阅读说明：本技术 一种高导电性永磁体凝胶及其制备方法和应用 (High-conductivity permanent magnet gel and preparation method and application thereof ) 是由 何志祝 尹涛 邓中山 桂林 于 2020-03-18 设计创作，主要内容包括：本发明公开了一种高导电性永磁体凝胶及其制备方法和应用,永磁体凝胶包括液态金属基质和磁化后的表面具有镀层的永磁体颗粒,永磁体颗粒均匀分散在液态金属基质内；其制备方法包括,在未磁化的永磁体颗粒表面均匀沉积镀层；酸洗去除永磁体颗粒表面的氧化物,并在真空条件下采用物理搅拌的方法将永磁体颗粒和液态金属基质混匀；采用脉冲充磁法进行充磁。本发明通过将微米级或者纳米级永磁体颗粒与低熔点室温液态金属掺混的方式得到磁极可调且形态可重构的高导电性永磁体凝胶,其在兼具液态金属的高导电性和永磁体颗粒所具备的剩磁之外,还可通过外部磁场来调控其磁极方向,解决了现有磁流体在没有外部磁场情况下不具备磁性的问题,应用前景好。(The invention discloses a high-conductivity permanent magnet gel and a preparation method and application thereof, wherein the permanent magnet gel comprises a liquid metal matrix and permanent magnet particles with plated layers on the magnetized surfaces, and the permanent magnet particles are uniformly dispersed in the liquid metal matrix; the preparation method comprises uniformly depositing a coating on the surface of unmagnetized permanent magnet particles; removing oxides on the surfaces of the permanent magnet particles by acid washing, and uniformly mixing the permanent magnet particles and the liquid metal matrix by adopting a physical stirring method under a vacuum condition; and magnetizing by adopting a pulse magnetizing method. The invention obtains the high-conductivity permanent magnet gel with adjustable magnetic poles and reconfigurable shape by mixing the micron-sized or nano-sized permanent magnet particles with the low-melting-point room-temperature liquid metal, and the high-conductivity permanent magnet gel can regulate and control the magnetic pole direction of the liquid metal through an external magnetic field besides the high conductivity of the liquid metal and the residual magnetism of the permanent magnet particles, thereby solving the problem that the existing magnetic fluid has no magnetism under the condition of no external magnetic field and having good application prospect.)

1. The high-conductivity permanent magnet gel is characterized by comprising a liquid metal matrix and permanent magnet particles with coatings on the magnetized surfaces, wherein the permanent magnet particles are uniformly dispersed in the liquid metal matrix.

2. The highly conductive permanent magnet gel of claim 1, wherein the liquid metal matrix is present in the highly conductive permanent magnet gel in a proportion of 50-80% by mass.

3. The highly conductive permanent magnet gel according to claim 1 or 2, wherein the permanent magnet particles have a particle size of 10nm to 100 μm, and the plating layer is a copper gallium alloy having a thickness of 3 to 5 nm.

4. A highly conductive permanent magnet gel according to any of claims 1-3, wherein the permanent magnet particles are rare earth permanent magnet particles or ferrite permanent magnet particles having a high remanence;

preferably, the permanent magnet particles are one or more of neodymium iron boron, samarium cobalt, alnico, and ferrite permanent magnet particles.

5. A highly conductive permanent magnet gel according to any of claims 1-3 wherein the liquid metal matrix is a gallium-based liquid metal alloy;

preferably, the liquid metal matrix is one of gallium, gallium indium tin and gallium indium tin zinc.

6. The highly conductive permanent magnet gel according to any one of claims 1 to 5, characterized in that the viscosity of the highly conductive permanent magnet gel is greater than 10000 Pa-s.

7. The highly conductive permanent magnet gel of any one of claims 1-5, wherein the highly conductive permanent magnet gel has an electrical conductivity greater than 10⁶S/m。

8. The method for preparing a highly conductive permanent magnet gel according to any one of claims 1 to 7, comprising:

uniformly depositing a coating on the surfaces of unmagnetized permanent magnet particles by a magnetron sputtering method; pickling the permanent magnet particles with the plating layer on the surface to remove surface oxides, and uniformly dispersing the permanent magnet particles with the plating layer on the surface in a liquid metal matrix by adopting a physical stirring method under a vacuum condition; and magnetizing by adopting a pulse magnetizing method to obtain the high-conductivity permanent magnet gel.

9. Use of the highly conductive liquid permanent magnet according to any one of claims 1 to 7 for thermal management of electronic devices and flexible robots.

Technical Field

The invention relates to the technical field of magnetic functional composite materials, in particular to a high-conductivity permanent magnet gel and a preparation method and application thereof.

Background

The magnetic fluid is a suspension formed by mixing paramagnetic nano-sized or micron-sized particles (such as ferroferric oxide, metallic iron or nickel) into a base fluid (water, oil or room-temperature liquid metal), and can show the characteristics of obvious viscosity increase, form change and the like under the excitation of an external magnetic field.

Due to the unique magnetic control effect of the magnetic fluid, the magnetic fluid has unique advantages in the fields of soft robots, flexible electronic equipment, 3D printing, heat dissipation systems, biomedicine and the like, and is paid more and more attention by researchers; among them, the liquid metal magnetofluid using a room-temperature liquid metal alloy as a base liquid has shown many unique advantages in many fields such as soft robots, flexible electronic devices, 3D printing, heat dissipation systems, and biomedicine.

However, the application of the existing liquid metal magnetic fluid is limited by the following problems: on one hand, the magnetic particles in the magnetic fluid are easy to precipitate; on the other hand, the magnetic fluid has magnetism that exists only when excited by an external magnetic field, and does not have permanent magnetic characteristics by itself.

Therefore, how to fully consider the application limitation of the liquid metal-based magnetofluid in certain specific fields can ensure that the liquid metal-based magnetofluid can keep certain residual magnetism for a long time besides keeping the high conductivity of the liquid metal; meanwhile, the problems that magnetic particles in the existing magnetofluid liquid are easy to precipitate, the shape and the magnetic poles of the magnetic particles are not easy to control and the like are solved, and the key technical problems are urgently needed to be solved by technical personnel in the field.

The present invention has been made in view of the above circumstances.

Disclosure of Invention

In order to solve or partially solve the technical problems, the invention provides a high-conductivity permanent magnet gel and a preparation method and application thereof.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a high-conductivity permanent magnet gel, which comprises a liquid metal matrix and permanent magnet particles with coatings on the magnetized surfaces, wherein the permanent magnet particles are uniformly dispersed in the liquid metal matrix.

In detail, in the technical scheme, the magnetic poles of the high-conductivity permanent magnet gel are adjustable and the shape of the high-conductivity permanent magnet gel is reconfigurable, and the magnetized permanent magnet particles have remanence, so that strong interaction occurs among the particles, the permanent magnet particles are connected with each other to form a three-dimensional network structure, the precipitation of the permanent magnet particles is inhibited, and the flow of the liquid metal matrix is restrained, so that the high-conductivity permanent magnet gel is similar to a gel structure in a microscopic view, and is similar to a plasticine with a reconfigurable shape in a macroscopic view. The macroscopic magnetism of the high-conductivity permanent magnet gel is caused by the ordered arrangement of the magnetic poles of a large number of permanent magnet particles in the high-conductivity permanent magnet gel; therefore, the regulation and control of the high-conductivity permanent magnet gel can be realized by regulating and controlling the arrangement mode of the permanent magnet particles. For example, the arrangement of the inner permanent magnet particles of the permanent magnet gel can be disturbed by a simple manner such as kneading, so that the macroscopic magnetism of the permanent magnet gel disappears; or, the permanent magnet particles in the permanent magnet gel can rotate under the action of an applied external magnetic field to obtain oriented magnetism.

Specifically, in the above technical solution, the mass ratio of the liquid metal matrix in the highly conductive permanent magnet gel is 50-80%.

In detail, when the mass proportion of the liquid metal matrix in the high-conductivity permanent magnet gel is 50-80%, the high-conductivity permanent magnet gel can be ensured to be always in a gel state. When the proportion of the liquid metal base liquid is more than 80 wt%, the permanent magnet particles in the liquid metal base liquid are less and difficult to form a three-dimensional network structure, so that the permanent magnet gel is viscous; whereas when the proportion of the liquid metal-based liquid is less than 50 wt%, too many permanent magnet particles may make the permanent magnet gel difficult to shape.

Specifically, in the above technical scheme, the particle size of the permanent magnet particles is 10nm-100 μm, and the plating layer is a copper-gallium alloy with a thickness of 3-5 nm.

In detail, when the particle diameter of the permanent magnet particles is less than 10nm, it is difficult to plate them; when the particle size of the permanent magnet particles is smaller than 100 μm, the total magnetic moment of the permanent magnet particles is large, so that the acting force between the permanent magnet particles is large, and the permanent magnet particles are difficult to regulate and control.

In detail, the copper-gallium alloy coating is used for solving the problem that the liquid metal matrix and the permanent magnet particles are not wetted, enhancing the wetting and the adhesion performance of the permanent magnet particles and the liquid metal matrix and achieving the purpose of improving the electrical conductivity of the permanent magnet particles.

Further, in the above technical solution, the permanent magnet particles are rare earth permanent magnet particles or ferrite permanent magnet particles having high remanence.

Preferably, in the above technical solution, the permanent magnet particles are one or more of neodymium iron boron, samarium cobalt, alnico, and ferrite permanent magnet particles.

Further, in the above technical solution, the liquid metal matrix is a gallium-based liquid metal alloy.

Preferably, in the above technical solution, the liquid metal matrix is one of gallium, gallium indium tin, and gallium indium tin zinc.

Still further, in the above technical means, the viscosity of the highly conductive permanent magnet gel is greater than 10000Pa · s.

Still further, in the above technical solution, the conductivity of the highly conductive permanent magnet gel is greater than 10⁶S/m。

In another aspect, the present invention provides a method for preparing the above high-conductivity permanent magnet gel, including:

uniformly depositing a coating on the surfaces of unmagnetized permanent magnet particles by a magnetron sputtering method; pickling the permanent magnet particles with the plating layer on the surface to remove surface oxides, and uniformly dispersing the permanent magnet particles with the plating layer on the surface in a liquid metal matrix by adopting a physical stirring method under a vacuum condition; and magnetizing by adopting a pulse magnetizing method to obtain the high-conductivity permanent magnet gel.

In detail, in the technical scheme, a sample is placed in the center of a coil by a pulse magnetizing method, pulse heavy current is injected into the coil, and the generated pulse magnetic field can magnetize permanent magnet gel; the pulse type magnetizing method can reduce the electromagnetic force action of the magnetizing process on the magnetic particles.

The invention further provides application of the high-conductivity liquid permanent magnet in electronic device thermal management and flexible robots.

The invention has the advantages that:

the invention obtains the high-conductivity permanent magnet gel with adjustable magnetic poles and reconfigurable shape by mixing the micron-scale or nano-scale permanent magnet particles and the gallium-based liquid metal according to a certain proportion, and the invention can change the direction of the magnetic poles of the liquid metal by an external magnetic field besides the high conductivity of the liquid metal and the remanence of the permanent magnet particles, thereby solving the problem that the existing liquid metal magnetic slurry has no magnetism under the condition of no external magnetic field, and simultaneously, can realize better application in the fields of electronic device heat management, soft body robots and the like.

Drawings

FIG. 1 is a schematic diagram of a method for preparing a highly conductive permanent magnet gel and physical diagrams of permanent magnet gels of different forms according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a remodeling process of a highly conductive permanent magnet gel according to an embodiment of the present invention;

FIG. 3 is a schematic diagram of the magnetic pole direction control of a highly conductive permanent magnet gel according to an embodiment of the present invention;

FIG. 4 is a schematic diagram of the movement of a highly conductive permanent magnet gel according to an embodiment of the present invention;

FIG. 5 is a Halbach array of highly conductive permanent magnet gels according to an embodiment of the invention;

FIG. 6 is a schematic diagram of an embodiment of a highly conductive permanent magnet gel for use as thermal management in an electronic device;

FIG. 7 is a hysteresis curve of a highly conductive permanent magnet gel according to an embodiment of the present invention;

in the figure: 1-permanent magnet particles, 2-liquid metal matrix, 3-stirring rod, 4-beaker, 5-permanent magnet gel, 6-magnetic line, 7-coil, 8-permanent magnet, 9-electronic device, 10-ferrite system 430 stainless steel sheet.

Detailed Description

The following describes the embodiments of the present invention in further detail with reference to specific examples.

The following examples are intended to illustrate the present invention, but not to limit the scope of the invention, which is defined by the claims.

Unless otherwise specified, the test reagents and materials used in the examples of the present invention are commercially available; unless otherwise specified, the technical means used in the examples of the present invention are conventional means well known to those skilled in the art.