Sintered Neodymium Iron Boron Magnets or "NdFeB" magnets offer the highest energy product of any material today and are available in a wide range of shapes, sizes and grades. NdFeB magnets can be found in a variety of applications including high performance motors, brushless DC motors, magnetic separation, magnetic resonance imaging, sensors and loudspeakers.
Magnetic properties will differ depending upon alignment direction during compaction and upon size and shape. Download individual spec sheets from the table below, or get the full neo catalog here for specific grades and their magnetic properties, including the trade-off in Br (and energy product) for HcJ (intrinsic coercivity, resistance to demagnetization).
Ferrite magnet or ceramic magnet is the cheapest magnetic material available with the lowest cost/energy ratio, also known as Ceramic Magnets, they are mainly Strontium based (SrFe2O3), manufactured with Strontium Carbonate additive to increase performances from the obsolete Barium based (BaFe2O3).
Their good coercive force results from high crystal anisotropy of Strontium iron oxide. However, isotropic parts can also be produced where a simple and easy multi-pole magnetization is required. The most common shapes are simple, such as blocks, cylinders, rings and arcs. Ferrite is not conductive and has high resistance against corrosion, acids, salts, lubricants.
Samarium-Cobalt magnets have the best Br temperature coefficient (-0,035%/°C) granting the absolute higher available induction above 150°C working temperature. Despite a higher cost than other magnetic materials, SmCo provides an outstanding combination of high energy, thermal stability and corrosion resistance. Protective coatings are generally not required except for particular applications.
The typical final shapes such as blocks, cylinders, rings and arcs are obtained by cutting and grinding processes of pressed standard blocks or unitary compression pre-moulded part. Extremely fine tolerances can be obtained although, because of its high brittleness, it has to be handled and assembled with care to avoid chips and cracks.
AlNiCo (Aluminium, Nickel, Cobalt and Iron alloy) is obtained by casting process, shaped in cheap phenolic resin sand moulds. It is the oldest and most stable magnetic material, with temperature coefficients of -0,03%/°C (Br) and -0,02%/°C (HcJ). It can operate in environments up to 500 °C with a very good resistance against corrosion, therefore coatings are seldom required. For multi-pole magnetizing patterns isotropic material is available. Higher energy anisotropy is obtained by external coils orientation during the thermal treatment.
Because Alnico magnets are coarse-grained, hard and brittle, conventional machining such as drilling is not possible, however, finished surfaces may be obtained by grinding.
A unique characteristic of AlNiCo is its very high residual induction vs. a very low coercivity, therefore in most applications it can be effectively used by magnetizing after assembly in the magnetic circuit, and it is specially recommended in applications where only a temporary demagnetization is required (magnetic chucks, lifters...). For small sized models, due to the typical porosity of the casting process, sintered versions (ALSINT) are available upon request.
Bonded Neodymium magnets are manufactured through the compression process. This process involves mixing neodymium powder with epoxy as a binder and pressing it into a die cavity with no magnetic field, thus making these magnets Isotropic. Pressed parts are then placed into the oven for curing. Compression bonded neodymium magnets are an excellent choice over other magnet types (sintered neodymium, sintered samarium cobalt, and hard ferrite magnets ) that have limits to some shapes that compression bonded magnets do not have. With their high energy product reaching up to 12 MGOe it makes them ideal for many applications requiring high magnetic strength and tight tolerances. Since no magnetic field is applied during the compression the finished product can be magnetized in any direction. Having epoxy as a binder in the manufacturing process for compression bonded magnets makes the magnets resistant to most industrial automotive fluids. With relative low tooling cost and quick turnaround compression bonded neodymium magnets are the choice for a wide variety of applications. The final product can be epoxy coated for durability and more resistant to corrosion