Polymer - Bonded Magnetic Materials with Various Nd-Fe-B Filler Content

Abstract

One of the more important developments in magnetic materials, polymer bonded magnets, have opened a new world of application opportunities. The Nd-Fe-B/polymer composite materials offer an excellent combination of strong magnetic and dynamical-mechanical properties. However, the transition temperatures of filler and matrix should be selected carefully considering the future application. Uniform particle distribution and good adhesion between Nd-Fe-B powder particles and polymer are essential for the quality of the composite, while stiffness of polymer matrix is one of the influencing factors as well. The damping properties of Nd-Fe-B/polymer composites with 15 wt.%, 50 wt.% and 75 wt.% of Nd-Fe-B powder were studied by dynamic mechanical analysis and compared with a pure polymer sample. Thermal stability was analyzed using a simultaneous differential scanning calorimetric and thermogravimetric analysis technique.

Magnetic and Dynamic Mechanical Properties of Nd-Fe-B Composite Materials with Polymer Matrix

“…In this region, approximately above 75 ºC, the dynamic storage modulus is a function of the hydrodynamic effect, well-known to be dependent on the shape of the filler particles or agglomerates, on the concentration of the filler, and on the fillers interactions with polymer. Comparing to pure epoxy sample values for storage modulus these are 1.7, 2.9, 9.1 and 40 times higher for composites with 15 wt%, 50 wt%, 75 wt% and 85 wt% of Nd-Fe-B, respectively, which is a significant improvement of storage modulus (Grujić et al, 2010a). DMA tests for highly filled Nd-Fe-B/epoxy polymer composite (95 wt% of Nd-Fe-B) showed an 11 times higher storage modulus values at ambient temperature and up to 87 times higher at 75 °C (in rubbery state), compared with the polymer matrix.…”

Nanocrystalline Nd-Fe-B Alloys for Polymer-Bonded Magnets Production

“…Taking into consideration shape, mechanical and physical properties of the used Nd-Fe-B alloys it can be assumed that dynamic mechanical properties of these composites are similar. Previously studied polymer magnetic composites [18,19] suggest that there is no significant deviations in dynamic mechanical properties between composites that contain low and stoichiometric Nd-Fe-B fillers in the same type of polymer matrix. Glass transition temperatures and temperatures of decomposition strongly depend on used polymer matrix while changes of enthalpy depend on concentration of magnetic filler.…”

Dynamic Mechanical Behaviour of Polymer Bonded Nd–Fe–B Composite Materials

“…9,10) The dynamic mechanical properties of the pure epoxy polymer and the NdFeB/epoxy magnetic composite materials are studied as a function of temperature, from the glassy to the rubbery state, as reported elsewhere. 11,12) The results presented in Fig. 1(a) show a considerable improvement in the storage modulus (elastic component) caused by the presence of the NdFeB magnetic filler.…”