阅读说明：本技术 一种基于氟碳复配的耐高温磁流变液及其制备方法 (Fluorocarbon-based compound high-temperature-resistant magnetorheological fluid and preparation method thereof ) 是由 田祖织 谢方伟 季锦杰 王书友 李昊鹏 黄咸康 于 2020-07-20 设计创作，主要内容包括：本发明涉及智能材料制备技术领域,具体涉及一种基于氟碳复配的耐高温磁流变液及其制备方法。本发明以羰基铁粉作为基材,硅油作为载液,通过使用氟碳表面活性剂和钛酸酯偶联剂作为添加剂进行复配,并辅以硅藻土作为触变剂制备得到耐高温磁流变液。磁流变液由下述组分按质量百分比组成：软磁性颗粒70～76％,载液20～26％,表面活性剂2～5％,触变剂2～3％。复配氟碳表面活性剂和钛酸酯偶联剂并采用基液置换与直接添加相结合的制备方法,有效提高了磁流变液的沉降稳定性和温度使用范围,适用于磁流变液传动装置、磁流变液阻尼器等场合。(The invention relates to the technical field of intelligent material preparation, in particular to a fluorocarbon-based compound high-temperature-resistant magnetorheological fluid and a preparation method thereof. The high-temperature-resistant magnetorheological fluid is prepared by taking carbonyl iron powder as a base material and silicone oil as a carrier liquid, compounding by taking a fluorocarbon surfactant and a titanate coupling agent as additives and taking diatomite as a thixotropic agent. The magnetorheological fluid consists of the following components in percentage by mass: 70-76% of soft magnetic particles, 20-26% of carrier liquid, 2-5% of surfactant and 2-3% of thixotropic agent. The compound fluorocarbon surfactant and titanate coupling agent are prepared by adopting a preparation method combining base liquid replacement and direct addition, so that the sedimentation stability and the temperature application range of the magnetorheological fluid are effectively improved, and the compound is suitable for occasions such as a magnetorheological fluid transmission device, a magnetorheological fluid damper and the like.)

1. A high-temperature-resistant magnetorheological fluid based on fluorocarbon compounding is characterized by comprising the following components in percentage by mass: soft magnetic particles: 70-76%, carrier liquid: 20-26%, surfactant: 2-5%, thixotropic agent: 2-3%; the surfactant comprises the following components: fluorocarbon surfactant and titanate coupling agent, the thixotropic agent comprises the following components: diatomaceous earth.

2. The fluorocarbon-based compounded high-temperature-resistant magnetorheological fluid as claimed in claim 1, wherein: the soft magnetic particles are carbonyl iron powder, and the particles have a regular spherical structure, uniform particle size distribution and an average particle size of 3 mu m.

3. The fluorocarbon-based compounded high-temperature-resistant magnetorheological fluid as claimed in claim 1, wherein: the surfactant is compounded by adopting fluorocarbon and titanate coupling agent.

4. The preparation method of the fluorocarbon-based compounded high-temperature-resistant magnetorheological fluid according to claim 1,

the preparation method comprises the following steps:

1) taking a proper amount of soft magnetic particles and a surfactant, and putting the soft magnetic particles and the surfactant into a vacuum drying oven for drying and high-temperature treatment;

2) a portion of the surfactant is added to the absolute ethanol, followed by the soft magnetic particles. Stirring for 6h at the rotating speed of 400r/min and the water bath temperature of 40 ℃;

3) placing the magnetorheological fluid treated in the step 2) in a vacuum drying oven to remove air bubbles and redundant absolute ethyl alcohol, and then grinding carbonyl iron powder particles treated by a surfactant and a coupling agent and screening to prevent agglomeration;

4) adding carrier liquid into the carbonyl iron powder treated in the step 3), simultaneously adding the residual surfactant into the magnetorheological fluid drop by drop, and stirring for 1h at the water bath temperature of 40 ℃ and the rotating speed of 400r/min to prepare the magnetorheological fluid.

Technical Field

The invention relates to the technical field of intelligent material preparation, in particular to a fluorocarbon-based compound high-temperature-resistant magnetorheological fluid and a preparation method thereof.

Background

The magnetorheological fluid is a novel intelligent material, a unique two-phase suspension system is formed by uniformly dispersing micro-sized soft magnetic particles in a carrier fluid, and the magnetorheological fluid contains three main components, namely particles, the carrier fluid and additives and has the magnetic field controllable characteristic. The method is characterized in that: under the action of an external magnetic field, particles in the magnetorheological fluid form fiber bundle-shaped chains along the direction of the magnetic field, so that the free flow of base carrier fluid is hindered, the magnetorheological fluid is converted into visco-plastic fluid with certain shearing force from Newtonian fluid, and a strong 'solidification' phenomenon occurs; and when the external magnetic field disappears, the magnetorheological fluid returns to a free flowing state (liquid state). The magnetorheological fluid has unique rheological property, simple and convenient speed regulation, high response speed and good constant torque property, and is widely applied to the fields of dampers, shock absorbers, transmission devices (clutches, brakes and the like), polishing devices, composite members and the like.

At present, most of magnetorheological fluids are used for dampers and shock absorbers, and the main performance indexes are sedimentation stability and apparent viscosity. However, for the transmission device, due to the severe heat dissipation problem under the working condition, the working temperature range is also an important index for measuring the performance of the magnetorheological fluid. However, the maximum working temperature of current commercial magnetorheological fluids is typically less than 130 ℃, which limits the use of magnetorheological fluids in actuators. A Chinese patent applied in 2018, 4 and 17.2018, namely 'three-phase magnetorheological fluid and a preparation method thereof' (application number: 201810342889.X), the magnetorheological fluid prepared by the method has low zero-field viscosity, high magnetic storage energy modulus and stronger magnetorheological effect. Chinese patent application No. 10/11/2018, a double-dispersion magnetic currentLiquid and its preparing process (application No. 201811185919.7) features that the magnetic Fe nanoparticles are added to the micron-class carbonyl iron powder₃O₄Particles, and gelatin and multi-wall carbon nano-tubes are adopted to wrap carbonyl iron powder and Fe₃O₄The double-dispersion magnetorheological fluid is prepared as a dispersion phase, and the method can obviously improve the sedimentation stability of the magnetorheological fluid and can enhance the magnetism and rheological property of the magnetorheological fluid. Most of the prior patents are dedicated to solving the problem of sedimentation of the magnetorheological fluid, and the problem of urgent need to be solved by improving the working temperature range of the magnetorheological fluid.

Disclosure of Invention

Aiming at the problems in the prior art, the invention provides a fluorocarbon-based compound high-temperature-resistant magnetorheological fluid and a preparation method thereof. The preparation method adopts the preparation process of compounding the fluorocarbon surfactant and the titanate coupling agent and combining the base liquid replacement and the direct addition, effectively improves the temperature application range and the sedimentation stability of the magnetorheological fluid, and is suitable for occasions such as a magnetorheological fluid transmission device, a magnetorheological fluid damper and the like.

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

the magnetorheological fluid comprises the following components in percentage by mass: 70-76% of soft magnetic particles, 20-26% of carrier liquid, 2-5% of surfactant and 2-3% of thixotropic agent.

Further, the soft magnetic particles are carbonyl iron powder, and the particles have a regular spherical structure, a uniform particle size distribution, and an average particle size of 3 μm.

Furthermore, the magnetorheological fluid carrier liquid adopts silicone oil with excellent viscosity-temperature characteristics and working temperature of 200 ℃.

Furthermore, the surface additive in the magnetorheological fluid respectively uses fluorocarbon and titanate coupling agent, and the thixotropic agent is diatomite.

Further, the magnetorheological fluid is oil-based magnetorheological fluid, and a base fluid displacement method and a direct addition method are mixed for use. Dissolving part of fluorocarbon and titanate by absolute ethyl alcohol, and mixing and stirring the dissolved fluorocarbon and titanate with carbonyl iron powder for 6 hours at the water bath temperature of 40 ℃; then the treated material is put into a vacuum drying oven, and redundant bubbles and absolute ethyl alcohol are discharged; the treated carbonyl iron powder particles are then ground and sieved to prevent agglomeration. Finally, the liquid-carrying silicone oil and the thixotropic agent diatomite are added into the treated carbonyl iron powder and stirred for 1 hour again, the stirring temperature is 40 ℃, the stirring speed is 400r/min, and the stirring time is 6 hours (the time of the primary stirring process) +1 hour (the time of the secondary stirring process). And simultaneously, dropwise adding the residual fluorocarbon and titanate into the solution by adopting a direct addition method, and finally dispersing the stirred solution by an ultrasonic disperser to prepare the high-temperature magnetorheological fluid.

Compared with the prior art, the high-temperature-resistant magnetorheological fluid based on fluorocarbon compounding is prepared by compounding two chemical reagents of fluorocarbon and titanate according to a certain proportion and adding diatomite; the method combining base liquid displacement and direct addition is adopted in the process, so that the sedimentation stability and the temperature application range of the magnetorheological fluid are effectively improved.

Drawings

FIG. 1 is a process flow for preparing high-temperature-resistant magnetorheological fluid based on fluorocarbon compounding

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

A high temperature resistant magnetorheological fluid based on fluorocarbon compounding is characterized in that: the composition comprises the following components in percentage by mass: 70-76% of soft magnetic particles, 20-26% of carrier liquid, 2-5% of surfactant and 2-3% of thixotropic agent;

the soft magnetic particles are carbonyl iron powder, and the particles have a regular spherical structure, uniform particle size distribution and an average particle size of 3 mu m;

the magnetorheological fluid carrier liquid adopts silicone oil with excellent viscosity-temperature characteristics and working temperature of 200 ℃;

the additive in the magnetorheological fluid adopts fluorocarbon surfactant and titanate as surface additives, diatomite is used as a thixotropic agent, and the three chemical reagents are gradually added according to a certain proportion.

The specific preparation process is as follows:

190g of carbonyl iron powder, 3.8g of titanate, 1.2g of fluorocarbon, 50g of silicone oil and 5g of diatomite are weighed and placed in an environment with the vacuum degree of 0.1MPa and the temperature of 120 ℃, the mixture is kept for 1 hour and then taken out, and the physically adsorbed water on the surfaces of the materials such as the carbonyl iron powder is removed.

And (3) adding a part of the treated fluorocarbon surfactant and titanate coupling agent into a certain amount of absolute ethyl alcohol by adopting a base liquid displacement method, and dispersing in an ultrasonic disperser for 5 minutes to fully dissolve the chemical reagent in the absolute ethyl alcohol. And adding the treated solution into a beaker filled with carbonyl iron powder, and maintaining the temperature to be 40 ℃ in the preparation process through a water bath kettle, wherein the rotating speed of a stirrer is 400r/min, and the time is 6 hours.

Further, the mixed solution of the stirred and dispersed particles was dried in a vacuum oven at 80 ℃ and a vacuum degree of 0.2MPa for 1 hour. And redundant bubbles and absolute ethyl alcohol in the coated carbonyl iron powder can be volatilized through drying in a vacuum drying oven. The surfactant and coupling agent treated carbonyl iron powder particles are then ground and sieved to prevent agglomeration.

Further, 50g of silicone oil and 5g of diatomaceous earth were added to the treated carbonyl iron powder, and the mixture was stirred twice. The diatomite is rich in silicon dioxide and has high silicon hydroxyl content, so that the diatomite has a good thixotropic effect and can improve the sedimentation stability of the magnetorheological fluid. The time of the secondary stirring process is 1 hour, the temperature is kept constant at 40 ℃ by adopting a water bath kettle, and the rotating speed is 400 r/min. And in the stirring process, the rest part of the fluorocarbon surfactant and the titanate coupling agent are dropwise added into the solution by adopting a direct addition method, so that the coating rate of the additive on the surface of the carbonyl iron powder is further improved.

The high-temperature-resistant magnetorheological fluid based on fluorocarbon compounding prepared by the invention has better sedimentation stability, obviously improves the anti-sedimentation effect of the magnetorheological fluid, improves the highest working temperature of the magnetorheological fluid, still keeps better performance through high-temperature detection of a vacuum drying oven at 180 ℃, and has simple preparation process and low cost.