Neodymium Magnets (NdFeB)

information-iconNeodymium Iron Boron (NdFeb) Technical Information

information-iconMagnetization Options for Neodymium Iron Boron Magnets

size-iconAvailable Neodymium Magnet Sizes

shipping-iconNeodymium Magnets – Handling, Packaging, Shipping, and Storage

Neodymium iron boron (NdFeb) magnets, also known as rare earth magnet and neo magnets, offer the best value when comparing performance, size and cost. Neodymium Magnets (also known as neo and rare earth magnets), are moderate in price and typically Neodymium Magnets allow for dimensional reductions. Neo magnets or rare earth magnets have poor resistance to corrosion and should have a coating or plating applied. Consideration should be given to the grade of alloy when exposing Neodymium iron boron ( neo and rare earth magnets ) to temperatures above ambient room. Neo Magnets have good resistance to external demagnetization fields because of its high Intrinsic Coercive Force (Hci). This resistance makes Neodymium iron boron magnets an excellent choice for electromechanical applications. neodymium-magnets

Intellectual property rights exist for commercially viable Neodymium Magnet alloys. Many infringing manufacture’s from the Pacific Rim can offer cheap pricing because they pay no royalties to the patent holders, utilize substandard raw materials, and have poor Neodymium magnet manufacturing methods. Utilization of infringing Neodymium magnets may lead to legal issues, delays, and product failures. Dura Magnetics, Inc. only provides licensed Neodymium magnet alloys which are traceable to the patent holders. This assertion of compliant Neodymium iron boron magnet alloy is supported by on-site inspections and contractual obligations initiated with alloy producers.

(NdFeb) Neodymium Magnet Manufacturing Process

Fully dense Neodymium Iron Boron Magnets “neo magnets & rare earth magnets” are usually manufactured by a powdered metallurgical process. Micron size Neodymium and iron boron powder is produced in an inert gas atmosphere and then compacted in a rigid steel mold or in a rubber mold. The rubber mold is compacted on all sides by fluid and it is referred to as isostatic pressing. The steel molds will produce shapes similar to the final product, while the rubber mold will only create large blocks (loaves) of Neodymium iron boron “commonly known as neo or rare earth” magnet alloy. The Neodymium iron boron alloys magnetic performance in both compacting methods is optimized by applying a magnetic field before or during the pressing operation. This applied field imparts a preferred direction of magnetization, or orientation to the Neodymium Iron Boron Magnet alloy. The alignment of particles results in an anisotropic alloy and vastly improves the residual induction (Br) and other magnetic characteristics of the finished rare earth magnet named Neodymium Iron Boron magnet which is also called “neo magnet”. After pressing, the neo “Neodymium Iron Boron” magnets are sintered and heat treated until they reach their fully dense condition. The die pressed neo / rare earth magnets are ground to the final dimensions, but the brick magnets from the rubber mold method are usually squared on large grinders and then sliced to the final geometry. Isostaticly pressed alloy has higher magnetic properties than the die pressed material, but it may lack the uniformity. The choice of Neodymium iron boron “rare earth / neo” magnet manufacturing method is usually application driven and is typically not a concern of the customer.

(NdFeb) Neodymium Iron Boron Magnets Temperature Characteristics

Sintered Neodymium Iron Boron “neo / rare earth” magnets are susceptible to demagnetization when exposed to elevated temperatures. There are many grades which can withstand high temperatures, but several factors will dictate the performance of the Neodymium Iron Boron magnet. One of the most pertinent variables is the geometry of the neo / rare earth magnet or magnetic circuit. Neo / rare earth magnets which are thin relative to their pole cross-section (Magnetic Length / Pole Area) will demagnetize easier than neo magnets which are thick. Magnetic geometries utilizing backing plates, yokes, or return path structures will respond better to increased temperatures. The maximum recommended operating temperatures listed on the Neodymium iron boron magnet magnetic characteristics page does not take into account all geometry conditions. Please contact a Dura team member for Neodymium magnets design assistance when elevated temperatures are involved in your application.

The various elements that compose a neodymium magnet - neodymium/praseodymium (PrNd), iron (Fe), boron/iron (B-Fe), and dysprosium/iron (DyFe).

The various elements that compose a neodymium magnet -
neodymium/praseodymium (PrNd), iron (Fe), boron/iron (B-Fe), and dysprosium/iron (DyFe).

Neodymium Magnets Corrosion Characteristics (Surface Treatment)

Neodymium Magnets are very susceptible to corrosion. A variety of coating and plating options are available to protect your neo magnet from the environment. The rapid oxidation of Neodymium magnets requires rigorous surface preparation before coating or plating. Most Neodymium Iron Boron magnet surface treatment facilities are not familiar with this type of magnet alloy and are not capable of successfully coating or plating it. Neodymium Iron Boron does not take plating like other metal alloys and it will corrode from the inside-out. A Dura team member will assist with the selection of best Neodymium Iron Boron, “rare earth / neo” magnet surface treatment option for your application.

Neodymium Magnets Machining

Neodymium rare earth magnets are produced from a material that is very hard and brittle. On average, this rare earth magnet materials hardness is 58 Rc and conventional machine tools and cutters are not appropriate. The hardness combined with the powder metal grain/crystal structure inhibits the use of carbide tools. Diamond tooling, electrostatic discharge machines (EDM), and some abrasives are the conventional means of fabrication for neo / rare earth magnet alloy. Another concern with machining is the volatility of the powder or dry grinding swarf. These particles can combust while machining or in swarf storage containers. Machining will also remove the “skin” of the Neodymium Iron Boron magnet alloy and make the material more susceptible to corrosion. Most magnet materials are machined in the un-magnetized state. Once the fabrication and cleaning operation are complete the magnet is then magnetized to saturation.

Dura Magnetics is capable of fabricating simple or complex shapes from Neodymium Iron Boron (NdFeb) magnet alloy. We stock a variety of standard and exotic Neodymium grades for production or prototype fabrication.

A Dura Magnetics team member can help determine if custom machining is required or if “pressed to size” geometry is possible. The determining factors are usually required lead-time, cost, and the alloy required.

Neodymium Magnet Magnetizing Process

Neodymium Magnets, commonly known as neo magnets, are a rare earth magnet and require a large magnetizing field. The large magnetizing fields require special equipment and Neodymium magnets are not generally magnetized by customers. The anisotropic nature of sintered Neodymium magnets results in a single direction of magnetization. This direction must be observed when magnetizing and when integrating the magnet into the final magnetic assembly. Often times an indicator is used to identify a specific magnetic pole for the customer’s Neodymium iron boron (NdFeb) magnet assembly process. This indicator can be a simple paint dot or a laser engraved mark.

The high field required for magnetizing Neodymium Iron Boron will often times restrict the design of the Neodymium magnet or Neodymium magnetic assembly. Many variables must be taken into account and a Dura team member can assist with the design process.

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