Neodymium magnets (FeNdB)

Introduction

Permanent magnets on based on FeNdB (sometimes also NdFeB) contain elements of the rare earths neodymium (Nd), dysprosium (Dy), and possibly praseodymium (Pr). They achieve the highest values of the inner magnetic energy.

They are manufactured by sintering very finely ground substances, as their direct casting is impossible - see Manufacturing technology.

These magnets allow for considerable miniaturisation of dimensions, as they exert the same portative force with much smaller dimensions than, for example, ferrite magnets.
 

Properties

FeNdB magnets are hard and fairly brittle which needs to be borne in mind especially when manipulating magnetised products in the vicinity of other magnets or ferromagnetic materials (iron,...). Magnets are manufactured in standard shapes which can be slightly modified by grinding. However, care needs to be taken so that the ground surfaces do not get hot (see the table of magnetic properties - max. application temperature).

Neodymium magnets are generally prone to corrosion and their surfaces receive a special finish or their corrosion-resistivity is enhanced by a special technology (so-called HAST magnets).

The magnetic characteristics of the individual magnet classes are shown in the table below.
 

Applications

The neodymium magnet has a wide range of uses in applications where strong magnetic interaction (portative force) needs to be developed or where small dimensions are important. They include, for example, rotors and stators of electric motors, linear motors, magnetic clutches and brakes, magnetic polarisers of liquids, magnetic separators and protection systems against shoplifters. Magnets from rare earths are also used in the following sectors: automated devices and robots, cars, toys, kitchen machines, washing machines, dishwashers, wrist watches, computer technology, etc.
 

Magnetic properties – neodymium magnets