Active solid-liquid phase change method for magnetic gallium-indium alloy

Abstract

The invention relates to an active solid-liquid phase change method for a magnetic gallium-indium alloy, and belongs to the technical field of treatment of alloys or non-ferrous metals. According to the method for active solid-liquid phase change of the magnetic gallium-indium alloy, magnetic gallium and magnetic indium are in contact through a magnetic field to be alloyed to form the liquid magnetic gallium-indium alloy; the magnetic gallium is in a solid state and comprises metal gallium and magnetic particles; the magnetic indium is in a solid state and comprises metal indium and magnetic particles. According to the method, alternating magnetic field heating is not needed, magnetic gallium and magnetic indium can be alloyed to form the liquid-state magnetic gallium-indium alloy only by making contact with each other, active solid-liquid conversion at any time and any position in the movement process is achieved, and then the solid state of the magnetic gallium or the magnetic indium is easy to control and high in stability. And the liquid-state high fluidity of the magnetic gallium-indium alloy is realized.

Description

Technical Field

[0001] The invention relates to the technical field of alloy or nonferrous metal processing, and in particular to a method for active solid-liquid phase change of a magnetic gallium-indium alloy. Background Art

[0002] Liquid metals have the characteristics of high biocompatibility, excellent thermal and electrical conductivity, self-healing ability, fluidity, low viscosity and low vapor pressure. They can sense external stimuli and appropriately judge and process stimuli to respond to environmental changes. Among them, gallium-based alloy liquid metals have attracted people's attention due to their deformability, non-toxicity, self-healing ability, high electrical conductivity, high thermal conductivity and unique surface chemical properties. At present, the most commonly used gallium-based liquid metals are eutectic gallium-indium alloys and eutectic gallium-indium-tin alloys. Compared with eutectic gallium-indium-tin alloys, eutectic gallium-indium alloys have a very thin oxide layer (0.7-3nm) on their surface, which can form a mechanically stable structure and can be cast into various complex shapes. In addition, eutectic gallium-indium alloys not only have most of the characteristics of traditional liquid metals (such as excellent electrical and thermal conductivity, low viscosity and high fluidity, etc.), but also have a variety of unique characteristics (such as instantaneous oxidation, shape variability, stretchability, self-healing and biocompatibility, etc.).

[0003] Magnetic liquid metal is a material prepared by mixing liquid metal and magnetic particles. The material has good fluidity, high thermal conductivity and magnetism. At the same time, the melting point of liquid metal close to room temperature can be used to enable it to reversibly transform between solid and liquid states, and show obvious performance changes (such as thermal enthalpy, mechanical stiffness, morphology, surface adhesion, catalytic activity, etc.) when approaching its equilibrium melting point. These variable properties benefit from the melting and solidification process of liquid metal at near room temperature, which realizes the reversible regulation of its performance. The reversible phase change of magnetic liquid metal between solid and liquid has been applied in many fields, including thermal management, variable stiffness electronics and robotics, conversion of insulators and conductors, controlled release, tumor cell elimination, shape memory devices, flexible electronics, low-temperature welding and the realization of electrocatalytic switches.

[0004] At present, in the field of industrial manufacturing or biomedicine, alloying technology is mainly used to control the temperature to control the morphological phase change of magnetic liquid metal, and an external magnetic field is used to control its movement, deformation, splitting and healing. For example, the magnetic liquid metal is moved to a specific position on the circuit board in liquid form and solidified into a solid to repair the circuit; for another example, the magnetic liquid metal is made into a miniature magnetically controlled solid-liquid phase change robot, which enters the human body under the control of an external magnetic field to perform medical tasks such as targeted drug delivery or foreign body removal. However, the above-mentioned way of realizing solid-liquid phase change of magnetic liquid metal is completely dependent on the external environment, which brings great inconvenience to practical application. At the same time, during human application, the high-frequency heating magnetic field will cause harm to the human body. Summary of the invention

[0005] The object of the present invention is to overcome the deficiencies of the prior art and provide a method for active solid-liquid phase change of a magnetic gallium-indium alloy.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The present invention provides a method for active solid-liquid phase change of a magnetic gallium-indium alloy, which utilizes a magnetic field to bring magnetic gallium and magnetic indium into contact to alloy and form a liquid magnetic gallium-indium alloy;

[0008] The magnetic gallium is in solid state, comprising metallic gallium and magnetic particles;

[0009] The magnetic indium is in solid state and includes metal indium and magnetic particles.

[0010] As a preferred embodiment of the method for active solid-liquid phase change of a magnetic gallium-indium alloy according to the present invention, taking the total mass of metal gallium and metal indium in the liquid magnetic gallium-indium alloy as 100%, the mass fraction of metal indium in the liquid magnetic gallium-indium alloy is ≤50%, preferably 5% to 45%, and more preferably 10% to 40%; specifically, it can be 60%, 55%, 50%, 45%, 40%, 35%, 30%, 25%, 20%, 15%, 10%, or 5%.

[0011] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the mass ratio of metal gallium to magnetic particles in the magnetic gallium is (8-12):(0.5-1.5). Optionally, in parts by weight, the metal gallium in the magnetic gallium can be 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts, and the magnetic particles can be 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts.

[0012] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the mass ratio of metal indium in the magnetic indium to magnetic particles is (8-12): (0.5-1.5). Optionally, in parts by weight, the metal indium in the magnetic indium can be 8.5 parts, 9 parts, 9.5 parts, 10 parts, 10.5 parts, 11 parts, 11.5 parts, and the magnetic particles can be 0.6 parts, 0.8 parts, 1 part, 1.2 parts, 1.4 parts.

[0013] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the magnetic particles in the magnetic gallium and magnetic indium are independently selected from at least one of neodymium iron boron particles, iron oxide particles, cobalt oxide particles and nickel oxide particles.

[0014] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the average particle size of the magnetic particles in the magnetic gallium or magnetic indium is 4 to 6 μm. Optionally, the average particle size of the magnetic particles in the magnetic gallium or magnetic indium can be 4.5 μm, 5 μm, or 5.5 μm.

[0015] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the magnetic gallium is obtained by mixing liquid metal gallium and magnetic particles.

[0016] As a preferred embodiment of the method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention, the magnetic indium is obtained by mixing liquid metal indium and magnetic particles.

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

[0018] The method for active solid-liquid phase change of magnetic gallium-indium alloy of the present invention does not require alternating magnetic field heating. It only requires contacting solid magnetic gallium with solid magnetic indium to alloy the two to form a liquid magnetic gallium-indium alloy, so as to realize active solid-liquid conversion at any time and any position during the movement process, and the magnetic domains of the magnetic particles are variable, thereby giving full play to the advantages of easy solid-state control of magnetic gallium or magnetic indium and high liquid fluidity of magnetic gallium-indium alloy. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a graph showing the melting point measurements of different gallium-indium alloys;

[0020] Figure 2 This is a schematic diagram of the preparation process of a magnetic gallium or magnetic indium robot;

[0021] Figure 3 The solid and liquid representation diagram of the magnetic gallium-indium alloy formed by the contact between the magnetic gallium robot and the magnetic indium robot;

[0022] Figure 4 A diagram showing the process of repairing circuits using a magnetic gallium robot and a magnetic indium robot;

[0023] Figure 5 Diagram of the process of biomedical drug delivery using magnetic gallium robots and magnetic indium robots. DETAILED DESCRIPTION

[0024] In order to better illustrate the purpose, technical solutions and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments.

[0025] Unless otherwise specified, other materials, reagents, etc. used in the examples can be obtained from commercial sources.

[0026] Example 1

[0027] Melting point measurement of different gallium-indium alloys: Differential scanning calorimetry (eg Figure 1 The melting points of metallic gallium, gallium-indium alloys with different mass ratios (Ga:In = 9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8, 1:9) and metallic indium (as shown in a) were measured. Figure 1 c), where the DSC curves of some gallium-indium alloys are shown in Figure 1 b shown; according to Figure 1 It can be seen that the melting point of metallic gallium is 30°C, and the melting point of metallic indium is 160°C, and both are in solid form at room temperature (25°C); at the same time, it is found that when Ga:In in the gallium-indium alloy is 9:1, 8:2, 7:3 or 6:4, the melting point of the gallium-indium alloy is lower than room temperature (25°C), indicating that the gallium-indium alloy is liquid at room temperature at this time, indicating that the gallium-indium alloy has the ability to undergo active solid-liquid phase change at room temperature.

[0028] Example 2

[0029] Preparation of magnetic gallium or magnetic indium robots (eg Figure 2 As shown in the figure): ferromagnetic neodymium iron boron (NdFeB) particles (average particle size of 5 μm) are mixed into a liquid metal matrix (liquid metal gallium or liquid metal indium) by a mechanical mixing method to obtain a magnetic liquid metal; the magnetic liquid metal is then placed in a mold and solidified to obtain a magnetic gallium or magnetic indium with a specific shape; the magnetic gallium or magnetic indium is then magnetized by a magnetizer to make the magnetic moment directions of the internal magnetic domains consistent, to obtain a magnetic gallium or magnetic indium robot.

[0030] The mass ratio of the liquid metal to the NdFeB particles is 10:1; the mechanical mixing method specifically refers to mixing the NdFeB particles with metal gallium or metal indium in an agate mortar to obtain liquid magnetic gallium and liquid magnetic indium.

[0031] When the above-mentioned magnetic gallium robot and magnetic robot are directly brought into contact at room temperature (25°C), alloying can occur to form a liquid magnetic gallium-indium alloy with good fluidity (wherein the mass ratio of metal gallium to metal indium is 3:1), which means that when solid magnetic gallium is brought into contact with solid magnetic indium, active solid-liquid transformation will occur to form a liquid magnetic gallium-indium alloy; when pressure is applied to the surface of the liquid magnetic gallium-indium alloy, the liquid magnetic gallium-indium alloy can be squeezed, moved or changed in shape (such as Figure 3 c), indicating that the liquid magnetic gallium-indium alloy has the characteristic of easy deformation and can be suitable for different complex application scenarios.

[0032] In addition, the solid magnetic gallium-indium alloy formed after the liquid magnetic gallium-indium alloy solidifies has a fixed volume and shape and a relatively hard texture (such as Figure 3The surface of the liquid has granular protrusions, which are mainly caused by the added magnetic particles. However, the addition of magnetic particles does not affect the fluidity of the magnetic gallium-indium alloy. The liquid magnetic gallium-indium alloy can still be squeezed out of the syringe (as shown in Fig. Figure 3 b), indicating that the liquid magnetic gallium-indium alloy still maintains good fluidity.

[0033] Example 3

[0034] Repair circuit testing, including the following steps:

[0035] 1) Using the magnetic response characteristics of magnetic gallium and magnetic indium, the magnetic gallium robot and the magnetic indium robot are accurately moved to the breakpoint of the circuit (i.e., the location that needs to be repaired) through an external magnetic field;

[0036] 2) After reaching the breakpoint, the magnetic gallium robot and the magnetic indium robot come into contact and alloy to form a liquid gallium-indium alloy (where the mass ratio of metal gallium to metal indium is 3:1);

[0037] 3) Taking advantage of the good fluidity of liquid gallium-indium alloy, the liquid gallium-indium alloy is manipulated by magnetic field to fill the breakpoints, and with its excellent conductive properties, effective connection of the breakpoints and conduction of the circuit can be achieved.

[0038] Repair circuit test process and test results Figure 4 As shown, Figure 4 a is an example of an electronic device in a confined space that is difficult to reach; Figure 4 b is a schematic diagram of breakpoint repair; Figure 4 c is the circuit diagram to be repaired; Figure 4 d is a physical diagram of the circuit connection, in which the circuit between points P and Q is not connected; Figure 4 e is to move the solid-state magnetic gallium robot and magnetic indium robot to the breakpoint through magnetic manipulation; Figure 4 f is the contact between the magnetic gallium robot and the magnetic indium robot to form a liquid gallium-indium alloy; Figure 4 g is the magnetic field controlling the liquid gallium-indium alloy to pass through the perforated board (radius 1mm) to reach the back circuit and turn on the circuit; Figure 4 h is the circuit connection diagram on the back of the perforated board at the beginning, and it can be seen that points P and Q are not conducting; Figure 4 i represents the liquid metal penetrating into the back of the pegboard, repairing the breakpoint and turning on the circuit; the final results show that the magnetic gallium robot and the magnetic indium robot were used to successfully connect the breakpoints P and Q, turn on the circuit and light up the LED light, proving the obvious advantage of using magnetic gallium and magnetic indium in contact to achieve active solid-liquid phase change of magnetic gallium-indium alloy.

[0039] Example 4

[0040] Biomedical drug delivery test: Sodium fluorescein was selected as a model drug and embedded in a magnetic gallium robot for drug delivery research; the magnetic gallium robot and magnetic indium robot containing the model drug were moved to the drug release area respectively, and then the magnetic gallium robot and magnetic indium robot were manipulated by a magnetic field to reach the affected area and contact with each other to form a liquid gallium-indium alloy (the mass ratio of metal gallium to metal indium is 3:1), thereby destroying the structure of the magnetic gallium robot and releasing the embedded drug.

[0041] The test process and results are as follows Figure 5 As shown, Figure 5 a~5c are water-free human stomach model experiments, where Figure 5 a is the initial distribution position of the magnetic gallium robot and the magnetic indium robot in the human stomach model. Figure 5 b is the situation when the magnetic gallium robot and the magnetic indium robot just come into contact. Figure 5 c is the situation when the magnetic gallium robot and the magnetic indium robot are in contact for 20 minutes. It can be found that as the contact time of the magnetic gallium robot and the magnetic indium robot increases, the magnetic gallium and magnetic indium are alloyed, so that the structure of the magnetic gallium robot is destroyed and the drug is released accurately. Figure 5 d~5f are human stomach model experiments with water, Figure 5 d is the initial distribution position of the magnetic gallium robot and the magnetic indium robot in the human stomach model. Figure 5 e is the situation when the magnetic gallium robot and the magnetic indium robot just come into contact. Figure 5 f is the situation when the magnetic gallium robot and the magnetic indium robot are in contact for 5 minutes. It can be seen that even in a water environment, as the contact time between the magnetic gallium robot and the magnetic indium robot increases, the magnetic gallium and the magnetic metal indium can still be alloyed, causing the structure of the magnetic gallium robot to be destroyed and the drug to be released accurately.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for active solid-liquid phase change of a magnetic gallium-indium alloy, characterized in that: Using a magnetic field to bring magnetic gallium and magnetic indium into contact to alloy them and form a liquid magnetic gallium-indium alloy; The magnetic gallium is in solid state, comprising metallic gallium and magnetic particles; The magnetic indium is in solid state and includes metal indium and magnetic particles.

2. The method according to claim 1, characterized in that Taking the total mass of metal gallium and metal indium in the liquid magnetic gallium-indium alloy as 100%, the mass fraction of the metal indium is ≤50%.

3. The method according to claim 2, characterized in that Taking the total mass of metal gallium and metal indium in the liquid magnetic gallium-indium alloy as 100%, the mass fraction of the metal indium is 5% to 45%.

4. The method according to claim 3, characterized in that Taking the total mass of metal gallium and metal indium in the liquid magnetic gallium-indium alloy as 100%, the mass fraction of the metal indium is 10% to 40%.

5. The method according to claim 1, characterized in that The mass ratio of the metal gallium to the magnetic particles in the magnetic gallium is (8-12):(0.5-1.5).

6. The method according to claim 1, characterized in that The mass ratio of the metal indium to the magnetic particles in the magnetic indium is (8-12):(0.5-1.5).

7. The method according to claim 1, characterized in that The magnetic particles in the magnetic gallium and magnetic indium are independently selected from at least one of neodymium iron boron particles, iron oxide particles, cobalt oxide particles, and nickel oxide particles.

8. The method according to claim 1, characterized in that The average particle size of the magnetic particles in the magnetic gallium or magnetic indium is 4 to 6 μm.

9. The method according to claim 1, characterized in that: The magnetic gallium is obtained by mixing liquid metal gallium and magnetic particles.

10. The method according to claim 1, characterized in that The magnetic indium is obtained by mixing liquid metal indium and magnetic particles.

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