CN114672365B

CN114672365B - Vacancy-dominated giant electrorheological fluid and preparation method thereof

Info

Publication number: CN114672365B
Application number: CN202210303339.3A
Authority: CN
Inventors: 沈容; 陆坤权
Original assignee: Institute of Physics of CAS
Current assignee: Institute of Physics of CAS
Priority date: 2022-03-24
Filing date: 2022-03-24
Publication date: 2022-11-11
Anticipated expiration: 2042-03-24
Also published as: CN114672365A

Abstract

The invention provides a vacancy-dominated giant electrorheological fluid which is prepared by mixing dielectric particles and insulating liquid, wherein vacancies and/or vacancy combined distribution are formed in the inner part and the surface of the dielectric particles. The presence of vacancies in the dielectric particles is a key factor in the generation of novel electrorheological effects. The invention adopts a high-energy ball milling method to enable dielectric particles to generate a large number of vacant sites. The vacancy-dominated giant electrorheological fluid has high shear yield strength which can reach hundreds of kPa; abrasion resistance, and the performance of the electrorheological fluid is unchanged after friction for hundreds of hours; low leakage current (<20μA/cm ² ) (ii) a Small change with temperature (the change of yield strength can be less than 10 percent within the range of 0-100 ℃); the shear strength is fast to the response time of the electric field (about 10 ms); the anti-settling property is good; the preparation method is simple. The novel giant electrorheological fluid material can enable the electrorheological technology to become practical.

Description

Vacancy-dominated giant electrorheological fluid and preparation method thereof

Technical Field

The invention belongs to the field of electrorheological fluid materials, and particularly relates to a vacancy-dominated giant electrorheological fluid and a preparation method thereof.

Background

Electrorheological fluids (ER fluids) are suspensions of solid particles mixed with an insulating liquid. Under the action of an external electric field, the shear strength of the electrorheological fluid is increased along with the increase of the electric field. When the electric field strength is sufficiently high, the electrorheological fluid may be transformed from a liquid-like state to a solid-like substance. The change in shear strength can be continuously and rapidly adjusted with a response time of about 10 milliseconds. The electrorheological fluid intelligent material with adjustable hardness has wide application prospect in the technical and industrial fields of damping, shock absorption, transmission, valves, polishing, electromechanical integrated intelligent control and the like. As early as the early 90 s of the last century, reports of the united states department of energy suggest that electrorheological techniques can have revolutionary impact in several industrial technology sectors. However, electrorheological fluid materials suitable for practical applications have not been successfully researched and developed.

The electrorheological effect is discovered in 1948, and over 70 years, two generations of electrorheological fluid materials are developed successively. The first generation of electrorheological fluid is compounded with solid dielectric particles and insulating oil. The principle is that dielectric particles are polarized in an electric field, and the dielectric mismatch between solid particles and oil generates an electrorheological effect, which is generally called dielectric electrorheological fluid or traditional electrorheological fluid. Despite the numerous different material types tested, the yield strength of the electrorheological fluids produced was only a few kPa. Research shows that the theoretical upper limit of the yield strength of the dielectric electrorheological fluid is about 10kPa, and the requirement of practical application cannot be met. Giant electrorheological fluid developed in about 2000 years is also called polar molecular electrorheological fluid and is the second generation electrorheological fluid. Preparing nano solid particles by a wet chemical method and carrying out surface coating or modification, wherein the surface coating comprises polar molecules. The action principle of the electrorheological fluid is different from that of the traditional electrorheological fluid: because the local electric field between the polarized particles is about 2-3 orders of magnitude higher than the external electric field, the surface polar molecules between the particles are oriented along the direction of the electric field, the interaction caused is far greater than the acting force between the polarized particles, and the shear yield strength of the electrorheological fluid can reach hundreds of kPa. However, the coating or finishing layer on the particle surface of the electrorheological fluid is easy to wear, so that the shear strength of the electrorheological fluid is continuously reduced along with the wear time. The wear test shows that the shear yield strength is reduced by half after about several tens hours of friction. Therefore, such a polar molecular type electrorheological fluid (second generation electrorheological fluid) cannot be practically used either.

Another class of materials corresponding to electrorheological fluids is magnetorheological fluids, whose yield strength has been adjusted by the application of a magnetic field, and has gained widespread use internationally. Compared with magnetorheological fluids, the electrorheological fluid has the following advantages: the applied power is low (about 1-2 orders of magnitude less than that of the magnetorheological fluid); short response times (about several times to an order of magnitude shorter); the manufactured device has small volume and light weight (the weight is several times): the shape of the electrode can be changed (more convenient for application in various occasions); the shear yield strength can reach hundreds of kPa (magnetorheological fluids can only reach about 50kPa due to the limitation of the magnetic saturation effect). Therefore, the obtained electrorheological fluid which can be practically applied has obvious superiority compared with the magnetorheological fluid. However, as mentioned above, the electrorheological fluids developed over the past decades either have low shear strength or are susceptible to wear and failure, and thus cannot be put to practical use.

Compared with the magnetorheological fluid, the novel electrorheological fluid has the defects of higher zero-field viscosity, is not suitable for occasions with high-speed motion, and needs further research and improvement.

In view of the above, in the field of electrorheological fluids, it is highly desirable to provide a giant electrorheological fluid material with excellent comprehensive performance and practical application. Moreover, the preparation method has the advantages of high efficiency, good repeatability, low cost and convenient production.

Disclosure of Invention

The present invention aims at overcoming the demerit of available electrorheological fluid and solving the problem that these electrorheological fluids may not be used practically.

In order to achieve the above object, a first aspect of the present invention provides a vacancy-dominated giant electrorheological fluid which is configured by mixing dielectric particles and an insulating liquid, wherein the inside and/or surface of the dielectric particles contain vacancies and/or vacancy combinations;

preferably, the vacancies are selected from one or more of the following: oxygen vacancies, oxygen vacancy combinations, anion vacancies, cation vacancies, preferably oxygen vacancies and/or oxygen vacancy combinations; and/or

Preferably, the volume fraction of the dielectric particles in the prepared giant electrorheological fluid is 5% to 65%, more preferably 5% to 60%, and further preferably 10% to 60%.

The vacancy-dominated giant electrorheological fluid according to the first aspect of the invention, wherein,

the size of the vacancies and/or vacancy combinations existing in the dielectric particles is 0.15-1 nm, preferably 0.15-0.6 nm; and/or

The number of the vacant sites is 1 to 20%, preferably 2 to 20%, and more preferably 3 to 15% of the total number of atoms.

the dielectric particles are prepared by high-energy ball milling of primary particles, preferably:

the dielectric constant of the primary particles is greater than 5, more preferably greater than 8, and even more preferably greater than 10;

the initial particles have a resistivity greater than 10 ³ Ω · m, more preferably greater than 10 ⁴ Ω · m, more preferably greater than 10 ⁵ Ω·m；

The size of the initial particles is 10 nanometers to 100 micrometers, more preferably 10 nanometers to 50 micrometers, and further preferably 10 nanometers to 10 micrometers;

the density of the primary dielectric particles is less than 7g/cm ³ More preferably less than 6g/cm ³ More preferably less than 5g/cm ³ (ii) a And/or

The primary particles are selected from one or more of the following combinations of compounds: tiO2 ₂ 、CaTiO ₃ 、BaTiO ₃ 、SrTiO ₃ 、CaCu ₃ Ti ₄ O ₁₂ 、LaTiO ₃ 、LiB ₃ O ₅ (LBO)、LiNbO ₃ 、KNbO ₃ 、Al ₂ O ₃ More preferably TiO ₂ 、CaTiO ₃ 、BaTiO ₃ 、SrTiO ₃ 、LaTiO ₃ 、LiB ₃ O ₅ (LBO)、LiNbO ₃ 、Al ₂ O ₃ Further preferred is TiO ₂ 、CaTiO ₃ 、SrTiO ₃ 、LaTiO ₃ 、LiB ₃ O ₅ (LBO)、LiNbO ₃ 、Al ₂ O ₃ 。

the insulating liquid has a resistivity of more than 1 × 10 ⁸ Ω · m, more preferably greater than 1 × 10 ⁹ Ω·m；

The dielectric constant of the insulating liquid is less than 8, more preferably less than 5, and even more preferably less than 3; and/or

The insulating liquid is selected from one or more of: silicone oil, machine oil, hydraulic oil, transformer oil, vegetable oil, preferably 100 ^# Silicone oil, 32 ^# Machine oil, 32 ^# Hydraulic oil, 10 ^# And (4) aviation hydraulic oil.

A second aspect of the present invention provides a method for producing the vacancy-dominated giant electrorheological fluid of the first aspect, which is characterized by comprising the steps of:

(1) Pre-treating the primary particles;

(2) Carrying out high-energy ball milling on the initial particles obtained in the step (1) to obtain dielectric particles containing vacancy and/or vacancy combination distribution;

(3) And (3) mixing and grinding the dielectric particles containing the vacancies and/or vacancy combination distribution prepared in the step (2) with insulating liquid to obtain the vacancy-dominated giant electrorheological fluid.

The method according to the second aspect of the present invention, wherein, in the step (1): the pre-treated primary particles comprise: removing adsorbate on the surface of the primary particles by heating in a muffle furnace;

preferably, the heating temperature is 200-800 ℃, more preferably 200-700 ℃, and further preferably 300-650 ℃; and/or

Preferably, the heating time is 1 to 8 hours, more preferably 2 to 7 hours, and still more preferably 2 to 5 hours.

The method according to the second aspect of the present invention, wherein the step (2) further comprises: heating in inert gas or vacuum, and performing high-energy ball milling on the dielectric particles in a ball mill to obtain dielectric particles with the inside and the surface containing the vacancies and/or the vacancy combination;

preferably, the ball mill is selected from one or more of the following: 4-pot planetary vertical ball mill, horizontal ball mill, stirring nano ball mill, vibration ball mill, drum-type rod mill, centrifugal ball mill;

preferably, the ball milling jar is selected from one or more of the following: agate cans, alumina cans, zirconia cans, tungsten carbide cans; and/or

Preferably, the rotational speed of the ball mill is more than 200 revolutions per minute, more preferably more than 250 revolutions per minute, and even more preferably more than 300 revolutions per minute.

The method according to the second aspect of the present invention, wherein, in the step (2): the mass ratio of the grinding balls used in the high-energy ball milling to the primary particles is 2 to 30, preferably 3 to 20, and more preferably 5 to 15.

The method according to the second aspect of the present invention, wherein, in the step (2):

when the ball milling is continued and the intensity of the prepared electrorheological fluid is not improved, the ball milling is stopped; and/or

The total time of the ball milling is 2 to 200 hours, preferably 5 to 100 hours, and more preferably 5 to 50 hours.

The method according to the second aspect of the present invention, wherein the step (2) further comprises:

shoveling the sticky wall particles for continuous ball milling in the ball milling process, and/or arranging a stirring method in a ball milling tank, and after high-energy ball milling, sieving the particles by a mesh screen to obtain dielectric particles containing vacancies and/or vacancy combined distribution;

preferably, the frequency of shoveling the sticky wall particles is 1 to 5 hours and 1 time, and further preferably 1 to 2 hours and 1 time; and/or

Preferably, the mesh number of the mesh screen is 20 to 400 mesh, more preferably 20 to 200 mesh, and further preferably 40 to 100 mesh.

According to one embodiment of the invention, the vacancy-dominated giant electrorheological fluid can enable TiO to be used for preparing particles by a high-energy ball milling method ₂ A large number of vacancies and/or vacancy combinations are created in the isodielectric particles, with a vacancy distribution both within and at the surface of the particles.

The action principle of the giant electrorheological fluid is briefly described as follows: the vacancy itself and the charges trapped by the vacancy in the particle can be approximately considered as quasi-free charges limited in the vacancy area, and the vacancy can become an induced dipole by polarization of the quasi-free charges. The electric field intensity among particles can reach 10 of the external electric field intensity ² -10 ³ The result is that the particle surface vacancies here induce dipole moments which are so large that strong interactions are caused. The current change effect is very strong and the shear yield strength can reach hundreds of kPa. The principle is described with figure 1. The action form of the induced dipole moment makes the shear strength tau and the electric field intensity E of the electrorheological fluid mainly show that tau is in proportion to E ² This property is different from the polar molecular type electrorheological fluid. The polar molecule type electrorheological fluid is an action of intrinsic dipole moment of polar molecules, and the shear strength tau and the electric field intensity E are in a relation of tau ^ E.

The preparation method of the vacancy-dominated giant electrorheological fluid comprises the following steps:

the giant electrorheological fluid is prepared by mixing dielectric particles containing a large number of vacancies with insulating oil. The fact that the prepared particles contain a large number of vacancies is the key to the new electrorheological effect principle and good performance.

The invention adopts a high-energy ball milling method (also called a mechanical alloying method) to process initial dielectric particles, and a large amount of vacancies, vacancy combination and other lattice defects are introduced into the prepared nano dielectric particles. The size of the introduced vacancies and vacancy combinations is in the range of about 0.15 to 0.6nm, and the number of vacancies can be 5% or more of the total number of atoms. These vacancies are an integral part of the dielectric particles, both internal and surface. If surface vacancies are lost due to wear, other vacancies will also appear and function. The high-energy ball milling method is adopted to make the dielectric particles generate vacant sites, and compared with other methods, the method has the advantages of easy control, high efficiency and low cost, and can also avoid the influence of complex factors caused by preparing the particles by other chemical methods.

The primary particles used in the present invention are particles having a relatively high dielectric constant and a high resistivity, the dielectric constant being greater than 5 and the resistivity being greater than 10 ³ Omega. M. The primary particle used is TiO ₂ ，CaTiO ₃ ，BaTiO ₃ ，SrTiO ₃ ，CaCu ₃ Ti ₄ O ₁₂ ，LaTiO ₃ ，LiB ₃ O ₅ (LBO),LiNbO3，KNbO3，Al ₂ O ₃ And the like in one or more combinations. The primary particle size is 10 nanometers to 100 microns. Before high-energy ball milling, the particles are placed in a muffle furnace and baked for several hours at a temperature of more than 300 ℃ to remove moisture and other impurities possibly adsorbed on the surfaces of the particles.

The invention uses high-energy ball milling to prepare particles, and the key points of the method are as follows: the ball milling tank used for high-energy ball milling is an agate tank, an alumina tank, a tungsten carbide tank or a zirconia tank; the mass ratio of the grinding balls to the primary particles is in the range of 5:1 to 15:1; the rotating speed of the ball mill is more than 200 revolutions per minute; the ball milling time is 5-100 hours; the powder can accumulate at the bottom and stick to the wall in the ball milling process, and the ball milling effect is improved and the ball milling time is reduced by shoveling or stirring; the particles after high-energy ball milling need to be screened by a screen mesh to remove the fragments mixed in by the damaged ball mill in the ball milling process.

The detection result of the high-energy ball milling prepared particles used by the invention is as follows: density measurement after high-energy ball milling shows that the density is lower than the initial particle density; some samples have a crystal structure which is changed after ball milling, for example, tiO with anatase structure ₂ The density of the particles after ball milling is 3.9g/cm ³ The reduction is 3.6g/cm ³ Changing from anatase structure to particles with rutile structure as main phase; the particle size is 10 nm to 50 nm by the methods of X-ray diffraction (XRD), electron microscope and the like; and observing that the crystal lattice has serious distortion and contains a large number of oxygen vacancies and crystal lattice defects; selecting TiO treated under 3 different ball milling conditions ₂ The particles are analyzed by synchrotron radiation X-ray absorption spectroscopy (XAFS) on the ball-milled TiO ₂ The coordination number of O of the Ti atom of the particle is found to decrease, and the numbers of oxygen vacancies are calculated to reach 7%,10% and 12% of the total number of oxygen atoms, respectively.

The vacancy-dominated giant electrorheological fluid is prepared by mixing high-energy ball-milled nano particles with insulating liquid. The volume fraction of the particles is 5-65%. The insulating liquid can be one or a mixture of silicone oil, mechanical oil, mineral oil, vegetable oil or other organic liquid. Its resistivity is greater than 1 × 10 ⁸ Ωm。

The yield strength of the vacancy-dominated giant electrorheological fluid prepared by the invention is measured by a rheometer; other properties were tested and measured using appropriate methods.

The vacancy-dominated giant electrorheological fluid obtained by the invention has the advantages of high shear strength, small leakage current, good temperature stability, long wear-resisting service life, good anti-settling property and simple preparation method. The main performance indexes are as follows: the shear yield strength can reach hundreds of kPa; the leakage current density is less than 20 muA/cm ² (ii) a The change of the shear yield strength can be less than 10% at 0-100 ℃, which is mainly determined byThe temperature characteristics of the insulating liquid used; at a shear rate of 30s ^-1 Under the condition, the half-height widths of the front edge and the rear edge of the shear strength to the electric field response time are respectively about 4ms and 14ms; at a shear rate of 300s ^-1 Under the condition, the shearing yield strength is not reduced after a 350-hour abrasion test; the prepared giant electrorheological fluid is placed for months without obvious sedimentation.

The vacancy-dominated giant electrorheological fluid provided by the invention is a new generation electrorheological fluid with excellent comprehensive performance, and can provide practical application. The problem that the performance of the electrorheological fluid can not meet the application requirement for decades is solved. The principle of the vacancy-dominated giant electrorheological effect determines that the giant electrorheological fluid has excellent properties; the high-energy ball milling method is adopted to prepare the particles, so that the vacancy is technically realized on the surface and in the particle, the influence of complex factors caused by the preparation of the particles by a common chemical method is avoided, and the excellent performance of the prepared giant electrorheological fluid is ensured.

The vacancy-dominated giant electrorheological fluid provided by the invention is characterized in that a large number of vacancies are introduced during particle preparation, the particle structure is greatly different from that of particles prepared by the prior art, and the physical principle is greatly different. In the giant electrorheological fluid, the voids on the surfaces of the particles form induced dipole moments in a strong local electric field between the particles, and generate strong attraction with polarization charges or induced dipoles on another particle, so that high shearing strength can be achieved. The shear strength tau and the electric field intensity E are tau- ² And (4) relationship. Since voids are present on and in the surface of the particles, new surface voids will appear even if the voids on the surface of the particles are worn down. Therefore, the vacancy-dominated giant electrorheological fluid can resist wear and is suitable for practical application.

As an intelligent material with adjustable strength, the giant electrorheological fluid has wide application range and can have great economic and social benefits. Mainly comprises the following steps:

(1) The damping and shock-absorbing device is used for damping and shock-absorbing systems, like a spring with adjustable and controlled elastic coefficient or a shock-absorbing pad with adjustable strength, the damping adjusting range is large (several orders of magnitude), the response time is fast (about 10 milliseconds), and semi-active intelligent control can be realized.

(2) The speed-variable transmission device is used for a transmission system, and can realize stepless speed transmission and regulation, such as a clutch and the like.

(3) The valve can be used for a liquid conveying system and can be used as an adjustable valve to intelligently control liquid flow. The regulation and control of the flow rate, the diversion, the mixing and the like of liquid flowing in a liquid pipeline and a micro-flow system.

(4) Application in the field of polishing: polishing is one of the key technologies in the field of semiconductor devices and optical devices, and generally adopts hard contact polishing. The electro-rheological fluid polishing is used, and soft contact is used for replacing hard contact polishing, so that flexible polishing is realized. Not only can greatly improve the roughness of the surface, but also can be attached to the surface, and the surface accuracy is improved. Compared with the existing magnetorheological fluid polishing, the electrorheological fluid polishing has the advantages that: the polishing head has small volume, low power and convenient regulation.

(5) Fitness, rehabilitation and equipment for disabled people: the motion force of pushing, pulling, pressing, rotating and the like can be adjusted, and intelligent regulation and control such as fitness and physical training equipment and the like are realized; a semi-autonomous power-assisted walking device for the disabled and an external power-assisted skeleton of a joint; an intelligent control reader for blind people, etc.

The electrorheological fluid has wide application prospect in the technical and industrial fields. The new electrorheological fluids will have a huge market that is difficult to estimate specifically.

The vacancy-dominated giant electrorheological fluid of the invention can have the following beneficial effects:

1. high shearing strength, small leakage current, good temperature stability, long wear-resisting life, good anti-settling property and simple preparation method. The main performance indexes are as follows: the shear yield strength can reach hundreds of kPa; the leakage current density is less than 20 muA/cm ² (ii) a The shear yield strength may vary by less than 10% at 0-100 ℃, which is mainly dependent on the temperature characteristics of the insulating liquid used; at a shear rate of 30s ^-1 Under the condition, the half-height widths of the front edge and the rear edge of the shear strength to the electric field response time are respectively about 4ms and 14ms; at a shear rate of 300s ^-1 Under the condition, the shearing strength is not reduced after a 350-hour abrasion test; the prepared giant electrorheological fluid is placed for months without obvious sedimentation; the preparation method is simple, the manufacturing cost is low, and the mass production is easy.

2. The giant electrorheological fluid material provided by the invention has comprehensive performance greatly superior to that of the existing electrorheological fluid, and can solve the problem that the electrorheological fluid cannot be applied for more than half a century, so that the development of electrorheological technology becomes practical.

Drawings

Embodiments of the invention are described in detail below with reference to the attached drawing figures, wherein:

fig. 1 shows that the vacancies inside the nanoparticles of the vacancy-dominated giant electrorheological fluid of the invention are indicated by gray circles after high-energy ball milling. Vacancies, including charge-trapping vacancies, form induced dipoles under the influence of an electric field. Local electric field E at inter-particle spacing _loc Up to 10 of external electric field E ² -10 ³ The vacancy-induced dipole moment is large here, causing strong interactions. The magnified inset shows the effect of the absence and presence of electric fields at the surface of the particle spacing. The surface of the A particle induces dipoles, and the A particle polarizes charges (1) and interacts with the induced dipoles (2) on the surface of the B particle.

Fig. 2 is a graph showing the relationship between the yield strength and the electric field strength of the vacancy-dominated giant electrorheological fluid of example 1 of the invention. Ball-milled TiO ₂ Powders and 10 ^# The volume fractions of the giant electrorheological fluid prepared from the silicone oil are respectively 40%,45.5%,47% and 49%.

Fig. 3 shows the yield strength versus electric field strength of the vacancy-dominated giant electrorheological fluid of example 2 of the invention. Ball-milled TiO ₂ Powders and 32 ^# The volume fractions of giant electrorheological fluid prepared from mechanical oil are 43.5%,48%,50% and 52.6%, respectively.

Fig. 4 shows the yield strength versus volume fraction of the vacancy-dominated giant electrorheological fluid of example 14 of the invention. By ball-milled TiO ₂ The powders are respectively 10 ^# Silicone oils (triangles) and 32 ^# Giant electrorheological fluid prepared from mechanical oil (circles) has yield strength varying with volume fraction at 3kV/mm (hollow) and 5kV/mm (solid).

Fig. 5 shows the yield strength, leakage current density and electric field strength of the vacancy-dominated giant electrorheological fluid of example 3 of the inventionDegree relation graph. Ball-milled TiO ₂ Powders and 32 ^# Machine oil/10 ^# The volume fraction of the giant electrorheological fluid prepared from the aviation hydraulic oil mixed liquid is 52 percent.

FIG. 6 shows the rutile TiO after ball milling in the vacancy-dominated giant electrorheological fluid of example 4 of the invention ₂ The giant electrorheological fluid prepared from the powder has a relationship graph of yield strength and electric field strength. The volume fraction was 49%.

FIG. 7 shows BaTiO after ball milling in vacancy-dominated giant electrorheological fluid of example 5 of the invention ₃ The giant electrorheological fluid prepared from the powder has a relationship diagram of yield strength, current density and electric field intensity. The volume fraction was 54%.

FIG. 8 shows CaTiO after ball milling in vacancy-dominated giant electrorheological fluid of example 6 of the invention ₃ The giant electrorheological fluid prepared from the powder has a relationship diagram of yield strength, current density and electric field intensity. The volume fraction was 53%.

FIG. 9 shows a CaCu ball-milled vacancy-dominated giant electrorheological fluid of example 7 of the invention ₃ Ti ₄ O ₁₂ The giant electrorheological fluid prepared from the powder has a relationship diagram of yield strength, current density and electric field intensity. The volume fraction was 49%.

FIG. 10 shows the ball-milled Al in vacancy-dominated giant electrorheological fluid of example 8 of the invention ₂ O ₃ The giant electrorheological fluid prepared from the powder has a relationship diagram of yield strength, current density and electric field intensity. The volume fraction was 51%.

Fig. 11 is a graph showing the relationship between the yield strength, the current density and the electric field strength of the giant electrorheological fluid prepared from the LBO powder after ball milling in the vacancy-dominated giant electrorheological fluid of example 9 of the present invention. The volume fraction was 48%.

FIG. 12 shows TiO after ball milling in vacancy-dominated giant electrorheological fluid of example 13 of the invention ₂ And Al ₂ O ₃ The relationship diagram of yield strength, leakage current density and electric field intensity of the prepared giant electrorheological fluid.

FIG. 13 shows high energy ball milling of SiO in vacancy-dominated giant electrorheological fluid of example 10 of the invention ₂ Particles, giant electrorheological fluid prepared from the particles and ball-milled TiO ₂ (rutile type), baTiO ₃ ,CaTiO ₃ ,CaCu ₃ Ti ₄ O ₁₂ (CCTO),LiB ₃ O ₅ (LBO),Al ₂ O ₃ ,SiO ₂ And (3) comparing the yield strength of the giant electrorheological fluid prepared by the particles with the electric field strength relationship.

Fig. 14 shows the results of measuring the response time of the shear strength of the giant electrorheological fluid to the square-wave electric field (the dashed line represents the electric field) according to example 11 of the present invention. Wherein fig. 14 (a) shows: square wave electric field E _max Shear strength response at frequency of 1Hz of =4 kV/mm; square wave width 400ms, shear rate

The sampling rate is 1k/s. FIG. 14 (b) shows the normalized shear strength of the leading edge of a square wave at 3kV/mm and a frequency of 1Hz as a function of shear rate, with a sampling rate of 4k/s. FIG. 14 (c) shows the variation of the normalized shear strength with shear rate at a sampling rate of 4k/s after a square wave of 3kV/mm at a frequency of 1 Hz.

Fig. 15 shows a comparison of the abrasion resistance of the vacancy-dominated giant electrorheological fluid of example 12 of the present invention and a polar molecule-based giant electrorheological fluid sample: (A) Is prepared by high-energy ball milling TiO2 particles for vacancy leading type giant electrorheological fluid; the (B) and the (C) are the existing polar molecular giant electrorheological fluid. Wherein the yield strength is a measurement at an electric field strength of 3kV/mm after the sample has been abraded.

Fig. 16 shows the change in size, morphology and density of the particles after high energy ball milling of the vacancy-dominated giant electrorheological fluid of example 19 of the invention. FIG. 16 (a) shows TiO ₂ STEM (upper) and high resolution electron microscope (lower) images of nanoparticles before (left) and after (right) high energy ball milling. (b) Shows TiO in anatase structure ₂ The X-ray diffraction spectra of the powder before high-energy ball milling (dotted line) and after high-energy ball milling for 36h (solid line) were compared. For analytical comparison, rutile and anatase TiO are given above and below respectively ₂ Powder X-ray diffraction standard pattern.

Fig. 17 shows a flow chart for the preparation of the vacancy-dominated giant electrorheological fluid of the invention.

Detailed Description

The invention is further illustrated by the following specific examples, which, however, are to be construed as merely illustrative and not limitative of the remainder of the disclosure in any way whatsoever.

This section generally describes the materials used in the testing of the present invention, as well as the testing methods. Although many materials and methods of operation are known in the art for the purpose of carrying out the invention, the invention is nevertheless described herein in as detail as possible. It will be apparent to those skilled in the art that the materials and methods of operation used in the present invention are well within the skill of the art, provided that they are not specifically illustrated.

The reagents and instrument sources used in the following examples are as follows:

materials:

TiO ₂ powder, available from Xuancheng crystal rui new materials Co.

BaTiO ₃ ，CaTiO ₃ Powder, purchased from south-ton, austin new electronics, ltd.

CaCu ₃ Ti ₄ O ₁₂ Powder, available from Shanghai Dian industries, inc.

Al ₂ O ₃ ，SiO ₂ Powder, taken from laboratory stored chemical reagents.

LiB ₃ O ₅ (LBO), obtained from the Crystal growth laboratory of Beijing institute of science, china.

Mechanical oil, hydraulic oil: beijing Yanshan petrochemical company.

100 ^# Silicone oil: purchased from Beijing chemical industry II.

10 ^# Aviation hydraulic oil: purchased from oil field company yumen, china.

The instrument comprises the following steps:

muffle furnace, purchase dead weight celebration jacobia science and technology ltd, model: FO510C.

Ball mill (1), purchased from fries instruments ltd, model: F-P4000,4 ball milling pots, each of which has a capacity of 1 liter.

Ball mill (2), purchased from Nanjing university instruments plant, type: QM-SP04 planetary ball mill, 4 ball-milling jars, each ball-milling jar capacity is 0.1 liter.

Example 1

This example is intended to illustrate the preparation process of the vacancy-dominated giant electrorheological fluid of the present invention.

Fig. 17 shows a flow chart for the preparation of the vacancy-dominated giant electrorheological fluid of the invention. The method comprises the following specific steps:

1. using TiO with anatase structure of about 20-30 nm diameter purchased from market ₂ And (3) placing the powder in a muffle furnace to be baked for 5 hours at 600 ℃, and removing possible adsorbates on the surface of the powder.

2. Taking TiO ₂ 100g of the powder was placed in an agate jar having a capacity of 1 liter. About 800g of mixed agate balls of different sizes were placed. Ball milling is carried out on a 4-pot vertical ball mill at the rotating speed of 400rpm, the ball milling pot is opened every several hours, sticky wall particles are shoveled down and stirred, and then ball milling is continued, wherein the total ball milling time is 100 hours.

3. And sieving the powder sample after ball milling by using a 40-mesh screen, and removing debris mixed in the ball milling process by using agate balls.

4. Ball milled TiO ₂ The powder density was 3.6g/cm ³ 。

5. Taking ball-milled TiO ₂ 4g of powder, by volume percentage, is 10 ^# Mixing silicon oil, grinding into uniform electrorheological fluid with mortar, wherein the prepared electrorheological fluid comprises 40%,45.5%,47% and 49% by volume.

The method for calculating the volume fraction of the dielectric particles in the electrorheological fluid comprises the following steps: from the given mass of the powder, divided by its density, the powder volume V is known _S . Volume V of oil _L Directly measuring by using a pipette or a measuring cylinder. For volume fraction formula

The volume fraction is calculated.

Example 2

The same ball-milled particles and treatment steps as in example 1 were used, and TiO ₂ The grams used for the powder were different in that:

using ball-milled TiO ₂ Powder modification and 32 ^# The mechanical oil is mixed to prepare the electrorheological fluid with the volume fractions of 43.5 percent, 48 percent, 50 percent and 52.6 percent respectively.

Example 3

The same method, procedure, and TiO were used as in example 1 for the preparation and treatment of solid particles ₂ The grams of powder used. The difference is that:

1. the ball milling time of the agate tank is 50 hours.

2. Will 32 ^# Machine oil and 10 ^# The aviation hydraulic oil is prepared from the following components in percentage by weight: 1, and mixing with the TiO after high-energy ball milling ₂ The powders are mixed to prepare the electrorheological fluid. The volume fraction of the prepared electrorheological fluid is 52 percent.

Example 4

The method comprises the following specific steps:

1. the TiO with rutile structure and diameter of about 50 nanometers purchased from the market ₂ And (3) placing the powder in a muffle furnace to be baked for 5 hours at 600 ℃, and removing possible adsorbates on the surface of the powder.

2. Taking TiO ₂ 25g of the powder was placed in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 42 hours.

4. Ball-milled TiO ₂ Powders 5g and 32 g ^# Mixing mechanical oil, grinding with mortar, and mixingA rheological fluid. The volume fraction of the prepared electrorheological fluid is 49 percent.

Wherein, the calculation method of the volume fraction of the dielectric particles in the electrorheological fluid is the same as that of the embodiment 1.

Example 5

The method comprises the following specific steps:

1. using commercially available BaTiO ₃ Powder with a diameter greater than 1 micron.

2. Taking BaTiO ₃ 30g of the powder was placed in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 42 hours.

4. Taking ball-milled BaTiO ₃ Powders 5g and 32 g ^# The mechanical oil is mixed and ground by a mortar to obtain uniform electrorheological fluid. The volume fraction of the prepared electro-rheological fluid is 54 percent.

Example 6

The method comprises the following specific steps:

1. using commercially available CaTiO ₃ Powder, about 1 micron in diameter.

2. Taking TiO ₂ 30g of the powder was placed in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 42 hours.

4. Taking the ball-milled CaTiO ₃ Powders 4g and 32 g ^# The mechanical oil was mixed and ground with a mortar to a uniform electrorheological fluid. The volume fraction of the prepared electrorheological fluid is 53 percent.

Example 7

The method comprises the following specific steps:

1. CaCu purchased from market ₃ Ti ₄ O ₁₂ (CCTO) powder having a powder diameter greater than 1 micron.

2. Taking CaCu ₃ Ti ₄ O ₁₂ 30g of the powder was placed in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 42 hours.

4. Taking the ball-milled CaCu ₃ Ti ₄ O ₁₂ Powders 5g and 100g ^# Mixing the silicon oil, and grinding the mixture evenly by a mortar. The volume fraction of the prepared electrorheological fluid is 49 percent.

Example 8

The method comprises the following specific steps:

1. with commercially available Al ₂ O ₃ Reagent, powder diameter greater than 1 micron.

2. Taking Al ₂ O ₃ 30g of the powder was placed in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 40 hours.

3. And sieving a powder sample subjected to ball milling by using a 40-mesh screen, and removing debris mixed in the ball milling process due to the loss of agate balls.

4. Taking ball-milled Al ₂ O ₃ Powders 3g and 32 g ^# The mechanical oil was mixed and ground with a mortar to a uniform electrorheological fluid. The volume fraction of the prepared electrorheological fluid is 51 percent.

Example 9

The method comprises the following specific steps:

1. using lithium triborate (LiB) ₃ O ₅ Abbreviated as LBO) crystals, the powder size is greater than 10 microns after crushing and grinding.

2. 30g of LBO powder was put in an agate jar having a volume of 0.1 liter. 165g of mixed agate balls of different sizes were placed. And (3) performing ball milling on a 4-pot vertical ball mill at the rotating speed of 551rpm, opening the ball milling pot every 2 hours, shoveling down the sticky-wall particles, stirring, and continuing ball milling for 40 hours.

4. Taking 3g and 32 g of LBO powder after ball milling ^# The mechanical oil was mixed and ground with a mortar to a uniform electrorheological fluid. The volume fraction of the prepared electrorheological fluid is 48 percent.

The calculation method of the volume fraction of the dielectric particles in the electrorheological fluid is the same as that in example 1.

Example 10

This example is used to illustrate the preparation method of the vacancy-dominated giant electrorheological fluid of the present invention, so as to show that the shear strength of the electrorheological fluid prepared from low dielectric constant particles is very low.

The method comprises the following specific steps:

chemical reagent SiO to be purchased in the market ₂ 30g of the powder was placed in a 0.1 l agate jar and ball milled at 551rpm for 40 hours. SiO after ball milling ₂ Pellets 3g and 32 g ^# The mechanical oil is mixed to prepare the electrorheological fluid, and the volume fraction is 52 percent. See example 17 and fig. 13 for a comparison of formulated electrorheological fluids after ball milling of high dielectric constant particles.

Example 11

This example is used to illustrate the preparation method of the measurement sample of shear strength of vacancy-dominated giant electrorheological fluid versus electric field response time.

The method comprises the following specific steps:

anatase TiO2 was treated in the same manner as in example 1 ₂ Powder powders, differing in: the method comprises the following steps of (1) using 5: mixed 32 in 1 volume ratio ^# Machine oil and 10 ^# The aerohydraulic oil is prepared into electrorheological fluid. The volume fraction was 48%. The method of measuring the response time and the results are set forth in example 16.

Example 12

This example serves to illustrate the preparation of the vacancy-dominated giant electrorheological fluid of the invention for wear test measurements.

The method comprises the following specific steps:

the same procedure and procedure used to prepare and treat the solid powder of example 1,2 was used. The changes are as follows:

1. the ball milling time of the agate pot is 60 hours.

2. Will 32 ^# Mechanical oil ball and 10 ^# The aviation hydraulic oil is prepared from the following components in percentage by weight: 1, and mixing with the TiO after high-energy ball milling ₂ The powders are mixed to prepare the electrorheological fluid. The volume fraction was 47%.

3. The electrorheological fluid is placed in a sealed cylinder, rotated at a shear rate of 300s < -1 >, and subjected to a 350-hour abrasion test to detect the change of yield strength.

The results show that the yield strength is not reduced by wear.

Example 13

This example is used to illustrate the relationship between the yield strength, leakage current density and electric field strength of the prepared electrorheological fluids obtained by mixing vacancy-dominated giant electrorheological fluids prepared in examples 2 and 9 of the present invention.

The method comprises the following specific steps:

1. ball-milled TiO ₂ (same as example 2) and Al ₂ O ₃ (same as example 8) the electrorheological fluid prepared according to the method is as follows: 1 mass ratio and 50 volume percent.

2. The shear yield strength was measured with a home-made flat shear apparatus.

FIG. 12 shows TiO after ball milling in vacancy-dominated giant electrorheological fluid of example 13 of the invention ₂ And Al ₂ O ₃ The relationship diagram of yield strength, leakage current density and electric field intensity of the prepared electrorheological fluid. The vacancy-dominated giant electrorheological fluid prepared by different high-energy ball-milling particles can be mixed for use, so that the concentration, the settleability, the fluidity, the yield strength and the like can be adjusted according to different particle densities and yield strength characteristics.

Example 14

This example illustrates a vacancy-dominated giant electrorheological fluid 10 of examples 1 and 2 of the present invention ^# Silicone oil and 32 ^# The yield strength and volume fraction of electrorheological fluid prepared from mechanical oil at 3kV/mm and 5kV/mm are related.

The method comprises the following specific steps: wherein with 10 ^# Electrorheological fluid prepared from silicone oil, tiO prepared by the same method as in example 1 ₂ Particles, modified particles and 10 ^# Obtaining electrorheological fluid samples with different volume fractions according to the volume ratio of the silicone oil, and measuring the yield strength to obtain the electrorheological fluid sample; and 32 ^# When mechanical oil is mixed to form electrorheological fluid, tiO is prepared in the same way as in example 2 ₂ Granules, modified granulesGranules 32 ^# And obtaining electrorheological fluid samples with different volume fractions according to the volume ratio of the mechanical oil, and measuring the yield strength.

FIG. 4 shows a vacancy-dominated giant electrorheological fluid 10 of example 14 of the invention ^# Silicone oils (triangles) and 32 ^# The yield strength and volume fraction of the electrorheological fluid prepared from the mechanical oil (circle) at 3kV/mm (hollow) and 5kV/mm (solid) are plotted.

This example shows that the vacancy-dominated giant electrorheological fluid of the invention has the following properties: the yield strength of the electrorheological fluid is increased rapidly along with the increase of volume fraction, and can reach more than 100 kPa; the yield strength values of the electrorheological fluid prepared by using the silicone oil and the mechanical oil are almost the same.

Example 15

This example is used to illustrate the relationship between the yield strength, leakage current density and electric field strength of the vacancy-dominated giant electrorheological fluids prepared in examples 1 to 14 of the present invention; yield strength versus volume fraction; and example 16 electrorheological fluid response time measurement method.

The specific embodiment comprises the following operation and measurement steps:

(1) The powder prepared by high-energy ball milling is mixed with silicone oil or mechanical oil according to a set mixing ratio, and is ground by a mortar to prepare the electrorheological fluid.

(2) The volume fraction is calculated by the formula when the electrorheological fluid is prepared

Wherein V _S And V _L The volumes of solid powder and insulating liquid, respectively. V _S And V _L All can be calculated from weight and density, V _L Or directly using a measuring cylinder or a pipettor. The volume fraction of the electrorheological fluid described in the present patent is calculated in this way.

(3) The change of yield strength with electric field strength was measured with a homemade lithographic rheometer. The use of plate-sprayed diamond particles from a lithographic rheometer with a rough surface to prevent surface slip allows the measurement of samples with yield strengths up to 200kPa and above. Shear for measuring yield strengthThe shear rate was 0.2s ^-1 。

(4) Shear strength is measured with a lithographic rheometer or a drum rheometer. By adjusting the rotating speed of the flat plate or the rotating drum to change the shear rate, the shear strength can be measured when different shear rates are obtained.

(5) The relation between the current density of the electrorheological fluid and the electric field intensity is measured by a resistance voltage division method connected with the electrode plate in parallel and a precise multimeter.

(6) Electrorheological fluid response time measurements self-made drum rheometers were used. The response of the shear strength to the electric field under different shear rates is measured by a Trek 10/40A type electric field frequency and waveform adjustable high-voltage power supply. The rate of change of the front edge and the back edge of the square wave of the electric field is 750V/mu s. The data acquisition rate was 4k/s.

Example 16

This example is intended to illustrate the results of measuring the response of the shear strength of the vacancy-dominated giant electrorheological fluid of the present invention to an electric field of square waves and the response time. The method of making electrorheological fluid samples is described in example 11. The response to a square wave electric field and the response time measurement method have been explained in example 15.

The response times of the measured shear strengths with the leading and trailing edges of the square wave electric field, and their relationship to shear rate, are normalized as shown in FIG. 14 using method 6 provided in example 15.

Fig. 14 shows the response of the shear strength to the square-wave electric field (the electric field is indicated by a dotted line) and the change of the response time thereof with the shear rate of an electrorheological fluid formulated in example 11 of the invention. Wherein fig. 14 (a) shows: square wave electric field E _max Shear strength response at frequency of 1Hz of =4 kV/mm; square wave width 400ms, shear rate

The sampling rate is 1k/s. FIG. 14 (b) shows a cross-sectional view at E _max =3kV/mm, frequency 1Hz square wave front normalized shear strength variation with shear rate, sampling rate 4k/s. FIG. 14 (c) shows that at E _max Variation of normalized shear strength with shear rate after 1Hz square wave at frequency of 3kV/mm, sampling rateIs 4k/s. FIGS. 14 (b), (c) show the response of the shear strength at the leading and trailing edges of a square wave electric field, respectively, as a function of shear rate, and also show the half width at half maximum of the t leading edge and the half width at half maximum of the trailing edge at half maximum of the t trailing edge at different shear rates.

These results show that the vacancy-dominated giant electrorheological fluid has good response to an applied electric field and short response time. The response time at the leading edge of the electric field decreases rapidly with increasing shear rate, while at the trailing edge it does not change much with shear rate. At a shear rate of 30s ^-1 Under the condition (2), the full widths at half maximum of the leading and trailing edge response times are about 4ms and 14ms, respectively.

Example 17

This example illustrates the processing of SiO with very low dielectric constant by high energy ball milling in the vacancy-dominated giant electrorheological fluid of the invention ₂ Particles, electrorheological fluid prepared (see example 10 for preparation method), and ball-milled TiO with higher dielectric constant ₂ (rutile type), baTiO ₃ ,CaTiO ₃ ,CaCu ₃ Ti ₄ O ₁₂ (CCTO),LiB ₃ O ₅ (LBO),Al ₂ O ₃ ,SiO ₂ And (3) comparing the yield strength of the electrorheological fluid prepared from the particles with the electric field strength. The results of measurements of the yield strength of the electrorheological fluids formulated with these particles as a function of the electric field strength are shown in fig. 13. Due to differences in other properties and processing conditions of these particles, the measured yield strength does not increase monotonically with increasing dielectric constant for electrorheological fluids formulated for different samples.

The vacancy-dominated giant electrorheological fluid of the invention is explained to require particles with higher dielectric constant according to the action principle, and the electrorheological fluid prepared by high-energy ball milling can reach high yield strength. SiO with very low dielectric constant ₂ The prepared electrorheological effect of the particles (the dielectric constant of which is 4.4) is definitely weak after high-energy ball milling.

Example 18

This example is intended to illustrate the abrasion resistance comparison of the vacancy-dominated giant electrorheological fluid of the present invention with a polar molecule-based giant electrorheological fluid sample.

Placing electrorheological fluid in a sealed cylinder, and rotating at shear rate of 300s ^-1 The yield strength was not changed as measured by the 350 hour abrasion test (see fig. 15). The polar molecule type giant electrorheological fluid sample has poor abrasion resistance.

Fig. 15 shows a comparison of the abrasion resistance of the vacancy-dominated giant electrorheological fluid of example 12 of the present invention and a polar molecule-based giant electrorheological fluid sample: (A) Vacancy leading giant electrorheological fluid and high-energy ball-milling TiO ₂ Preparing particles; and (B, C) is the existing polar molecular type electrorheological fluid. Wherein the yield strength is a measurement at an electric field strength of 3kV/mm after the sample has been abraded.

Compared with polar molecule type giant electrorheological fluid samples, the vacancy-dominated giant electrorheological fluid has the advantages of much better wear resistance, high shear strength, small leakage current, good temperature stability, good anti-settling property and simple preparation method.

Example 19

This example illustrates the variation in size, morphology and density of the particles of the invention after high energy ball milling:

the initial anatase TiO used ₂ Nanoparticles having a diameter of about 20-30 nanometers. Ball milling was carried out for 42.5 hours using a zirconia ball mill jar. FIG. 16 (a) is a photograph of TiO ₂ TiO before and after ball milling of sample ₂ Scanning Transmission Electron Microscope (STEM) and high resolution electron microscope (HTEM) images of the particles. FIG. 16 (b) is an X-ray diffraction spectrum showing that high energy ball milling causes TiO ₂ The anatase structure is changed into the nano particles mainly taking the rutile phase, the X-ray diffraction line is widened, and the disorder degree is increased. From the analysis, the particle size was reduced to about 10-15nm.

TiO measurement before and after ball milling was carried out with a gas densitometer (AccuPyc II 1340, micromeritics) ₂ Of anatase type TiO ₂ The nano-particles are 3.85g/cm ³ After ball milling, the concentration is reduced to 3.55g/cm ³ . With measured rutile TiO ₂ Density 4.20g/cm ³ By contrast, a reduction of about 15%.

Although the present invention has been described to a certain extent, it is apparent that appropriate changes in the respective conditions may be made without departing from the spirit and scope of the present invention. It is to be understood that the invention is not limited to the described embodiments, but is to be accorded the scope consistent with the claims, including equivalents of each element described.

Claims

1. A vacancy-dominated giant electrorheological fluid is characterized in that the vacancy-dominated giant electrorheological fluid is prepared by mixing dielectric particles and insulating liquid, wherein the interiors and/or surfaces of the dielectric particles contain vacancies and/or vacancy combinations;

the vacancies are selected from one or more of: oxygen vacancies, anion vacancies, cation vacancies; and/or

The volume fraction of the dielectric particles in the prepared giant electrorheological fluid is 5-65%.

2. A vacancy-dominated giant electrorheological fluid according to claim 1, characterized in that:

the vacancy is an oxygen vacancy;

the vacancy combination is an oxygen vacancy combination; and/or

The volume fraction of the dielectric particles in the prepared giant electrorheological fluid is 5-60%.

3. A vacancy-dominated giant electrorheological fluid according to claim 2, characterized in that: the volume fraction of the dielectric particles in the prepared giant electrorheological fluid is 10-60%.

4. A vacancy-dominated giant electrorheological fluid according to claim 1, characterized in that:

the size of the vacancy and/or the combination of the vacancies existing in the dielectric particles is 0.15-1 nm; and/or

The number of empty sites accounts for 1 to 20 percent of the total atomic number.

5. A vacancy-dominated giant electrorheological fluid of claim 4, which is characterized in that:

the size of the vacancy and/or the combination of the vacancies existing in the dielectric particles is 0.15-0.6 nm; and/or

The number of empty sites accounts for 2 to 20 percent of the total atomic number.

6. A vacancy-dominated giant electrorheological fluid of claim 5, which is characterized in that: the number of empty positions accounts for 3 to 15 percent of the total atomic number.

7. A vacancy-dominated giant electrorheological fluid of claim 1, characterized in that: the dielectric particles are prepared from primary particles by high-energy ball milling.

8. A vacancy-dominated giant electrorheological fluid according to claim 7, characterized in that:

the dielectric constant of the primary particles is greater than 5;

the initial particles have a resistivity greater than 10 ³ Ω·m；

The size of the initial particles is 10 nanometers to 100 micrometers;

the density of the primary dielectric particles is less than 7g/cm ³ (ii) a And/or

The primary particles are selected from one or more of the following combinations of compounds: tiO2 ₂ 、CaTiO ₃ 、BaTiO ₃ 、SrTiO ₃ 、CaCu ₃ Ti ₄ O ₁₂ 、LaTiO ₃ 、LiB ₃ O ₅ 、LiNbO ₃ 、KNbO ₃ 、Al ₂ O ₃ 。

9. A vacancy-dominated giant electrorheological fluid according to claim 8, characterized in that:

the dielectric constant of the primary particles is greater than 8;

the initial particles have a resistivity greater than 10 ⁴ Ω·m；

The size of the initial particles is 10 nanometers to 50 micrometers;

the density of the primary dielectric particles is less than 6g/cm ³ (ii) a And/or

The primary particles are selected from one or more of the following combinations of compounds：TiO ₂ 、CaTiO ₃ 、BaTiO ₃ 、SrTiO ₃ 、LaTiO ₃ 、LiB ₃ O ₅ 、LiNbO ₃ 、Al ₂ O ₃ 。

10. A vacancy-dominated giant electrorheological fluid according to claim 9, characterized in that:

the dielectric constant of the primary particles is greater than 10;

the initial particles have a resistivity greater than 10 ⁵ Ω·m；

The size of the initial particles is 10 nanometers to 10 micrometers;

the density of the primary dielectric particles is less than 5g/cm ³ (ii) a And/or

The primary particles are selected from one or more of the following combinations of compounds: tiO2 ₂ 、CaTiO ₃ 、SrTiO ₃ 、LaTiO ₃ 、LiB ₃ O ₅ 、LiNbO ₃ 、Al ₂ O ₃ 。

11. A vacancy-dominated giant electrorheological fluid according to claim 1, characterized in that:

the insulating liquid has a resistivity of more than 1 × 10 ⁸ Ω·m；

The dielectric constant of the insulating liquid is less than 8; and/or

The insulating liquid is selected from one or more of: silicone oil, mechanical oil, hydraulic oil, transformer oil, and vegetable oil.

12. A vacancy-dominated giant electrorheological fluid according to claim 11, characterized in that:

the insulating liquid has a resistivity of more than 1 x 10 ⁹ Ω·m；

The dielectric constant of the insulating liquid is less than 5; and/or

The insulating liquid is selected from one or more of: 100 ^# Silicone oil, 32 ^# Machine oil, 32 ^# Hydraulic oil, 10 ^# And (4) aviation hydraulic oil.

13. A vacancy-dominated giant electrorheological fluid according to claim 12, characterized in that: the dielectric constant of the insulating liquid is less than 3.

14. A method of preparing the vacancy-dominated giant electrorheological fluid of any one of claims 1 to 13, characterized in that the method comprises the steps of:

(1) Pre-treating the primary particles;

15. The method of claim 14, wherein in step (1): the pre-treated primary particles comprise: and removing adsorbate on the surface of the initial particles by heating with a muffle furnace.

16. The method of claim 15,

the heating temperature is 200-800 ℃; and/or

The heating time is 1-8 h.

17. The method of claim 16,

the heating temperature is 200-700 ℃; and/or

The heating time is 2-7 h.

18. The method of claim 17,

the heating temperature is 300-650 ℃; and/or

The heating time is 2-5 h.

19. The method of claim 14, wherein the step (2) further comprises: heating in inert gas or vacuum, and subjecting the dielectric particles to high energy ball milling in a ball mill to obtain dielectric particles having interior and surface inclusions that produce said vacancies and/or vacancy combinations.

20. The method of claim 19,

the ball mill is selected from one or more of the following: 4-pot planetary vertical ball mill, horizontal ball mill, stirring nano ball mill, vibration ball mill, drum-type rod mill, centrifugal ball mill;

the ball milling tank is selected from one or more of the following: agate cans, alumina cans, zirconia cans, tungsten carbide cans; and/or

The rotating speed of the ball mill is more than 200 revolutions per minute.

21. A method according to claim 20, characterized in that the rotational speed of the ball mill is more than 250 revolutions per minute.

22. A method according to claim 21, characterized in that the rotational speed of the ball mill is more than 300 revolutions per minute.

23. The method of claim 19, wherein in step (2): the mass ratio of the grinding balls used in the high-energy ball milling to the initial particles is 2-30.

24. The method of claim 23, wherein in step (2): the mass ratio of the grinding balls used in the high-energy ball milling to the initial particles is 3-20.

25. The method of claim 24, wherein in step (2): the mass ratio of the grinding balls used in the high-energy ball milling to the initial particles is 5-15.

26. The method of claim 14, wherein in step (2):

when the ball milling is continued to ensure that the intensity of the prepared electrorheological fluid is not improved, the ball milling is stopped; and/or

The total time of ball milling is 2-200 h.

27. The method of claim 26, wherein in step (2): the total time of ball milling is 5-100 h.

28. The method of claim 27, wherein in step (2): the total time of ball milling is 5-50 h.

29. The method of claim 14, wherein the step (2) further comprises:

shoveling the sticky wall particles down in the ball milling process to continue ball milling, and/or arranging a stirring method in a ball milling tank, and after high-energy ball milling, sieving the particles by a mesh screen to obtain dielectric particles containing vacancies and/or vacancy combination distribution.

30. The method of claim 29, wherein step (2) further comprises:

the frequency of shoveling the wall-sticking particles is 1-5 hours and 1 time; and/or

The mesh number of the mesh screen is 20-400 meshes.

31. The method of claim 30, wherein step (2) further comprises:

the frequency of shoveling the wall-sticking particles is 1-2 hours and 1 time; and/or

The mesh number of the mesh screen is 20-200 meshes.

32. The method of claim 31, wherein step (2) further comprises: the mesh number of the mesh screen is 40-100 meshes.