Epoxy resin effect on anisotropic Nd–Fe–B rubber-bonded magnets performance

A novel anisotropic Nd–Fe–B flexible bonded magnet with epoxy resin lubricant was prepared by the two-step method to enhance its performance. Temperature characteristics of epoxy resin and its effect on magnetic properties and preparation of anisotropic Nd–Fe–B flexible bonded magnets were investigated and optimized. DOA of aligned flexible bonded magnets with epoxy resin lubricant increases significantly due to epoxy resin lower viscosity and subsequent better powder particles lubrication at a certain aligning temperature. Meanwhile, Hirr decreases sharply due to improved oxidation resistance of epoxy resin fully encapsulating magnetic powder during magnetic alignment process. Utilizing 1 wt% optimized encapsulating epoxy resin and heating unaligned flexible bonded magnets to 80 °C for 30 min during magnetic alignment resulted in the largest Δ(BH)max and ΔDOA. Δ(BH)max increased to over 126% along with ΔDOA increase to over 75%, much higher compared with unaligned flexible bonded magnets prepared exclusively by calendering.