Which Neodymium Magnets Nd₂Fe₁₄B to Buy?

Neodymium magnets are composed of a mixture of iron, boron, neodymium, and other additives. The production process starts with selecting appropriate quantities of each component, which are then melted and cast. The resulting sheets are crushed using the hydrogen decrepitation method, and then ground into powder. The obtained powder undergoes a consolidation process. The material is pressed using the pseudo-isostatic method under high pressure, allowing for high density and homogeneity. During the forming process, the material is magnetized using a magnetic field that determines the magnetization direction for anisotropic magnets or without the use of a magnetic field for isotropic magnets. The formed shapes are then sintered and subjected to mechanical and surface treatments (including protective coatings). Finally, the finished product is magnetized in a magnetizer, becoming a magnet.

Neodymium magnets are typically available in very simple shapes such as ring. These are commonly referred to as block magnets, but it should be noted that both block and ring magnets can be made with specially chamfered holes to facilitate flush mounting, aligning with the surface of the magnet the head of a screw or bolt. Neodymium magnets can also be made in the shape of a sphere or segment magnets (arc-shaped) that are cut pieces of a ring. It is also possible to order magnets in the shape of a trapezoid or other geometric figures, provided that the shape can be cut using EDM (electric discharge machining) without fracturing the magnet. The brittleness of neodymium magnets limits the production of complex shapes; for example, it is not possible to create threads directly on the magnet.

Magnetism is permanent. Technically speaking, magnetism weakens over the years, but the demagnetization is so minimal that even after several decades, there is no significant loss of magnetism. Therefore, neodymium magnets are commonly considered to be resistant to demagnetization and are referred to as permanent magnets. Demagnetization is more likely to occur due to temperature changes and repelling forces rather than the passage of time. Magnets made of Alnico material may require remagnetization as they are more susceptible to demagnetization due to repelling forces.

No, it does not double.
The magnetic flux density refers to the amount of magnetic flux per unit area. Although the magnetic flux density will become slightly stronger when two magnets are vertically stacked on top of each other, the surface area remains the same, so there won't be a significant difference. For example, if two magnets with the size of 10mm x 10mm are placed on top of each other, the magnetic flux density will be almost the same as that of a single magnet with the size of 10mm x 10mm.

To magnetize neodymium magnets, magnetizers capable of generating a sufficiently large constant electromagnetic field are used. After increasing the field (current) to a point called the saturation point, further increasing it has no effect on the magnet's magnetic induction. Subsequently, the external field value is reduced to zero. The properties of neodymium magnets, made of hard magnetic materials, mean that when the field is turned off, the magnetization value does not drop to zero but settles at the remanence point, also known as the residual magnetization point (residual magnetism). The magnetization process is best described by the first quadrant of the magnetization hysteresis loop.

Neodymium magnets are commonly used in various electrical devices, including gauges, alarm systems, electric locks, speakers, monitors, televisions, motors, drones, and wind turbines. The main industries that utilize neodymium magnets include the automotive, furniture, food, energy, textile, toy, and medical industries.

A neodymium magnet strongly attracts iron and any alloys containing iron, as well as metals such as gadolinium, nickel, erbium, cobalt, and dysprosium. Whether an object is more easily or less easily attracted by a magnet also depends on the shape of the object. In a long object, such as an iron nail, when it becomes magnetized by the magnetic field of a permanent magnet, magnetic poles will quickly establish themselves, with one end of the nail becoming 'N' and the other end becoming 'S'. If we melt the same nail and shape it into a sphere, especially if the sphere is in motion, it will be more difficult to capture it with a magnetic field.

The strongest magnet will be made from the material with the highest magnetic properties (e.g., N54 magnet). However, such materials are much more expensive than standard ones. A higher-grade magnet will have a greater magnetic reach, with magnetic field lines shooting up sharply from the pole surface, and it has a chance to attract iron or another magnet from a greater distance. On the other hand, a flat magnet will practically have a higher lifting capacity, as it can hold and lift larger surface area objects.

The first documented tests and research on metal alloys that could be suitable for production of strong magnets began over 50 years ago. Then, scientists K. Strnat and G. Hoffer from the Air Force Materials Laboratory in Dayton decided to start a wide range of research magnets made of rare earth group metals. Initially, first alloys and materials intended for use in the creation of high-power magnets were based on cobalt, iron, and a few lanthanides, including praseodymium Pr, neodymium Nd, cerium Ce, yttrium Y, samarium Sm, and lanthanum La. The above-mentioned lanthanides exhibit characteristic abilities, such as the ability to be strongly magnetized, but their Curie temperature was very low. The neodymium magnets made today have besides iron a mixture of suitable lanthanides, which giving them a high level of magneto-crystalline anisotropy, and in addition, they are supplemented with a few percent of cobalt to raise the total temperature Curie. The first strong magnets were developed in the early 1970s using samarium in the form of powdered grains along with several additional lanthanides. The previously unknown SmCo₅ magnet was developed. The production involved grain alignment during sintering in the presence of a magnetic field at temperatures around 1120°C with a final annealing temperature of 850°C. One of the stages in creating a pressings was subjecting the material to magnetization of 2T. Through this technology, the Curie temperature of the prototype magnet reached around 745°C.

Currently, neodymium magnets are mainly produced in Asia, particularly in China, which has control over the majority of rare earth element deposits in the world. The production of high-power magnets utilizes two types of compounds: Nd₂Fe₁₄B and Sm₂Fe₁₇N₂. These are neodymium-based magnets and nano-crystalline magnets characterized not only by high magnetization but also by high magnetic remanence. The use of powerful neodymium magnets is extremely versatile. The primary recipients of these products are manufacturers of electrical and electronic devices, particularly those in the automotive industry that employ high-performance hybrid and electric motors. These motors employ neodymium magnets containing compounds such as dysprosium (Dy) or terbium (Tb) that reduce the decrease in magnet efficiency at elevated temperatures. In the United States, scientific research has been conducted for many years by the Rare Earth Alternatives in Critical Technologies (REACT) institute, dedicated to the development of advanced materials and alloys. In recent years, ARPA-E allocated nearly $32 million for supporting advanced projects within the Rare-Earth Substitute program, aiming to find substitutes for rare earth metals controlled by China.

The production of neodymium magnets relies on two methods: the powder metallurgy method used in Japanese companies and the technique of rapid cooling that gained popularity in the United States. Depending on the requirements, neodymium magnets can be produced by incorporating additional elements, such as copper, aluminum, or gallium, to adjust the magnetic parameters of the magnet itself, including its strength and resistance to high temperatures and corrosive conditions. Continuous improvement in metallurgical processes has led to the development of various material alloys, significantly increasing the Curie temperature of neodymium magnets. Modern production of neodymium magnets allows them to achieve magnetization levels exceeding 1.6T, much higher than the Earth's magnetic field, thanks to advancements in powder metallurgy.

Manufacturers of neodymium magnets use specific letters to indicate the magnetic material, such as H, followed by two-digit numbers like 42... The number in the material designation indicates the maximum energy product (BH)max of the magnetic material, expressed in CGS units, such as 35 MGsOe (mega-gauss-oersteds). The letters in the designations refer to the coercivity value (the higher the coercivity, the greater the magnet's resistance to demagnetization due to high temperatures or the application of an opposing magnetic field), and these letter designations can be expanded and explained as follows: M - 'medium', H - 'high', SH - 'super high', UH - 'ultra high', EH - 'extra high'. For example, a material labeled N45SH will have the letter N at the beginning, indicating neodymium, the number 42 indicating the energy product 45 MGsOe, and the letters SH indicating 'super high'.

The most important criterion in choosing magnets made of neodymium is its purpose. Factors to consider include operating temperature, weather conditions, and the force required for the magnet to operate. The magnetic strength of neodymium magnets is often measured in kilograms of lifting force. However, it is important to note that this value is measured in laboratories under ideal conditions, with perfect contact between the magnet and the ferromagnetic surface, and the force direction is perpendicular to the contact surface. If you have any doubts, please contact the advisors at Dhit sp. z o.o. using the phone number provided in the contact section.

Rare-earth magnets are magnets that contain at least some metals known as rare-earth elements. These elements include scandium, yttrium, lanthanum, cerium, praseodymium, neodymium, promethium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. The most well-known of these elements for magnet users are neodymium, which is used in the production of NdFeB magnets, and samarium, which is used in the production of SmCo magnets. Rare-earth elements are not actually rare in the Earth's crust. They are relatively abundant, but their deposits are usually dispersed and scarce, making their extraction economically challenging. Hence, they have been named 'rare-earth elements'.

Neodymium-based magnets are nowadays the most powerful types of magnets that have been created so far. In the late 20th century, at the Trinity College Dublin, scientist Michael Coey invented a hitherto unknown magnetic compound with the chemical formula Sm₂Fe₁₇N₂. The production process involved the synthesis of finely powdered samarium and iron, which were compacted in a strong magnetic field together with the addition of nitrogen, resulting in a Curie temperature of 470°C and magnetization level of 0.9T. Although these results were not comparable to the parameters of neodymium magnets, the newly developed samarium material surpassed the initial magnets utilizing samarium. In the late 1990s, new ideas in the field of high-power magnets and methods of their production emerged.

A magnetic material with a nano-crystalline structure consisting of grains with a diameter less than 100 nm was developed. The nano-crystalline grains, in contrast to monocrystalline structures, are separated by larger spaces with higher surface power and less ordered internal structure. By utilizing the mixture of rare earth elements along with iron during the sintering process, the nano-crystalline magnets exhibit high magnetic remanence properties. The very good magnetic properties are also due to the magnetic moment coupling between neodymium and iron. This enables the great magnetization of neodymium magnets.

While, when subsequent strong magnets using samarium were being designed, unknown magnetic properties of neodymium with the addition of boron and iron were discovered in 1983. The American company GM created a new compound with the chemical formula Nd₂Fe₁₄B, with a composition of over 70% iron, 15% neodymium, 6% boron. The technology for producing strong neodymium magnets involves two methods. The Sumitomo plant in Japan, a part of Hitachi, utilized the powder metallurgy method, just like in the case of samarium magnets, enabling the production of dense magnets. In the United States, strong neodymium magnets were produced in GM's plants using the technique of rapidly cooling the molten isotropic powder mixture. Why did the use of iron, neodymium, and boron yield much better results than samarium compounds? The use of neodymium was much cheaper than samarium, and neodymium also has much better magnetic parameters. Unfortunately, the Curie temperature of this element was not at an appropriate level, so it was decided to raise it to 530°C. This value was achieved by adding a small amount of boron to the composition of the neodymium magnet. Additionally, the magnet's properties can be tuned by incorporating auxiliary compounds or elements, such as gallium Ga, copper Cu, niobium Nb, and aluminum Al.

Neodymium magnets are often equipped with coating layers that prevent corrosion and protect from adverse weather effects by applying a thin layer of nickel or copper, for example, in holders used in searches in aquatic environments. Engineers are constantly developing more advanced neodymium magnets, and thanks to advancements in powder metallurgy, increasingly new metal alloys with enhanced coercivity and higher than 1.6T are being devised.

Yes, there are several ways to demagnetize neodymium magnets. The simplest way is to first heat the magnet above its defined maximum operating temperature, which will cause partial demagnetization, and then heat it above the Curie temperature, at which point the ferromagnetic material becomes paramagnetic, resulting in complete demagnetization. Other methods of demagnetizing neodymium magnets include applying a sufficiently large constant and opposite magnetic field or subjecting the magnet to decaying and alternating magnetic fields.

The primary recipients of magnets are companies offering measurement, electronic, electrical equipment, companies in the automotive industry, and manufacturers of various industrial machinery. The furniture industry, clothing industry (especially medical clothing), companies producing closures for wallets and bags, and the advertising and marketing industry also greatly value the magnetic strength.

Neodymium magnets made from the compound Nd₂Fe₁₄B are a sintered iron, boron, and neodymium. In reality, neodymium magnets contain only about 30% of Nd₂Fe₁₄B compound, and it is due to their atomic structure that these magnets are so strong.

Yes, you can buy neodymium magnets in our store. They are available in various sizes, shapes, and prices, depending on their strength and quality. We encourage you to explore our offer and choose the suitable magnets for yourself.

A neodymium magnet is the one of the strongest permanent magnets available on the market. Its exceptionally strong magnetic field is a result of using a combination of iron, neodymium, and boron to achieve the tetragonal crystalline structure of the compound Nd₂Fe₁₄B. This unique combination provides unprecedented magnetic properties, including exceptionally high magnetocrystalline anisotropy.
Neodymium magnets can be produced as sintered magnets or as bonded magnets using plastic or resin as a binder.