Why do magnets demagnetize?

How to strengthen a magnet at home

Employees of the site p-magnit.ru are sometimes asked about how to make a neodymium magnet with your own hands. Let's try to figure out how possible this is, and what the process of producing such products is all about.

So, the devices we sell consist of an alloy that is 70% iron and almost 30% boron. Only a fraction of a percent in its composition is made up of the rare earth metal neodymium, natural deposits of which are extremely rare in nature. Most of them are in China; they are found in only a few other countries, including Russia.

Before making neodymium magnets, manufacturers create molds for them from sand. Then the tray with the molds is doused with gas and subjected to heat treatment, due to which the sand hardens and retains the future outlines of the metal workpiece on its surface. Hot metal will later be placed in these forms, from which, in fact, the necessary products will be obtained.

Now let's directly look at how a neodymium magnet is made. Unlike ferromagnetic products, the metal here is not melted, but sintered from a powder mixture placed in an inert or vacuum environment.

Then the resulting magnetoplast is pressed while simultaneously exposing it to an electromagnetic field of a certain intensity. As you can see, even at the initial stage of production, it is noticeable that the question of how to make neodymium magnets at home sounds inappropriate.

The operations and equipment used are too complex. Creating such conditions at home is hardly possible.

After the workpieces are removed from the molds, they are subjected to mechanical processing - they are carefully polished, then they are fired to improve the coercive force of the products.

Finally, we come to the last steps, which will help to finally answer the question of how neodymium magnets are made. The sintered NdFeB alloy is again machine-finished using a special tool. During operation, a cooling lubricant is used to prevent overheating or ignition of the powder.

A protective coating is applied to the magnets. This is due, firstly, to the fact that sintered metals are quite fragile and need to be strengthened, and, secondly, the metal will be protected from corrosion processes and other environmental influences.

So manufacturers worry in advance about how to make a neodymium magnet stronger and more durable. The coating can be copper, nickel, zinc. In the last phase of the production process, magnetization is applied through a strong magnetic field.

Then they are sent to the warehouse, and from there to customers.

So, after we examined the production process in more or less detail, it became clear that we probably shouldn’t seriously ask the question “how to make a neodymium magnet at home.” After all, this requires not only certain knowledge, but many complex units.

How to completely demagnetize a neodymium magnet

Neodymium magnets are very popular in modern industry and in solving a number of everyday problems. If the buyer (for example) chose strong magnets for delivery in St. Petersburg, but violated the storage or transportation conditions, as a result of which they stuck together, it may be necessary to carry out a demagnetization procedure. The same action may be necessary in other cases when it is necessary for the product to lose its qualities.

The process can be carried out in various ways, including using factory equipment, and it is necessary to decide how to demagnetize a neodymium magnet taking into account your capabilities.

Methods for demagnetizing a magnet

Loss of the ability to attract metal objects can occur both naturally and during a number of actions. Subject to the rules of operation and storage, the qualities of neodymium elements are maintained for 100 years or more, and ferrite analogues continue to attract metal for 8-10 years. Degaussing neodymiums naturally is not practical if the procedure is to be performed on a new item.

Product heating

This method is used both in industrial and domestic conditions: if the magnet is made of a standard alloy of neodymium with boron and iron, it will lose its properties when placed in water boiling at 80 degrees Celsius or in case of contact with a surface heated to the specified temperature.

If we are talking about a product with increased resistance to thermal shocks, it is unlikely that it will be possible to perform the procedure at home: the demagnetization temperature of neodymium magnets with such properties is 200 degrees Celsius.

To carry out the procedure in such cases, special industrial equipment is used.

Mechanical Actions

Neodymium can lose its qualities as a result of a strong directed impact, for example, an impact: this material has a powder structure that is destroyed when dropped from a height or when exposed to impact equipment. In addition, demagnetization can occur accidentally during the process of drilling or cutting a magnet: this is due to excessive mechanical pressure or an increase in the temperature of the product without forced cooling.

Treatment with external magnetic influence

Most often, if it is possible to use industrial equipment of increased power, another magnet is used, which allows the formation of a field with an induction force of about 4 Tesla. A neodymium magnet is demagnetized in a matter of seconds, so this method, despite its technological complexity, is characterized by the fastest possible result.

How to magnetize demagnetized neodymium

If the demagnetization of an element occurs accidentally, and it is necessary to return the product to its properties, it is impossible to do this at home. Restoring a neodymium magnet requires the use of a product that can create a very powerful field, and this requires the use of professional equipment used to create such items.

Usually, if you need to return the magnetization properties for a specific element, you contact a factory that specializes in the production of such products.

Is there anything I can do to make the magnet stronger?

If neodymium used for household purposes has become demagnetized, often a more appropriate solution would be to purchase a new element. The cost of magnetization work varies depending on the required properties and pricing policy of a particular production.

Application of neodymium magnet

These products are available in various shapes and sizes and are used for the following tasks:

• Creating a clamping effect, fixing metal elements to each other. Using neodymium magnets, you can attach an antenna, license plate, plate, other metal part, device or entire mechanism.
• Filtration of oil systems in cars and other equipment: neodymium magnets allow you to easily and quickly remove metal shavings.
• Creation of magnetic locks and fasteners used in industrial sectors and household purposes.
• Search work related to the search for metal objects (search for treasures, historical values, weapons, mine clearance work, etc.).
• Restoring other magnetic elements: using a neodymium element, you can create a magnetic field that will return the product to its ability to attract metal.
• Deleting information recorded on floppy disks, disks, flash drives and other electronic media for security purposes.
• Creation of devices for universal use (hangers, stirring devices, compasses, etc.).
• Construction of current generators that can be used as experimental models or devices suitable for domestic use.
• Making jewelry: Neodymium can come in different shapes and sizes, and beads made from this material are often given a chrome finish and can be painted in different colors.
• Treatment of water using magnetic influence, as a result of which the formation of scale is reduced, and the liquid itself acquires an improved taste and smell.
• Fuel conditioning, which allows you to reduce fuel consumption for cars and motorcycles.
• Sorting small metal items that need to be removed from a variety of non-metal items.

Conclusion

Neodymium magnets are products that are widely used in commercial, industrial and household applications, they are characterized by high load capacity, excellent attractive properties and durability.

Before demagnetizing neodymium magnets, it is important to make sure that you have the necessary equipment: this requires either an industrial installation or a device for heating to at least 80 degrees.

Magnetizing products that have lost their quality is rarely advisable, but if necessary, you can order the procedure by contacting the manufacturer.

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Demagnetize magnets

Man has been using magnets in various areas of his life for a long time. Often we do not notice their presence in the devices around us and the additional convenience of their use. Today, the vast majority of household appliances and appliances are created using magnets.

However, many unexpected problems arise in everyday life, especially of a technical nature. It happens that you need to maintain or strengthen the effect of a particular magnet, and especially vice versa - demagnetize it. Let's focus on the last problem - how to demagnetize permanent magnets?

After reading a selection of our practical tips, you will find out how, in what way, and whether it is possible to demagnetize “home” magnets without outside help.

Basic methods for permanent magnets

In everyday life, it is sometimes convenient to use magnetized tools, for example, a screwdriver, which will prevent the screw from falling off at the most inopportune moment and in a hard-to-reach place. But the properties of a permanent magnet are not always useful or necessary. With the same files, drills, taps, etc. magnetized during work. It will be obviously more difficult to work due to sticking metal filings.

In this case, there are several solutions to this problem. Let's note two of them.

Method 1. Heating to a temperature above the Curie point

The Curie point is the temperature at which the symmetry of ferromagnetic atoms is destroyed. Simply put, you take your magnetized tool and heat it up quite a lot. Strict atomic symmetry is broken, and the instrument loses its magnetic properties under the influence of heat.

Method 2 . Homemade degausser

This method will require the presence of an electromagnet operating on alternating current, in the form of any coil (hollow solenoid) designed for the existing voltage in the house. There are many reel options.

Suitable, say, is a coil from an old electromagnetic bell, a solenoid relay for a car starter, etc. The primary winding from some transformer is also suitable, especially if its frame is cylindrical. Secondary - can be wound up as unnecessary.

We place the demagnetized tool inside for a few seconds and turn on the “unit” to the AC power supply.

How to demagnetize a permanent magnet reliably, and at what voltage? There are a couple of nuances:

• We connect the coil, designed for 220 V, directly to the electrical network. A 110-volt coil can similarly be connected directly to the network, but not for long. We connect the 12 volt coil through a step-down transformer.

• When demagnetizing, first remove the tool from the coil and only then turn off the power supply. Otherwise, the metal may not be demagnetized.

If there are no mentioned solenoids (from an old coil or transformer winding), you can wind a small demagnetizer coil with your own hands. How to successfully demagnetize a permanent magnet with it? A number of parameters will need to be met:

The resistance of such a winding will be about 8 ohms if:

- the solenoid frame will be 80 mm long, with an internal diameter of 30-35 mm;

— at the edges of the frame, when winding, leave cheeks 80 mm in diameter and 5-6 mm thick;

- wrap approximately a thousand turns of PEL (or PEV) wire with a diameter of 0.7-0.9 mm around the solenoid.

For large plumbing tools, you will need a more powerful (larger diameter) demagnetizer. It can be mounted from the demagnetization loop(s) of an old picture tube.

The magnets are connected to each other - how to separate them

How to demagnetize a magnet from a magnet (disconnect), especially if they are powerful? Let us immediately make a reservation that it is useless to separate powerful magnets by simply breaking them, and you can get injured. In this case, you can also give at least two pieces of advice:

Method 1: Using diamagnetic metal sheet

1. Using a metal wedge made of some diamagnetic material (duralumin, copper, etc.), try to widen the gap between the magnets, but be careful - do not use an iron hammer (it attracts).
2. Insert a sheet (can be metal) into the gap that is larger in area than the magnets, which will serve as a guarantee that everything can come back and the magnets will attract each other again.
3. Secure the lower magnet, and begin to move the upper one until you feel that it is freed from the attraction of the lower one.

Method 2. Using plywood

1. To separate the magnets, a sheet of thick plywood (10 mm) is used. A hole is made in it for the magnet (if it is impossible to create a gap between the magnets). This sheet will serve as a kind of stop for one of the magnets during the separation process.
2. Disconnection occurs in the same way as in the first example.

Everything described above are little tricks mainly for amateur locksmiths. And now a little about the twists and turns with magnets during shopping, which most of our lovely ladies so adore.

Shopping and magnets

Today, in the vast majority of supermarkets, special magnetic alarms are attached to goods, and sometimes it happens that a customer finds herself in an unpleasant situation after purchasing, for example, a new coat. The purchase is completed, but at the exit from the store this “stop light” still signals “theft” - the seller forgot to neutralize the sensor from the product.

Or the electronics may malfunction. Guard magnets are designed in a special way and vary depending on the product they “protect” - with visible or invisible labels (stickers), plastic clips, etc. And they are attached to clothes in different ways, and you can’t just unhook them, since when removed they can even ruin the material of the coat with paint.

But if this happens, and you come home with a working sensor, you still need to remove it from your new purchase, because the next time you go to the store wearing new clothes, it may not work in your favor.

But it is not necessary to physically remove the magnet from clothing (especially in inconvenient places). This problem can be solved in another way; the most effective and safest way is demagnetization with a so-called neodymium (which has the highest power) disk-shaped permanent magnet with a sufficiently large working area. It is on free sale. It is enough to move this magnet over the clip, and the sensor will be demagnetized.

You can answer the question in the same way: “How to demagnetize magnets on shoes”?

Conclusion

As you can see, there are a lot of ways to demagnetize any household magnets. If you can’t make a demagnetizer yourself, then you can contact the Internet and order it from the World of Magnets. They have a store in St. Petersburg.

Contact us!

Source: https://lesprom-spb.ru/news/razmagnichivaem-magnity