Plastic-bonded magnets are composite materials in which permanent magnets are embedded in plastic binders in powder form. Normally, in measurement technology, hard ferrites are used as magnetic powder.
At MAGNOPOL, exclusively elastomer systems - also called gum - are used to bind magnetic particles.
Depending on the material composition and manufacturing technique, isotropic and anisotropic magnets with various magnetic and mechanical values can be produced.
Because it is not just the type of magnet and elastomer material, but also the degree of filling and degree of alignment that determine the characteristics of the composite material, there is a wide variety of magnetic parameters and a wide variety of products and shapes.
Temperature behaviour / operating temperature
The magnetic characteristics’ temperature behaviour basically corresponds to that of compact hard ferrites. For the temperature coefficients of the remanent magnetisation TK(Br) and the temperature coefficients of the coercive field strength TK(HcJ), TK(Br) = 0.2%/K und TK(HcJ) = 0.3%/K.
In particular, the temperature behaviour of the remanent magnetisation must be noted when designing and constructing the sensor system.
The maximum operating temperature permitted is primarily dependent on the binder system used. For the elastomer-bonded hard ferrite magnets, it lies between -40° and +160° C.
The favourable magnetic behaviour of the elastomer-bonded hard ferrite magnets in comparison to sintered hard ferrites should be mentioned. As a result of the mixture of the ferrite particles with the elastomer matrix, the magnets show clear elasticity or ductility. The brittleness that is typical of hard ferrite is no longer applicable. This offers significant benefits for the mechanics of the magnets. The flexibility that was added makes it possible to bond them to other parts of the construction, such as with a pressure bond.
Types of magnets
All of them can be produced in forms that can be realised in classic moulding procedures, with some limitations. This is very positive for the designer with regard to creating individual shapes. Therefore, as a result, there is a various range of parts that once again can be found in our product range.
Our product range includes a wide breadth of elastomer-bound hard ferrite magnets for magnetic measurement systems. At the same time, the magnetic and mechanical characteristics vary widely. We would be happy to advise you extensively on this.