Liquid magnetic mixture recipes. DIY ferromagnetic liquid with a laser printer cartridge. DIY magnetic fluid

In the early nineties of the last century, the film “Terminator 2” was released on cinema screens. All viewers were amazed by the ability of the cyborg killer made of viscous metal, played by Robert Patrick, to take on a variety of guises.

Back then, admiring professionally made computer animation, we did not think about the fact that the effect of the fantastic transformations of a cyborg killer can be simulated in real conditions.

Ferromagnetic fluid is the material that allows you to see moving sculptural compositions. All substances can be attracted or repelled to the classical one. But the reaction of most of them is so weak that it can only be detected with special devices. It would be great if it were possible to increase materials without destroying their structure and radically changing their original properties.

Everything changed when chemists intervened in resolving this issue and created ferromagnetic liquids with good fluidity. They were able to obtain the smallest magnetic particles that were introduced into liquids, and when exposed to a magnetic field, they did not bunch up and settle, but made the liquid “solid.”

Ferromagnetic fluid is a colloidal dispersion of very small particles stabilized in an aqueous or hydrocarbon medium, supported by surfactants. Such liquids are stable for several years and have good fluidity in combination with magnetic properties.

Ferromagnetic fluid can be produced in many ways. The process is quite simple and consists of two stages. First, it is necessary to obtain magnetic particles with sizes close to colloidal. And the next step is to stabilize them in a liquid base.

The topic of the possibility of practical use of such liquids remains very relevant for researchers. IN recent years they are working on treating wastewater with such liquids from petroleum products. The principle of this process is the magnetization of petroleum products by introducing magnetic fluids into waste water. And then the magnetized petroleum products are separated by special systems.

Ferromagnetic fluid will also find its application in medicine. For example, anticancer medications harm healthy cells. But if you mix medications with such a liquid and inject it into the patient’s blood, and place a magnet near the tumor, the mixture will concentrate in the right place and will not damage the entire body.

Here's another example. Companies that produce shock absorbers pour ferromagnetic fluids into their shock absorbers. An electromagnet connected to them instantly makes the liquid viscous or fluid. In this way, the car's suspension is adjusted.

Such liquids also have interesting properties. If you pass a sound wave through a magnetized liquid, then an electric wave arises in the one located nearby. driving force. And one more thing. If you add magnetic liquid to the solution for soap bubbles, you will get a mesmerizing performance.

To a person far from scientific discoveries, who said goodbye to physics or chemistry in school, many things seem unusual. Using, for example, electrical appliances in everyday life, we do not think about how exactly they work, taking the benefits of civilization for granted. But when it comes to something that goes beyond everyday perception, even adults are amazed, like children, and begin to believe in miracles.

How, other than magic, can one explain the phenomenon of the emergence of three-dimensional figures, flowers and pyramids, magical paintings replacing each other from a seemingly ordinary liquid? But it’s not magic, science provides a rationale for what’s happening.

What is ferrofluid?

We are talking about a ferrofluid - a colloidal system consisting of water or other organic solvent containing tiny particles of magnetite, and any material that contains iron. Their sizes are so small that it’s even hard to imagine: they are tens of times thinner than a human hair! Such microscopic size indicators allow them to be evenly distributed in the solvent using thermal movement.

For the time being, as long as there is no external influence, the liquid is calm, resembling a mirror. But as soon as you bring a directed magnetic field to this “mirror”, it comes to life, showing the viewer amazing three-dimensional pictures: magical flowers bloom, moving figures grow on the surface, changing under the influence of the field.

Depending on the strength and direction of the magnetic field, the pictures change before our eyes - from light, barely noticeable ripples appearing on the surface of the liquid, through needles and peaks that change sharpness and slope and grow into flowers and trees.

The ability to create color paintings using backlighting, truly mesmerizing to the observer, reveals an unknown world to him.

Unfortunately, metal particles, although called ferromagnetic, are not ferromagnetic in the full sense, since they cannot retain their resulting shape after the disappearance of the magnetic field. Because they do not have their own magnetization. In this regard, the use of this discovery, which, by the way, is not entirely new - it was made by the American Rosenzweig in the middle of the last century, has not found wide application.

How to make and where is ferromagnetic fluid used?

Ferrofluids are used in electronics and the automotive industry, and I would like to believe that their widespread use is just around the corner, and with the development of nanotechnology they will be used quite widely. In the meantime, this is mostly fun for the admiring public, spoiled various types spectacle.

Three-dimensional paintings make you watch them with bated breath, doubt whether this is a montage, and look for an explanation for what is happening, at least on the Internet. Who knows, maybe a little boy who today watches metallic “living” colors and figures with his mouth open will tomorrow find a fundamentally new application for this phenomenon, making a revolution in science and technology. But that’s tomorrow, but for now, watch and enjoy!

Have you ever seen magnetic fluid? It looks like liquid metal and expands with needles if you bring a magnet to it. Here you will find instructions on how to make ferromagnetic liquid with your own hands at home.

The theory is this: modern laser printers contain the mineral magnetite (Fe3O4). It is needed so that the paint particles stick to the paper. This mineral reacts to magnetic fields and is thus well suited for our experiment.

Step 1: Materials

  • Protective gloves
  • Protective mask
  • Glass measuring cup
  • Cartridge (old) from a printer or copier
  • Stirring stick
  • Small container and piece of paper
  • Strong neodymium magnet

Step 2: Collect Toner

Carefully pour the toner from the cartridge into a glass cup. You need about 50 ml.
Run a magnet across the OUTSIDE OF THE CUP to make sure the toner is magnetic.

Be careful: The toner is relatively safe as long as you don't inhale or drink it, but it does spray very easily and creates a lot of mess, so wear protective gloves and a mask.

Step 3: Add Oil

Add two tablespoons of oil.

Step 4: Stir

Stir until the liquid becomes completely homogeneous.

Step 5: Magnet Reaction

  1. Pour some liquid into a small container.
  2. Place a magnet under the bottom of the container
  3. The liquid will begin to expand!

If the result does not look like what you see in the photo, then there is most likely a problem with the toner. Some brands contain more or less magnetic components. You can also try adding a little more oil, or vice versa, removing it. Some brands do not contain ferrofluid at all - then you will need to find another cartridge.

Step 6: Magic Ink

  1. Now pour some magnetic fluid onto the paper
  2. Move the magnet under the paper
  3. You get “magnetic drawings”!

If you stain everything around with toner, use a vacuum cleaner to clean or rinse cold water. Do not use hot water or rub areas that are stained with toner - this may cause the toner to rub into the surface permanently.

(surfactant) that forms a protective shell around the particles and prevents them from sticking together due to van der Waals or magnetic forces.

Despite their name, ferromagnetic liquids do not exhibit ferromagnetic properties because they do not retain residual magnetization after the disappearance of the external magnetic field. In fact [ ] Ferromagnetic liquids are paramagnetic and are often called “superparamagnetic” due to their high magnetic susceptibility. It is currently difficult to create truly ferromagnetic liquids. [ ]

Encyclopedic YouTube

    1 / 4

    Ferromagnetic fluid/Ferrofluid

    How to make ferrofluid from sparklers!Ferromagnetic liquid!How to make ferrofluid

    MAGNETIC FLUID LIQUID METAL ferrofluid IGOR BELETSKY

    How to make MAGNETIC FLUID

    Subtitles

Description

Ferromagnetic fluids consist of nanometer-sized particles (typical size 10 nm or smaller) of magnetite, hematite, or other iron-containing material, suspended in a carrier fluid. They are small enough that thermal motion will distribute them evenly throughout the carrier fluid so that they contribute to the response of the fluid as a whole to the magnetic field. Similarly, ions in aqueous solutions of paramagnetic salts (for example, an aqueous solution of copper(II) sulfate or manganese(II) chloride) impart paramagnetic properties to the solution.

Ferromagnetic liquids are colloidal solutions - substances that have the properties of more than one state of matter. In this case, the two states are the solid metal and the liquid in which it is contained. This ability to change state under the influence of a magnetic field allows the use of ferromagnetic fluids as sealants, lubricants, and may also open up other applications in future nanoelectromechanical systems.

Ferromagnetic liquids are stable: their solid particles do not stick together and do not separate into a separate phase even in a very strong magnetic field. However, surfactants in a liquid tend to disintegrate over time (approximately several years), and eventually the particles will stick together, separate from the liquid, and no longer affect the liquid's response to a magnetic field. Also, ferromagnetic liquids lose their magnetic properties at their Curie temperature, which for them depends on the specific material of the ferromagnetic particles, the surfactant and the carrier liquid.

The term "magnetorheological fluid" refers to fluids that, like ferromagnetic fluids, solidify in the presence of a magnetic field. The difference between ferromagnetic fluid and magnetorheological fluid is the particle size. The particles in a ferromagnetic fluid are mainly nanometer-sized particles that are suspended due to Brownian motion and do not settle under normal conditions. Particles in a magnetorheological fluid are mostly micrometer-sized (1-3 orders of magnitude larger); they are too heavy to be suspended by Brownian motion and therefore settle over time due to natural differences in the densities of the particles and the carrier fluid. As a result, these two types of fluids have different applications.

Instability in a normally directed field

Under the influence of a fairly strong vertically directed magnetic field, the surface of a liquid with paramagnetic properties spontaneously forms a regular structure of folds. This effect is known as " instability in a normally directed field" The formation of folds increases the free energy of the surface and the gravitational energy of the fluid, but decreases the energy of the magnetic field. This configuration occurs only when the critical value of the magnetic field is exceeded, when the decrease in its energy exceeds the contribution from the increase in the free energy of the surface and the gravitational energy of the liquid. Ferromagnetic liquids have very high magnetic susceptibility, and a small bar magnet may be sufficient for a critical magnetic field to cause wrinkles on the surface.

Typical surfactants for ferrofluids

To envelop particles in a ferromagnetic fluid, in particular, the following surfactants are used:

  • sodium polyacrylate

Surfactants prevent particles from sticking together, preventing them from forming clusters that are too heavy and cannot be held in suspension due to Brownian motion. In an ideal ferromagnetic fluid, magnetic particles do not settle even in a very strong magnetic or gravitational field. Surfactant molecules have a polar “head” and a non-polar “tail” (or vice versa); one of the ends is adsorbed to the particle, and the other is attached to molecules of the carrier liquid, respectively, forming a regular or reverse micelle around the particle. As a result, spatial effects prevent particles from sticking together. Polyacrylic and citric acids and their salts form an electric double layer on the surface of the particles as a result of the adsorption of polyanions, which leads to the emergence of Coulombic repulsive forces between the particles, which increases the stability of the water-based liquid.

Although surfactants are useful for prolonging the settling time of particles in a ferromagnetic liquid, they are harmful to its magnetic properties (in particular, to the magnetic saturation of the liquid). The addition of a surfactant (or other foreign substances) reduces the packing density of ferromagnetic particles in the activated state of the liquid, thereby reducing its viscosity in this state, giving a “softer” activated liquid. Although for some applications the activated viscosity of a ferromagnetic fluid (its “hardness,” so to speak) is not very important, for most commercial and industrial applications it is the most important property of the fluid, so some compromise is required between activated viscosity and particle settling rate . An exception is surfactants based on polyelectrolytes, which make it possible to obtain highly concentrated liquids with low viscosity.

Application

Electronic devices

Ferromagnetic fluids are used to create liquid sealing devices around rotating axes in hard drives. The rotating axis is surrounded by a magnet, and a small amount of ferromagnetic fluid is placed in the gap between the magnet and the axis, which is held in place by the attraction of the magnet. The liquid forms a barrier that prevents particles from the outside from entering the hard drive. According to engineers Ferrotec Corporation, liquid seals on rotating axles normally withstand pressures of 3 to 4 psi (about 20 to 30 kPa), but such seals are not very suitable for linear motion components (such as pistons), since the liquid is mechanically drawn out from the gap.

Ferromagnetic fluid is also used in some tweeters to remove heat from the voice coil. At the same time, it works as a mechanical damper, suppressing unwanted resonance. The ferromagnetic fluid is held in the gap around the voice coil by a strong magnetic field, being simultaneously in contact with both magnetic surfaces and the coil.

Mechanical engineering

Ferromagnetic fluid can reduce friction. When applied to the surface of a sufficiently strong magnet, such as neodymium, it allows the magnet to glide over a smooth surface with minimal resistance.

Defense industry

Aerospace industry

Medicine

Many experiments are being conducted on the use of ferromagnetic fluids to remove tumors.

Heat transfer

If a magnetic field is applied to a ferromagnetic fluid with different susceptibility (for example, due to a temperature gradient), a non-uniform magnetic volume force arises, which leads to a form of heat transfer called thermomagnetic convection. This form of heat transfer can be used where conventional convection is not suitable, such as in microdevices or in reduced gravity environments.

The use of ferromagnetic fluid to dissipate heat in speakers has already been mentioned. The liquid occupies the gap around the voice coil, held in place by the magnetic field. Since ferromagnetic liquids are paramagnetic, they obey the Curie-Weiss law, becoming less magnetic as the temperature increases. A strong magnet located near the voice coil, which produces heat, attracts cold fluid more than hot fluid, drawing the hot fluid away from the coil and towards the cooler. This is an effective cooling method that does not require additional energy.

Generators

A frozen or polymerized ferromagnetic fluid, located in a combination of constant (magnetizing) and alternating magnetic fields, can serve as a source of elastic vibrations with the frequency of the alternating field, which can be used to generate ultrasound.

Mining industry

Ferromagnetic fluid can be used as part of a magnetic fluid separator for cleaning

The toners found in printer cartridges have interesting magnetic properties that you can experiment with at your leisure. The effect they produce is very interesting, because the liquid begins to be drawn towards the magnet, and moreover, individual elements form bizarre geometric shapes. True, not all toners are suitable for repeating this step by step instructions. Only dark-colored toners will be needed, since color ones are made without the use of dark magnetic particles.

Materials

To make your own magnetic fluid, you will need:

  • thick sheet of paper;
  • protective gloves;
  • protective mask;
  • empty glass cup;
  • plastic sticker for stirring;
  • vegetable oil;
  • spoon;
  • a wide plastic container, such as a plate.

Step 1. Open the cartridge very carefully to pour the toner out of it into a glass cup. In total you will need about 50 mm of liquid. To check whether the liquid you have chosen has magnetic properties, just run a magnet along the wall of the glass. If it is activated, the experiment can continue.

The toner liquid is not harmful to your health unless you inhale or drink it. This is why you need to wear protective gloves and a mask before doing this work. This way you will reduce the likelihood of poisoning if liquid accidentally gets on your hands.

Step 2. You need to add two tablespoons to the volume of goods you have already received. vegetable oil. Using a plastic sticker, thoroughly mix the mixture you have received. To continue the experiment, it must be homogeneous.

Step 3. You need to carefully pour the resulting magnetic fluid into a wide container. This is exactly what is needed to see everything that will happen to the resulting magnetic fluid.

Apply a magnet from the bottom of the plate to the outside. Pay attention to what is happening inside the container. At the point of contact of the magnet, the liquid should be collected in a voluminous tubercle in the shape of a hedgehog. These are the magnetic particles that manufacturers add to the toner. They can be smaller or larger, which again depends on the manufacturer.

Step 4. Using this liquid you can make a magnetic pattern. To do this, you need to pour some of the liquid onto thick paper and hold a magnet on the back side. By moving it from side to side, you will draw.

If you stain any objects or furniture with toner, rinse everything off with cold water, you should be able to do this without any problems. Under no circumstances should you use hot water; it will fix the pigment and make it impossible to wash it out.



Related publications