A quaternary gallium-based liquid alloy and a method for preparing the same

Abstract

The application relates to the technical field of liquid metals, and particularly discloses a quaternary gallium-based liquid alloy and a preparation method thereof, the quaternary gallium-based liquid alloy comprises the following raw materials: gallium powder, indium powder, tin powder, bismuth powder and two-dimensional nano hetero reinforcing bodies; the two-dimensional nano hetero reinforcing bodies are composed of modified hexagonal boron nitride and modified molybdenum disulfide. The application reduces the alloy melting point through the multi-element low-eutectic effect, compensates the solidification volume change by using the low shrinkage rate of bismuth, and constructs a heat conduction-wetting synergistic network in the alloy through the two-dimensional nano hetero reinforcing bodies, so that the thermal conductivity of the liquid alloy is significantly improved, the surface tension of the liquid alloy is reduced, and the wettability of the liquid alloy to a substrate is improved. The preparation method combining step-by-step cooling melting with ultrasonic dispersion ensures the uniformity of the alloy composition and the two-dimensional nano hetero reinforcing body distribution. The liquid alloy prepared by the application has a wide application prospect in flexible electronic devices, thermal interface materials and wearable sensors.

Description

Technical Field

[0001] This invention relates to the field of liquid metal technology, specifically to a quaternary gallium-based liquid alloy and its preparation method. Background Technology

[0002] Gallium-based liquid metals are liquid near room temperature and possess high electrical and thermal conductivity as well as excellent flow and deformation capabilities. They also have extremely low saturated vapor pressure, making them a research hotspot in fields such as flexible electronics and thermal interface materials in recent years.

[0003] Nevertheless, the practical application of gallium-based liquid alloys is still constrained by the following issues: First, the liquidus temperature of common binary gallium-indium alloys is still relatively high, making them prone to liquid-solid transitions in sub-zero or low-temperature environments, causing devices to lose functionality. Although ternary gallium-indium-tin alloys formed by introducing tin can further lower the melting point, their homogeneous composition range is limited, and the freedom of formulation design is small. In certain low-temperature scenarios, it is still difficult to completely avoid the risks of overcooling and solidification, thus affecting the operational reliability of devices.

[0004] Second, gallium undergoes significant volume expansion when transitioning from a liquid to a solid state, while other alloying elements such as indium and tin experience volume contraction upon solidification. This mismatch in dimensional changes induces internal stress accumulation during repeated thermal cycling. This phenomenon not only deteriorates the long-term stability of the thermal interface material but also causes fatigue cracking in microfluidic structures or packages, threatening the overall lifespan of the system.

[0005] Third, liquid gallium-based alloys rapidly form a dense surface oxide layer in air or oxygen-containing environments, which significantly increases the macroscopic surface tension of the system and results in poor wetting and adhesion properties with flexible substrates such as polydimethylsiloxane and various polymer materials. This directly affects the forming accuracy and interface quality of liquid metals in manufacturing processes such as flexible printed circuits and stretchable interconnects.

[0006] Fourth, the thermal conductivity of current gallium-based liquid metal alloys is still insufficient to meet the heat dissipation requirements of highly integrated, high-power electronic devices. Faced with increasingly demanding heat dissipation conditions involving confined spaces and high heat flux densities, developing novel liquid alloy systems with higher thermal conductivity has become an urgent technical challenge.

[0007] Based on the above statements, the present invention provides a quaternary gallium-based liquid alloy and its preparation method. Summary of the Invention

[0008] To address the problems of insufficient low-temperature fluidity, significant volume change during solidification, high surface tension and poor wettability, and the need for further improvement in thermal conductivity of existing gallium-based liquid alloys, this invention provides a quaternary gallium-based liquid alloy and its preparation method.

[0009] In a first aspect, the present invention provides a quaternary gallium-based liquid alloy, which adopts the following technical solution: A quaternary gallium-based liquid alloy comprises the following raw materials in parts by weight: 60-75 parts gallium powder, 14-22 parts indium powder, 3-10 parts tin powder, 2-6 parts bismuth powder, and 2-6 parts two-dimensional nano-heterogeneous reinforcement.

[0010] Preferably, the two-dimensional nano-heterogeneous reinforcement is composed of modified hexagonal boron nitride and modified molybdenum disulfide in a mass ratio of 1:1-2.

[0011] The method for preparing the modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to NaOH solution and subjected to hydrothermal treatment. After cooling, it was centrifuged, washed, and dried to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride was added to anhydrous ethanol, ultrasonically dispersed, and then 3-aminopropyltriethoxysilane was added. The mixture was stirred, centrifuged, washed, and dried to obtain modified hexagonal boron nitride.

[0012] Preferably, the specific preparation method of the modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to a 2-5 mol / L NaOH aqueous solution at a mass ratio of 1:20-40 for hydrothermal treatment. After cooling to room temperature, it was centrifuged at 8000-10000 rpm for 5-10 min, washed with deionized water until neutral, and vacuum dried at 60-80℃ for 5-9 h to obtain hydroxylated hexagonal boron nitride. Hydroxylated hexagonal boron nitride was then added to anhydrous ethanol at a mass ratio of 1:30-60 and ultrasonicated at 25-40 kHz and 300-500 W. After stirring for 20-40 minutes, 3-aminopropyltriethoxysilane was added. The mass ratio of 3-aminopropyltriethoxysilane to hydroxylated hexagonal boron nitride was 0.5-1.0:1. The mixture was stirred at 60-80℃ and 300-600 rpm for 6-12 hours. After the reaction was completed, the mixture was centrifuged at 8000-10000 rpm for 5-10 minutes. The precipitate was washed 2-3 times each with anhydrous ethanol and deionized water, and then vacuum dried at 60-80℃ for 8-12 hours to obtain modified hexagonal boron nitride.

[0013] Preferably, the hydrothermal treatment temperature is 150-180℃ and the hydrothermal treatment time is 18-24h.

[0014] Preferably, the modified molybdenum disulfide is prepared by: Molybdenum disulfide powder was added to N-methylpyrrolidone, ultrasonically exfoliated, centrifuged and classified, and the upper dispersion was collected by vacuum filtration to collect molybdenum disulfide nanosheets. The molybdenum disulfide nanosheets were added to anhydrous ethanol, ultrasonically dispersed, and then 3-mercaptopropyltrimethoxysilane was added. The mixture was stirred, centrifuged, washed, and dried to obtain modified molybdenum disulfide.

[0015] Preferably, the specific preparation method of the modified molybdenum disulfide is as follows: Molybdenum disulfide powder was added to N-methylpyrrolidone at a mass ratio of 1:30-50, and ultrasonically exfoliated at 200-500W and 10-30℃ for 4-10 hours. After exfoliation, the mixture was centrifuged at 2000-4000rpm for 20-40 minutes to fractionate the mixture. The upper dispersion was collected and vacuum filtered to collect molybdenum disulfide nanosheets. The molybdenum disulfide nanosheets were added to anhydrous ethanol at a mass ratio of 1:30-60, and ultrasonically dispersed at 25-40kHz and 300-500W for 15-30 minutes. Then, 3-mercaptopropyltrimethoxysilane was added, and the mixture was stirred at 50-70℃ and 300-600rpm for 8-16 hours. After the reaction, the mixture was centrifuged at 8000-10000rpm for 5-10 minutes, washed 2-3 times each with anhydrous ethanol and deionized water, and vacuum dried at 50-70℃ for 10-14 hours to obtain modified molybdenum disulfide.

[0016] Preferably, the mass ratio of 3-mercaptopropyltrimethoxysilane to molybdenum disulfide nanosheets is 0.5-1.5:1.

[0017] Secondly, the present invention provides a method for preparing a quaternary gallium-based liquid alloy, which adopts the following technical solution: A method for preparing a quaternary gallium-based liquid alloy includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, ultrasonically clean them with citric acid-ethanol mixed solution, rinse them with anhydrous ethanol, vacuum dry them and set them aside. S2. Under an argon protective atmosphere, tin powder and bismuth powder are added to a crucible, heated to 350-400℃, stirred and melted to obtain a tin-bismuth pre-alloyed liquid; S3. Cool the tin-bismuth pre-alloyed liquid to 160-180℃, add indium powder, stir and melt to obtain a ternary pre-alloyed liquid; S4. Cool the ternary pre-alloy liquid to 80-110℃, add gallium powder, stir evenly, add two-dimensional nano-heterogeneous reinforcement, continue stirring, and ultrasonically disperse to obtain an alloy mixture. S5. The alloy mixture is refined and degassed, then cooled to obtain a quaternary gallium-based liquid alloy.

[0018] Preferably, in step S1, the mass fraction of citric acid in the citric acid-ethanol mixed solution is 3-8%; the ultrasonic cleaning frequency is 25-40kHz, the ultrasonic cleaning power is 300-500W, and the ultrasonic cleaning time is 10-30min.

[0019] Preferably, in step S4, the ultrasonic dispersion frequency is 20-40kHz, the ultrasonic power is 300-500W, and the ultrasonic dispersion time is 30-50min.

[0020] Preferably, in step S5, the refining and degassing vacuum degree is ≤1Pa, the refining and degassing temperature is 60-80℃, and the refining and degassing time is 20-30min.

[0021] Thirdly, the present invention provides an application of the above-mentioned quaternary gallium-based liquid alloy in flexible electronic devices and thermal interface materials.

[0022] In summary, the present invention has the following beneficial effects: 1. This invention adopts a quaternary alloy system of gallium, indium, tin and bismuth. By rationally controlling the mass ratio of each component, the melting point and supercooling of the alloy are significantly reduced by utilizing the multi-element low eutectic effect, so that the alloy can maintain good liquid fluidity at room temperature or even low temperature, effectively widening the service temperature window of gallium-based liquid alloys.

[0023] 2. This invention uses modified hexagonal boron nitride and modified molybdenum disulfide to form a two-dimensional nano-heterogeneous reinforcement. Both are two-dimensional layered structures that can form a cross-overlapping heterogeneous network structure in a liquid metal matrix. Specifically, the hexagonal boron nitride nanosheets possess excellent in-plane thermal conductivity, enabling the construction of efficient thermally conductive bridging pathways within the alloy matrix and significantly improving the alloy's thermal conductivity. The molybdenum disulfide nanosheets exhibit low interlayer shear force characteristics, effectively reducing the surface tension of the alloy and improving the wetting and spreading properties between the liquid metal and the substrate material. The two types of nanosheets functionally form a synergistic "thermal conductivity-wetting" effect, achieving a multi-dimensional and simultaneous improvement in the overall performance of the liquid alloy.

[0024] 3. This invention modifies hydroxylated hexagonal boron nitride and molybdenum disulfide nanosheets by silane coupling, introducing active functional groups on the surface of the nanomaterials. This significantly improves their interfacial wettability, dispersion stability and interfacial bonding strength in high surface tension liquid metal matrices, effectively suppresses the agglomeration problem of nanomaterials, and ensures the long-term service stability of the two-dimensional nano-heterogeneous reinforcement.

[0025] 4. This invention employs a step-by-step cooling and melting process, introducing each metal component in descending order of melting point, followed by the introduction of a two-dimensional nano-heterogeneous reinforcement. By combining step-by-step cooling and melting with ultrasonic dispersion, the invention effectively avoids local segregation caused by excessive differences in melting points among the components, while also solving the problem of agglomeration of the two-dimensional nano-heterogeneous reinforcement in liquid metal, thus ensuring the uniformity of the alloy composition and the distribution of the reinforcement.

[0026] 5. The preparation method of this invention has a clear process flow and mild operating conditions. All raw materials used are commercially available common materials, which have good feasibility for industrial scale-up and mass production. The prepared quaternary gallium-based liquid alloy has broad application prospects in the fields of flexible electronic devices and thermal interface materials. Detailed Implementation

[0027] The present invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0028] Where specific techniques or conditions are not specified in the examples, they shall be performed in accordance with the techniques or conditions described in the literature in this field, or in accordance with the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels.

[0029] Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the experimental materials used in the following embodiments are commercially available products.

[0030] The gallium powder was purchased from Zhongnuo New Materials (Beijing) Technology Co., Ltd., with a purity of 99%. Indium powder was purchased from Shanghai Maclean Biochemical Technology Co., Ltd., with a purity of 99%. The tin powder was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 99%. Bismuth powder was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 99%. Hexagonal boron nitride was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of ≥99% and a particle size of ≤2μm. Molybdenum disulfide was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of ≥99% and a particle size of ≤2μm.

[0031] Examples 1-3 provide a quaternary gallium-based liquid alloy and its preparation method.

[0032] Example 1 A quaternary gallium-based liquid alloy comprises the following raw materials in parts by weight: 60 parts gallium powder, 14 parts indium powder, 3 parts tin powder, 2 parts bismuth powder, and 2 parts two-dimensional nano-heterogeneous reinforcement.

[0033] The two-dimensional nano-heterogeneous reinforcement is composed of modified hexagonal boron nitride and modified molybdenum disulfide in a mass ratio of 1:1.

[0034] The specific preparation method of modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to a 2 mol / L NaOH aqueous solution at a mass ratio of 1:20, and hydrothermally treated at 150℃ for 18 h. After cooling to room temperature, it was centrifuged at 8000 rpm for 5 min, washed with deionized water until neutral, and vacuum dried at 60℃ for 5 h to obtain hydroxylated hexagonal boron nitride. Hydroxylated hexagonal boron nitride was added to anhydrous ethanol at a mass ratio of 1:30, and ultrasonically dispersed at 25 kHz and 300 W for 20 min. Then, 3-aminopropyltriethoxysilane was added, with a mass ratio of 3-aminopropyltriethoxysilane to hydroxylated hexagonal boron nitride of 0.5:1. The mixture was stirred at 60℃ and 300 rpm for 6 h. After the reaction was completed, it was centrifuged at 8000 rpm for 5 min, and the precipitate was washed twice each with anhydrous ethanol and deionized water. It was then vacuum dried at 60℃ for 8 h to obtain modified hexagonal boron nitride.

[0035] The specific preparation method of modified molybdenum disulfide is as follows: Molybdenum disulfide powder was added to N-methylpyrrolidone at a mass ratio of 1:30 and ultrasonically exfoliated at 200W and 10℃ for 4 hours. After exfoliation, the mixture was centrifuged at 2000rpm for 20 minutes to fractionate the mixture. The supernatant was collected and vacuum filtered to collect molybdenum disulfide nanosheets. The molybdenum disulfide nanosheets were then added to anhydrous ethanol at a mass ratio of 1:30 and ultrasonically dispersed at 25kHz and 300W for 15 minutes. Subsequently, 3-mercaptopropyltrimethoxysilane was added, with a mass ratio of 3-mercaptopropyltrimethoxysilane to molybdenum disulfide nanosheets of 0.5:1. The mixture was stirred at 50℃ and 300rpm for 8 hours. After the reaction, the mixture was centrifuged at 8000rpm for 5 minutes and washed twice each with anhydrous ethanol and deionized water. The mixture was then vacuum dried at 50℃ for 10 hours to obtain modified molybdenum disulfide.

[0036] A method for preparing a quaternary gallium-based liquid alloy includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, and clean them separately with a citric acid-ethanol mixed solution with a citric acid mass fraction of 3% at 25kHz and 300W for 10min. Then rinse them twice with anhydrous ethanol and dry them in vacuum at 60℃ for 1h for later use. S2. Under an argon protective atmosphere, tin powder and bismuth powder are added to a crucible and heated to 350°C at a heating rate of 5°C / min. The mixture is stirred and melted at 200 rpm for 10 min to obtain a tin-bismuth pre-alloyed liquid. S3. Cool the tin-bismuth pre-alloyed liquid to 160°C at a cooling rate of 3°C / min, add indium powder, and stir and melt at 300 rpm for 10 min to obtain a ternary pre-alloyed liquid. S4. Cool the ternary pre-alloy liquid to 80°C at a cooling rate of 2°C / min, add gallium powder and two-dimensional nano-heterogeneous reinforcement, stir at 500 rpm for 10 min, and then ultrasonically disperse at 20 kHz and 200 W for 30 min to obtain an alloy mixture. S5. Transfer the alloy mixture to a refining and degassing device, refine and degas at a vacuum of 1 Pa and 60°C for 20 min, and then cool it to room temperature in the furnace to obtain a quaternary gallium-based liquid alloy.

[0037] Example 2 A quaternary gallium-based liquid alloy comprises the following raw materials in parts by weight: 70 parts gallium powder, 18 parts indium powder, 5 parts tin powder, 4 parts bismuth powder, and 4 parts two-dimensional nano-heterogeneous reinforcement.

[0038] The two-dimensional nano-heterogeneous reinforcement is composed of modified hexagonal boron nitride and modified molybdenum disulfide in a mass ratio of 1:1.5.

[0039] The specific preparation method of modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to a 3.5 mol / L NaOH aqueous solution at a mass ratio of 1:30 and hydrothermally treated at 160℃ for 22 h. After cooling to room temperature, the mixture was centrifuged at 9000 rpm for 8 min, washed with deionized water until neutral, and vacuum dried at 70℃ for 7 h to obtain hydroxylated hexagonal boron nitride. Hydroxylated hexagonal boron nitride was added to anhydrous ethanol at a mass ratio of 1:45 and ultrasonically dispersed at 30 kHz and 400 W for 30 min. Then, 3-aminopropyltriethoxysilane was added, with a mass ratio of 3-aminopropyltriethoxysilane to hydroxylated hexagonal boron nitride of 0.75:1. The mixture was stirred at 70℃ and 400 rpm for 9 h. After the reaction was completed, the mixture was centrifuged at 9000 rpm for 7.5 min. The precipitate was washed twice each with anhydrous ethanol and deionized water and vacuum dried at 70℃ for 10 h to obtain modified hexagonal boron nitride.

[0040] The specific preparation method of modified molybdenum disulfide is as follows: Molybdenum disulfide powder was added to N-methylpyrrolidone at a mass ratio of 1:40 and ultrasonically exfoliated at 300W and 20℃ for 7 hours. After exfoliation, the mixture was centrifuged at 3000rpm for 30 minutes to fractionate the mixture. The upper dispersion was collected and vacuum filtered to collect molybdenum disulfide nanosheets. Molybdenum disulfide nanosheets were added to anhydrous ethanol at a mass ratio of 1:45 and ultrasonically dispersed at 30kHz and 400W for 25 minutes. Then, 3-mercaptopropyltrimethoxysilane was added, with a mass ratio of 3-mercaptopropyltrimethoxysilane to molybdenum disulfide nanosheets of 1:1. The mixture was stirred at 60℃ and 400rpm for 12 hours. After the reaction, the mixture was centrifuged at 9000rpm for 8 minutes and washed twice with anhydrous ethanol and deionized water, respectively. The mixture was then vacuum dried at 60℃ for 12 hours to obtain modified molybdenum disulfide.

[0041] A method for preparing a quaternary gallium-based liquid alloy includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, and clean them separately with a citric acid-ethanol mixed solution with a mass fraction of 5% citric acid at 30kHz and 400W for 20min. Then rinse them twice with anhydrous ethanol and dry them in vacuum at 65℃ for 2h for later use. S2. Under an argon protective atmosphere, tin powder and bismuth powder are added to a crucible and heated to 380°C at a heating rate of 7.5°C / min. The mixture is stirred and melted at 300 rpm for 15 min to obtain a tin-bismuth pre-alloyed liquid. S3. Cool the tin-bismuth pre-alloyed liquid to 170°C at a cooling rate of 4°C / min, add indium powder, and stir and melt at 400 rpm for 15 min to obtain a ternary pre-alloyed liquid. S4. Cool the ternary pre-alloy liquid to 100℃ at a cooling rate of 4℃ / min, add gallium powder and two-dimensional nano-heterogeneous reinforcement, stir at 600rpm for 15min, and then ultrasonically disperse at 30kHz and 300W for 35min to obtain an alloy mixture. S5. Transfer the alloy mixture to a refining and degassing device, refine and degas at a vacuum of 1 Pa and 70°C for 25 min, and then cool it to room temperature with the furnace to obtain a quaternary gallium-based liquid alloy.

[0042] Example 3 A quaternary gallium-based liquid alloy comprises the following raw materials in parts by weight: 60-75 parts gallium powder, 22 parts indium powder, 10 parts tin powder, 6 parts bismuth powder, and 6 parts two-dimensional nano-heterogeneous reinforcement.

[0043] The two-dimensional nano-heterogeneous reinforcement is composed of modified hexagonal boron nitride and modified molybdenum disulfide in a mass ratio of 1:2.

[0044] The specific preparation method of modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to a 5 mol / L NaOH aqueous solution at a mass ratio of 1:40, and hydrothermally treated at 180℃ for 24 h. After cooling to room temperature, it was centrifuged at 10000 rpm for 10 min, washed with deionized water until neutral, and vacuum dried at 80℃ for 9 h to obtain hydroxylated hexagonal boron nitride. Hydroxylated hexagonal boron nitride was added to anhydrous ethanol at a mass ratio of 1:60, and ultrasonically dispersed at 40 kHz and 500 W for 40 min. Then, 3-aminopropyltriethoxysilane was added, with a mass ratio of 3-aminopropyltriethoxysilane to hydroxylated hexagonal boron nitride of 1.0:1. The mixture was stirred at 80℃ and 600 rpm for 12 h. After the reaction was completed, it was centrifuged at 10000 rpm for 10 min, and the precipitate was washed three times each with anhydrous ethanol and deionized water. It was then vacuum dried at 80℃ for 12 h to obtain modified hexagonal boron nitride.

[0045] The specific preparation method of modified molybdenum disulfide is as follows: Molybdenum disulfide powder was added to N-methylpyrrolidone at a mass ratio of 1:50 and ultrasonically exfoliated at 500W and 30℃ for 10 h. After exfoliation, the mixture was centrifuged at 4000rpm for 40 min for fractionation. The upper dispersion was collected and vacuum filtered to collect molybdenum disulfide nanosheets. Molybdenum disulfide nanosheets were added to anhydrous ethanol at a mass ratio of 1:60 and ultrasonically dispersed at 40kHz and 500W for 30 min. Then, 3-mercaptopropyltrimethoxysilane was added, with a mass ratio of 3-mercaptopropyltrimethoxysilane to molybdenum disulfide nanosheets of 1.5:1. The mixture was stirred at 70℃ and 600rpm for 16 h. After the reaction, the mixture was centrifuged at 10000rpm for 10 min and washed three times each with anhydrous ethanol and deionized water. The mixture was then vacuum dried at 70℃ for 14 h to obtain modified molybdenum disulfide.

[0046] A method for preparing a quaternary gallium-based liquid alloy includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, and clean them separately with a citric acid-ethanol mixed solution with a mass fraction of 8% citric acid at 40kHz and 500W for 30min. Then rinse them three times with anhydrous ethanol and vacuum dry them at 70℃ for 3h for later use. S2. Under an argon protective atmosphere, tin powder and bismuth powder are added to a crucible and heated to 400°C at a heating rate of 10°C / min. The mixture is stirred and melted at 400 rpm for 20 min to obtain a tin-bismuth pre-alloyed liquid. S3. Cool the tin-bismuth pre-alloyed liquid to 180°C at a cooling rate of 5°C / min, add indium powder, and stir and melt at 500 rpm for 20 min to obtain a ternary pre-alloyed liquid. S4. Cool the ternary pre-alloy liquid to 110°C at a cooling rate of 5°C / min, add gallium powder and two-dimensional nano-heterogeneous reinforcement, stir at 800 rpm for 20 min, and then ultrasonically disperse at 40 kHz and 400 W for 40 min to obtain an alloy mixture. S5. Transfer the alloy mixture to a refining and degassing device, refine and degas at a vacuum of 1 Pa and 80°C for 30 min, and then cool it to room temperature in the furnace to obtain a quaternary gallium-based liquid alloy.

[0047] Comparative Example 1 This comparative example provides a gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that bismuth powder is not added to the alloy raw materials, and the weight parts of the raw materials are adjusted to: 74 parts gallium powder, 18 parts indium powder, 5 parts tin powder, and 4 parts two-dimensional nano-heterogeneous reinforcement. The other types of raw materials and preparation process parameters are completely consistent with those of Example 2.

[0048] Comparative Example 2 This comparative example provides a pentagonal gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that: no two-dimensional nano-heterogeneous reinforcement is added to the alloy raw materials, and the weight parts of the raw materials are adjusted to: 74 parts gallium powder, 18 parts indium powder, 5 parts tin powder, and 4 parts bismuth powder; only gallium powder is added in step S4, and no two-dimensional nano-heterogeneous reinforcement is added; the other types of raw materials and preparation process parameters are completely consistent with those of Example 2.

[0049] Comparative Example 3 This comparative example provides a pentagonal gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that the two-dimensional nano-heterogeneous reinforcement is replaced by a modified hexagonal boron nitride of equal mass; the other raw material types and preparation process parameters are completely consistent with Example 2.

[0050] Comparative Example 4 This comparative example provides a pentagonal gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that the two-dimensional nano-heterogeneous reinforcement is replaced by a modified molybdenum disulfide of equal mass; the other raw material types and preparation process parameters are completely consistent with Example 2.

[0051] Comparative Example 5 This comparative example provides a pentagonal gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that the two-dimensional nano-heterogeneous reinforcement is composed of unmodified hexagonal boron nitride and unmodified molybdenum disulfide in a mass ratio of 1:1.5; the other raw material types and preparation process parameters are completely consistent with Example 2.

[0052] Comparative Example 6 This comparative example provides a pentagonal gallium-based liquid alloy and its preparation method. The only difference from Example 2 is that the step-by-step melting process is not used in the alloy preparation process. The other raw material types, amounts, and the composition and preparation method of the nanocomposite reinforcing phase are completely consistent with Example 2.

[0053] Specifically: A method for preparing a quaternary gallium-based liquid alloy includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, and clean them separately with a citric acid-ethanol mixed solution with a mass fraction of 5% citric acid at 30kHz and 400W for 20min. Then rinse them twice with anhydrous ethanol and vacuum dry them at 65℃ for 2h for later use. S2. Under an argon protective atmosphere, gallium powder, indium powder, tin powder, bismuth powder and two-dimensional nano-heterogeneous reinforcement are added to a crucible and heated to 380°C at a heating rate of 7.5°C / min. The mixture is stirred and melted at 300 rpm for 15 min to obtain the first pre-alloyed liquid. S3. Cool the first pre-alloy liquid to 170°C at a cooling rate of 4°C / min, and stir and melt it at 400 rpm for 15 min to obtain the second pre-alloy liquid. S4. Cool the second pre-alloy liquid to 100℃ at a cooling rate of 4℃ / min, stir at 600rpm for 15min, and then ultrasonically disperse at 30kHz and 300W for 35min to obtain an alloy mixture. S5. Transfer the alloy mixture to a refining and degassing device, refine and degas at a vacuum of 1 Pa and 70°C for 25 min, and then cool it to room temperature with the furnace to obtain a quaternary gallium-based liquid alloy.

[0054] Performance testing 1. Detection Object The quaternary gallium-based liquid alloys prepared in Examples 1-3 and Comparative Examples 1-6.

[0055] 2. Testing Methods (1) Melting point test Differential scanning calorimetry (DSC) was used for testing. The instrument was a TA Instruments DSC 250. Under a high-purity nitrogen protective atmosphere, the temperature was increased from -30℃ to 60℃ at a heating rate of 5℃ / min. The onset temperature of the endothermic peak was taken as the melting point of the alloy.

[0056] (2) Test of volume change rate of solidified solids The liquid displacement method was used for testing. The quaternary gallium-based liquid alloy was completely melted at 70°C and then injected into a calibrated quartz capillary tube, and the liquid volume V1 was recorded. Subsequently, it was kept in a constant temperature oven at -10°C for 2 hours until it was completely solidified, and the solid volume V2 was recorded.

[0057] The formula for calculating the volume change rate of solidified solids is: △V = (V2 - V1) / V1 × 100%.

[0058] (3) Thermal conductivity test Laser flare analysis (LFA) was used for testing. The instrument was a Netzsch LFA 467, the testing temperature was 25℃, and the sample disk was a graphite-coated disc with a diameter of 12.7 mm and a thickness of 1.0 mm. The thermal conductivity λ was calculated using the formula: λ = α × ρ × Cp, where α is the thermal diffusivity (measured using LFA), ρ is the density (measured using the Archimedes method), and Cp is the thermal conductivity. p Specific heat capacity (DSC measured).

[0059] (4) Contact angle test The contact angle was measured using a Dataphysics OCA 25 instrument. A 5 μL drop of quaternary gallium-based liquid alloy was placed onto a plasma-cleaned PDMS substrate. After standing for 10 seconds at 25°C in atmospheric conditions, images were acquired. The droplet profile was fitted using the Young-Laplace equation, and the contact angle values ​​were read. Five different locations were measured for each sample, and the average value was taken.

[0060] (5) Thermal cycling stability test Thermal cycling experiments were conducted in a programmable temperature chamber. The conditions for one cycle were: holding at 70℃ for 10 min → cooling to -10℃ at a rate of 5℃ / min → holding at -10℃ for 10 min → heating back to 70℃ at a rate of 5℃ / min, for a total of 100 cycles. The ratio of thermal conductivity before and after the thermal cycle was taken as the thermal conductivity retention rate, calculated using the formula: Thermal conductivity retention rate = (λ...) 100 / λ0)×100%, where λ0 is the initial thermal conductivity of the alloy before thermal cycling, λ 100 The thermal conductivity of the alloy after 100 thermal cycles.

[0061] 3. Statistical processing methods All experiments were performed in triplicate, and results are expressed as mean ± standard deviation. One-way ANOVA was used for comparisons between groups, and a p-value < 0.05 was considered statistically significant.

[0062] 4. Test Results and Analysis The specific test results are shown in Table 1.

[0063] Table 1 Performance test results of quaternary gallium-based liquid alloys

[0064] As shown in Table 1, the quaternary gallium-based liquid alloys prepared in Examples 1-3 have significantly better overall performance than Comparative Examples 1-6 in terms of melting point, solidification volume change rate, thermal conductivity, contact angle, and thermal cycling stability. Among them, Example 2 has the best overall performance. Each comparative example showed a significant decrease in at least one key indicator, indicating that there is a significant synergistic effect between the components and processes of the present invention.

[0065] Compared with Example 2, Comparative Example 1 removed bismuth powder, resulting in a significant increase in melting point and a marked increase in solidification volume change rate. This indicates that the introduction of bismuth helps to form a deeper multi-element low eutectic system to reduce the alloy melting point. At the same time, the low shrinkage rate of bismuth during solidification can effectively compensate for the net volume change caused by gallium solidification expansion.

[0066] Compared with Example 2, Comparative Example 2, without the addition of two-dimensional nano-heterogeneous reinforcement, showed a significant decrease in thermal conductivity, a significant increase in contact angle, and a marked deterioration in thermal cycling stability. This indicates that the heterogeneous thermal conductive network constructed by modified hexagonal boron nitride and modified molybdenum disulfide is the core of improving thermal conductivity. At the same time, the disruption of the continuity of the oxide film on the surface of the liquid metal by the reinforcement helps to reduce the spreading resistance and improve the wettability between the alloy and the substrate.

[0067] Compared with Example 2, Comparative Example 3, which only used modified hexagonal boron nitride, showed a significantly increased contact angle. This indicates that although hexagonal boron nitride is the main contributing component to the improvement of thermal conductivity, it cannot effectively reduce surface tension. The low interlayer shear force characteristics of molybdenum disulfide play an irreplaceable role in improving wetting and spreading behavior.

[0068] Compared with Example 2, Comparative Example 4, which only used modified molybdenum disulfide, showed a significant decrease in thermal conductivity, indicating that the intrinsic thermal conductivity of molybdenum disulfide is much lower than that of hexagonal boron nitride, and it cannot independently construct an efficient thermal conduction pathway. When the two are used in combination, molybdenum disulfide plays a "bridging" role between the hexagonal boron nitride layers, reducing interfacial thermal resistance and enhancing network connectivity. The two reinforcing phases have a significant "thermal conduction-wetting" synergistic effect.

[0069] Compared with Example 2, Comparative Example 5, which used unmodified hexagonal boron nitride and unmodified molybdenum disulfide, showed a significant decrease in all properties, especially in thermal cycling stability. This indicates that silane coupling modification is the key to ensuring uniform dispersion and stable interfacial bonding of nanomaterials in high surface tension liquid metals. Unmodified nanomaterials cannot form an effective thermally conductive network due to severe agglomeration and sedimentation, and their performance deteriorates rapidly due to continuous interface degradation during repeated thermal cycling.

[0070] Compared with Example 2, Comparative Example 6 adopted a one-step melting process, which resulted in a higher melting point, lower thermal conductivity, and reduced thermal cycling stability. This indicates that the step-by-step melting process can effectively avoid local segregation caused by the large differences in melting points of the components and oxidation burn-off of low-melting-point components. At the same time, it can prevent the functionalized modification layer on the surface of the two-dimensional nano-heterogeneous reinforcement from thermally decomposing and failing at high temperatures, which is crucial for maintaining the overall performance of the alloy.

[0071] This specific embodiment is merely an explanation of the present invention and is not intended to limit the invention. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they are within the scope of the claims of the present invention.

Claims

1. A quaternary gallium-based liquid alloy, characterized in that, The raw materials include the following parts by weight: 60-75 parts gallium powder, 14-22 parts indium powder, 3-10 parts tin powder, 2-6 parts bismuth powder, and 2-6 parts two-dimensional nano-heterogeneous reinforcement.

2. The quaternary gallium-based liquid alloy according to claim 1, characterized in that, The two-dimensional nano-heterogeneous reinforcement is composed of modified hexagonal boron nitride and modified molybdenum disulfide in a mass ratio of 1:1-2.

3. The quaternary gallium-based liquid alloy according to claim 2, characterized in that, The method for preparing the modified hexagonal boron nitride is as follows: Hexagonal boron nitride powder was added to NaOH solution and subjected to hydrothermal treatment. After cooling, it was centrifuged, washed, and dried to obtain hydroxylated hexagonal boron nitride. The hydroxylated hexagonal boron nitride was added to anhydrous ethanol, ultrasonically dispersed, and then 3-aminopropyltriethoxysilane was added. The mixture was stirred, centrifuged, washed, and dried to obtain modified hexagonal boron nitride.

4. The quaternary gallium-based liquid alloy according to claim 3, characterized in that, The hydrothermal treatment temperature is 150-180℃, and the hydrothermal treatment time is 18-24h.

5. The quaternary gallium-based liquid alloy according to claim 2, characterized in that, The method for preparing the modified molybdenum disulfide is as follows: Molybdenum disulfide powder was added to N-methylpyrrolidone, ultrasonically exfoliated, centrifuged and classified, and the upper dispersion was collected by vacuum filtration to collect molybdenum disulfide nanosheets. The molybdenum disulfide nanosheets were added to anhydrous ethanol, ultrasonically dispersed, and then 3-mercaptopropyltrimethoxysilane was added. The mixture was stirred, centrifuged, washed, and dried to obtain modified molybdenum disulfide.

6. The quaternary gallium-based liquid alloy according to claim 5, characterized in that, The mass ratio of 3-mercaptopropyltrimethoxysilane to molybdenum disulfide nanosheets is 0.5-1.5:

1.

7. A method for preparing a quaternary gallium-based liquid alloy as described in any one of claims 1-6, characterized in that, Includes the following steps: S1. Weigh gallium powder, indium powder, tin powder and bismuth powder raw materials according to the weight parts, ultrasonically clean them with citric acid-ethanol mixed solution, rinse them with anhydrous ethanol, vacuum dry them and set them aside. S2. Under an argon protective atmosphere, tin powder and bismuth powder are added to a crucible, heated to 350-400℃, stirred and melted to obtain a tin-bismuth pre-alloyed liquid; S3. Cool the tin-bismuth pre-alloyed liquid to 160-180℃, add indium powder, stir and melt to obtain a ternary pre-alloyed liquid; S4. Cool the ternary pre-alloy liquid to 80-110℃, add gallium powder, stir evenly, add two-dimensional nano-heterogeneous reinforcement, continue stirring, and ultrasonically disperse to obtain an alloy mixture. S5. The alloy mixture is refined and degassed, then cooled to obtain a quaternary gallium-based liquid alloy.

8. The method for preparing the quaternary gallium-based liquid alloy according to claim 7, characterized in that, In step S1, the mass fraction of citric acid in the citric acid-ethanol mixed solution is 3-8%; the ultrasonic cleaning frequency is 25-40kHz, and the ultrasonic cleaning time is 10-30min.

9. The method for preparing the quaternary gallium-based liquid alloy according to claim 7, characterized in that, In step S5, the refining and degassing vacuum degree is ≤1Pa, the refining and degassing temperature is 60-80℃, and the refining and degassing time is 20-30min.

10. The application of a quaternary gallium-based liquid alloy as described in any one of claims 1-6 in flexible electronic devices and thermal interface materials.

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