Magnetic Products

Goudsmit supply a full range of permanent magnet materials, both as standard catalogue items and as specific designs to client specification. We can carry out manufacture, coating, magnetisation, inspection and shipping of our products to ISO 9001. As one of the largest suppliers of magnets globally we ship between 50 and 100 million magnets per annum to a range of clients as diverse as automotive and white goods manufacturers to laboratory equipment producers.

In general terms there are five main groups of materials:

(1) Ferrite

A material which is cheap both in raw material and manufacturing cost. It is the most widely used magnetic product worldwide. Shapes tend to be geometric such as rings, discs and blocks and the manufacturing process is one of pressing, sintering and grinding. Energy product levels are around 4-5 MGOe, meaning that ferrite is about 7 times weaker in magnetic strength than Neodymium. Maximum operating temperatures are around 250-300^oC.

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(2) Neodymium

Goudsmit supply our range of these alloys under our trade name Neoflux. A rare earth material based on the alloy Nd-Fe-B, Neoflux magnets have an energy product of 30-50 MGOe and so are much stronger than any other commercially available magnetic materials. Made by the pressing and sintering process, the magnets are more expensive than ferrite due to raw material costs and processing technology. Initially these magnets were always coated, however lately Goudsmit has introduced a corrosion resistant range of Neoflux magnets. This complements our new range of very high energy product magnets. Maximum operating temperatures are now reaching 200^oC.

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(3) Samarium Cobalt

This is the most expensive magnet material primarily due to raw material costs. Resistant to corrosion and operating to very high temperatures, SmCo is mostly used in environments where Neoflux cannot operate. Energy products are in the region of 22-30 MGOe. The material is very stable with increasing temperature losing only a small proportion of its magnetism compared to ferrite or Neoflux.

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(4) AlNiCo

Based on an alloy of Aluminium, Nickel and Cobalt this material can be made by sintering or casting and although it has a low energy product of 3-6 MGOe it is incredibly stable to temperature increases with a maximum operating temperature of 450^oC. AlNiCo is resistant to corrosion and is primarily used in instrumentation applications, however it is expensive due to the high Cobalt content and the need to grind the product.

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(5) Plastic bonded magnets

These are subdivided into two main categories:

(5 a) Compression bonded magnets – A powder of one of the four main materials is mixed with epoxy in powder or liquid form. This material is pressed and cured. Compression bonded materials are less dense than their sintered counterparts and therefore have weaker magnetic properties. Temperature co-efficients tend to be similar however the maximum operating temperature is defined by the properties of the epoxy resin used.

(5 b) Injection moulded magnets – A powder of one of the four main materials is compounded with a thermoplastic and injected into a mould tool. The main advantage of this manufacturing technique is that parts can be made to complex shapes and also to net shape removing the need for grinding. Functionality features such as gear teeth or drives can be added to the part. Performance, when compared to the sintered counterpart material, is lower due to a lower density, while the maximum operating temperature is defined by the thermoplastic used.

For more information on Bonded Magnets, click here