Hard ferrite polymer-bonded

Our polymer-bound hard ferrite products


Sprox® magnets are manufactured from isotropic or anisotropic magnet materials. Barium ferrite or strontium ferrite powder is compounded with thermoplastic binders to form a granulate suitable for injection molding. The granulate is then processed in customized injection molding machines using specially developed tools. This inexpensive material can be magnetized in a variety of patterns by applying magnetic fields in the injection molding machine. Subsequent magnetization is often not required. This technique is particularly cost-effective for long production runs.

The advantage of the injection molding process for producing magnets lies in the wide range of shapes that can be produced. It is also possible for inserts such as axles, bushes or rings to be molded in, with the inserts being loaded by hand or fully automatically, depending on the quantity produced. The costs of assembly operations can be reduced as such materials allow press-fit, snap-fit and positive-fit connections with motor shafts etc.

The production process allows products to be manufactured within such tight tolerances that no reworking is generally necessary. Depending on the size of the molding, the tolerances that can be achieved are in the range 0.03 through 0.25 mm. As required, polymer-bonded materials can be turned, drilled, milled and ground and they are not as brittle as sintered materials.

The proportion of synthetic plastic materials of typically ten percent by weight mean that the magnetic properties lie below those of unmixed material. On the other hand, with anisotropic grades, it is possible to achieve a directional magnetization during the injection molding process. This in turn improves the magnetic properties.

DescriptionDIN IEC 60404-8-1 codes 1i/aBH(max) [kJ/m3] 6 8Br [mT] 6 8HcB [kA/m] 6 8HcJ [kA/m] 6 8Density [g/cm3] Water absorption [%] 7 CompositionProduction
Sprox 3/20pHard ferrite 2.7/20pi2.7128852003.20.2Hard ferrite + PA6
Sprox 10/20pHard ferrite 10/20pa9.82221512073.20.2Hard ferrite + PA6
Sprox 11/22pHard ferrite 10/24pa102251592393.20.05Hard ferrite + P12
Sprox 11/21pHard ferrite 10/21pa10.32351592153.20.2Hard ferrite + PA6
Sprox 14/21pHard ferrite 14/20pa14.32691792073.40.15Hard ferrite + PA6
Sprox 13/21pHard ferrite 15/22pa14.72731792223.550.15Hard ferrite + PA6
Sprox 15/22pHard ferrite 15/21pa15.12751792143.570.04Hard ferrite + PA12
Sprox 15/21pHard ferrite 16/23pa16.52901892263.790.13Hard ferrite + PA6
Sprox 5FHard ferrite 10/20pa10.32401681993.6t.b.dHard ferrite + NBRCalendering 3 4


1 Combined of approximated minimum values of (B * H)max and HcJ according to DIN IEC 60404-8-1.
Gebildet aus angenäherten Mindestwerten von (B * H)max und HcJ nach DIN IEC 60404-8-1.
Composé de valeurs minimales (B * H)max et HcJ suivant DIN IEC 60404-8-1.
2 PA = Polyamid/ Nylon
NBR = Nitrile Butadiene Rubber
EPH = Expoxydharz/Resin
PPS = Polyphenylensulfid
3 Prefered axis to rolling direction.
Vorzugsrichtung zur Kalandrierrichtung.
Sens préférentielle d’ aimantation au sens de calandrage.
4 Machinable by cutting.
Spanabhebend bearbeitbar.
Usinable par enlèvement de copeaux.
5 The maximum operating temperature for a magnet matrials is dependent upon the specific application and magnet geometry. Do not hasitat to contact our Application Engineers for more information.
Die maximale Einsatztemperatur ist abhängig von der Anwendung, von der Magnettype sowie der Magnetgeometrie. Für weitere Informationen kontaktieren Sie bitte unsere Anwendungstechniker.
La température maximale d'utilisation d'un aimant dépend de son application spécifique ainsi que de sa géométrie. N'hésitez pas à prendre contact avec nos ingénieurs d'application pour plus d'informations.
6 Indicated values only with optimum dimensions: shortest edge > 8 mm, volume 1 – 200 cm³.
Angegebene Werte nur bei optimalen Abmessungen: Kürzeste Kante > 8 mm, Volumen 1 – 200 cm³.
Valeurs uniquement pour dimensiones optimales côté le plus court > 8 mm, volumes 1 – 200 cm³.
7 t.b.d.
to be defined
noch festzulegen
à établir
not applicable
nicht angegeben / anwendbar
pas applicable
8 Minimum values.
Valeurs minimales.