A neodymium magnet (also known as NdFeB, NIB, Neo magnet and rare earth magnet) is the most widely used type of rare-earth magnet. It is a permanent magnet made from an alloy of neodymium, iron, and boron to form the Nd2Fe14B tetragonal crystalline structure. Neodymium magnets are the strongest type of permanent magnet available commercially.
Neodymium magnets are 5 to 7 times stronger than Ferrite magnets and offer the best value for money. These magnets are able to provide high energy, efficienct and extreme stability when exposed to other electromagnetic fields. Therefore, neodymium magnets are commonly used in engineering, electronics and medical fields.
Magnetic Properties of Neodymium Magnets in Different Grades
|Grade||Br (kg)||HcB (KOe)||Hci (KOe)||BHmax (MGOe)||Working Temperature TW|
Manufacture and Handling of Neodymium Magnets
Neo magnets are not a solid block of metal but a mixture of chemical powders as neodymium magnets are produced by the powder metallurgical methods. Therefore, neo magnets are very hard but brittle. Please refrain from machine cutting neo magnets. This magnet is also highly resistant to magnetic demagnetization.
The strength of Neodymium magnets depends on a range of factors. But the most impactful factor is the Nd2Fe14B structure that magnetizes a specific axis but not in other directions. Because of a specialized manufacturing process to align the NeFeB microcrystalline grains of the Nd2Fe14B structure, neodymium magnet have a very high resistance to being demagnetized.
The magnetic energy value of neo magnet is about 18 times greater than ferrite magnet by volume and 12 times by mass. NdFeb magnet also has higher magnetic energy property than samarium cobalt magnets – the first commercialized rare-earth magnet. The relatively lower rare-earth material (12% by volume) and relatively better abundance of neodymium and iron to samarium and cobalt help neo magnets to be more affordable than SmCo magnets.
Neodymium Magnet Manufacturing Methods
A neodymium magnet can be produced in two principal methods: sintering and bonding.
Sintered magnet process begins from melting the raw materials in a furnace, casting the product into a mold, and cooling it to form ingots. Then, the ingots are pulverized and milled into a powder. The powder is sintered into dense blocks which will be heat-treated, cut to shape, surface treated, and magnetized.
Bonded magnet process starts from melt spinning a thin ribbon of NdFeB alloy. The ribbon is then pulverized into particles and mixed with a polymer. The resulting product is compressed or injection-molded into bonded magnets.
Essen Magnetics mostly used the sintered magnet process in our manufacturing facilities with the trialed and tested production method.
Grades and Properties of Neodymium Magnets
Grades of neodymium magnets are graded to their maximum energy product, relative to the magnetic flux output per unit volume. The higher the value, the stronger the neo magnet is. The grade range of neo magnets is recognized internationally with a value from 28 to 55. Neodymium magnets from Essen Magnetics range from N35 to N55, N35M to N52M, N35H to N52H and N35SH to N50SH.
Remanence (Br), coercivity (Hci), and maximum energy product (BHmax) are commonly used for comparing magnets:
Remanence (Br) refers to the strength of the magnetic field;
Coercivity (Hci) refers to the resistance to becoming demagnetized;
Maximum Energy Product (BHmax) refers to the density of magnetic energy with the maximum value of magnetic flux (B) times magnetic field strength (H).
Common Shapes and Uses of Neodymium Magnets
Neodymium magnets are often manufactured into the following shapes:
Discs: Round disc magnets to be easily affixed into pre-drilled holes. Disc-shaped neodymium magnets are known for their great size to magnetic power ratio. This type of neodymium magnets is commonly used in school science experiments, jewelry making, packaging, book-binding, displays, and engineering.
Blocks: Rectangular shaped magnets for applications requiring straight-edged bars. This shape of neodymium magnets is highly versatile in a range of applications, including magnetic separators, flow control systems, and water conditioning.
Holding Pots: Neo Pot Magnets are encapsulated within a protective steel casing. The casing helps to prevent chipping or cracking of the magnet while also creating a single-sided magnet.
Rings: Round magnets with a central hole for various applications such as joinery and shop-fitting. The hole in the center of the magnet offers versatility to mount the magnet at a range of materials.
Rods: Cylindrical magnets for pre-drilled holes. This form is ideal for acrylic signage, picture frames, and joinery.
Spheres: Ball-shaped magnets for bearings. This spherical magnet is axially magnetized with a distinct north and south pole. And it makes sphere magnets ideal for building model shape, structure, mechanical applications, and repairments.
Neo magnets are ideal for applications that require a strong magnet. These magnets can be used by jewelers to engineers with their strength and efficiency for its size. Popular applications include metal separation, mining, construction, designing, printing, generators, holding, and industrial purposes. Essen also manufactures and supplies large neo magnets for electric motors ad wind turbines.
Neodymium magnet is known for its cost to performance ratio and very stable at different temperatures. Neo magnets manufactured by Essen Magnetics can withstand up to 150 degree-Celcius.
As a lifting magnet manufacturer, quality neodymium magnets from Essen Magnetics are used for great reliability and lifting ability.