Preparation method of phase change capsule with low-melting-point alloy core packaged by ceramic shell
Through the preparation method of phase change capsules for packaging low-melting point alloy cores with ceramic shells, the leakage problem caused by volume expansion of low-melting point alloy phase change materials is solved, and efficient and reliable packaging effect is achieved, and is suitable for a variety of heat storage applications.
Patent Information
- Application Number
- CN202510316288.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-18
- Publication Date
- 2025-05-06
AI Technical Summary
Low-melting point alloy phase change materials cause equipment damage and material leakage due to volume expansion during the phase change process. The existing packaging methods are complex, costly and poorly stable.
The preparation method of phase change capsules with a low melting point alloy core using a ceramic shell encapsulated with a ceramic powder, and combined with an appropriate calcination temperature, the microporation of the ceramic shell layer is achieved and the volume expansion of the metal phase change material is buffered.
It effectively prevents leakage of metal materials during high-temperature phase transition, improves the circulation durability, thermal stability and oxidation resistance of phase transition capsules, and is suitable for industrial waste heat recovery and solar heat storage systems.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of phase change heat storage, and in particular relates to a method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell. Background Art
[0002] With the sustained and rapid economic development, my country's energy demand is also increasing. As an important branch of energy storage, thermal storage technology can improve energy efficiency and play a vital role in solving the problem of "abandoning wind and solar power" and participating in the regulation of power systems.
[0003] Phase change heat storage technology based on phase change materials can absorb or release a large amount of latent heat during the phase change process, and has significant advantages such as high heat storage density and small temperature fluctuation. Phase change materials can be divided into four types of phase change materials: solid-liquid, solid-solid, solid-gas or liquid-gas. Compared with solid / liquid-gas phase change materials and solid-solid phase change materials, solid-liquid phase change materials usually have a larger latent heat value, a wide range of sources and large reserves. They are currently the most promising large-scale phase change heat storage materials. Among them, metal-based solid-liquid phase change materials have the advantages of high thermal conductivity, high energy storage density, and no supercooling phenomenon. They are widely used in medium and high temperature phase change heat storage systems. However, the high melting point of metal phase change materials limits their application in medium and low temperatures, and their energy storage density is limited, which cannot meet high-demand scenarios. In addition, some thermal cycle stability is poor, and performance decreases after multiple phase changes. Low-melting-point alloy phase change materials have the advantages of low melting point, high energy storage density, stable thermal cycle, low cost, good fluidity, and easy processing and molding. However, they still have the risk of equipment damage and material leakage due to volume expansion during the phase change process. In order to solve the above problems, the development of efficient and reliable packaging methods for low-melting-point alloy phase change materials has attracted widespread attention. Among them, microcapsule encapsulation is complex to prepare, costly, and has a low partial encapsulation rate and poor stability; in porous carrier encapsulation, foam metal is costly and prone to corrosion; geometric container encapsulation may still cause material leakage and corrosion; fiber encapsulation has high process requirements and low encapsulation efficiency. Therefore, it is urgent to use a stable packaging method to solve the problem caused by the volume expansion of low-melting-point alloy phase change materials, thereby laying a solid foundation for the widespread application of low-melting-point alloy phase change materials in the field of heat storage. Summary of the invention
[0004] One of the purposes of the present invention is to provide a method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell, which can encapsulate the low melting point alloy in a dense ceramic shell to prevent leakage of the metal material during high temperature phase change.
[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell, comprising the following steps:
[0006] (1) Two or more elemental metal powders are mixed evenly to obtain a mixed metal powder, and then the mixed metal powder is stirred and mixed with an organic binder solution to obtain a viscous embryo, which is then formed into a sphere. After drying, the sphere is pressed using an isostatic press to obtain a spherical metal embryo.
[0007] (2) The ceramic powder and the organic binder solution are stirred and mixed to obtain a viscous embryo, which is used as a shell layer to coat the spherical metal embryo obtained in step (1) to obtain a ceramic shell-coated metal capsule embryo.
[0008] (3) The capsule is heated and pre-sintered, and then subjected to high-temperature heat treatment to obtain a core-shell structure phase change capsule with an alloy core and a ceramic shell.
[0009] Preferably, the elemental metal described in step (1) can be selected from two or more of bismuth, tin, lead, indium, gallium, and antimony, and the mass ratio of the mixed metal powder to the organic binder is 80:20~99.5:0.5.
[0010] Preferably, the ceramic powder in step (2) is selected from one or more of kaolin, silicon carbide, aluminum oxide, magnesium oxide, and silicon dioxide, and the mass ratio of the ceramic powder to the organic binder is 80:20 to 99.5:0.5.
[0011] Preferably, the binder in step (1) and step (2) can be selected from one or more of sodium carboxymethyl cellulose, polyvinyl alcohol, polyvinylidene fluoride, polyethylene glycol, and polymethyl methacrylate, and the concentration of the organic binder is 0.2-10 wt%.
[0012] Preferably, the pre-sintering temperature in step (3) is 300-500°C, and the sintering time is 1-12 hours; the high-temperature heat treatment temperature is 500-1000°C, and the sintering time is 1-24 hours.
[0013] Preferably, the size of the spherical metal embryo obtained in step (1) is 2-30 mm, and the thickness of the ceramic shell film coated in step (2) is 1-5 mm.
[0014] The phase change capsule with a low melting point alloy core encapsulated in a ceramic shell prepared by the present invention exhibits excellent cycle durability, thermal stability and oxidation resistance in 500 cycle tests and 12h overload high temperature oxidation tests in air atmosphere, without shell rupture and leakage. The capsule can be widely used in the fields of industrial waste heat recovery and solar energy thermal storage systems.
[0015] Compared with the prior art, the present invention has the following beneficial effects:
[0016] 1. The present invention uses ordinary single metal powder to skillfully synthesize low-melting-point alloy-based phase change materials as the core through the alloying reaction of metal-based phase change materials. The shell membrane is prefabricated by ceramic powder and coated with low-melting-point alloy-based phase change materials to obtain a capsule embryo of ceramic shell-coated alloy. Finally, combined with an appropriate calcination temperature, the capsule shell layer is made microporous, and the pores between the alloy powders are gathered and transformed into a buffer cavity that can accommodate the volume expansion of the metal phase change material. It effectively solves the leakage and corrosion problems caused by the heating or melting of the low-melting-point alloy phase change material, while avoiding the internal metal core material from contacting the outside world to prevent it from oxidation.
[0017] 2. The present invention preforms the shell membrane with ceramic powder and combines it with an appropriate calcination temperature to achieve the microporous capsule shell layer, so that the gas can enter and exit freely, thereby effectively eliminating the problem of capsule rupture caused by increased air pressure in the capsule. In addition, the present invention relies on isostatic pressing to increase the packing density of metal powder to indirectly reduce the cavity volume of the capsule, thereby increasing the heat storage density of the phase change capsule.
[0018] 3. The preparation method of the present invention can flexibly control the core-shell size of the capsule to be suitable for different scenarios by adjusting the coating quality of the ceramic viscous embryo, as well as the high-temperature heat treatment temperature and time. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the accompanying drawings are only schematic representations and should not be regarded as limiting the scope of protection. In the accompanying drawings:
[0020] Figure 1 This is a macroscopic picture of the capsule after high-temperature sintering at 1000°C in Example 12.
[0021] Figure 2 This is an SEM image of the cross-section of the capsule core and ceramic shell obtained in Example 12.
[0022] Figure 3 The following are actual pictures of the capsules obtained in Example 12 before the cycle test and after 50, 200, and 500 cycles.
[0023] Figure 4 is the mass change rate of the capsule obtained in Example 12 after 50, 200 and 500 cycles.
[0024] Figure 5 This is a physical picture of the capsule obtained in Example 12 subjected to oxidation test at overload high temperature of 200°C, 300°C and 400°C for 12 hours. DETAILED DESCRIPTION
[0025] Example 1
[0026] 45g of lead powder and tin powder metal powder (including 19g of lead powder and 26g of tin powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyvinylidene fluoride solution with a concentration of 5wt% (the mass of polyvinylidene fluoride was 0.24g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 15g of silicon carbide ceramic powder and polyvinylidene fluoride solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. A core-shell structure phase change capsule with a core material of lead-tin alloy and an outer shell of silicon carbide ceramic is obtained.
[0027] Example 2
[0028] 45g of indium powder and lead powder metal powder (including 19g of indium powder and 26g of lead powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyethylene glycol solution with a concentration of 5wt% (the mass of polyethylene glycol was 0.24g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 15g of kaolin ceramic powder and polyethylene glycol solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above-mentioned capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. The obtained core-shell structure phase change capsule has a core material of indium-lead alloy and a shell of kaolin ceramic.
[0029] Example 3
[0030] 45g of gallium powder and indium powder metal powder (including 19g of gallium powder and 26g of indium powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polymethyl methacrylate solution with a concentration of 5wt% (the mass of polymethyl methacrylate was 0.24g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 15g of magnesium oxide ceramic powder and polymethyl methacrylate solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, kept for 1h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 2h, and then naturally cooled to room temperature. A core-shell structure phase change capsule is obtained, the core material of which is gallium-indium alloy and the shell of which is magnesium oxide ceramic.
[0031] Example 4
[0032] 50g of bismuth powder and gallium powder metal powder (including 21g of bismuth powder and 29g of gallium powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a sodium carboxymethyl cellulose solution with a concentration of 7.5wt% (the mass of sodium carboxymethyl cellulose was 0.32g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 20g of silica ceramic powder and sodium carboxymethyl cellulose solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, kept for 1h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 2h, and then naturally cooled to room temperature. A core-shell structure phase change capsule with a core material of bismuth-gallium alloy and an outer shell of silicon dioxide ceramic is obtained.
[0033] Example 5
[0034] 50g of tin powder and bismuth powder metal powder (including 21g of tin powder and 29g of bismuth powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyvinylidene fluoride solution with a concentration of 7.5wt% (the mass of polyvinylidene fluoride was 0.32g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 20g of kaolin ceramic powder and polyvinylidene fluoride solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. A core-shell structure phase change capsule with a core material of tin-bismuth alloy and an outer shell of kaolin ceramic is obtained.
[0035] Example 6
[0036] 50g of lead powder and tin powder metal powder (including 21g of lead powder and 29g of tin powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyethylene glycol solution with a concentration of 7.5wt% (the mass of polyethylene glycol was 0.32g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 20g of silicon carbide ceramic powder and polyethylene glycol solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. A core-shell structure phase change capsule with a core material of lead-tin alloy and an outer shell of silicon carbide ceramic is obtained.
[0037] Example 7
[0038] 50g of indium powder and lead powder metal powder (including 21g of indium powder and 29g of lead powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polymethyl methacrylate solution with a concentration of 7.5wt% (the mass of polymethyl methacrylate was 0.32g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 20g of alumina ceramic powder and polymethyl methacrylate solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, kept for 1h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 800℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 2h, and then naturally cooled to room temperature. The obtained core-shell structure phase change capsule has a core material of indium-lead alloy and a shell of alumina ceramic.
[0039] Example 8
[0040] 74g of gallium powder and indium powder metal powder (including 31g of gallium powder and 43g of indium powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a sodium carboxymethyl cellulose solution with a concentration of 10wt% (the mass of sodium carboxymethyl cellulose was 0.48g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 25g of magnesium oxide ceramic powder and sodium carboxymethyl cellulose solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. A core-shell structure phase change capsule is obtained, the core material of which is gallium-indium alloy and the shell of which is magnesium oxide ceramic.
[0041] Example 9
[0042] 74g of bismuth powder and gallium powder metal powder (including 31g of bismuth powder and 43g of gallium powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyvinylidene fluoride solution with a concentration of 10wt% (the mass of polyvinylidene fluoride was 0.48g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 25g of silica ceramic powder and polyvinylidene fluoride solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, kept for 1h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 2h, and then naturally cooled to room temperature. A core-shell structure phase change capsule with a core material of bismuth-gallium alloy and an outer shell of silicon dioxide ceramic is obtained.
[0043] Example 10
[0044] 74g of tin powder and bismuth powder metal powder (31g of tin powder and 43g of bismuth powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polyethylene glycol solution with a concentration of 10wt% (the mass of polyethylene glycol was 0.48g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 25g of kaolin ceramic powder and polyethylene glycol solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, and cooled naturally to room temperature after holding for 1h. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, and cooled naturally to room temperature after holding for 2h. A core-shell structure phase change capsule with a core material of tin-bismuth alloy and an outer shell of kaolin ceramic is obtained.
[0045] Embodiment 11
[0046] 74g of lead powder and tin powder metal powder (including 31g of lead powder and 43g of tin powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a polymethyl methacrylate solution with a concentration of 10wt% (the mass of polymethyl methacrylate was 0.48g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 25g of silicon carbide ceramic powder and polymethyl methacrylate solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 500℃ at a heating rate of 5℃ / min, kept for 6h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 12h, and then naturally cooled to room temperature. A core-shell structure phase change capsule with a core material of lead-tin alloy and an outer shell of silicon carbide ceramic is obtained.
[0047] Example 12
[0048] 45g of tin powder and bismuth powder metal powder (including 19g of tin powder and 26g of bismuth powder) were mixed evenly to obtain a mixed metal powder, and then the mixed metal powder was stirred and mixed with a sodium carboxymethyl cellulose solution with a concentration of 5wt% (the mass of sodium carboxymethyl cellulose was 0.24g) to obtain a viscous embryo, and a sphere was manually made. After drying, it was pressed using an isostatic press to obtain a spherical metal embryo. 15g of alumina ceramic powder and sodium carboxymethyl cellulose solution were stirred and mixed to obtain a viscous embryo, which was used as a shell layer to coat the above-mentioned spherical metal embryo to obtain a ceramic shell-coated metal capsule embryo. The above capsule was placed in a muffle furnace for heating and pre-sintering, heated to 300℃ at a heating rate of 5℃ / min, kept for 1h, and then naturally cooled to room temperature. After the pre-sintering was completed, it was placed in a tubular furnace for high-temperature heat treatment: heated to 1000℃ at a heating rate of 5℃ / min in an air atmosphere, kept for 2h, and then naturally cooled to room temperature. A core-shell structure phase change capsule with a core material of tin-bismuth alloy and an outer shell of alumina ceramic is obtained.
[0049] Figure 1 This is a macroscopic picture of the capsule obtained in this embodiment after pre-sintering at 300°C for 1 hour and high temperature heat treatment at 1000°C for 2 hours. It can be seen that the obtained capsule is well formed and has no cracking phenomenon.
[0050] Figure 2 This is a SEM image of the capsule obtained in this embodiment after pre-sintering at 300°C for 1 hour and high temperature heat treatment at 1000°C for 2 hours. Figure 2 As can be seen in (a1), during the high-temperature metallurgical process, the tin powder and bismuth powder melt, combine, and solidify to form a Sn-58Bi alloy block with a smooth and flat cross section. Figure 2(b1) It can be seen that the dense ceramic shell prepared by using alumina ceramic powder can improve the wear resistance and corrosion resistance of the capsule.
[0051] Figure 3 The following are the actual pictures of the capsules obtained in this example before the cycle test and after 50, 200 and 500 cycles. It can be seen that all the capsules can maintain their integrity, and no rupture or leakage is observed even after 500 cycles in air, which indicates that the cavity volume of the capsule is sufficient to accommodate the volume expansion of the low-melting-point metal during heat storage.
[0052] Figure 4 The mass change rates of the capsules obtained in this example after 50, 200 and 500 cycles are shown in Figure 1. It can be seen that the lines connecting the average mass retention rates of the capsules after 50, 200 and 500 cycles are almost straight and almost coincide with the horizontal baseline of 100%. This reflects that even if the capsules are subjected to up to 500 thermal cycle tests in an air atmosphere, their mass retention rates are basically close to 100% (the mass change rate does not exceed 0.1%).
[0053] Figure 5 The following is a photo of the capsule obtained in this example undergoing an oxidation test at 200°C, 300°C and 400°C for 12 hours. It can be seen that even under such harsh overload high temperature oxidation conditions, the degree of oxidation of the capsule is still very low, which indicates that the capsule has good thermal stability and oxidation resistance.
Claims
1. A method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell, characterized in that: The following steps are involved: (1) Two or more elemental metal powders are mixed evenly to obtain a mixed metal powder, and then the mixed metal powder is stirred and mixed with an organic binder solution to obtain a viscous embryo, which is then formed into a sphere. After drying, the sphere is pressed using an isostatic press to obtain a spherical metal embryo. (2) The ceramic powder and the organic binder solution are stirred and mixed to obtain a viscous embryo, which is used as a shell layer to coat the spherical metal embryo obtained in step (1) to obtain a ceramic shell-coated metal capsule embryo. (3) The capsule is heated and pre-sintered, and then subjected to high-temperature heat treatment to obtain a core-shell structure phase change capsule with an alloy core and a ceramic shell.
2. The method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell according to claim 1, characterized in that: The elemental metal described in step (1) can be selected from two or more of bismuth, tin, lead, indium, gallium, and antimony, and the mass ratio of the mixed metal powder to the organic binder is 80:20~99.5:0.5; the ceramic powder described in step (2) is selected from one or more of kaolin, silicon carbide, aluminum oxide, magnesium oxide, and silicon dioxide, and the mass ratio of the ceramic powder to the organic binder is 80:20~99.5:0.5; the binder described in step (1) and step (2) can be selected from one or more of sodium carboxymethyl cellulose, polyvinyl alcohol, polyvinylidene fluoride, polyethylene glycol, and polymethyl methacrylate, and the concentration of the organic binder is 0.2~10wt%.
3. The method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell according to claim 1, characterized in that: The pre-sintering temperature in step (3) is 300-500°C, and the sintering time is 1-12 hours; the high-temperature heat treatment temperature is 500-1000°C, and the sintering time is 1-24 hours.
4. The method for preparing a phase change capsule with a low melting point alloy core encapsulated in a ceramic shell according to claim 1, characterized in that: The size of the spherical metal embryo obtained in step (1) is 2-30 mm, and the thickness of the ceramic shell film coated in step (2) is 1-5 mm.