What temperature can a neodymium magnet withstand

Neodymium magnets: what are they?

December 14, 2019

Neodymium magnets are characterized by very high power and resistance to demagnetization. They appeared relatively recently, a little less than 40 years ago. They quickly gained popularity due to their high magnetic induction. Even magnets of small mass can provide very high adhesive force. For example, a neodymium magnet in the form of a cube with an edge of 10 centimeters will provide an adhesion force of 4.5-5 kg, which cannot be compared with traditional magnets.

In addition, they have other properties that are extremely useful. They lose from 0.1 to 2% of magnetization in 10 years (during this time any ordinary magnet will demagnetize almost completely). That is, under ideal conditions, neodymium magnets can last several thousand years. But this is in theory, in practice the real terms are up to a hundred years or more. But this is still a lot when compared with conventional magnets.

They also have certain disadvantages that make their use somewhat limited. Firstly, they are susceptible to corrosion, to prevent which they are coated with nickel (but not all). They cannot be heated, and the maximum permissible temperature depends on the brand:

EH – up to 200 degrees;
M – up to 100;
N – up to 80.

They are fragile, you should avoid any mechanical impacts, let alone falls from a height. They can also negatively affect the performance of electronics. Although, because of this property, they are used for not entirely legal purposes, which we will write about below.

It is worth noting that the disadvantages include their price, which is very high (compared to conventional magnets). They especially began to rise in price recently, after China introduced export quotas for rare earth metals. China contains more than 50% of neodymium deposits, which is the main component of magnets. Obviously, this trend will continue in the future, so neodymium magnets will become more expensive.

They are produced in various shapes and sizes: disks, cubes, rods, balls and others. Some products are capable of lifting masses weighing more than one ton.

Neodymium magnet for stopping meters: which one is needed

Many common models of water and electricity meters have rotating metal parts inside, which can be influenced by the magnetic field of a neodymium magnet in such a way as to slow down their operation and reduce the final readings.

Before recommending magnet models for stopping meters, let us remind you that such influence on the meter is illegal and, if detected, is punishable by a fine and recalculation of consumption for the period of operation of the magnet. With a high degree of probability, you will simply lose a lot of money.

However, we will consider the theory (this can also be used for other purposes that do not involve deception or harm).

The main characteristic of a magnet is its power, which depends on the size of the product. It is important not only to choose a sufficiently powerful magnet, but also not to buy one that is too large so as not to affect your neighbors’ meters. One of the recommended brands of neodymium magnets is Rexant.

What kind of neodymium magnet is needed to stop water meters:

For the simplest models: Metron, Neva, Gerrida, a 45x15 mm magnet is suitable;
For Novator, Minol, Betar, Norma, etc. you need a larger magnet - 50x20 or 50x30 mm;
Valtec, Itelma, Meteor and the like - magnet 60x30 mm;
Elster - magnet 70x40 mm;
For heat and water meters - magnet 70x50 mm

What kind of neodymium magnet is needed to stop electricity meters:

An electric automatic meter cannot be stopped in this way, but for mechanical models the recommendations are as follows:

Mercury 201-203, Mikron SEO, Neva, SKAT 101 - magnet 50x20 mm;
Meridian, Energomera - magnet 45x30 mm;
Mercury 230-231, Micron PSCH, NIK, STE - magnet 50x30 mm;
SKAT 301 - magnet 60x30;
CA4, SO, SOLO, ESR powerful magnets 70x30 and 70x50 mm are suitable.

Why are neodymium magnets needed?

Magnets made from an alloy of rare earth neodymium, boron and iron are widely used both in industry and in everyday life.

Due to the fact that neodymium magnets create a more powerful field than conventional ferrite ones and are also more resistant to demagnetization, they are used for the production of generators, electronics (headphones, computer hard drives), magnetic resonance imaging scanners and much other equipment.

Quite often, ordinary people ask why neodymium magnets are needed in everyday life. And it turns out that in this area there are a lot of ways to use them.

search and lifting of metal objects: a key at home or on a property is lost, or a bucket has fallen into a well - a neodymium magnet will solve these problems;
fixing objects when gluing: 2 magnets are attached from different sides and provide uniform and constant compression;
fastening metal objects in the kitchen or garage;
securing signs, plates, navigator or radio remote control and other similar items in cars;
destruction of data on magnetic media: if you need to securely delete information from old cassettes or floppy disks;
from a couple of magnets you can make excellent latches for furniture and save yourself from the need to screw in screws;
such magnets will simplify the collection of metal debris (for example, shavings);
This is an excellent material for visually explaining to children the effects of a magnetic field.

In addition, you can find many reviews online about the use of neodymium magnets to magnetize water (which some claim improves its properties), condition fuel (and save it), and even accelerate the maturation of wines and liqueurs.

Whether to believe that neodymium magnets are needed for these purposes is a personal choice. These facts have not been scientifically confirmed, and our people believe in many things that have no justification.

Therefore, in our opinion, there is no need to buy expensive neodymium magnets and use them for other purposes. You'll just be wasting your money.

Source: https://tze1.ru/articles/detail/neodimovye-magnity-chto-eto-takoe/

Neodymium magnets. Device and application. Kinds

Almost everyone is familiar with a magnet, because they often played with it in childhood or used it at school to attach thematic materials to the board. Today, magnets are used almost everywhere; they are an essential component for various electronic devices, engines, electric generators, and transformers. Very often, magnets are used to create clips, holders, souvenirs and toys.

The most powerful are neodymium magnets, which are made of a special alloy whose structure includes boron, iron and neodymium. It is these elements that determine their advantages and disadvantages in comparison with magnets made of other materials. It is neodymium magnets that today are universally replacing standard ferrite magnets, finding increasing use.

Neodymium magnets are extremely powerful magnets that are made from rare earth metals. Also known as Neo magnet, NIB or NdFeB. In most cases it is an alloy of neodymium, iron and boron, which forms Nd2Fe14B tetragonal crystal structure.

Neodymium magnets:

They are distinguished by high resistance to demagnetization.
They are distinguished by high power of attraction.
They have a metallic appearance.
They are extremely in demand; they are used in various fields of electronics, industry, medicine and in everyday life.

The first countries to master the production of neodymium magnets were Japan and the USA.

It was the actively developing potential of these countries that stimulated the emergence of new technologies for creating permanent magnets. The neodymium magnet was first developed by General Motors together with Sumitomo Special Metals in 1982. Currently, these are the strongest permanent magnets from a whole list of commercially available ones.

The magnets have a magnetic energy value that is more than 18 times that of conventional magnets.

The composition of the new magnet was as follows:

Bor.
Iron.
The metal of the lanthanide group is neodymium.

The last element in the new alloy is a rare-earth element; it functions as the main element in the alloy. Boron is present in the alloy in negligible quantities, while iron is a binding element.

Thanks to this composition, magnets have incredibly high adhesive force. Ferrite magnets simply cannot compare with them in this indicator. For example, if you connect two powerful ferrite rings together, then by applying a certain force, you can use your hands to separate them. This simply cannot be done with neodymium magnets. It will be impossible to separate two neodymium magnets connected to each other with bare hands without the use of tools.

The price of the first neodymium magnets, which appeared on the market in the mid-90s of the last century, was quite high. Currently, their cost has decreased slightly, but it still remains high. This is explained by the relatively high rarity of neodymium, including the patent struggle between different manufacturers and developers of magnets.

There are a wide variety of brands and shapes of neodymium magnets. The varied shapes of neodymium magnets are due to their different purposes. So they can have the shape of cones, cylinders, rings, spheres, balls, rectangles, disks and the like. Using the ingredients of neodymium magnets, plastic materials that have magnetic properties are also created. For example, this is magnetic vinyl.

Magnets can be classified according to:

Magnetic energy.
Operating temperature range.
Dimensions.
Grip strength.

Depending on the brand, magnets differ in operating temperature ranges:

Brand N (Normal) - up to 80 C, that is, at normal temperatures.
M (Medium) - up to 100 C, that is, at elevated temperatures.
H (High) – up to 120 C, that is, at high temperatures.
SH (Super High) - up to 150 C.
UH (Ultra High) - up to 180 C.
EH (Extra High) - up to 200 C.

The numbers that are indicated in the magnet class designation: 40UH, 38SH, 33M, N30 and so on, indicate magnetic energy, it is measured in kJ per cubic meter. This criterion is responsible for the power, that is, the “pull force” that is required to be applied to the magnet in order to lift it from the surface. The higher the magnet designation, the higher the pull-out force will be.

At the same time, the “pull-off force” will also depend on the weight and size of the magnet. For example, a 2520 mm magnet will be an order of magnitude easier to tear off, for example, from a steel sheet than a magnet with an area of 405 mm.

Magnets are also differentiated into classes based on the magnitude of their magnetic moment per unit of volume. Classes of neodymium magnets:

N35-N52;
N33M-N48M;
N30H-N45H;
N30SH-N42SH;
N30UH-N35UH;
N28EH-N35EH.

When using neodymium magnets, their features should be taken into account

The service life of neodymium magnets is at least 30 years; if properly used and stored, it can be an order of magnitude longer. But in some conditions they can be easily damaged and damaged beyond repair. Neodymium magnets are not flexible at all. They can break under a certain load and even crack, including losing their properties.
Dropping or striking a magnet may cause magnet particles to break off, which may result in reduced adhesion properties. In addition, a strong enough impact can lead to loss of magnet properties. Therefore, dropping neodymium magnets should be avoided, including where parts and components may hit each other or fall.
The magnetic properties of a magnet when exposed to high temperatures are lost irrevocably. Depending on the current brand of magnet, the heating limit can be in the range of 80-250 degrees Celsius. If heated above the standard temperature, the magnet loses all its properties. Self-demagnetization of neodymium magnets is about 1% over 10 years. This figure is quite high.
Machining a neodymium magnet is almost impossible. When creating serial samples of magnets, after purchasing them for any purpose, it will be almost impossible to give the magnet any other shape. This is due to the fact that drilling the alloy, cutting with a cutting tool or grinding can cause the alloy to ignite. Including the high temperature that will be generated during friction, will cause a harmful effect on the magnet itself, as well as its properties.

Neodymium magnets are quite widely used in industry; they are used in conducting various experiments and experiments in the field of electrical engineering and physics

Filters are equipped with powerful magnets that capture small metal particles in liquids or gases.
Neodymium alloy magnets are also used in the production of souvenirs and toys.
Magnets, due to their high adhesive force, are used to search for metal objects that lie underground. Today they are actively used by search engines involved in the restoration of wartime equipment.
Neodymium alloys are used to create magnetic fasteners, which are used to secure various objects.
For connecting parts of metal structures: strong, but easily separated if necessary.
For fastening blinds, curtains and other elements associated with windows.
Creation of levitating interior items and furniture. Recently, many designers, and even ordinary creative people, have been using neodymium magnets to make their tables, stands, trays, and beds truly floating.
Creation of free energy generators, Tesla generators, magnetic valves, Searle generators, magnetic tunnels and Hall sensors. High-grade magnets are used in the Large Hadron Collider.
Magnets are widely used in medicine, for example, in magnetic resonance imaging machines, and also to relieve arthritis pain.
Neodymium magnets can be widely used in everyday life, from plumbing to attaching photographs or a calendar to the refrigerator.
Magnets are used in the creation of computer hard drives.
Leveling out small scratches and dents on musical instruments and parts. It is enough just to attach a powerful neodymium magnet to one side of the part, as well as a large steel ball to the other.
Cleaning technical fluids and motor oils of a car from foreign metal particles and impurities leading to engine wear.
Magnetization of water. A number of doctors recommend drinking water that has been treated with a magnetic field in order to increase immunity and improve well-being.
Magnets are used to create lightweight, compact, but very powerful electric current generators, for example, wind turbines , hydroelectric power plants, and other alternative energy facilities.

The advantages of neodymium magnets include:

The attractive power is tens of times greater than the power of a conventional magnet.
They are in demand from large manufacturers, but they can also be purchased for household use. Magnets are sold in specialty stores and regular online stores.
Due to the fairly high power, demagnetization does not occur for a long time. Over 10 years, only 1% demagnetization occurs.
Possibility of wide application in various industries.
Light weight and compact dimensions compared to other magnets with the same adhesion force.

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The disadvantages of neodymium magnets include:

Neodymium magnets can be hazardous to health and surrounding products in inexperienced and inept hands. They can damage the upholstery of metal furniture, cars and even walls. They should not be given to children.
The magnets are very difficult to disengage, which in certain cases is a big drawback.
Negative impact on the operation of electronics.
Neodymium magnets cannot withstand strong drops or impacts.
They lose their properties at relatively high temperatures.

Properties of neodymium magnets

We are often asked questions - “What is a neodymium magnet?”, “What is its strength?”, “How long will it retain its magnetization?”, “Why is it better than a regular ferrite magnet?” Now we will try to figure this out and answer all the questions in order.

Neodymium NdFeB magnets are the strongest permanent magnets available today.

They are made from an alloy containing the rare earth material neodymium Nd, as well as iron and boron. Neodymium magnets have very high levels of residual magnetic induction and resistance to demagnetization. According to these indicators, they are many times superior to ordinary black, ferrite magnets.

Which makes them much more attractive when used in products and equipment that require a strong magnetic field. The only serious drawback of these magnets is their rather high price. Moreover, over time, it tends to grow, since the needs of the world industry for strong magnets are also constantly growing.

Technological progress is accelerating year by year, new models of smartphones, televisions, computers, navigators and similar high-tech gadgets are constantly being released, the production of which uses rare earth metals.

The main supplier, so to speak, the leader of the global market, is the People's Republic of China, which controls up to 95% of the supply of rare earth materials, and, accordingly, their prices. Another sharp increase in prices was noted in the summer of 2017, when in 3 months the price of neodymium increased by more than 50 percent.

Technical characteristics of neodymium magnets

Magnetic characteristics are set at the magnet manufacturing stage and cannot be changed subsequently. The main parameters are residual magnetic induction and resistance to demagnetization (coercive force). Magnetic induction is measured in Tesla (Ts) and Gauss (G), 1 T = 10,000 Gauss. Neodymium magnets have a residual induction of about 1.2-1.4 T (12000-14000 Gas).

It should be taken into account that such values can only be obtained by testing magnetic material in a closed circuit. When measuring the strength of the magnetic field on the surface of a magnet, the Teslameter usually shows from 200 to 500 mT (2000-5000 Gas). In addition, the readings of the residual magnetic induction strongly depend on the shape and size of the magnet - the larger it is, the stronger its magnetic field will be.

Loss of magnetic properties over time usually does not exceed 2-3% over 10 years of operation (of course, subject to temperature conditions). A distinctive feature of neodymium magnets is their rather low operating temperature. With strong heating, demagnetization of the material begins, and the hotter it is, the faster this process occurs.

The temperature at which a material begins to lose its magnetic properties is called the “Curie point.” In this case, a so-called “phase transition” occurs—the rapid destruction of the magnetic structure of the substance. Magnets made of ordinary grades of neodymium alloy, type N38, N42, etc. can withstand heating no higher than 80 degrees Celsius.

This greatly limits their use in equipment subject to high heat - for normal operation in such conditions, additional cooling of the installation is required. There are also high-temperature grades of alloys, such as N38H (120°C), N38UH (180°C). If higher operating temperatures are required, then magnets made of Alnico material (UNDC) should be considered, which can withstand heating up to 550°C.

Neodymium magnets most often have an anti-corrosion coating, nickel or zinc, less often epoxy. Magnets can be produced without any coating at all, but since they tend to rust in a humid environment, they are in much less demand. The direction of the magnetic field can be axial (along dimension h), diametrical (along dimension D) and radial (along dimension r).

Magnetic characteristics of various neodymium alloys

Brand of material	Residual magnetic induction Br	Coercivity (current) Hcj	Maximum energy product (BH) max.	Operating temperature t
Tl (Tesla)	kG (kGauss)	kA/m	kOe	MGOe	Kj/m3	WITH
N35	1,17-1,20	11,7-12,0	955	12	35	279	80
N35M	1,17-1,20	11.7-12,0	1115	14	35	279	100
N35H	1,15-1,17	11,5-11,7	1355	17	35	279	120
N35SH	1,17-1,20	11,7-12,0	1590	20	35	279	150
N35UH	1,17-1,20	11,7-12,0	1990	25	35	279	180
N38	1,17-1,20	12,2-12,6	955	12	38	303	80
N38M	1,22-1,26	12,2-12,6	1115	14	38	303	100
N38H	1,22-1,26	12,2-12,6	1355	17	38	303	120
N38SH	1,22-1,26	12,2-12,6	1590	20	38	303	160
N38UH	1,22-1,26	12,2-12,6	1990	25	38	303	180
N40	1,26-1,29	12,6-12,9	955	12	40	318	80
N40M	1,26-1,29	12,6-12,9	1115	14	40	318	100
N40H	1,26-1,29	12,6-12,9	1355	17	40	318	120
N40SH	1,26-1,29	12,6-12,9	1590	20	40	318	160
N40UH	1,26-1,29	12,6-12,9	1990	25	40	318	180
N42	1,30-1,33	13,0-13,3	955	12	42	334	80
N42M	1,30-1,33	13,0-13,3	1115	14	42	334	100
N42H	1,30-1,33	13,0-13,3	1355	17	40	318	120
N42SH	1,3-1,33	13,0-13,3	1590	20	42	334	160
N45	1,33-1,37	13,3-13,7	955	12	45	358	80
N45M	1,33-1,37	13,3-13,7	1115	14	45	358	100
N45H	1,33-1,37	13,3-13,7	1355	17	45	358	120
N48	1,36-1,42	13,6-14,2	955	12	48	382	80
N48M	1,36-1,42	13,6-14,2	1115	14	48	382	100
N48H	1,36-1,42	13,6-14,2	1355	17	48	382	120
N50	1,41-1,45	14,1-14,5	876	11	50	398	70

Application of neodymium magnets

Neodymium magnets are widely used in various fields of human activity. Due to their high performance indicators, they are widely used in the production of radio equipment, measuring instruments, household appliances, medical equipment, mobile phones and other high-tech gadgets. These magnets are in high demand among wind generator manufacturers.

Neodymium is also used to produce search magnets; for reference, magnetic fishing is an interesting hobby that is gaining popularity. To meet the needs of consumers, neodymium magnets are produced in a variety of shapes and sizes and are able to satisfy the most demanding demands. Magnets can be made in the form of a disk, cube, rod, cylinder, prism, bar, ring, sector or ball.

In addition to standard geometric shapes, it is possible to manufacture more complex and bizarre configurations - the properties of the material allow this.

Safety precautions for handling neodymium magnets

The main advantage of neodymium magnets is their colossal magnetic force, which also poses the greatest danger in inept or careless hands. The larger the magnet, the more harm it can cause to health. Large neodymium magnets, when colliding with each other, can seriously injure limbs caught between them at that moment.

The impact will be approximately the same as hitting a sledgehammer or large hammer on an anvil. You need to understand that magnets close with terrible force and this happens in an instant. Even a person experienced in handling magnets does not always have time to react and withdraw his hand at the right moment.

Another unpleasant feature is that if, after being hit with a hammer, a person simply gets a bruised finger, then in the case of magnets, after the blow, this finger remains clamped between them as if in a vice, and getting it out of there is quite a difficult task. If you try to simply pull your finger out of the magnets, then with a high degree of probability they will pinch off a piece of skin from the tip of your finger or tear off your nail.

To avoid such consequences, keep large neodymium magnets away from each other and from iron objects , the recommended distance is at least 1 meter. If this does happen and the hand remains pinched between the magnets, then first of all you need to insert some spacers made of non-magnetic materials - plastic or wood - between the magnets; they will prevent further closing of the magnets.

After this, you can try to pull your hand out yourself or wait for the Ministry of Emergency Situations employees to arrive. Small magnets, 20-40 mm in size, can also pose a danger and, if handled carelessly, leave bruises, cuts or hematomas on the hands. It is very important to protect children from contact with neodymium magnets. Even small magnets can pose a serious threat to a child's health.

Swallowing small magnets can lead to extremely negative consequences, in which case you should immediately call an ambulance.

Keep neodymium magnets out of the reach of children! Large neodymium magnets create a strong magnetic field around themselves; to avoid damage, keep them away from sensitive equipment - computers, external drives, watches, smartphones, pacemakers, navigation equipment, bank cards, etc. In addition, neodymium magnets are quite fragile and can crack under strong impacts, which is also unpleasant and costly in terms of money. Always use extreme caution and caution when handling powerful magnets.

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Source: https://supermagnet.ru/content/info.html

Neodymium magnet – what is it useful for and how to use it for health?

There are many metals with magnetic properties that are used in industry. But the neodymium magnet is recognized as the most powerful today - it is an alloy of rare earth metals: neodymium, boron and iron. The magnet has high power, is resistant to demagnetization, and due to its availability, is used for medical and industrial purposes.

What is a neodymium magnet?

Neodymium magnets are the most powerful magnets. Nd2Fe14B alloy is a tetragonal crystal structure with high attractive power and resistance to demagnetization. The question of what kind of neodymium magnet looks like can be answered: gray at the fractures and with a metallic sheen over the entire surface.

What are magnets in physiotherapy?

Alternative medicine offers a group of techniques for influencing the body using magnetic fields. This intervention is called magnetotherapy. The procedure has a therapeutic and preventive effect. Often, neodymium magnet disks are used to treat osteochondrosis, joints and fractures of varying severity. The method is used in gynecology to dull pain and resolve tumors.

Like any other therapy, there are a number of contraindications:

blood clotting disorder;
thrombosis, during exacerbation;
disturbances in the functioning of the heart muscle;
presence of a pacemaker;
mental illness;
oncology;
pregnancy;
younger children's age.

Neodymium magnet - what is the difference from a regular one?

Neodymium magnets are used everywhere for treatment and have a number of features. The first thing that distinguishes this type from the usual one is its adhesion strength. It is much higher because the characteristics of such an alloy are many times higher than those of conventional magnets.

To make sure that you have a neodymium magnet in front of you, you need to try to unhook it from the iron surface. Ordinary, will easily succumb to pressure and will be in your hands in a second. Neodymium, on the other hand, will hold tightly to the surface and will require effort to remove it.

The main differences between a neodymium magnet and a conventional one:

Life time. Ordinary representatives last for about 10 years, neodymium ones last forever.
Form. Strong magnets are available in various forms, ordinary ones - only in the shape of a horseshoe.
Price. The cost of a regular magnet is several times lower than its “eternal” counterpart.

Magnets for health - benefits and harm

Magnets, the benefits and harms of which have been proven, should be used for treatment only as indicated by doctors. There are many magnetic devices, each of which has a positive or negative effect on the body.

The use of magnetic therapy helps maintain good health and tone of the body, but only when there are no individual contraindications. Before starting treatment, it is important to pass all the necessary tests and consult with your doctor.

Home treatment magnets can be life-threatening.

A neodymium magnet, the benefits of which are undeniable and proven, has the following healing properties:

increases blood flow due to the supply of more oxygen;
changes the speed of movement of calcium ions in the human body, which allows the use of magnets for the treatment of arthritis;
changes the pH (acid-base) balance of body fluids;
regulates the production of endocrine hormones;
changes for the better enzyme activity and the speed of biological processes;
changes blood viscosity.

Neodymium magnet - harm

Agreeing to magnetotherapy, many patients wonder whether a neodymium magnet is harmful to health.

The use of this type is still being studied to this day, but we can say for sure that when used correctly and safety precautions are followed, magnets do not harm the human body. Only alternating magnetic fields can have a harmful effect.

Therefore, there are exclusion zones around powerful power lines, which are dangerous to stay in for a long time. Neodymium magnets can only harm people with pacemakers.

Neodymium magnet – application in medicine

Only a trained specialist knows how to use a neodymium magnet correctly. This alloy is used in many areas of industry, mechanical engineering, agriculture and medicine. Neodymium magnets are an integral part of many devices for diagnosing diseases: tomographs, X-ray machines and other important devices.

Among other things, magnets are used for:

manufacturing of insoles;
in physiotherapy (by applying to painful points);
production of magnetic belts.

Magnets for treating joints at home can be used by applying an alloy to sore joints. But self-medication is dangerous, so it would be more advisable to first consult with your doctor and rule out diseases for which the use of magnets is prohibited.

Magnetic therapy is aimed at:

reduction of pain syndrome;
relieving inflammation;
improving the patient's general health.

Source: https://womanadvice.ru/neodimovyy-magnit-chem-polezen-i-kak-primenyat-ego-dlya-zdorovya

Neodymium rectangular magnets – MAGNET STANDARD

Neodymium rectangular magnets

Neodymium magnets are modern, efficient devices made of neodymium alloy with the addition of iron and boron, which have excellent adhesion characteristics, durability and an affordable price. The level of residual magnetization of such magnets exceeds standard ones by tens of points. The range of neodymium alloy magnets is quite wide. Popular shapes include rectangular, square and block.

Rectangular universal shape

Primarily due to the properties of the alloy itself, rectangular neodymium magnets are ready to hold hundreds of times their mass. They have found application in various fields of industry and modeling:

Automotive Industry;
Manufacturing of medical equipment;
Cleaning grains during agricultural work;
Purification plants for industrial purification of liquids;
Educational and scientific sphere – neodymium magnets are strong and wear-resistant for use in experimental research;
Production of toys and puzzles, etc.

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Restrictions on use

A number of neodymium magnets are wear-resistant to critical temperatures and can withstand up to 200°C, but most are ready to work at temperatures no higher than 80°C;
The properties of magnets are also affected by the level of radiation - the higher it is, the faster they lose their magnetizing properties;

Household use

Correcting defects on metal objects - I use powerful magnets for dents on cars, household appliances damaged after moving, etc.;
Using two rectangular magnets, containers are cleaned: one is attached to a sponge and lowered to the bottom, with the help of the second, the control of the first is regulated;
Fastening parts - some devices need to be assembled and disassembled periodically. Magnets help simplify this process and save time;
The rectangular shape of the magnet is convenient for showing magic tricks and other performances;
To lift things that have fallen behind a bed or sofa, just tie a magnetic block to a string and slightly lower it behind the wall of the furniture;
Purification of oils and fuels - magnets will easily collect all metal debris;
Water supersaturated with iron easily returns to normal if neodymium is added to it for a certain time;
Neodymium magnets provide all possible assistance in the treatment of joints, sprains and other diseases of the musculoskeletal system. Even in space, crew members apply magnets to maintain muscle tone;
Using rectangular magnets, it is easy to make original gifts at home (magnets for a refrigerator, car, metal doors - a figurine made of polymer clay is attached to a magnet);
In educational institutions, magnetic plates will help secure material on the board.

Main technical characteristics

The strength of the magnetic field of neodymium blocks or plates depends on the size and composition of the alloy. When choosing a magnet, pay attention to:

Length/width/thickness - varies depending on the purpose of the product: 20x20x3, 20x10x1.5, 80x60x20, 50x50x30, 40x40x20, 30x5x5, 15x8x2 mm, etc.
Adhesion force - depends on which side the magnetization occurs: 0.4, 0.75, 0.9, 1, 5.1, 5.5, 4.9, 65, 150 kg;
Type of magnetization - along the thickness, along the length, along the width;
Upper operating temperature: up to +80◦C;
Alloy class: No. 38;
The top protective coating is nickel (less commonly copper, zinc and other alloys).

Adhesion force is an indicator characterizing the force required to lift a magnet from a 10 mm steel plate. Calculated in kilograms.

Alloy class is a numerical value indicating the operating temperature range and magnetic energy.

The top protective layer is a special coating to prolong magnetic properties, resistance to fragility, mainly performs anti-corrosion functions, and prevents the formation of rust.

Source: http://www.magnitstandart.ru/stati/84-neodimovye-pryamougolnye-magnity

Neodymium magnet - super strong and super useful

Neodymium magnets are the most powerful magnetic material of the new generation today, which has found wide application in many branches of science and technology, as well as in everyday life. Each of us today can encounter them in everyday life, be it buying holders for a refrigerator, headphones, a metal detector, or a computer hard drive in which they are also used.

Neodymium is an active and fairly hard rare earth metal, which, when combined with iron and boron, acquires an incredibly high magnetization ability. This NdFeB alloy, first obtained in 1982, is used to make neodymium magnets of various shapes and sizes. Strong little magnets are most likely located near you right now, for example in your computer or smartphone.

What are neodymium magnets capable of?

Their main advantage over ferrite and other permanent magnets known to man is the high efficiency of the generated magnetic field, which is approximately 10 times higher than that of analogues. At the same time, the process of their demagnetization occurs very slowly - only 5% every 100 years, respectively, and their service life is practically unlimited, that is, they are “permanent” in the literal sense of the word.

Due to their powerful adhesion force to metals, neodymium magnets can hold objects that are 50 and even 100 times their own weight. For example, to unhook a magnetic cube with a side of 5 mm from a metal product, you will need to apply a force of 1 kg. Tiny disc or rectangular magnets can be used as magnetic holders for objects, eliminating the usual mounting methods such as screwing or gluing.

Did you know? A magnet disk with a diameter of 8 mm and a thickness of 5 mm weighs only 2 grams and at the same time creates a force of more than 1.7 kilograms!

Magnet adhesion force for detachment and shear

Adhesive strength is an important characteristic of a neodymium magnet that you should pay attention to when choosing one. It is important to select a product with a certain power reserve. There are two types of adhesive force: peel and shear. Which of the two characteristics is more important depends on the tasks that the magnet performs.

Pull-off adhesive force is the force that must be applied to lift a magnetic material from a surface. The characteristics of the product indicate its attractive force under ideal conditions, under which it is completely adjacent to a smooth, even steel sheet with a thickness of at least 20 mm and is torn away from it at a right angle. Since in practice the conditions are far from ideal, the holding force in reality will be lower than declared.
Shear adhesive force is applied when the magnet moves along the surface of the product. This parameter is approximately 15-50% of the pull-out force. If the load is higher than the declared characteristics, then the object will slide along the vertical surface. For example, a rectangular magnet 20x10x4 mm can withstand a pull-out load of 4 kg, but when used for shear, its maximum load will be 1.8 kg. For many applications, shear force is the main characteristic of a neodymium magnet.

Traction force depends on many factors. For example, on a rough surface it is slightly lower than on a smooth and even surface. The thinner the metal on which the magnet is attached, the weaker it will hold. Objects do not always completely adhere to the magnetic surface, and the larger the area of their contact, the stronger the attraction.

But there are other factors that should not be forgotten. For example, not all metals and alloys are magnetic in the same way. If the product is painted, has a polymer coating or rust, then the adhesion force will also decrease somewhat. It is also necessary to pay attention to the class of neodymium alloy. The higher its serial number, the higher the magnetic energy. For example, N45 > N38.

Thus, the adhesive strength of a magnet depends on the following main factors:

product size;
magnetic alloy class;
fastening method - pull-off or shear;
thickness and roughness of the metal base;
contact areas of contact surfaces;
presence of paint and varnish coatings and rust.

Did you know? To make it easier to separate two magnets, apply force not to separate, but to shear.

What is the class of neodymium magnet?

Confused about what the letters and numbers on a magnet mean? – The letter “N” is the grade of the alloy, and the number behind it indicates the class - the maximum magnetic force in megaGauss-Oersted (1 megaGauss-Oersted ≈ 0.8 kgf).

On sale, as a rule, there are products made from materials from N35 to N52. The most popular classes are N38 and N45. Higher grades should be used where very strong adhesion is required and the available magnet space is limited.

Otherwise, it is more profitable to use two N38 magnetic holders instead of one N52.

Table. Alloys and their magnetic properties.

Brand/Class	Residual magnetic induction, mT (kG)	Coercive force, kA/m (CE)	Magnetic energy, kJ/m3 (MGsE)
N35	1170-1220 (11,7-12,2)	≥955 (≥12)	263-287 (33-36)
N38	1220-1250 (12,2-12,5)	≥955 (≥12)	287-310 (36-39)
N40	1250-1280 (12.5-12.8)	≥955 (≥12)	302-326 (38-41)
N42	1280-1320 (12,8-13,2)	≥955 (≥12)	318-342 (40-43)
N45	1320-1380 (13,2-13,8)	≥876 (≥12)	342-366 (43-46)
N50	1400-1450 (14.0-14.5)	≥876 (≥11)	382-406 (48-51)
N52	1430-1480 (14,3-14,8)	≥876 (≥11)	398-422 (50-53)

Effect of temperature on magnetic properties

Neodymium magnets “love” the cold, and their effectiveness does not weaken even at -130°C. Manufacturers must indicate the maximum operating temperature in the product characteristics. This is the temperature above which a magnetic material begins to lose its magnetism, either temporarily or permanently.

All N (Normal) brands usually operate at temperatures up to +80°C and lose, as a rule, 0.11% of energy when the temperature is exceeded by 1°C. Small losses will be recovered by cooling, but frequent heating and cooling cycles will degrade magnetic performance. Additionally, a rapid transition from cold to warm can cause the magnet to break or crack.

Corrosion resistance of neodymium

Neodymium magnets contain iron, which means they are susceptible to corrosion. Even elementary moisture from the air can lead over time to the appearance of rust, weakening of power, and destruction. Under normal dry conditions they do not rust and retain their magnetism for a long time. They are usually supplied nickel plated, but other types of protective coatings are also available, including zinc, copper, gold, rubber, and Teflon.

Where can neodymium magnets be used?

Since their creation, they have confidently held the title of the most powerful and resistant to demagnetization magnets. Without them, many of the latest scientific developments in the field of motor engineering, medicine and electronics would be impossible. They are also useful for home, office work, hobbies, modeling and jewelry making.

Examples of everyday use - useful ideas

For fixing plates, signs, hooks, shelves, photographs, artwork, and other interior elements.
As holders for mosquito nets, screws on various tools, souvenirs or notes on the refrigerator.
For organizing the storage of tools in the workshop, keys, knives, and various small items.
For collecting small metal products in hard-to-reach places and removing metal debris.
Cleaning engine and transmission oils.
Inspection of walls for the presence of hardware inside.
As locks for cabinet doors, hatches, and box lids.
Manufacturing of devices for washing windows from the outside.
Small magnets are used in the manufacture of handmade cards and folders, jewelry, and bag clasps.
When conducting experiments and tricks.
Using fastening magnets, you can secure a flashlight in the desired position, objects on a car body, a tarpaulin cover covering equipment, or a tablecloth on an outdoor table.
Production of magnetic tiebacks for curtains.
In needlework, modeling and creativity for fastening parts.

You can attach magnets to non-metallic materials in different ways - by gluing them to a base, sewing them into fabric or leather, or using electrical tape or tape. Any thermoplastic or epoxy adhesive of the “Moment” type is suitable for gluing.

Safety precautions when working with strong magnets

Improper handling of powerful magnets can result in personal injury and life-threatening damage. When attracted to each other, they move with great acceleration and can pinch fingers or make a dent on an easily damaged surface. Neodymium products are very fragile, and when struck or dropped, sharp fragments break off.

Never attempt to split, cut or drill into them. Drilling products can easily ignite. Magnets affect the operation of some devices, magnetic media, and pacemakers. Do not place them near credit cards, telephones, electronic devices, mechanical watches, CRT monitors, televisions, floppy disks, or cassette tapes.

Keep them out of the reach of children (!).

Where to buy a neodymium magnet?

Neodymium magnets of various shapes, sizes and holding forces are offered by the Krepcom company, whose central store-warehouse is located in St. Petersburg. To familiarize yourself with the range and detailed technical characteristics of magnetic products made of neodymium, we suggest following the link.

Types of magnets available for ordering through the website:

disks;
rings;
rectangles;
squares;
rods (cylinders);
discs and plates with a countersunk hole for a screw.

A neodymium disk is a universal form of magnetic fastener that has an adhesive force of up to 55 kg and is used as a holder or retainer. Its variety - a disk with a hole for a self-tapping screw - is used when it is necessary to fix a magnetic holder on a wooden, plastic or concrete surface (wall, cabinet, panel) for subsequent storage of keys or other small iron items.

Magnets in the shape of a ring (washer) have found application in souvenirs, advertising products, products with magnetic locks and clamps. They can be tied to a rope and used to clean liquids and bulk products, and search for hardware in water. Magnets rods (rods) and rectangles are widely used to create household magnetic fasteners, door latches, as well as in modeling, advertising, and electronics.

Most consumers buy neodymium magnets in China, since this country is the leader in the extraction and production of neodymium. Today there is no need to order them on AliExpress and wait a long time for delivery.

The Krepcom company supplies these products wholesale to Russia, and the price of neodymium magnets is no higher than on the Chinese website. Small disk magnets with a diameter of 3 to 10 mm can be purchased at prices ranging from 5 to 20 rubles. Medium models with a diameter of 20-30 mm will cost no more than 100 rubles.

The cost of the most powerful and largest magnets does not exceed 2000 rubles.

magnet review:

All about fasteners 01/15/2020 10:47:25

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Source: https://Krepcom.ru/blog/vse-o-krepezhe/neodimovyy-magnit-supersilnyy-i-superpoleznyy/

Characteristics of neodymium magnets

We wrote this article to answer the question about classes of magnets, their standards, and physical characteristics.

Despite the fact that the magnets we offer are called neodymium, they can be very different from each other, because each magnet has its own physical characteristics, not just size, shape and coating. Therefore, the question of which neodymium magnets are of interest to you should not confuse you. In this article you will get answers to many of your questions.

What do the letters and numbers mean in the classes of neodymium magnets?

Often, we, as manufacturers and sellers, want to hear the technical characteristics of the magnet, namely the letters and numbers in which they (the technical characteristics) are encrypted.
And the buyer often thoroughly knows his field of application of magnets, but does not know the nomenclature, especially the international one. So, let's begin to understand the international nomenclature of magnets, namely classes, technical characteristics and designations.

First of all, neodymium magnets are divided into classes, which are designated by letters and numbers (for example, N35), which contain basic information about the magnet. Below is a standard nomenclature table of characteristics of neodymium magnets (look in the left column - the classes are indicated there).

THIS IS INTERESTING: What does hypoallergenic alloy mean?

In the table, we presented all numerical values in two units of measurement. The first, without brackets, is the measurement value in the SI system (this is the system in which our country operates), and the second (indicated in brackets) is the measurement in the international CGSE system (European standards). For your convenience, we decided to indicate both units of measurement in the table.

Neodymium magnet characteristics table

We begin to study the table from right to left. As you can see from the right column of the table, the main class difference between magnets is their operating temperature of use, that is, the permissible maximum temperature, above which the magnet begins to lose its magnetic properties. Thus, the temperature range of use of the magnet is indicated by the letter part of its marking (left column). Let's decipher these letters:

Magnets brand N (Normal) – can be used at normal temperatures, that is, up to 80 degrees Celsius;
Magnets brand M (Medium) – can be used at elevated temperatures, that is, up to 100 degrees Celsius;
Magnets of grade H (High) – can be used at high temperatures, up to 120 degrees Celsius;
SH (Super High) magnets
Magnets of the UH (Ultra High) brand – can be used at temperatures up to 180 degrees Celsius;
Magnets brand EH (Extra High) - can be used at temperatures up to 200 degrees Celsius.

It is worth mentioning that negative temperatures do not affect the magnetic properties of most magnets.

The numbers indicated in the magnet class designation: N30, 33M, 35H, 38SH, 40UH, etc., indicate Magnetic Energy (fourth column of the table), measured in kiloJoules per cubic meter.

This criterion of magnets is responsible for their power or the so-called “tearing force,” that is, the force that must be applied to the magnet in order to “tear” it from the surface. It is necessary to understand that the surface (steel sheet) must be perfectly flat, and the applied force must be perpendicular to the sheet.

These are the so-called ideal or theoretical conditions. It is absolutely clear that the higher the digital designation of the magnet, the higher its pull-out force.

Magnet pull-out force

But, in addition, the “pull force” depends not only on the physical characteristics of the magnet, but also on its size and weight. For example, a 25*20 mm magnet is easier to tear off a steel sheet than a 40*5 mm magnet, since the contact area of the second magnet is larger (25 mm versus 40 mm). But the magnetic field lines, if visualized, extend “further” at the first magnet (25*20 mm), which means it “clings” to the steel sheet better.

Class	Residual magnetic induction, milliTesla (KiloGauss)	Coercive force, KiloAmpere/meter (KiloOersted)	Magnetic energy, kiloJoule/m3 (MegaGauss-Oersted)	Operating temperature, degrees Celsius
N35	1170-1220 (11,7-12,2)	≥955 (≥12)	263-287 (33-36)	80
N38	1220-1250 (12,2-12,5)	≥955 (≥12)	287-310 (36-39)	80
N40	1250-1280 (12,5-12,8)	≥955 (≥12)	302-326 (38-41)	80
N42	1280-1320 (12,8-13,2)	≥955 (≥12)	318-342 (40-43)	80
N45	1320-1380 (13,2-13,8)	≥955 (≥12)	342-366 (43-46)	80
N48	1380-1420 (13,8-14,2)	≥876 (≥12)	366-390 (46-49)	80
N50	1400-1450 (14,0-14,5)	≥876 (≥11)	382-406 (48-51)	80
N52	1430-1480 (14,3-14,8)	≥876 (≥11)	398-422 (50-53)	80
33M	1130-1170 (11,3-11,7)	≥1114 (≥14)	247-263 (31-33)	100
35M	1170-1220 (11,7-12,2)	≥1114 (≥14)	263-287 (33-36)	100
38M	1220-1250 (12,2-12,5)	≥1114 (≥14)	287-310 (36-39)	100
40M	1250-1280 (12,5-12,8)	≥1114 (≥14)	302-326 (38-41)	100
42M	1280-1320 (12,8-13,2)	≥1114 (≥14)	318-342 (40-43)	100
45M	1320-1380 (13,2-13,8)	≥1114 (≥14)	342-366 (43-46)	100
48M	1380-1420 (13,8-14,3)	≥1114 (≥14)	366-390 (46-49)	100
50M	1400-1450 (14,0-14,5)	≥1114 (≥14)	382-406 (48-51)	100
30H	1080-1130 (10,8-11,3)	≥1353 (≥17)	223-247 (28-31)	120
33H	1130-1170 (11,3-11,7)	≥1353 (≥17)	247-271 (31-34)	120
35H	1170-1220 (11,7-12,2)	≥1353 (≥17)	263-287 (33-36)	120
38H	1220-1250 (12,2-12,5)	≥1353 (≥17)	287-310 (36-39)	120
40H	1250-1280 (12,5-12,8)	≥1353 (≥17)	302-326 (38-41)	120
42H	1280-1320 (12,8-13,2)	≥1353 (≥17)	318-342 (40-43)	120
45H	1320-1380 (13,2-13,8)	≥1353 (≥17)	326-358 (43-46)	120
48H	1380-1420 (13,8-14,3)	≥1353 (≥17)	366-390 (46-49)	120
30SH	1080-1130 (10,8-11,3)	≥1592 (≥20)	233-247 (28-31)	150
33SH	1130-1170 (11,3-11,7)	≥1592 (≥20)	247-271 (31-34)	150
35SH	1170-1220 (11,7-12,2)	≥1592 (≥20)	263-287 (33-36)	150
38SH	1220-1250 (12,2-12,5)	≥1592 (≥20)	287-310 (36-39)	150
40SH	1240-1280 (12,4-12,8)	≥1592 (≥20)	302-326 (38-41)	150
42SH	1280-1320 (12,8-13,2)	≥1592 (≥20)	318-342 (40-43)	150
45SH	1320-1380 (13,2-13,8)	≥1592 (≥20)	342-366 (43-46)	150
28UH	1020-1080 (10,2-10,8)	≥1990 (≥25)	207-231 (26-29)	180
30UH	1080-1130 (10,8-11,3)	≥1990 (≥25)	223-247 (28-31)	180
33UH	1130-1170 (11,3-11,7)	≥1990 (≥25)	247-271 (31-34)	180
35UH	1180-1220 (11,7-12,2)	≥1990 (≥25)	263-287 (33-36)	180
38UH	1220-1250 (12,2-12,5)	≥1990 (≥25)	287-310 (36-39)	180
40UH	1240-1280 (12,4-12,8)	≥1990 (≥25)	302-326 (38-41)	180
28EH	1040-1090 (10,4-10,9)	≥2388 (≥30)	207-231 (26-29)	200
30EH	1080-1130 (10,8-11,3)	≥2388 (≥30)	233-247 (28-31)	200
33EH	1130-1170 (11,3-11,7)	≥2388 (≥30)	247-271 (31-34)	200
35EH	1170-1220 (11,7-12,2)	≥2388 (≥30)	263-287 (33-36)	200
38EH	1220-1250 (12,2-12,5)	≥2388 (≥30)	287-310 (36-39)	200

How to compare the strength of magnets?

If there is a need to compare which of two selected magnets is stronger, we recommend that you use the following methods.

With the same linear dimensions (exact method):

To understand how much stronger one magnet is than another, it is necessary to divide the value of the residual magnetic induction of one magnet (second column of the table) by the value of the residual magnetic induction of the other magnet. Example: neodymium magnet N40 with B=1250 mT and neodymium magnet N50 with B=1400 mT, we divide their magnetic inductions and get 1400/1250 = 1.12, that is, the N50 magnet is “stronger” than the N40 magnet by 12%, provided that the linear dimensions of the magnets are the same.

For different linear dimensions (rough method):

To understand how much stronger one magnet is than another, you need to compare their masses. Example: a 30*10 mm magnet weighs approximately 55 grams, and a 25*20 mm magnet weighs 76 grams. We divide their masses 76/55=1.38, that is, a 25*20 mm magnet is stronger than a 30*10 mm magnet by about 38%, provided that their classes, that is, physical characteristics, are the same.

Magnet coercive force

And there is one unaffected column left in the table - Coercive Force (third column). Briefly, Coercivity is the amount of magnetic field a magnet must be placed in to “demagnetize” it. This value, as a rule, is very important in cases where the magnet is operated in conditions of a strong external magnetic field, as a rule, near powerful electrical components.

We hope that in this article (characteristics of neodymium magnets) you have found answers to some of your questions. We will be happy to answer other questions by phone or email, which are indicated in the contacts.

Source: https://magnit96.com/blog/article/harakteristiki_neodimovyh_magnitov/

What are neodymium magnets?

Details Details 30.11.-0001 00:00 2648

Neodymium magnets are permanent magnets composed of rare earth elements. They are used in many areas, but can cause injury if handled incorrectly.

Neodymium magnets, also called Neo-magnets, are an alloy of neodymium, iron and boron. Their chemical formula is Nd2Fe14B. They are called rare earth magnets because their main element, neodymium, falls into the lanthanide series of the periodic table. The chemical elements in this series are mostly rare on Earth. Although this element is part of this series, it is not that rare on the earth's surface.

Story

Neodymium (atomic weight 60) was discovered in 1885, by an Austrian scientist named Baron Karl Auer von Welsbach. The cost of permanent magnets - samarium cobalt (SmCo), which were developed earlier, was too high. Thus, the need to find a more economical option led to the discovery of neodymium magnets.

Properties

They are very strong compared to their size. One such magnet can support more than 1,300 times its own weight in material. They are caustic and brittle in nature and are always supplied with a protective coating. Their strength lies in the range N24-N55; N55 is the strongest. The crystal structure of Nd2Fe14B has a tetragonal shape.

Let's take a look at the terms associated with magnetism:

Curie Temperature: This is the temperature beyond which a magnet loses its magnetic properties.
Coercivity: This is the intensity of the magnetic field to demagnetize the magnet, i.e. the energy of the magnetic field that causes the magnet to lose its magnetic properties. This is also called the magnet's resistance to demagnetization. The higher the coercive force, the stronger the magnet.
Residual magnetization: a magnetic effect that remains in a medium after the magnet is removed.

The table below provides brief information on the magnetic properties of magnetoplasts and neodymium magnets:

Magnetic Properties	Block	Sintered neodymium magnet	Bonded neodymium magnet
Curie temperature (Tc)	Degrees Celsius	310 — 400	310 — 400
Coercivity (Hc)	kiloampere/meter (Oersted)	750 — 2000	600 — 1200
Residual magnetization (Br)	Tesla	1 — 1.4	0.6 — 0.7

Application

They have a wide range of applications in future technologies due to their economic cost and useful properties. Music systems, technical and computer equipment are some of the fields where these magnets can be used.

The following list gives a brief idea of their applications:

Security systems
Loudspeakers
Computer hard drives
Magnetic resonance imaging (MRI)
Household use (for storing metal objects)
Toys
Magnetic therapy for diseases such as arthritis

Dangers

Since neodymium magnets are the strongest permanent magnets, they must be handled appropriately and used carefully. They are very strong; two such magnets of opposite polarity can be broken into pieces when attracted to each other.

They should always be kept away from small children who have a habit of swallowing things; if they swallow two such magnets of opposite polarity; Serious injury to internal organs such as the esophagus may be caused.

The sudden attraction of a large magnet to metal objects can cause serious injury such as broken bones. Data stored on floppy disks, CDs, hard drives and credit cards can be erased if they come into direct contact with such magnets.

They should be kept away from electronic devices such as televisions and computer monitors. Pacemakers do not function properly in the presence of any magnet, so the person who uses this device should not come into contact with these magnets.

Source: http://electrowelder.ru/index.php/news/54-metalworking/1438-what-are-neodymium-magnets.html

Properties of neodymium magnets - Metals and their processing

Earlier in the article Properties of neodymium magnets, the question was addressed - which magnet is right for you and the main properties of neodymium magnets were considered. In this article we will look at the main characteristics of neodymium magnets in more detail, and also talk about how to compare the strength of magnets.

Let's see what the main characteristics of neodymium magnets consist of:

Residual magnetic induction is the magnetization that remains after magnetization of the material from which our magnet is made, measured on its surface, in a closed system.
Coercive force is the value of the magnetic field strength required to completely demagnetize the substance from which the magnet is made.
The SI unit of measurement is Ampere/meter. The greater the coercive force a magnet has, the more resistant it is to demagnetizing factors.
Magnetic energy - this parameter determines the main characteristic of a Neodymium magnet. Very often, this quantity is called “magnetic strength”

For ease of understanding, we have summarized all the data in a table.

We presented all numerical values in two units of measurement.

The first, without brackets, is the measurement value in the SI system (this system is adopted in Russia), and the second (in brackets) is the measurement unit in the international CGSE system (European standards). For greater convenience, we decided to indicate both values in the table.

Table - main properties and characteristics of neodymium magnets:

Magnet classResidual magnetic induction, milliTesla (KiloGauss)Coercive force, KiloAmpere/meter (KiloOersted)Magnetic energy, kiloJoule/m3 (MegaGauss-Oersted)Operating temperature, degrees Celsius

N35	1170-1220 (11,7-12,2)	≥955 (≥12)	263-287 (33-36)	80
N38	1220-1250 (12,2-12,5)	≥955 (≥12)	287-310 (36-39)	80
N40	1250-1280 (12,5-12,8)	≥955 (≥12)	302-326 (38-41)	80
N42	1280-1320 (12,8-13,2)	≥955 (≥12)	318-342 (40-43)	80
N45	1320-1380 (13,2-13,8)	≥955 (≥12)	342-366 (43-46)	80
N48	1380-1420 (13,8-14,2)	≥876 (≥12)	366-390 (46-49)	80
N50	1400-1450 (14,0-14,5)	≥876 (≥11)	382-406 (48-51)	80
N52	1430-1480 (14,3-14,8)	≥876 (≥11)	398-422 (50-53)	80
33M	1130-1170 (11,3-11,7)	≥1114 (≥14)	247-263 (31-33)	100
35M	1170-1220 (11,7-12,2)	≥1114 (≥14)	263-287 (33-36)	100
38M	1220-1250 (12,2-12,5)	≥1114 (≥14)	287-310 (36-39)	100
40M	1250-1280 (12,5-12,8)	≥1114 (≥14)	302-326 (38-41)	100
42M	1280-1320 (12,8-13,2)	≥1114 (≥14)	318-342 (40-43)	100
45M	1320-1380 (13,2-13,8)	≥1114 (≥14)	342-366 (43-46)	100
48M	1380-1420 (13,8-14,3)	≥1114 (≥14)	366-390 (46-49)	100
50M	1400-1450 (14,0-14,5)	≥1114 (≥14)	382-406 (48-51)	100
30H	1080-1130 (10,8-11,3)	≥1353 (≥17)	223-247 (28-31)	120
33H	1130-1170 (11,3-11,7)	≥1353 (≥17)	247-271 (31-34)	120
35H	1170-1220 (11,7-12,2)	≥1353 (≥17)	263-287 (33-36)	120
38H	1220-1250 (12,2-12,5)	≥1353 (≥17)	287-310 (36-39)	120
40H	1250-1280 (12,5-12,8)	≥1353 (≥17)	302-326 (38-41)	120
42H	1280-1320 (12,8-13,2)	≥1353 (≥17)	318-342 (40-43)	120
45H	1320-1380 (13,2-13,8)	≥1353 (≥17)	326-358 (43-46)	120
48H	1380-1420 (13,8-14,3)	≥1353 (≥17)	366-390 (46-49)	120
30SH	1080-1130 (10,8-11,3)	≥1592 (≥20)	233-247 (28-31)	150
33SH	1130-1170 (11,3-11,7)	≥1592 (≥20)	247-271 (31-34)	150
35SH	1170-1220 (11,7-12,2)	≥1592 (≥20)	263-287 (33-36)	150
38SH	1220-1250 (12,2-12,5)	≥1592 (≥20)	287-310 (36-39)	150
40SH	1240-1280 (12,4-12,8)	≥1592 (≥20)	302-326 (38-41)	150
42SH	1280-1320 (12,8-13,2)	≥1592 (≥20)	318-342 (40-43)	150
45SH	1320-1380 (13,2-13,8)	≥1592 (≥20)	342-366 (43-46)	150
28UH	1020-1080 (10,2-10,8)	≥1990 (≥25)	207-231 (26-29)	180
30UH	1080-1130 (10,8-11,3)	≥1990 (≥25)	223-247 (28-31)	180
33UH	1130-1170 (11,3-11,7)	≥1990 (≥25)	247-271 (31-34)	180
35UH	1180-1220 (11,7-12,2)	≥1990 (≥25)	263-287 (33-36)	180
38UH	1220-1250 (12,2-12,5)	≥1990 (≥25)	287-310 (36-39)	180
40UH	1240-1280 (12,4-12,8)	≥1990 (≥25)	302-326 (38-41)	180
28EH	1040-1090 (10,4-10,9)	≥2388 (≥30)	207-231 (26-29)	200
30EH	1080-1130 (10,8-11,3)	≥2388 (≥30)	233-247 (28-31)	200
33EH	1130-1170 (11,3-11,7)	≥2388 (≥30)	247-271 (31-34)	200
35EH	1170-1220 (11,7-12,2)	≥2388 (≥30)	263-287 (33-36)	200
38EH	1220-1250 (12,2-12,5)	≥2388 (≥30)	287-310 (36-39)	200

And finally we come to the question that our clients often ask - how to compare the strength of magnets? In order not to bore the reader with the abundance of information in one material, we decided to devote a separate article to this topic, in which we will fully discuss this issue.

Source: https://magnetline.ru/metally-i-splavy/svojstva-neodimovyh-magnitov.html