Polymer bonded magnets. II. Effect of liquid crystal polymer and surface modification on magneto-mechanical properties

We studied the effect of liquid crystal polymer (LCP) and surface modificat ion of neodymium-iron-boron (Nd-Fe-B) magnetic alloy on the magneto-mechani cal behavior of poly(phenylene sulfide) (PPS) bonded Nd-Fe-B magnets to acc elerate efforts to develop useful thermoplastic magnets with optimal perfor mance. The results indicate that blending the LCP with PPS provides the req uired balance of properties for the targeted applications. These properties include superior magnetomechanical performance at elevated temperatures, m inimal melt viscosity at optimal LCP volume fraction, high stiffness, and i mproved dimensional stability, making the thermoplastic magnets suitable fo r use at elevated temperatures and in chemically corrosive environments whe re commercial rare earth alloy magnets are not useable. Enhanced wetting of the magnetic Nd-Fe-B powders by the polymers, formation of reinforcing LCP domains, and interactions between the polymers and the magnetic powders ar e thought to be responsible for the beneficial function of the LCP and Nd-F e-B surface modifier in the PPS bonded Nd-Fe-B magnets.