can be seen, the phase interface is clear and the phase distribution is uniform.

[0051] Example 3:

[0052] In this embodiment, the liquid metal phase change material is composed of the following elements by mass percentage: Bi 48%, In 40%, and Sn 12%.

[0053] The preparation method is as follows:

[0054] A. Raw material pretreatment: Weigh out Bi, In and Sn metal particles with a purity ≥99.999% according to the mass percentages of Bi 48.0%, In 40.0% and Sn 12%, and then perform pickling, ultrasonic cleaning and drying treatment in sequence to remove impurities such as oil and oxide layer on the surface.

[0055] B. Vacuum Melting: Under a high-purity argon protective environment, the metal particles obtained after the pretreatment in step A are placed in a graphite crucible and sent into a vacuum induction melting furnace. The furnace door is closed, ensuring it is fully fitted against the reactor flange. The gas valve is closed, and a vacuum is evacuated inside the vacuum induction melting furnace until the vacuum degree is ≤1×10⁻⁶. -3 After Pa, argon gas is introduced to clean the furnace. After repeated vacuuming, the heating program is started. The temperature is raised to 300°C at a heating rate of 5°C / min and held for 60 minutes to fully melt the metal raw materials. The mixture is then stirred by the stirring paddle in the lowering chamber to form a uniform liquid alloy.

[0056] C. Post-forming treatment: The liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and then ultrasonically treated to remove surface stains to obtain Bi-In-Sn liquid metal phase change material.

[0057] Differential scanning calorimetry (DSC) was used for determination: 5-10 mg of sample was cut, heated at 0℃-150℃ with a heating / cooling rate of 10 K / min, and the test atmosphere was argon. The DSC curve was obtained as follows. Figure 4 The displayed DSC chart, based on the curve characteristics, yields values ​​such as the phase transition temperature range, melting peak, and latent heat of phase transition. The latent heat of this material is 40.51 J / g, the phase transition temperature range is 79.7~85.8℃, and the melting peak is 84.4℃.

[0058] Example 4:

[0059] In this embodiment, the liquid metal phase change material is composed of the following elements by mass percentage: Bi 45%, In 37%, and Sn 18%.

[0060] The preparation method is as follows:

[0061] A. Raw material pretreatment: Weigh Bi, In and Sn metal particles with a purity ≥99.999% according to the mass percentages of Bi 45.0%, In 37.0% and Sn 18%, and perform pickling, ultrasonic cleaning and drying treatment in sequence to remove impurities such as oil and oxide layer on the surface.

[0062] B. Vacuum Melting: Under a high-purity argon protective environment, the metal particles obtained after the pretreatment in step A are placed in a graphite crucible and sent into a vacuum induction melting furnace. The furnace door is closed, ensuring it is fully fitted against the reactor flange. The gas valve is closed, and a vacuum is evacuated inside the vacuum induction melting furnace until the vacuum degree is ≤1×10⁻⁶. -3 After Pa, argon gas is introduced to clean the furnace. After repeated vacuuming, the heating program is started. The temperature is raised to 300°C at a heating rate of 5°C / min and held for 60 minutes to fully melt the metal raw materials. The mixture is then stirred by the stirring paddle in the lowering chamber to form a uniform liquid alloy.

[0063] C. Post-forming treatment: The liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and then ultrasonically treated to remove surface stains to obtain Bi-In-Sn liquid metal phase change material.

[0064] Differential scanning calorimetry (DSC) was used for determination: 5-10 mg of sample was cut, heated at 0℃-150℃ with a heating / cooling rate of 10 K / min, and the test atmosphere was argon. The DSC curve was obtained as follows. Figure 5 The displayed DSC chart, based on the curve characteristics, yields values ​​such as the phase transition temperature range, melting peak, and latent heat of phase transition. The latent heat of this material is 40.93 J / g, the phase transition temperature range is 79.8~87.6℃, and the melting peak is 85.8℃.

[0065] The Field metal disclosed in the prior art has the following composition by mass percentage: In 51%, Bi 32.5%, and Sn 16.5%. Differential scanning calorimetry (DSC) was used to test the Field metal and obtain DSC curves. Based on the curve characteristics, the phase transition temperature range, melting peak, and latent heat of phase transition were obtained. The summary data of Examples 2, 3, and 4 and the Field metal are shown in Table 1.

[0066] Table 1. Phase transition temperature range, melting peak, and latent heat of phase transition

[0067] Experiment Items Latent heat of phase change (J / g) Phase transition temperature range (°C) Melting peak (°C) Example 2 41.74 80.0~87.3 84.7 Example 3 40.51 79.7~85.8 84.4 Example 4 40.93 79.8~87.6 85.8 Field Metals 25.4 60.0~62.0 62

[0068] As shown in Table 1, the Field metal disclosed in the prior art (components: In 51%, Bi 32.5%, Sn 16.5% by mass) has a latent heat of phase change of 25.4 J / g, which is low and has insufficient heat storage capacity. This invention, by precisely controlling the ratio of Bi, In, and Sn and combining it with a vacuum melting process, develops a liquid metal phase change material with a latent heat of up to 41.74 J / g when Bi is 42%, In is 33%, and Sn is 25%. Its melting peak is located in the range of 80℃–87℃, which is suitable for chip operating temperatures and significantly improves heat absorption capacity. Compared with existing Bi-In-Sn alloys, this invention achieves an unexpected improvement in latent heat performance (64% improvement over Field alloys) while maintaining the advantage of a low melting point, effectively solving the bottleneck problem of instantaneous thermal runaway of chips under extreme environments.

[0069] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the protection scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Bi-In-Sn liquid metal phase change material for chip heat dissipation, characterized in that, The liquid metal phase change material is composed of the following elements in percentage by mass: Bi: 42.0%-48.0%, In: 33.0%-40.0%, Sn: 12%-25%. 2.The Bi-In-Sn liquid metal phase change material for chip heat dissipation according to claim 1, wherein, The liquid metal phase change material has a melting peak in the range of 80-87℃, and a latent heat of fusion of at least 40 J / g. 3.The Bi-In-Sn liquid metal phase change material for chip heat dissipation according to claim 1, wherein, The liquid metal phase change material is composed of the following elements in percentage by mass: Bi: 42%, In: 33%, Sn: 25%. 4.The Bi-In-Sn liquid metal phase change material for chip heat dissipation according to claim 1, wherein, The liquid metal phase change material is composed of the following elements in percentage by mass: Bi: 48%, In: 40%, Sn: 12%.

5. The Bi-In-Sn liquid metal phase change material for chip cooling according to claim 1, wherein, The liquid metal phase change material is composed of the following elements in percentage by mass: Bi: 45%, In: 37%, Sn: 18%.

6. A method for preparing Bi-In-Sn liquid metal phase change material for chip heat dissipation, characterized in that, The method comprises the following steps: A. Raw material pretreatment: Bi, In and Sn metal particles are weighed according to the mass percentage of Bi: 42.0%-48.0%, In: 33.0%-40.0%, Sn: 12%-25%, and are sequentially subjected to acid pickling, ultrasonic cleaning and drying treatment; B. Vacuum melting: under the protection of high-purity argon, the metal particles obtained after pretreatment in step A are placed in a graphite crucible, and vacuum is drawn in a vacuum induction melting furnace to a vacuum degree of ≤1 x 10 -3 Pa, argon is introduced to wash the furnace, heating to 300°C at a heating rate of 5°C / min and keeping constant for 60 min, and stirring is carried out by a stirring paddle to form a uniform liquid alloy; C. Post-treatment after forming: the liquid alloy obtained in step B is poured into a preheated graphite mold, slowly cooled to room temperature, and subjected to ultrasonic treatment after forming ingot, to obtain the Bi-In-Sn liquid metal phase change material.

7. A chip heat dissipating device, characterized by comprising: The Bi-In-Sn liquid metal phase change material as claimed in any one of claims 1-5 is used as a heat dissipation medium for absorbing and storing heat generated by a chip.

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